Dear All,
I have a German Leopard 1/24 scale RC Battle Tank (imported)
& a RC Heli(bought from Masjid Road,Mumbai)

It seems that my 9.6V 1000mAh NiCd battery Pack(Factory supplied Yellow)has lost its capacity.
I searched a lot of places on the Net,but couldn't find anyone in the Mumbai selling it.
If anyone has a good idea,where i can buy a new pack for my RC Tank,it would be a great help.
Thanks Guys.

hi Tejwebworld ,
ur best bet is probably to try some hobby shops in mumbai
here is the link
http://www.rcindia.org/rc-locations-and-clubs/mega-list-of-rc-fields-locations-clubs-in-india/
if not..... try manish market....... u might get nicd batteries ..... these were earlier used in cordless phones....... but might not be exactly same one....... u might have to combine

if no success.....
try combing these  2
http://www.hobbyking.com/hobbyking/store/__10920__Futaba_AA_1000mah_Receiver_Battery_Ni_CD_4_8V_.html

but u knw what...... these r simple AA size cells soldered together in parallel...... u can ask to solder any person from electronics shop to solder for u........ if u r not good at soldering

Quote from: Tejwebworld on December 11, 2012, 05:11:36 PM

If anyone has a good idea,where i can buy a new pack for my RC Tank,it would be a great help.
Thanks Guys.

Tej, PM your contact information and I will organise one for you.

And Sameer, the cells would be in series and not parallel.

sory my mistake....... series.... ofcourse otherwise voltage wont add up

Thanks for your help guys,i just visited my Local electronics shop.He soldered a pack of 8 AA 9.6V 1000 NiCd Batteries.Charged 450 Rupees.Brought it home & tried,but no response from my Tank.Then i remembered that the Shopkeeper had told me to charge the Batteries full before testing.
Doing the same thing right now.Have no clue how many hours it will take to charge the Pack,but i am estimating around 2-3hrs?
Hope it works.
Sushil in our group has come forward to help me.
Lets see.Hope for the best.


For info.the shop keeper has used 2 pairs of Envie & 2 pairs of Uniross NiCad Batteries for soldering.


I had bought the Tank from LeadersHobby.com 2 yrs back.They were unable to help me as the Model is not available with them now.

Quote from: Tejwebworld on December 11, 2012, 09:09:35 PM
For info.the shop keeper has used 2 pairs of Envie & 2 pairs of Uniross NiCad Batteries for soldering.

You are not suppose to mix different types of NiMh or NiCd when using in a pack. Your pack will get spoiled very soon.

You could have just used this and eight same type of NiMh or NiCd if the space permitted



or used two receiver 4.8V Pack in series.

Ok, so completed charging my New Soldered battery pack for around 4 hours.Attached it to my tank.Worked for a few seconds and then The Tank gave Signal that Battery was low.
How can this happen when i charged the soldered battery for 4 hours??
It is seeming to be a lot tougher than i imagined.
Any Suggestions guys?

With NiCd you have to 'push' current into them to charge, the amount of charge your battery received is completely dependent on the current that your charger pushed through. if your battery capacity is 1000mAh and you charged at C/10 rating implies you charged at 100mA. For NiCd charged at C/10 (standard) it typically takes 10-12 hours for a complete charge. Also, NiCd tend to loose charge and should be completely discharged once in a while or else something known as 'memory effect' (wikipedia) comes into play. So you need to ensure how much is your charging current. Typically it should be mentioned on the charger, otherwise, you can get a close idea  by the formula (Vcharger - Vbattery)/resistance of battery. Resistance of battery can be estimated by

My Charger Output states 9.6V 250mAh
so for how many hours will it be ok for me to charge so that the Battery is fully Charged.
Also,the charger gets quite hot while charging.

Quote from: Tejwebworld on December 12, 2012, 12:38:59 PM
Also,the charger gets quite hot while charging.

The battery shouldn't get hot while charging. The charger getting hot is alright, heat will be much apparent if it is a transformer based supply (it is heavy).

Quote from: Tejwebworld on December 12, 2012, 12:38:59 PM
My Charger Output states 9.6V 250mAh
so for how many hours will it be ok for me to charge so that the Battery is fully Charged.

It totally depends on how much current is running through the circuit (250mAh here means capable of delivering 250mAh). You should perhaps leave it for about 10 hours to charge and see the results.

Thanks for the Tip,
I charged the Battery pack for almost 4 hours and tried to plug in.But no response.
Wondering whether it was a mistake getting a battery pack soldered from the local Electronics shop.
Isn't there a reliable supplier of these things in Mumbai?

The electrical connectors are Tamiya type,but no one seems to have those.

As like LiPO, No balance charger plug is available, i. e. you cannot get the battery interconnection terminal, the chances to damage is very high (In fact lost of balance). In envie and UniRoss, NiMH battery are more frequent and some comes with pre-charged condition, That means, the battery need no initial charging.

Else you need
a) initial charging for 1.4 times of full charging time depending upon battery capacity and charging current,
b) then rest for 1-2 hours (0.2 times of First Charge) and then again
c) 1.4 times of first charge. This results in heating in last quarter of 2nd charging, though you have to allow it for maximum use of it's capacity and higher numbers of discharge/Re-Charge cycle.

For NiCD, just do the same replace with 0.8 time of charging instead of 1.4.

For example,
for a 300 mA Charger, I have purchased 2100mAH NiMH camera cell.
So, inituial first charge = 2100*1.4/300 = 10 Hours
Then make off for 10*0.2 = 2 hour
Then second charging for again 10 hour.

But the main difference between a precharged cell and a uncharged cell is the self discharge. Precharge cells have very very low self discharge and so charge retentivity is much higher than uncharged cell. So, in mixed case, after a few month, you have to start charging when high self discharged cell deep discharged and cell pack voltage gone low (Still other cell have some amount of charge).
After start charging, it wiill indicate full charged voltage of cell pack very early when the precharged cells fully charged and their emf increased.

So, you get the following disadvantages for mixed cell pack.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1. As bad cells are not full charged, you have to see full charge of pack while good cells are slightly overcharged which reduce active material loss in heat by heating and leaking may occur.
2. As good cells are not totally discharged during cell pack low voltage condition, bad cells have to go extreme low discharge (or deep discharged), so in any case it may happen that the cell internal resistance increased so much that you cannot charge it.

And here the good battery mentioned above are pre-charged one.
In Kolkata, precharged 3cell 1600mAH battery are priced for Rs. 75/- and you need 3 cell pack at least.

Manish market is a fraud area to me. Look for the originality. I have cheated there in mid-2004 when I purchased 4 Nos of Panasonic 600mAH rechargeable cell for 100/- (while in Kolkata, that was 80/-, but I had urgent need), which cannot be charged after exhaust and opening I saw, that was a local ZnCl2 battery specially manufactured undersized to accommodate top cap, bottom plate and the sticker. So, the 100/- rupee give me the lesson, PATIENCE.

You please open the initial cell, charge individual cell to full charge, Check continuity of wire and battery terminal, repair the defective one and you will get a 80% efficient battery in most of cases.

For Rs.800, you may get 8 cell of 2100mAH of precharged cell of envie infinite from any Digital Camera Shop or even from Shopping Mall

Thanks for the Knowledge you provided about how cells can be mixed up or of cheap Quality.
But i am afraid that i might not be able to remove Batteries from the Soldered Pack Individually as i am not experienced in Electronics as yet.

I think it was a big mistake getting a pack soldered from local electronics shop.
Even after i charge for so many hours(4-5) the Voltage that i get from the Pack is very Low,
The Electronics guy told me that there might be a problem with my charger,which i doubt.

Anyways,i think it would be wise for me to buy a new charger & a battery Pack for My RC Tank's 9.6V 1000mAh Requirements.
If anyone deals in Battery Packs or knows where to buy one in Mumbai,please let me know.

Thanks for your help guys...   appreciate it..

No, No battery pack,
Just use the holder as sundaram shown and use camera NiMH precharged cell.
The cells need charging individual and individual attention. So, you get the UniRoss Charger for 600-800 also. You should be happy if the holder space permits.

I cannot charge Batteries from battery pack individually.Everytime i charge all the batteries,then i will have to solder them back again.


Anyways,i did some research & found that Nicd are now almost absolete.Therefore,i am now looking for a Brand New 9.6V 1000mAh Nimh Battery & charger. 

Ok,I got it what you meant.I was looking for 8 cell holder as Sundaram has shown but could not find it.
If i get a holder,then that would be great.Your idea should work....
Plus,i already have Nimh Rechargeable batteries so there will be a lot of cost saving.

Thanks...

Dear All,My 9.6V 250mA charger seems to be defective as the battery pack i got soldered from an electronics shop does not seem to fully charge.
The Electronic shop has suggested that he would use a normal charger of the same volt(9.6V) to charge my 9.6V NiCd 1000mAh soldered battery pack,by removing the Tamiya connector pin from the Original charger to the Local Charger.
I need your Expert Opinion on this.Only after consulting you guys,i am going to give the Electronics guys a Go Ahead.
Also,can anyone please tell me that if this is not possible,where can one her a NiCd charger in Mumbai?

Check your normal household supply voltage. It is near 190-200 volt and so It is not charged. Charge at night when you will get full voltage. Generally the DC Voltage out from Charger is about battery pack + Charger LEV Voltage (1.8 for red and 2.6 for green) with parallel resistance. So, we get the light off when charging current reduce it's design value (infact cell pack emf increased to Charger volt - LED Volt).
So, even after LED become off please keep charging on and check if any improvement in charge status.
So, you need the modification of either your transformer changer or have to add an 12-0-12 200mA Transformer for voltage boost or you may fix an 2200uF/16 Volt 85 deg C Capacitor just after diode bridge. Surely you got some effective DC Boost. Just try once.

Thanks

http://geb.ebay.in/g/10-Pcs-New-8-AA-2A-Battery-12V-Clip-Holder-Box-Case-with-6-Leads-Black?itemid=170860794410

http://geb.ebay.in/g/EIGHT-AA-BATTERY-HOLDER-BOX-CASE-9-6VOLT-TO-12VOLT-W-LEADS-HOLDS-8-AA-BATTERIES?itemid=271029400362

http://geb.ebay.in/g/TEN-AA-BATTERY-HOLDER-BOX-CASE-12VOLT-TO-15VOLT-W-LEADS-HOLDS-10-AA-BATTERIES?itemid=271027712711

Hi,

when you buy AA size Ni-Cd or Ni-MH batteries get them from a reputed seller who guarantees them because there are a lot of fake cells being sold as the original ones. I wasted a few Ks buying what were available locally several times hoping that I would get Real ones but I never did.

good luck.

Dear All,I appreciate you guys helping me through this.
So after many visits to the Local Electronics guy,i got the battery issue sorted out.
It seems that the battery is now charging.The Soldering guy told me that there was a lot of moisture in the Connectors(Green powder)There still is a lot though.He used paint thinner to reduce it.
SO,came home,plugged the battery in my tank after 4 hrs of charging,& noticed that the tank was working for a sec,then it stopped.While experimenting,i realized that current is not being passed from battery to tank properly.
There seems to be a loose connection.
One weird thing that happened while testing ,was that whenever i was trying to rectify the loose connection,the lights on the tank gave a constant glow.Never seen this happening before,
Normally when the battery is low,the lights just blink & flash(turn on & off in rythm)

So,i was lucky enough to find that RC Bazaar sells tamiya connector wires.Its in Bangalore,ordered two wires each with Male & Female connectors.should arrive in Mumbai in a couple of days.

Once my exam period gets over,i will focus on changing the connectors and then trying again.
Will have to learn a little bit soldering before doing it.

This is turning into one major project now..
Got to save all these findings & your Advice so that other RC fans can also benefit.