RC India

Can people who have used lipos for their receivers and their radios/transmitters post their experiences here, please.  

We are looking for what brands of lipos and BECs/regulators you  have used, sources for obtaining them etc.

Hi All,

Believe it or not, I have not used a single NiCd pack for any of my Rxs till date.  I always fly on Lipo+regulator combo.  And I have never bothered about Rx voltage.  This weekend I took 9 flights on a single Lipo charge and didnt even bother to check the voltage.  I was so confident.  With good quality Lipos / BEC, you would never have a problem.  The BECs I use are Dong Yang, Turborix and Dualsky.  All 3 serve me very well till date with never a problem!!  Quality wise, the Dualsky and the Turborix are better off and you can switch between 5V and 6V outputs. Get a 2 cell Lipo (say 1300 to 1600 mAh) for .40 to .60 size planes.  They would last you atleast 15 flights.  My personal best is 10 flights on a 1350 mAh pack flying the Funstar on 2.4Ghz and 5 standard servos.  Even for the 50cc, I might put in a 3000 mAh 2 cell pack.  But that is yet to be decided.  Alternatively, do some research on A123 Rx packs.  They work without a regulator and they are more reliable and robust.  The Lipos I use for Rx are mostly Dong Yang.  Only one of my Rx pack is a Hextronix.

My Futaba 6EX 2.4Ghz Tx runs on a Lipo I got from Mr.Sai.  One of the best investments I have made till date.  I can fly for more than a month without bothering about Tx voltage.  Its that reliable and safe.  But we should be careful of leaving the pack on the Tx for long as it might over discharge and damage the Tx as well.

- Chan

My first experience with lipo for powering receivers came with the Align Trex 600 nitro heli.  It came with a two-in-one unit which would be the BEC was the electronics and a glow igniter power source with 15 seconds cut off, driven by a 2s lipo.

http://www.google.com/search?q=align+RCE-B6T

It was hugely convenient that no separate glow driver was needed.  And even with serious 3D flying, we could fly 4 or 5 times before we ate up the 1200mah battery.  Soon enough, some of the nitro aircraft fliers noticed the unit, and they also started putting them on their planes  :o  They also found it convenient that they don't have to worry about charging the glow driver.  And if the plane engine could be started with a chicken stick, all they needed to fly was the radio, a charged receiver lipo and fuel !

I did have one incident when the heli crashed nose down and the receiver lipo got damaged that it started fuming.  I had to disconnect and throw it away, and it burned down.  In retrospect, better placement of the lipo may have prevented that incident.

Now I see people using receiver lipos on all helis all the time.  Some plankers do it also.

As for transmitter lipo, this was one of the best investments I have made in RC ever !  I got a Dualsky 2500mah low discharge TX lipo from the local store for my Futaba 9CHP (at that time), and it would allow me to fly for a whole month ! 

With the 12FG I have now, finding a TX lipo was a little bit of a challenge because of the flat size of the battery compartment and also the operating voltage is around 7v instead of around 10v for most others. Finally found a match in the Outrage RX lipo http://outragexp.com/index.php?c=27&p=96 .  So now I have one type of lipo that can be both the TX lipo and RX lipo at the same time !

well i am getting the rds8000 but i want to know that which lipo can i use as i have zero experience with tx lipo's please help

Send me the dimensions and the voltage of the battery  , I will check if the Tx Lipos I have will fit.
Based on the enclosed Image , this should fit :
http://cgi.ebay.in/BATTERY-11-1V-1800-Tx-battery_W0QQitemZ110403617557QQcmdZViewItemQQptZLH_DefaultDomain_203?hash=item19b4918315&_trksid=p4634.c0.m14.l1262&_trkparms=|301%3A0|293%3A1|294%3A30
rgds
sai

Seriously consider the hyperion A123 tx batteies. will try to put a link to the data sheet.
http://media.hyperion.hk/dn/fg3radio/ (http://media.hyperion.hk/dn/fg3radio/)
They charge to 3.3 v per cell and can be used with the overnight nicad charger.
But lipos in Txs are great. Only problem will be if the radio is laft on with the antenna collapse. The battery lasts so long that the RF module will be fried before the battery dies out.
Also safer to use the TX on a sim with the antenna extended.
Avijit

In rebuttal of Chan's post
'Seriously I have never used a lipo anywhere even near my Rx and Tx and never had nay problem with my setup. I ensure I take good care of batteries and they inturn serve me well! ;) ;) 

I think Chan (like me) is all excited about the convenience factor   (:|~  It is nice not to have to worry about charging one more thing before every flying session.

And it is even nicer if you want to spend hours in front of the sim  ;D (using your own TX)

I use Lipo for my Spektrum DX7. I made it LiPo safe after changing the voltage regulator to a "switching dc-dc" one from a linear one. It works awesome. Many tx manufactures dont support LiPo though, because the chances to mess up your system is high without proper voltage regulation. I use 15$ Hobbyking rhino batteries and ebay ones too.

I dont know why LHS(so called) asks for 1600rs+ for such batteries when they dont have to pay duty for that. I have bought thishttp://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170401871332&ssPageName=STRK:MEWNX:IT (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170401871332&ssPageName=STRK:MEWNX:IT) 3s 2200mAh from ebay for 690rs from china. It arrived Kerala in 12 days with no issues or Customs duty. If you dont get the item in 20days they will offer you a refund or will send you a new battery. Which is cool for me.

Well, Why does everyone goto Lipo, when SAFE LSDs exist and are of the same/Lesser price? I have 12 of these and i will make a battery pack from 8 of them. These batteries once charged can last longer than a 2500 Lipo, well depending on how infrequently you use your radio ;D

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=10456

Can anyone suggest a good LiPo (6 v) or any other recharable battery to be used in place of 4 AA batteries on a nitro monster truck for powering the Rx , servos and steering system because i need longer runtime than 4AA cells..............................


Regds



Kartik

You can get NiCD/NiMH/Eneloop etc cells in pretty much any electronics store, which you can use to create such packs.

Or you can use a 2s lipo with a regulator that brings the voltage down to 6v.

Remember that you will need to get an appropriate charger whichever way you go.

Try these... You would not need any regulator..

http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=8249&Product_Name=A123_Systems_2300_6.6v_2S1P_Rx_pack_Lithium_ion

;D

I had serious concerns about accidentally over discharging 3S Lipo as my Futaba Tx beeps the alarm well below 9v safe limit for Lipos. Apart from that neither I wanted to remove the batt cover for charging or cut a hole in my Tx to pop out the charge leads. I wish these Tx Lipo guys offer a kit which has
1. Tx Lipo with Dual connector for main lead - one for Tx and one for charge
2. A panel which neatly houses the Charge lead and main lead, one can simply fix at the back of the battery cover.

So I bet on LSD NiMh battery pack instead :

http://cgi.ebay.com/RC-Transmitter-TX-Battery-Futaba-Plug-NiMH-2600-Square_W0QQitemZ170448950397QQcmdZViewItemQQptZUK_ToysGames_RadioControlled_JN?hash=item27af8c947d

Now I have all the benefit of Lipo, don't need to bother for under voltage and charging hassles as I seamlessly charge with the original charger port.

Most transmitter specific "low C" lipos have 3 connectors (Futaba, JR and balance).

Like these :  http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=6955

You can use one for permanent connection to the TX, and use the other two for charging (which should be fairly periodic in case of lipos, I was charging them once a month).

Quote from: saurabhhsrivastavaa on March 02, 2010, 09:18:04 PM
Try these... You would not need any regulator..

Weight is a minor factor, and so is the need for chargers that are even more specific (but I guess most good chargers now support A123 too).

Like Ujjwaana I would surely bet on Ni Mh. Modification done to both my 6EX and 7C to receive a battery pack of 2500-2700 mah Ni Mh last for more than one and half month of usage (i.e. Plus 20 Hour) of flying on a single set of charged batteries.

Further no issue of charging out side tx, over discharge and separate charger port. you can use tx seemlessly as if with its original battery pack only longer.

Further on the receiver side though a Lipo may be a better option still a set of four Ni Mh lasts sufficiently long for two to three flights, further does not require a BEC, as regards to weight has a major advantage.

@ sundaramvelar

As far what I see in the photo you posted, I had ordered a similar setup. I got the 8 cell holder from ebay(very very good quality) and the Turnigy 2200 LSD from Hobby city.

As far as I know, When the cell were inserted, they were a snug fit inside the Holder. Some times the spring was not able to push the cell upwards with enough force causing milli seconds disconnect. I then and there decided not to crash an expensive plane and rather spend a few bucks and get a SAFE pack.

I had to get either a soldered NIMH battery back like Ujjwaana's photo(which are way too expensive including shipping.) or a Lipoly.

Then I decided to goto Lipoly from HC (Rhino) which based on user reviews holds 2800 mah of charge. Also the reason I went to lipoly is the cost effectiveness and the "COOOL FACTOR" ;).

Ofcourse, we have to keep an eye on the Low cutoff voltage manually. Considering that we check the voltage our RC flight pack every 10 mins in a flight ;D, keeping an eye on the TX battery voltage is no big deal ;) as the TX always keeps on displaying the battery voltage at the corner of the screen.

http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=7346 is on the way. Let me see how it goes. I have to reverse the polarity of the connector for the RDS as the center connect is ground in my case.

Quote from: vinay on March 03, 2010, 08:40:51 AM
As far as I know, When the cell were inserted, they were a snug fit inside the Holder. Some times the spring was not able to push the cell upwards with enough force causing milli seconds disconnect.

It is only my 7C which has the 8 cell battery holder which fits snug inside the battery compartment. I have two of them never faced problems experienced by you the AA cells fits perfect inside case and there is no break in supply. Second battery case is just a added bonus never had the requirement to use them arisen before. (The spring of case is so strong that the batteries never break contact even with any amount of jerks. Only as a good practice to ensure good contact the case with batteries is given a slight twist along the longer axis, once after inserting the cells inside the case)

On the other hand the 6EX is modified with battey holder clips and spring integral in the battery compartment. The AA cells are clicked inside the compartment.

For both  this is the first time I had to open the battey back cover to photograph for the thread post. 

Though I bought them in ebay.com, The 8 cell Holder is available with one of our LHS also.

However I agree with you that the, soldered pack fits easily in the battey compartment and not snug. I bought the 8 cell battery case to be able to replace with charged batteries, which the requirement had never arisen.

Quote from: sundaramvelar on March 03, 2010, 10:51:51 AM
Only as a good practice to ensure good contact the case with batteries is given a slight twist along the longer axis, once after inserting the cells inside the case)

I did this long back, but the cells are such a snug fit that once I take the TX to the field, the vibration due to transport can slightly move the cell apart. And the spring is not able to push it back even though the spring is strong due to snug fit. This was causing the Milli second disconnect causing the RX to loose signals and restart.

I could have loosened the holder somehow and heat shrinked the whole setup. Then decided that a plane/heli/safety are more expensive than the TX battery, and piece of mind I got from changing to lipo is TONS!

Good to know that you did not face any problems.  :o

I received my TX lipo today morning. Need to go home and open the parcel. Received 4 parcels today. My Record! :giggle:

Actually NiMh battery packs like mine are already available with few LHS like RCDhamaka for reasonable price. If they had listed it on their site, I would have definitely bought from them only instead of waiting hassle.
I would strongly suggest either to get OEM battery holder or get a pre-soldered packs. Don't try to solder normal AA cells ans the professionally assembled pack are made of a slightly differently looking AA cell which have proper solder 'Tabs'

Being an electric flyer myself, I know that Lipo has become an indispensable component of my kit as one of the most effective and efficient power source. However LIPO are to be treated with respect and handled carefully. Any lapses then they are accidents in the making.

Take them for granted you will have one of these........

Wish Manufacturers sell Tx with charging circuit and low voltage warning designed for LIPO since the LIPO's have become the norms of the day.

which transmitter is that?
how did such a thing happen?
any damages/injuries???

Hi All,

I see some people are extremly cautious of the high voltage of the 3 cell Lipo using as a tx battery and hence skeptical using the Lipo as a TX power source. There are numerous debates on the same. :argue:

I understand Mr. Sushil is an electronics engineer.  :bow: I would request him to please develop a linear regulator that is capable of converting 12.6V from a Lipo to 11.0V to ensure that high voltage of the Lipo (fully charged) does not damage the circuitry of the tx.  ;D

If such a regulator can be developed, I am sure more people would shift to Lipo as tx power. Though I have been using Lipo's only for a long time, I have not faced any problems on the voltage. But my tx module gets warm because of the high voltage.

Also, I do not see charging the lipo only to 11.1 V as a solution as you never know when the lipo may konck off (unless you are much experienced)

No Ankur this happened no where near me photographs are pulled down from the net ;)

Quote from: saurabhhsrivastavaa on March 03, 2010, 03:25:36 PM
Also, I do not see charging the lipo only to 11.1 V as a solution as you never know when the lipo may konck off (unless you are much experienced)

At 11.1 volts, the Lipo has only 15% of the charge left in it and is useless. In fact you should not use Lipos below 11.2 Volts at no load voltage.

Everyone knows that Lipos have almost constant discharge voltage (but only upto a certain voltage) (Compared to NiMH / NiCd)  ;D. A 3 cell Lipo will loose its power rapidly after falling below 9V which is dangerous. Deep discharge will cause the Lipo cells to swell and possibly catch fire.

A regulater can be disgned to take 12.6v as an input with 11.0v as output and ensuring that it gives warning signal, the moment INPUT voltage falls below 9v. I am sure Susheel can do some research and come up with some regulator of this nature. :salute:

Over charging a Lipo is as dangerous as deep discharging a lipo.

Quote from: saurabhhsrivastavaa on March 03, 2010, 03:32:38 PM
Everyone knows that Lipos have a constant discharge voltage (but only upto a certain voltage).

A lipo will not have a constant discharge voltage!

A lipo if fully charged at 4.25 V per cell and almost empty at 3.7. That cannot be called constant.

Quote from: vinay on March 03, 2010, 03:41:06 PM
A lipo will not have a constant discharge voltage!

A lipo if fully charged at 4.25 V per cell and almost empty at 3.7. That cannot be called constant.

Boss !!! By constant I mean almost constant discharge curve. I am comparing it with NiMh/NiCd discharge curves.

saurabh, Now I get it.

But a cut off of 11.0 volts is not very good for lipos, it can actually reduce your charge-discharge cycles by 30%.

In modern Lipo world, a voltage less than -load voltage of 3.3 or a no load voltage 3.7/cell are bad for Lipos. at 11.0 volts a Lipo has literally 5 % charge left and some Lipos unbalace very much right below 3.72 volts/cell. This may over discharge one of the cells if the low cutoff is kept at 11.0 as the monitor will be monitoring the total voltage.

EDIT: Sorry didn't read the thread completely. A cut of of 3V/cell or 9V for 3 cell is further worse.

Hi Vinay,

I certainly see your point.

But as far as my understanding goes, Lipos dead low voltage is 2.85v / cell. Anything below this will surely damage the cell. A brand new Lipo will be stored at 3.8v / cell which meas that there is no load on the cell. This is the ideal storage voltage for a Lipo.  ;D

Most of the Lipo Voltage monitors are designed to monitor individual cells through the balancing port and sound alarm at 3.4 V /cell. This means that you may (though not recommended) discharge your cells to a min of 3.0 v/cell without damage.

http://cgi.ebay.in/Lipo-Monitor-4S-A-must-have-for-all-lipo-users-pm-4-c_W0QQitemZ150368071429QQcmdZViewItemQQptZLH_DefaultDomain_203?hash=item2302a2af05

I leave it to the experts for comment.  :salute:

Cheers!!!

Saurabh,

The modern Lipo monitors are designed to monitor and sound alarm at 3.3 to 3.4 V per cell. This is the Load voltage. When the lipo is disconnected from the ESC/motor, it may immidiately show >3.7 volts per cell.

It is always a good idea to discharge a lipo by 85% charge / in other words stop using it at when there is 15% charge left.

As you pointed out, discharging a lipo near to 3 V will NOT destroy it. But it will GREATLY reduce the available charge-discharge cycles by more than 50%, they start to puff sooner if always discharged to 3.0 V

I agree that a lipo is stored at 3.8V, at this voltage a lipo has only about 25 to 30% charge, which is though ideal for storing for long term when not used, but not ideal for using. A fully charged lipo will be atleast above 4.15 V per cell.

Hope this helps.

Thanks,
Vinay.

Thanks Vinay. I am in agreement with you :) :salute:

Cheers !!!

I found that the whole issue of over-discharging TX lipos a non-issue, as it takes a month or more for the voltage to drop from 12.6 to around 10.5v.  So just recharge it  once a month of so (without worrying too much about whether you have some charge left in the lipo). And make sure the TX is powered off when not in use. That's all :)

Our own LHS links where you get 8 cell Ni Mh battery packs and battery cases are here

http://www.funnhobby.com/showdetails.aspx?id=988

http://www.funnhobby.com/showdetails.aspx?id=602

http://www.rotor.co.in/show-detail.asp?prodid={32877513-9877-49BD-BFE9-19B90131AEE4}&pn=1

http://www.rotor.co.in/show-detail.asp?prodid={DAF4585B-194F-4229-B9C1-A42A76AE8296}&pn=5

http://www.rotor.co.in/show-detail.asp?prodid={021FAD8B-DC58-49CC-A4DC-1839CB3E36EC}&pn=1

Ya thats what I was talking about. But already having a 1100mAh Nicd, 1600mAh was not a big leap. If you are choosing between LiPo and NiMH, the capacity should be in the range of 2200-2600mAh and preferably a Low Self Discharge (Sanyo Anelope type). one

Great that we at least have some options from LHS.

Those NIMH packs are not LSDs.  :(, you use it or not they needs to be charged once in 2 months.

Quote from: vinay on March 04, 2010, 05:41:20 PM
Those NIMH packs are not LSDs.  :(, you use it or not they needs to be charged once in 2 months.

Are you referring to the ones  offered by funhobby/Rotor as posted by Sundaram, or the ones I got ? The pack I got has  Vapex 'Instant' LDS Nimh cells, same as Sanyo 'Eneloop' technology

http://www.component-shop.co.uk/html/instant.html

Not your cells dude, I have seen your cells. they are good.

This is from Wikipedia

Brand names for LSD NiMH batteries include:

Prolife from Fujicell
Ready2Use Accu from Varta
AccuEvolution from AccuPower
Hybrid from Rayovac
eneloop from Sanyo
eniTime from Yuasa
Infinium from Panasonic
ReCyko from Gold Peak
Instant from Vapex
Hybrio from Uniross
Cycle Energy from Sony
MaxE and MaxE Plus from Ansmann
EnergyOn from NexCell
ActiveCharge/StayCharged/Pre-Charged from Duracell
Pre-Charged from Kodak
Always Ready from Camellion

The Sony Cycle energy Ni Mh cells are one of the most comonly available LSD Cells

When Pros and cons of LSD Ni MH batteries versus normal Ni MH batteries are as under: -

Ni Mh available at 2.7 to 2.8 AH whereas LSD Ni MH available at 1.9 AH to 2.1 AH only and only sanyo is having 2.3 AH LSD Ni MH.

2.7 AH Ni Mh available for Approx Rs 185 to 210 (Uniross, Sony) and 2.5 AH available for Rs 120 to 150 (Kodak, Uniross, Sony) Whereas a 2.0 to 2.1 AH LSD is available for Rs 200 to 250 a cell ( Sony, Uniross, sanyo) and 2.3 AH is available with only sanyo but at prohibitively high cost but with www.20north.com at Rs 100 a piece only( Pack of 24 pieces @ Rs 2400/- I don't know how) :headscratch:

Normal Ni Mh looses about 5% of its charge on the first day after charge and continues to loose 1% of their residual charge, every day at cool room temp. Loss rate is higher if the ambient temp is higher. Can be reduced if stored in refrigerator (However has to be brought to room temp before use). In other words a fully charged 2.7 AH will become 2.6 AH in the first day and in about 20 days time will become 2.1 AH. I will take longer if stores in cool place.

On the contrary a charged 2.1 AH LSD Ni MH is only 2.05 AH after the first day Since it is loosing on reducing balance 20% of charge in first year) it will loose its 2% charge in the same 20 days time and will be 2.0 AH. Further all the cheaper LSD Ni Mh of less known brands are available with much lower AH capacity.

For an electric flyer who is required to charge his LIPO at least once in every month and surely before flying every time, Month is the max interval I am looking at before the next charge of Tx Cell which any case I would have to do in case of a Lipo. Why there is such indispensible requirement of LSD cells for Tx battery pack.

I would surely go for a easily available, cheaper, higher AH Normal NiMh which stores much higher AH in comparison to the LSD in the first month after the recharge.

Non LSD NiMh cells of Sony and Uniross are also known for thier excellent performance.

OK, here is the answers, Its all about personal preference again.

1)There is no meaning in comparing a 2.1 Ah LSD to 2.7 non LSD. As we stay in Inida and for the temp, I have personally measured that non LSD reach 2.1 AH in less than 2 weeks. and you know what happens in less than a month.

2)Since LSDs dont discharge faster on the shelf, you will get more charge cycles.

3) LSDs are not all that expensive. Its not necessary that you have to buy eneloops, buy turnigy, they cost 100 Rs for 2.2 Ah shipped from hobbycity (you dont even have to leave home if you have a credit card), and the performance comes close to eneloops. I have both eneloops and turnigy.

4)My point is, when you can invest in LSDs easily, then why buy non-LSDs?

5)With the investment on LSDs, rare fliers(who flies for 1 hrs, say alternate weeks) dont have to think about charging every month. They can charge once in 2 months also.

6)Also for people like you, who would want to carry extra set of batteries, just in case the existing batteries go down, then you dont have to keep charging those extra set every month. Just charge them once a year.

7)LSDs truely discharge to their rated capacity, no doubt about it.

8)I have lots of LSDs at home, And randomly when ever I suddenly feel the need for batteries for heavy usage (say 2 months after they have been charged), then I dont have to think of charging them then (when I need it urgently). I just put them in the equipment, be it a radio control Chinese car, camera, wall clock, ANYTHING! ANd they work for hours, as if they were charged just before using.

9)For low consumption device like wall clocks, LSDs are the best, for obvious reasons. Obviously this is just an example. I dont use them in wall clocks.

Now tell me once reason to buy non-LSDs other than saying that you would charge and use all the capacity on the same day, which is a very less probability unless you are a heavy camera user or day night RC flier! :discuss:

It is all about purely personnel preference as you said. LSD and non LSD all are going to discharge rapidly in the first few month and then it reduces slowly since it is reducing balance only the rate is different for LSD and Non LSD. LSD survives with 75% to 85% at the end of year. Like it is convenient for me to recharge once in month plus similarly you are choosing to recharge once in two months plus.

For a person who flies only for one hour, two to three times in two month what difference it makes if you carry a battery with residual life of 10 hours or 15 hours in that period.

If you are going for LSD, if you can source it, have the finances for it, if surely do not want to charge the Tx and use all your charging time on LIPO than TX battery, then you should surely go in for LSD may be for the cool factor  ;) as you said earlier.

Then why at all settle for cheaper LSD of lower AH, you should go for the best brand available, preferably the one with 2.1 Amps charging capacity to reduce your rare charging time to about an hour (your cool factor is important ;) :D), why charge for 7 to 8 hour.

Why leave at that you should surely use for your wall clock which is the only device where you change your battery once in a year it is the ideal device for usage of LSD.

Horizon Singapore has already introduced fuel cell with 300 times energy density than any other power source which can be used in flying platforms. In year plus they will surely introduce a pack small enough to be used in Tx also.

If at all any one can invent an aero model engine which requires refilling once in a year, Lipo which requires recharging once in a year, Life would have been lot simpler.

When availability of LSD becomes common as High AH Ni MH now, I can easily and will surely switch to LSD with the modification I have in my TX.

For my cool factor now I use a Citizen Eco Drive wrist watch which does not require battery change at all.  ;D  :discuss:

My case in point here is, there is lot of prudence in going for an upgrade only when it is absolutely neccessary, which is easily available and which is economical in addition to keeping room for updating further when the availability of next higher technology becomes common.

There is no point in upgrading just because it has just been launched and you have the money for it. It is like computer RAM, In addition to the commonlly available just about latest RAM at cheaper rate, you will always have a newer 'The latest RAM' with higher GB and bus speed available for any one who can afford it. It is only that The latest will become half the cost in next six months and you will be surprised with next available "The latest technology".

When LSD becomes more common it will be available for 2.8 to 3.0 AH with More than 'C' charging rate. Then there is prudence in going for it and using the more commonly available Ni Mh for now.

I am not asking you to upgrade my friend, I am saying that people who are investing now on rechargeable Nimh can directly invest on LSDs. There is no problem with availability. HK always has it in stock!

And the price from HK is cheaper for LSDs even compared to local electronics shop Non LSD -NimH!

Also if you are charging once a month(even in case you/others don't use it) you reduce the charge cycles.

Also Using Turnigy LSDs does not reduce the Cool factor. They are in fact higher capacity then the eneloops. Eneloops = 2100 and Turnigy = 2200(but they store 2300). And its easily available, and its not like you need to invest in heaps in fact you invest less. Only thing is you need to wait for 20 days for it to get shipped


My final point is if you are investing/upgrading then it is best to use LSD as they are cheaper(from HK) and better than the non LSD nimh!

Even still if you insists that Ordinary Nimh are the way to go/ LSD are non available/ LSD are Costly / Still feel like charging every month for your satisfaction - Then Non LSDs are the way to Go. :thumbsup:

Amen! :-X

Wow!! thats a hell of a debate!! Keep on fellas!! :thumbsup:

Even in Mumbai, the cost difference between regular and LSD is not that much to warrant the use of "regular" NiMh cells.

QuoteLSD are non LSD all are going to discharge rapidly in the first few month

Not true. Regular cells can lose as much as 10-15% in the first day itself and be down by 50% or more in a month. In contrast, good LSD cells will have 85% capacity after 6 months! That IS quite a difference.

I agree completely with Vinay on moving to LSD cells when replacing or making new packs. More so as they are now available locally at not unreasonable prices.

Change for the sake of change, certainly unnecessary.

I will go home and install Lipo today on the TX  :thumbsup:  (:|~

Quote from: sundaramvelar on March 05, 2010, 08:41:27 AM
When availability of LSD becomes common as high AH Ni MH now, I can easily and will surely switch to LSD with the modification I have in my TX.

I believe you missed my total case in point there. ;) :D

But please at least charge your LIPO every month so that you do not end up with a Tx like the photographs posted by me earlier.  :bow: :bow:  >:D

The reason I got Lipo is due to the loose connect problems of the Nimh AND so that I don't have to change battery again and again :thumbsdown:

Quote from: sundaramvelar on March 05, 2010, 03:40:20 PM
But please at least charge your LIPO every month so that you do not end up with a Tx like the photographs posted by me earlier.  :bow: :bow:  >:D

Charging Lipo once a month is no way connected to those photographs.
Someone might have overcharged it, or used a crap charger or probably charged a puffed Lipo, or charged it every month with a crap charger thinking charging once in a month is good w/o even using the TX.  :P

I would charge my lipos when the voltage falls below 11.4 Volts not once a month unnecessarily.  ;) :D

Lipos are LSD! :thumbsup:

I think Vinay is talking fair here. Much has been already talked about Lipo. He is putting the LSD aspect as he originally wanted to use LSD than Lipo for all practical advantage (large shelf life, no fear of over discharging, in the box charging). Just that his idea of using individual Cell with Battery pack didn't work, he is going to Lipo, and he is earnestly accepting same and suggesting the pit falls to others.

Now between LSD and Nimh, I guess its more unanimous with even Sushil's opinion that given the negligible price difference, new investors in Nimh should go for LSD instead the aged Nimh. 300-400mAh difference is not deal breaking and charging Nimh at high charge rate is never a good idea. Nimh are not like 40C Lipos!!

Hope LHS are reading this and try to get LSD Nimh Tx pack for their next stock!! And do list them on thier site properly  :banghead: 8-)

Anyone who is very particular about LSD Ni MH please do not go running to hobby city or tower hobbies, whole lot of 2.0 AH LSD Ni MH of reputed brand like Sony Cycle Energy or sanyo eneloop is available in ebay india for approximately Rs 180 to 200 a piece. My only reservation is it is 2.0 AH.

Please type NH-AA-B4K or eneloop in the www.ebay.in search field and press enter.

Though you will need a 8 cell battery case to use them with Futaba 7C type.

However in case of futaba 6EX there is no space in the battery compartment for a battery case. It can only take a flat type soldered battery pack since the battery case is already built in without the clips and spring. You can though modify the inbuilt battery case to receive the batteries by fixing it with springs and clips from flat battery case of toy cars or any other electronic equipment which has a similar spring and clips which I have done and shown in the photos posted by me earlier.

From the loose connect problems I faced, Yes! I strongly recommend People to goto soldered NimH - LSD/ Non LSD/Lipo rather than preparing their own battery packs.
The reason I am recommending Turnigy LSD over Non-LSD is for the people who still prefer to use that 8 cell Holder and to carry along a spare cells like you do/ and for the people who would want to use those cells for other purposes also, LSDs are better any time over Non LSDs.

I actually Chose LSD NimH, but after the problems faced, I had a chance to choose between Lipo and soldered LSD nimh. Personally I chose Lipo because It was cheap/Cool factor/More capacity. ;)

vinay PS generally commercially available Nicd or Nimh or similar rechargeable battery packs are built using spot welding technique but not by soldering cells!

http://homepages.paradise.net.nz/bhabbott/straps.html

sahil

one can actually build a spot welder, its very simple (good DIY info on the net)

Oh is it? Sorry I was not aware of it. Was interchangeable using the words. Also there are few cells available with the leads given out for making packs, you mean even those have to be welded? :headscratch:

i was just talking about two different techniques, one can use any
method as long as the cells are not damaged in anyway  ;)

vinay the cells you are referring to come with tabs right?, then i think soldering would be good choice! but the soldering iron has to be in the 50-65watt range and appropriate soldering wire has to be used !

Probably to avoid the melting of the solder at high temp I guess!!

i think that would be on the extreme side of the battery use  :) may be to prevent mechanical failure or something of that sort  :headscratch:

I have seen that even Lipos come soldered with these kinda high temp soldering lead. Last time I dismantled a lipo, I had tough time unsoldering the battery packs with the 25 W soldering iron, I finally had to use the 60 watts wala soldering iron to dimantle the lipos.

yep one should use higher watt iron as it heat things up fast and quicker to de-solder preventing damage to cells

Mr Anwar,

I personally have not been able to convince myself till date to go for a LIPO in my Tx for various obvious reasons brought out earlier here and other places. To list out some are

1.   Fully charged LIPO voltage of 12.6 Volts against a rated 9.6 Volts of Tx.

2.   Requirement to remove the LIPO from Tx for charging for safety of Tx. (When removing and re-fixing the JST connectors in the card of Tx with your fingers through the restricted space was not comfortable for me especially if it has to be done every time)

3.   It is also not comforting for me to charge the LIPO in the Tx knowing fully well it is not safe.

4.   As per Tx design the battery low warning goes off only at 8.4 Volts which is far less than the safe lower voltage for LIPO.

5.   I cannot leave the LIPO unattended in the Tx for more than two months without charging.

6.   I have two different transmitters whose LIPO requirements are different dimensionally.

7.   By far the most obvious is the setup in the both my Tx posted earlier which I have been successfully using for last year and half. I can use NiMH as well as LSD NiMH get all the benefits of extended period of usage as good as a LIPO without the hassles of LIPO enumerated above.

Many places people who use LIPO have been able to negate the problem of High Voltage of a LIPO; LOW Voltage warning problems of Tx with LIPO by use of a simple forward biased Diode just before the JST Connecters.

Fact that a forward biased diode has a voltage drop of 1.2 Volts, effective volts seen by the Tx is only 11.4 Volts which is very much comparable to the 11.2 Volts of the fully charged Nicd/ Nimh. Further when the Tx is seeing 8.4 Volts The LIPO is safely at 9.6 Volts. Has anyone has any experience in this direction?

Further Tx LIPO is available with built in balancing circuit as well as without. What is the cost difference between them? What are the benefits and disadvantages of both of them?

Quote1.   Fully charged LIPO voltage of 12.6 Volts against a rated 9.6 Volts of Tx.

not true, suppose one is using a 8 cell battery holder with alkaline cells then the voltage would be above 12volts and more over the battery discharge curve to per cell voltages remains high upto 80% of the cells capacity which mean near 12 volts

Quote
4.   As per Tx design the battery low warning goes off only at 8.4 Volts which is far less than the safe lower voltage for LIPO.

can this voltage setting be changed ?

QuoteFact that a forward biased diode has a voltage drop of 1.2 Volts, effective volts seen by the Tx is only 11.4 Volts which is very much comparable to the 11.2 Volts of the fully charged Nicd/ Nimh. Further when the Tx is seeing 8.4 Volts The LIPO is safely at 9.6 Volts. Has anyone has any experience in this direction?

putting a diode is not a good idea, if the diode for some reason fails that's it end of story!

guys i have charged my SD-10G once and have been using it for simulator work! nearly 8 hours according to the radios internal clock and the battery still has some juice left in it  :) and according to my calculation full amp draw vs present battery capacity i should get 6.7 hours of run time which come to a week of flying before charge!

i seem to have lost my point  :headscratch:

Quote from: sundaramvelar on March 07, 2010, 04:04:42 AM
I personally have not been able to convince myself till date to go for a LIPO in my Tx for various obvious reasons brought out earlier here and other places. To list out some are

None of these are practical issues, really.

1.  The NiCD cells and NiMH cells that are used routinely (instead of the lipo upgrade) have a fully charged no-load voltage of close to 12.5v; for the lipo it is 12.6v.  Newer TXes are working on the 2s range (Futaba 12FG, 8FG etc), and the full charged voltage of 2s lipos are often less than the fully charged voltages of the NiMH packs that come with them.  I use the NiMH pack itself on the 12FG now, but I have a 2s lipo which will work as a drop in replacement if I need it with me all the time.  The same 2s lipo works as both TX lipo, and as an RX lipo for my heli ! The reason I am using NiMH is because the amount of flying I am doing USING MY OWN helis/planes have come down, I end up flying others' aircraft more for testing/trimming/training.

2.  About removing and/or reconnecting the lipo for charging, there are two broad cases.

a) People who remove the lipo : They use a small servo extension which stay permanently inserted into the TX battery connector pins, and they plug their lipo into this. It is no big deal at all that you pull out the lipo 10 to 12 TIMES A YEAR !

b) People who charge the lipo without removing it :  Most TX specific lipos come with 3 connectors (one Futaba, one JR and one Balance).  If, for examaple, I have a Futaba TX, I will permanently connect the Futaba lead into the TX, cut of the JR lead and convert into something like JST connectors and use that along with the balance connector to charge the lipo.  There is no pulling out and pushing in of the lipo connector into the TX battery connector pins.

3.  Many people think that if you invest in a good lipo and take good care of it, then charging/using a lipo for TX is just routine and very safe.

4.  The low voltage cut off is the only default issue, which can either be mitigated by using voltage drop circuitry, or just by being a bit diligent about charging at around 10.5v.  Who amongst us wait for the TX to beep before we recharge again anyways ?  And with lipos, this is so infrequent, that it is never a bother.

5.  You can very well leave a lipo unattended with the switch turned off, is what I remember.

6.  Lipos are available in any of the sizes.

7.  NiMH versus Lipo is largely a personal preference.  I do see that lipos tend to last longer than NiMH. One things I noticed is that if you are small heli flyer  (or even foamies) and you are travelling, you can have a simple 2s-3s charger which can be used to charge both the TX and main batteries ;)  This is no longer an issue with fully capable 6s chargers are available for $30 these days, but this was an issue couple of years back.

The lipos with balancing circuitry inside (I used such a TX lipo for a while) is convenient for people who want to charge using the regular charging leads (not opening the battery compartment at all).  But if you are charging 12 times A YEAR, all this is cosmetic.

All I can say is that it is NOT a small minority that is using lipos for the TXs.  The rest is a personal choice.

I am in total Sync with Anwar !!!  :thumbsup:

Quote "not true, suppose one is using a 8 cell battery holder with alkaline cells then the voltage would be above 12volts and more over the battery discharge curve to per cell voltages remains high upto 80% of the cells capacity which mean near 12 volts"

As per manual is it not the recommended battery for Tx is 8 cell pack NiCd.
I think NiCd, NiMh, and LSD all are similar with respect to rated voltage of 1.2V and fully charged voltage of 1.4X something and 8 cell pack to give about 11.2Volts. However I see that people have been using higher voltage LIPO/Alkaline without issues.

I read this high voltage issue on long term use LIPO on an international forum.

"1.   Fully charged LIPO voltage of 12.6 Volts against a rated 9.6 Volts of Tx."

Even I was surprised.

Quote "putting a diode is not a good idea, if the diode for some reason fails that's it end of story!"

I don't think, question of a PN diode failing does arise at all when the current drain required for a TX is only 170 to 200 Milli Amps which is far less than the rated amps of diode which is in Amps and not in Milli Amps. Further the Tx is as such full of diodes in the internal circuits. For that matter any diode can fail at any time due to any reason.

The diode in series in one of the wire of the JST connector was being used by him successfully. There is no issue in case of the diode fails as it is in series on the wire of the battery connector. If it shorts, the full voltage of a LIPO will reach Tx, which anyway is happening without the diode and if it becomes open junction no voltage will reach the Tx all you have to do is replace the diode or diode cable.

Yeah charging through the JST cable with diode is surely a big no go if you introduce it on the battery JST cable since it will be reverse biased for charging current. You have to rely on the balance connector only for charging. You can be obviating it by use of junction cable with diode, male and female JST.

Quote from: anwar on March 07, 2010, 11:06:03 AM
a) People who remove the lipo : They use a small servo extension which stay permanently inserted into the TX charge pins, and they plug their lipo into this. It is no big deal at all that you pull out the lipo 10 to 12 TIMES A YEAR !

I absolutely agree with you Mr Anwar. Though LIPO and Tx are not ideally compatible with each other most people have been able to use it successfully with various modification to the setup or the usage practice. :)

I am just bringing out some more modification which people are using in this direction with a querry for opinions of people who have tried them. ;)

AFAIK, I read in some of the Airtronics forums that it was officially OK to use a 3S lipo. So i dont have to worry I believe as I use Airtronics radio.

QuoteFact that a forward biased diode has a voltage drop of 1.2 Volts

I have built several battery packs for friends. Some are 5 cell units with a diode wired into the switch harness. Two packs are used in parallel for redundancy. The drop across the (silicon)  diode is typically 0.6V. Theoretically it should be 0.7V. I am unaware of 1.2V drop diodes.

Diodes are passive devices and would be as - or more - reliable than switches, connectors, etc.

I have seen several quotes, especially from Spektrum product support, who claim that the slight additional voltage can cause heat related RF section failures over longer periods of use.  But I have not seen anyone who have used it for 2 years (this is the longest duration I saw in people's posts) report anything wrong with their radios.

Added a poll, since we are on this topic anyways !

Anwar

You need to add the following options to your poll:

Self Assembled NiMh, NiCd packs for Tx and NiMh for Rx.

These are what I use and cannot cast my vote!

Updated.

It is interesting that all the voters so far use lipos with regulators on the receiver side !

Hi Sushil !!!  :salute:

Just wondering if you could throw some light on the linear regulator for Tx for Lipos.

Is there a possibility to build such a regulator ???  :o

Quote from: sushil_anand on March 08, 2010, 11:58:26 AM
The drop across the (silicon)  diode is typically 0.6V. Theoretically it should be 0.7V. I am unaware of 1.2V drop diodes.

They use two diodes in series to drop a total of 1.2v. 

http://heli.brixtonjunkies.com/2009/07/02/transmitter-lipo-3s-11-1v-stepdown/

http://www.wattflyer.com/forums/showthread.php?t=1213

Basically, add the diodes if you want added safety, preferably on a servo extension type setup, and charge the lipo outside of the diode setup.

Not recommended at all, but some Spectrum folks have been updating the voltage alarm using the service menu.

http://www.youtube.com/watch?v=5ogJSzV6gsM

Watch 2:46.

Again, not recommended.  Just do the diode thing if you have to.

Mr Anwar,

Still none have comented on use of LIPO with built in "Balancing circuit" and the LIPO without the balancing circuit and the cost difference vis a viz the benefits.

Are none of the forum members are using the LIPO for Tx with built in balancing circuit?

I thought "built in Balancing Circuit" is a vital componenet for a LIPO used in TX for extended durations, especially when charged LIPO left idle in the long run is bound to get unbalanced voltages.

Looks like you missed this part of my earlier post.

Quote from: anwar on March 07, 2010, 11:06:03 AM
The lipos with balancing circuitry inside (I used such a TX lipo for a while) is convenient for people who want to charge using the regular charging leads (not opening the battery compartment at all).  But if you are charging 12 times A YEAR, all this is cosmetic.

There is some discussion of a TX lipo here too : http://www.rcindia.org/batteries-and-chargers/battery-voltage-measurement-reliability/

Regardless of all of this, using low "C" TX lipos with balance connectors is more than enough, as you will be charging them once a month or so.  The built-in-balancer one is just "bling" for the most part.

QuoteIs there a possibility to build such a regulator

Very simple actually. Will do a bit of spadework on a few, accessible transmitters, to measure the current drawn. Don't expect it to exceed 300mA.

Thanks Mr Anwar,

I had actually missed that. From what I understand, further you cannot use LIPO with built in Balancing Circuit to charge fitted in the Tx from built in charging circuit of Tx if you are using Diode modification.

What might be the cost difference between the one with balancing circuit and the one without say for 11.1V 2200mah?

I am with Vinay, Ujjwana and Sunderamvelar on the preference of LSD NiMh over LiPo for Tx use. A set of 8 LSD cells cost less than the cheapest TX LiPO of similar capacity, in India. No further hassles of charging issues, safety, etc. They will last as long as the Lipo  under the same conditions.

In case of Rx packs, I think a 2 cell LiPo + Bec would cost significantly more than an LSD NiMh pack.  

So, other than the "in/cool" factor, practically, NiMh would/should be the preferred choice.

I agree that with current LSD NiMH availability, lipos may not have the advantage anymore.  Their advantage is pretty much limited to charging time now, which is not an issue for infrequent charging.

I guess the writing is on the wall, when most of the latest models of radios now come with NiMH packs, wish there were all LSD though.

With the present advancement of technology it is only in the near future, not far from now when LSD Ni Mh Batteries are going to be available aplenty at 2.8 AH to 3.0 AH further with Plus 1C charge rate which will reduce you're charging time to about to an hour. Then the charging time advantage of LIPO is also going to be non existent.

Presently some of the 2.1 AH LSD Ni MH batteries of Sanyo are available at 2.1 Amperes (1C) rate of charging ( Only that it is not available so commonly) which has a charging time of about an hour and a battery pack of 2100 mah 9.6V can be easily created with them.

Bump ;)  Reminder for everyone to vote !

Can i use a 3s 4400 mah battery with 15c on my tx with diode to reduce the voltage to 11.0. I can fix the lipo outside just like dave of rcpowers do :P. my doubt is can i use it on the tx so that it gives more time for my next recharge.

Anyone has experience with a 6.6v LiFe hump/straight pack for receivers? I would like to get one.

I use 6.6V LiFePo4 A123 batteries all the time for my Futaba FASST Rxs. Works wonderful !

Where is the best place to order the LiFes? The hump packs are not very common.

Quote from: azhaguvel on November 01, 2010, 10:59:33 PM
Can i use a 3s 4400 mah battery with 15c on my tx with diode to reduce the voltage to 11.0. I can fix the lipo outside just like dave of rcpowers do :P  my doubt is can i use it on the tx so that it gives more time for my next recharge.

Yes, many people do that.  The only concern is that even at 15C these have high discharge rates as compared to dedicated TX lipos (usually around 3C).  The high discharge may cause issues while plugging in to radios whose plugs are not designed for the same.  But in practice this seems to be rare enough that many people are doing it.

Quote from: azhaguvel on November 01, 2010, 10:59:33 PM
Can i use a 3s 4400 mah battery with 15c on my tx with diode to reduce the voltage to 11.0. I can fix the lipo outside just like dave of rcpowers do :P. my doubt is can i use it on the tx so that it gives more time for my next recharge.

See the earlier posts. The current consumption of "8 cell" Txs is of the order of 300 mA. A fully charged battery would last at least 4-5 hours of flying time. Can't see why you would need more than that for any session. Besides, what you would use for the Rx battery to get proportional time.

Quote from: anwar on November 02, 2010, 11:30:05 AM
Yes, many people do that.  The only concern is that even at 15C these have high discharge rates as compared to dedicated TX lipos (usually around 3C).  The high discharge may cause issues while plugging in to radios whose plugs are not designed for the same.  But in practice this seems to be rare enough that many people are doing it.

Anwar
The discharge rate is determined by the TX current draw. The capacity of the battery will not influence that in any way.

A good example is your mains supply. It may well be CAPABLE of suppling several kilowatts for, say, several air conditioning units. Yet you may use a phone charger with the same supply which will draw a few watts, at most.

Yes, that is clear.  The issue is "connection sparks" (for lack of a better word) . This is documented in many locations. Basically every manufacturer lists this as the reason why they came out with special "low discharge" lipos for use as TX lipos.

Quote from: mail4ajo on November 02, 2010, 10:29:48 AM
Where is the best place to order the LiFes? The hump packs are not very common.

Try SDSHobby.net for A123 packs, or if you want branded more expensive oned - try HobbyKings for A123 racing genuine cells or Readyheli.com for Hyperion ones.

I have used all of them and they work great !.

I cannot buy that theory. A spark will only occur when high current is DRAWN. It is not possible to FORCE current into any device as I have clarified.

ya i accept a normal battery last for 3-4 hours. but think of the advantage 4400 mah lipo & the transmitter gets only 300 mah, it last for 14.6 hrs. i can forget about charging them for a long time. About discharge rate,that is what i was wondering, anyway the tx is going to withdraw only the amount it wants (300mah). so why should i care about the c rating?

Hmmm... I thought arcs are possible when connectors are close enough.  This is how the Rhino lipo folks put it.

http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=7346

QuoteIt is a low discharge Lithium Polymer pack, designed specifically for R/C Radio use. We do not suggest you to use a standard Lipoly pack with Tx power plugs in your radio system as standard Lipoly are capable of a rapid energy release which can harm sensitive radio electronics.

Not sure if this is more of a marketing talk than it is a real life possibility.  

Another reason I have seen discussed is that a lower C rating pack's output voltage is pulled down more under load, as compared to a higher C pack, thus making their use without diodes easier on the TX.

Yes. You do not need to worry about the C rating. But I have a point to make about "I can forget about charging them for a long time". How would you know the state of the battery "after a long time"? What if it was on its last legs?

For safety's sake it is prudent to ensure that the Tx and Rx batteries are charged before  each flying session. And if one follows this rule, it really makes no difference as long as the battery can survive your days session. It is no effort and, in return, I (at least) get peace of mind.

Quote from: anwar on November 02, 2010, 12:43:30 PM
Hmmm... I thought arcs are possible when connectors are close enough.

Another reason I have seen discussed is that a lower C rating pack's output voltage is pulled down more under load, as compared to a higher C pack, thus making their use without diodes easier on the TX.

Sorry to be pedantic but "sparking"is between , say the male and female, connectors. Arcing is sparking between 2 (or more) terminals with different potentials.

If the current draw of a Tx or, more so, Rx is causing the supply to pull down , it would indicate insufficient battery capacity and a "no-no" in my book.

The display on the TX is a good indication, and recharging around 10.5v is what I have been doing.  Do NOT trust (and wait for) the TX lipo warning (unless you use 2 diodes).

If we charge the TX every time, that defeats the purpose of using a lipo in the first place.

Quote from: sushil_anand on November 02, 2010, 12:53:46 PM
If the current draw of a Tx or, more so, Rx is causing the supply to pull down , it would indicate insufficient battery capacity and a "no-no" in my book.

Wouldn't applying load to any battery pull down its voltage ? What am I missing :)

This is a possible scenario I was getting at:

Suppose you have flown a couple - or more -days spaced over a "long time". How would one have an idea of the remaining capacity?
And, without that information, I would not feel safe.

Lipos discharge very very slowly.  I charge once a month or so on the lipo one.  Any time I turn it on, I look at the TX voltage on the display, for confirmation.

I decide on the field itself whether I need to recharge it for the next session.

Quote from: anwar on November 02, 2010, 01:22:18 PM
Wouldn't applying load to any battery pull down its voltage ? What am I missing :)

When well within maximum ratings, the cell discharge curve is fairly flat until it starts to drop rapidly. In short, if the loading is not excessive, the drop will be gradual. A sudden drop or "pull down" as you describe it would certainly indicate that the currrent requirement and the battery capacity/type are mismatched. Try this experiment on your transmitter. Charge it fully and leave it aside (switched off) for a couple of hours. Switch it on, monitor the voltage and plot the results as voltage vs time.

I will,try and do this on my Tx and post the results. Let me know what you come up with!

I think a better test for how I understood the issue would be like this :

1.  Take two 3cell lipos, one low discharge (say 3C) and another high discharge (say 30C).

2.  Charge and balance them perfectly to 4.2v per cell / 12.6 volts total. (as much as possible, using a charger like the iCharger).

3.  Notice the voltage shown on the TX voltage monitor as soon as you connect each of the lipos to the TX as power source. 

Do not do this immediately after charging. Let them stabilise for an hour or more and THEN carry out your tests.

sushil any updates on the test?

Quote from: azhaguvel on November 09, 2010, 10:06:44 PM
sushil any updates on the test?

The methodology of the  tests were suggestions to Anwar .  Without the precaution of waiting for some time after ANY charge, you could get a result that would lead one to an incorrect conclusion. I am aware of what the results would be!

If your are interested in transmitter lipo then its the right time. HK has re-stocked some transmitter lipo's which is just 8$ today.
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9787

I got one  ;D.

Is it suitable for spektrum Dx6i?

This is 3s (over 12v).  I believe the DX6i users 4AA batteries, which mean 6v, so it would not work (without you adding some circuitry to bring the voltage down).  Even a 2s lipo may be too much, although some people seem to be using them.

Using rechargeable LSD NiMH cells seems to make more sense in this case. Even though they are 1.2v instead of 1.5v, many people are using these with their DX6is.

Looks like DX6i may now be shipping with NiMH cells :

http://www.horizonhobby.com/Products/Default.aspx?ProdID=SPMR6600

These are 1500mAH ones, you can get higher capacity LSD ones.

Thanks for the valuable input Anwar sir..

I conected my http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9787
Lipo to my turnigy 9x today. Soldered two 1A diode on one of the wires in series.
The diodes are reducing 1.7 V & my turnigy is detecting the voltage with .7V lesser then the actual.
so it sums up to 2.4 volt lesser then the actual volts
The manual tells that tx will start making warning sounds at 8.5V

volts at warning=>8.5+2.4=10.9
volt of individual cell =>10.9/3=3.63V
Is this ok. can the individual cells be at this volt(3.63).

Also the diodes are getting heated. Is this an issue?
What will happen if one of the diodes fail. Will it break the line or just pass the voltage directly?

Many people use 4 diodes in a parallel + serial combination for redundancy.

I have been using lipo, A123 for receiver but for my JR 10X the company dose not recommend using lipo batteries so i have dropped the idea.. but i have also found many using lipo in a 10X but that is on your own risk.. ;D apart for this radio i have used lipo without any problem in transmitter.

Is there any small circuit which breaks the line when the current exceeds 1A for 12V.

Don't know but the company says the might get damaged. I know some are using Lipo in 10X but the official word is not recommended. I am using 2500 NIMH & they are the best.

Quote from: anwar on January 02, 2011, 01:02:04 AM
Many people use 4 diodes in a parallel + serial combination for redundancy.

Diodes seldom go "open". If at all they "short". A shorted diode will create a problem  even if you have another set in parallel. Current will flow through the path of least resistance, which now is the shorted diode.

The whole point is handling an "open" diode, since a shorted diode will only be just as bad as them not being there, as if the lipo is connected directly.  Lowering the voltage is only a "nice to have", so shorting is not really a concern.  It is "open"ing that matters, and that is why the parallel path seems like a good idea.

BTW, requesting everyone to vote in this poll ! :)

True. But the odds of a diode going open are much, much less than shorting. From experience not connected to RC.

Hello friends,\
:headscratch: :headscratch: :headscratch:I have been wondering since a long time why cant we use self assembled tx and Rx batteries.

A normal Tx battery costs around  :Rs: 750 at least
which is generally a combination of 8*1.2v AA size NiMh/Nicd batteries.

In contrary, a set of 4 NiMh/Nicd AA cell costs  :Rs:160.
We need 8 so:   160*2= :Rs:320 for eight cells

The rate of whole assembly is for 700mah. which is confirmed.

Hope everyone knows to connect cells in series to form batteries:(ie +- +- +- +-..)
To make it permanant, one can use soldering, or spring and slit arrangement. You can also get batteries soldered and connected by your nearest electronic shop, who doesnt know how to.

Rest all u need is a JR connector(if im not wrong due to weak terminology), at the remainig ends, to form a plug.
The output you get is nearly same in weight, power output, as well as dimensions.
Same can be done with Rx using AAA size cells(cost not confirmed)

Then why cant we assemble and use yaar ;). Atleast those who are good and interested at RnDs. :thumbsup: Even i hope some might be using it too.
If there are any drawbacks, please let me know. Apart from the one created with poor workmanship while assembling.

Hope u understand my intensions >:D fly more at lesser cost :giggle: :giggle:

Hey sorry friends, regarding the name of brands present in pictures. My intension was upto demonstration itself.

Merged into existing thread... "self assembled" packs are discussed earlier in this thread.  Even the poll shows many people use them (like Sushil bhai).

PS: Requesting everyone to vote in the poll !

Now  I saw an LSD NiMH Sanyo Eneloop which was 2500 AH so decided to switch to LSD now. I have ordered two sets for my Tx's.

http://cgi.ebay.in/ws/eBayISAPI.dll?ViewItem&item=170635182575&ssPageName=STRK:MEWNX:IT

Sanyo Eneloop 2,000 mAH LSD are availabe here for around 600 for 4 .They are more than adequate for most applications.

I use Eneloop for pretty much every device that accepts AA cells. Not the one is the pic though. But the white ones. I also have a few Duracell 2650 mAH and also a set of Uniross Dynamic 1900 mAH.

The Uniross and Eneloop have the same tech. The precharged ready to use thingamagic watchamacallit.

Turnigy 1450mAh 3S 11.1v Transmitter Lipoly Pack (http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=9787), is this the biggest battery that can fit in a Futaba 6EXAP?

SLS

With Eneloop 2000 & 2500 mAH cells being available locally at reasonable prices, why look for an import substitute?

Hi Sushil,

Do you have an idea as to how much they cost ?

SLS

1450mah are more than enough to keep your radio charged over a month..

Quote from: sushil_anand on June 03, 2011, 11:51:00 AM
Eneloop 2000 & 2500 mAH cells being available locally at reasonable prices, why look for an import substitute?

Yes! i read the complete thread, and saw how you guys came to a conclusion that LSD'd are the best option. The problem is my radio doesn't have the metal contacts (springs) you need for AA cells :(

Quote from: atul_pg on June 03, 2011, 11:54:05 AM
1450mah are more than enough to keep your radio charged over a month..

Actually I am also using my tx on the sim hence looking for the biggest i can get.

I have this

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=14076

fits perfectly into any tx which uses 8AA Bat(turnigy & RDS8000). Fully charged to 10.8 V and Min is 9.9 V. dont need to solder any diodes.

SLS

I have a 2500mah tx lipo battery that would fit in the futaba 6exap perfectly. But..

One cell is dead..lets see if we can find one more cell then we can change the dead cell from the lipo and make it working.

Azhaguvel any LHS stocking it ?

Both ratings available in Mumbai. How many and which ones do you want?

How about the 8AA cells 2500mah.

Edit - Just found out a link

http://cgi.ebay.in/Sanyo-Eneloop-Color-AA-Rechargeable-Battery-Pack-8-/170647757485?pt=LH_DefaultDomain_203&hash=item27bb6622ad

Never try to make a Tx battery pack with normal batteries. You cannot solder the 'Tabs' of the normal batteries sold in grocerry store, and Battery holders tend to suffer loose connection many times. My friend Vinay on this forum had bad experience using battery holders.

Instead, go for professionally assembled LSD NiMH battery packs like :

http://cgi.ebay.com/Sanyo-Nimh-2700mAh-9-6v-Transmitter-Square-Pack-/270748076899?pt=UK_ConsumerElectronics_Batteries_SM&hash=item3f09d7cb63

http://cgi.ebay.com/9-6V-2100mAh-Transmitter-Flat-NiMH-Battery-Pack-Futaba-/400220346053?pt=UK_ToysGames_RadioControlled_JN&hash=item5d2efdd6c5

I would prefer a lipo instead of the AA for sure.

Quote from: ujjwaana on June 03, 2011, 12:42:44 PM
Never try to make a Tx battery pack with normal batteries. You cannot solder the 'Tabs'..

Thats what i'm afraid of. The second link you posted is the kind of pack (8xAA flat) I need. But want to buy locally or something from HK maybe.

Quote from: atul_pg on June 03, 2011, 12:14:26 PM
I have a 2500mah tx lipo battery that would fit in the futaba 6exap perfectly.

Which battery is it, can you please post a link or something.

Ujjwaana

I beg to disagree. I have been making and using soldered packs (Tx & Rx) for the past 30 years without any problem whatsoever. Soldering is a technique and, when mastered, can result in  a perfectly satisfactory job. The only problem is the slight increase in dimension because of the soldering. That has to be taken care of.

But, I have recently discovered someone who spot welds the cells. That is what ALL manufacturers do and would be acceptable to you also, I think!

Battery holders are a no-no.

I got this battery from sai. Don't remember the name. One cell is dead , was thinking of replacing it with another cell.

Not recommended. The new cell will be different in characteristics from the others. Maybe you could make a Rx pack out of 4 or 5 of the remaining good cells.

Guess you are right. I did change one cell of my earlier lipo battery but of course they were of the same brand and it worked fine.

In between, I bought a turnigy 9x and fitting in a 2.4ghz frsky module and saurabh is the guy who is helping me out here.

Thinking about getting this one  :-\
http://www.dealextreme.com/p/11-1v-2200mah-8c-replacement-li-poly-battery-pack-for-futaba-6ex-remote-controller-51219

Two of the radios I own use AA cells (for Tx, that is). Now, alkaline cells are impractical so most people use NiMh. But for radios with LCD, even NiMh cells get consumed fast.

I was thinking about using a 2s LiPo for my SD-5G. It has a battery slot for 6 AA cells (and gives a low voltage warning at 6.7V). A 2s LiPo can be accommodated with a bit of tinkering (cutting the plastic walls that separate the AA cells  >:D).

Has anyone tried this before? Are there any issues I should be concerned about?

hi,
   i got two radio
1: turningy 9x which is powered by 11.1v turningy 1450 mah low discharge transmitter pack from hobbyking.
2: hobbyking 4ch which is powered by 8 NiMh 1600mah cell.

now i can assure you that my tx no.1(5 channel working) runs for 6-7 time more than tx no.2(2ch working)
i bought 8 envia NiMh cell for Rs.500 and turningy lipo for $8 ie   :Rs:360.

( http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9787 (http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9787) )check this link for cheap tx lipo

for rx any rc flyer or sailor will be happy to remove 100-200 gms from his plane or boat.

i have 70A esc, before using BEC i used futaba rx battery pack, i had to give full throttle for hand launching my glider
but after replacing futaba battery with  5volt 3A BEC 60% throttle take my glider in air.

i saw the beauty of LiPo and hope above data will help you.
Cheap Powerful and BEC dont reduce your flight time.


enjoy..............
Amit

In how much time will 1450 mah turnigy (with hk 2.4 black) wil discharge, given 80% throttle all the time? 

And with simulator?

Today I have replaced and added one vote for transmitter lipo since one of my transmitter came with Lipos from manufactures which by design can be charged fitted inside Tx.  :P  8-)

It comes with a 2S 3400ah Lipos. I thought I will buy a spare 2s lipo of same dimension, but as I see the voltage at the balance terminal of the 2S lipo is  12-0-12 volts. I cannot use any standard 2S lipo. I can only conclude it has a balance and charging circuit inside the OEM Lipo. The OEM Lipo is more costly than a decent 2.4 Ghz 6 channel tx  ???

which is suitable tx battery my tx sanwa airtronics vg4r 72mhz FM i tried by lipo tx is heating i tried high ni-hm 2300 then also tx heating so which good may try regulator where i get it my old batt is ni-cad 600 help me

Can I use my 1300mah 2s 25c wolfpack lipo which i shorted by mistake on my tx wbich is rcb6i. I contacted rcb folks not to do so what do you people suggest.

@rcrcnitesh
Surely you know that no 2s can power a Tx, being at best 8.4v.

@ Nitesh. RCB 6i can be set in the menu to use a 2S. i.e. 7.4 lipo and you can use a 2S lipo or you can set it to use a 4 cell Nimh. But it's not recomended to use a shorted 3S lipo which is giving 2S voltage.

@ Iyer sir this radio RCB 6i has a menu feature to select various battery and voltage types.

QuoteCan I use my 1300mah 2s 25c wolfpack lipo which i shorted by mistake on my tx wbich is rcb6i. I contacted rcb folks not to do so what do you people suggest.

I read the RCB6i manual and you can use either a 4 cell rechargeable pack or lipo ! (does'nt your transmitter come with 4 cell NiMH pack?).

Quote@rcrcnitesh
Surely you know that no 2s can power a Tx, being at best 8.4v.

its not completely correct, i have a Sanwa SD-10G and it works on 2S so do many recent 2.4Ghz radios (please update yourself).

Bye
Sahil

Quote@ Iyer sir this radio RCB 6i has a menu feature to select various battery and voltage types.

interesting.

@sundaram sir
@rcrcnitesh
@sahilkit
'Please update yourself'
Oops. Deserved that.
Well, one lives and learns.
My Hitec is now on lipo, so the Nimh was free.
Used it with a RICCS Tx, but the green light never came on. Only red plus yellow.
Ie, 9.6v Nimh not enough for a system designed for 8x1.5v dry cells.
So only using it on wireless sim (courtesy Gusty!)

Nitesh,
Why didn't you just do a range check?

Quote@sahilkit
'Please update yourself'
Oops. Deserved that.

Please don't take it wrongly, even i was quite shocked seeing a Futaba 10J Promo Video (10J works on 4 dry cells)

The voltage is not a problem. My battery is a 2cell battery originally and i shorted it by mistake but still the voltage is correct and its not puffed i planned to use it on my tx as the tx will consume less current and the battery will not be at load but if i use it in my plane the current will be high and the battery will be at load. I was thinking if I use it on my tx it will be safe as it will be under less load.. When I contacted rcb they told the c rating is high so it is not recommended the battery will spoil. What should I do now, should I  keep using it on my plane or use it on my tx.

Why do you say after it was shorted it has to be used for Tx only. Was the battery in short circuit condition for that long to spoil the battery? Do you feel depreciated performance on Motor ESC Usage? Is the Lipo drooping voltage too much before it can deliver the recommended 'C' rating amperage discharge or the capacity but recovers voltage after some time? 

1.3 AH at 25 C rating should give ideally 32 Amps Max. You should be able to use it at a safe 20-25 Amps load continuous application without drastic drop in voltage. This you can check only if you have a watt meter. But if its not delivering say not even 10 Amps and dropping voltage drastically every time you attempt, but it recovers voltage after some time, and you are never able to charge the battery to the rated capacity say not even to its 50% capacity and the battery shows charged full capacity within short duration, Then you have a battery which has been damaged and depreciated  "C" ratings.

Though radio is a device which consumes not more than 200-300 ma max depending on the Type/ model for its operation, usage of a higher 'C' rated Lipo will in no way will affect its operation or performance or spoil it in anyway. ( All recommended Lipo's for radio (5C ratings) even if at 1C rating is much higher than what is required for radio).

Having said that Radio is a very important component of RC flying and I would not recommend usage of a product which you know for sure has been damaged or has a fault line. 

Sundaram Sir I have not checked all these things.

I am not sure whether the battery is damaged.

While I was checking the voltage of individual cells of the lipo using a multimeter I mistakenly shorted one of the cells but it was not in that condition for more that 0.2 seconds though the battery was not puffed and the voltage remained the same even after I shorted the battery.

A momentary short circuit is not a major deal. You can continue to use it for motor and ESC application and as well as Radio Application if you choose to.

I think of using it for radio and buy a new 1800mah indpower battery for my plane (this will solve the balance issue of my plane)
thanks everyone :hatsoff:

have been using only lipos for my Rx with a regulator have not faced a single issue till date