Wow, guys my 3 cell Parkzone Lipo is revived... Thanks to Anwar and Sujju.
My clubmates were insisting on binning it...

A lesson for them and can you imagine the feelings of them and other electric heli pilots at our field who are burning pound notes on 5 and 6 cells and have to throw them away.... OOOOOH that hurts..  and they could have revived them all.
Well once again, thanks lads.
I am proud to be a part of this forum.

I spent whole evening last Saturday tinkering with the charger to get it to work somehow, but it just would not switch on.
Tried without balance leads, with them, on 0.5 Amps, 1 amp, lipo setting, Nimh selection... NO GOOD.
At last by chance I tried connecting WITHOUT CONNECTING balance leads and tried various combinations again.
The charger initially did not like the name nimh but some how nicd tiptoed the trip mechanism (I know it is electronic... captain pls do not quote me on this;) I need to add some masala for the recipe....

Will fly with it at the weekend and see how it performs...
Deepak

deepak..that's great to hear...i would prefer that you go easy on the lipo for about 3 cycles and then treat them as normal... and pls keep posted on how they are behaving... would love to hear it... my "tinkered" lipos are like new and have now around 9 cycles.. going tomorrow to the field with my protos and will give the lipos a punch and will see the outcome..

Another tip, Store your lipos at lipo store voltage if you know you are not using them within 10 days. I already see a slight puff in my lipos for storing them fully charged like 25 days.

Quote from: vinay on April 16, 2010, 07:25:27 AM
Another tip, Store your lipos at lipo store voltage if you know you are not using them within 10 days.

How do you discharge them to the "store" voltage?

If you have a modern charger, they will have a store charge option in it. Mine stores it at 3.80 volts. You can also moniter the voltage as it charges and stop it there if your charger does not support it.

Another tip, when you come back from the flying field. Charge your lipo to store voltage until the next time you goto the field. this way you can prevent the puffing from your side atleast.

Like if you go fly on sundays, charge the lipos to 3.8 on sundays after you come back, and charge them completely the next saturday.

careful when you are charging lipo batteries, by the grace of god i just escaped from putting my house into fire.i put the charger on with alipo 22.2 volt  without a balancer and went for a movie, only my dog was inside,coming back i saw black smoke only, and my puppy was barking.lucklly i didnt connect with electricity so the charger was little away from the wooden furniture, i connect with car battery any charger and the 12v car burne4d and ashes left, two days to clear the smoke and smel

Oh my god! Everything is fine right?
Scary!!

really scary.That looks bad.Now,I am getting doubts about buying a LiPO.

Quote from: prakkat on July 06, 2010, 05:16:06 PM
and went for a movie,

Thats where the issue is. I dont leave any batteries unattended on charge even if its NiMH. Atleast we can take some corrective action.

When one has many batteries to charge, it is not practical to stay around the battery the whole time.  If a battery acts up, it can still be problematic if you are away in another room, and the fire has spread.  Simple precautions like below can greatly reduce the risk. 

1.  Charge away from carpets, cloths, curtains etc.

2.  Use a lipo charging pouch/bag that is fire resistent.  They were expensive before, but have become affordable now. They are good for carrying lipos around also. 

If a lipo was dropped or was impacted in a crash, it is pretty much a must that you wait around for 10s of minutes when you put it back on charge the first time, periodically testing the temperature.

I have had my own share of an accident in the initial days, when I got a new charger.  Even though I remember setting the amps to 0.8 for an 800mAH lipo, it had gone back to the default of 3A when I started charging.  The battery and foamie next to it got fire, but was caught in time to douse the flames.  The biggest mistake with lipos is NOT to limit the charging current to 1C, and NOT choosing the right number of cells (target voltage).  One cannot do much about equipment malfunction, but the other cases can be prevented with care.

Used with some respect, they are very very safe, and have made Rc accessible to so many people who would not be able to enjoy this hobby otherwise.  No need to worry about them unnecessarily, just take good care of them (which also includes disposing them off if the situation warrants!).

I have heard different opinions on what type and amount of "puffing" is acceptable. Soft seems  to be considered alright, but 
to what extent?

Any one knows the reason/s for puffing when stored in a charged state? Doesn't seem to affect other batteries, particularly in laptops.

Not sure if there is an exact answer to this.  We can only go by personal experiences.  I have not had issues of safety with puffed lipos (I would say "fairly" puffed), but the flight times do not last as long as before.  Not a huge loss, I would put around 20% in most cases initially, and then they gradually lose more (but then all lipos die down gradually).

If you are referring to why half-charge is recommended for long term storage, it would be cell chemistry differences.  I have not seen any of my lipos puff from storage alone (I have had them fully charged for many many months by mistake, like 7 months or so in some cases). But there must be a reason for the recommendation for long term storage at half charge, and slight puffing may be one of the consequences otherwise.

ALL my batteries have puffed up with hardly any use. Maybe it's just the quality (or lack of).

I have a DVR from a company called archos.My first battery got puffed like crazy.(It was a Li ion).It gave a life of 3minutes against 2hours when watching a movie. Even my brother said that it was dur to overcharging.Now,my new battery is also acting like taht but gives upto 1 and a half hours of life.It won't explode in flames right?I keep it on to record TV shows I miss.

Mine puffed slightly coz I stored them fully charged for 3 to 4 months. Batts were turnigy Flightmax and rhino. Not only puffed now they store 10 to 15% less charge then before. So if you plan to use ur battery after few weeks then better put them in store mode.

Quote from: iamahuman on July 07, 2010, 02:02:01 PM
I have a DVR from a company called archos.

Slightly off-topic.... the owner of the company which makes Archos is Sam from Bangalore, who is an avid RC enthusiast

What!!!I got mine from Germany.Actually,two.One for my bro and one for me.

Now we have all seen videos of LiPo's blowing up.. Now how about one that refuses to blow up..

Quote from: vinay on July 07, 2010, 02:15:06 PM
Mine puffed slightly coz I stored them fully charged for 3 to 4 months. Batts were turnigy Flightmax and rhino. Not only puffed now they store 10 to 15% less charge then before. So if you plan to use ur battery after few weeks then better put them in store mode.

PLEASE DO NOT STORE YOUR BATTERIES FULLY CHARGED. The storing voltage should be around 3.2V per cell.
Nowadays all chargers have an option of "Lipo Storage" in them. so when you select that option, input your battery specs, the charger will automatically balance your battery and set the voltage to the storage voltage, SAFE VOLTAGE, and then you can store it at room temperature...

I suggest all the newbies to ue a Lipo Sack. It prevents the fire... You will have to then use wire extenders for the balance plugs and the discharge plug so that you can use the Lipo Sack.
Have a look at this:

Quote from: anam_funny on July 07, 2010, 10:39:29 PM
[PLEASE DO NOT STORE YOUR BATTERIES FULLY CHARGED. The storing voltage should be around 3.2V per cell.

The storage voltage is around 3.8 to 3.85 volts per cell. Making the cells to go below 3.3 to 3.4V is a bad thing that can happen to a lipo.

Yes... Sorry... That is the low voltage....

do lipo safe bags really work?

Some Useful information on Lipos...

https://sites.google.com/site/tjinguytech/charging-how-tos