Lipo puffed up question/storage mode question
 

Hello guys, I am new to the forum and a RC newbie. My name is Dani.

Ive had my traxxas e-revo brushless for 3 years now but i havent used it for 2 years. I decided to play with it again, I bought 2 ZOP power 2s 8000mah lipos (pretty cheap, and I hope theyre not the problem) and Ive used my rc for 3 times now. 2 questions:
1- I noticed that one of the batteries puffed up and now im scared to charge it, because ive heard of lipos blowing up. it didnt puff up like crazy, but you can tell it puffed up. I can provide pics. Should I stop using this battery or discard or is it okay?

2- my second question is about the storage mode. I am a imax b6ac charger, and i read online that I should put the lipos in storage mode if I will not be using them. but storage mode is so slow on my charger, its max of 1A, so it takes sooo long to charge on storage mode after Im done playing with the car. Can I charge the lipos on balance mode on 5A until it reaches 7.6V and stop there? or do I have to do it on storage mode?

I hope someone can help me answer these questions.

Thank you,
Dani

1. some small puffing is usually ok, but without touching it, hard to tell, maybe pics would help

2. I prefer to charge at a very low rate if I have to recharge to attain 7.4-7.6V, you can charge them at a higher rate if you like for storage, just try to be in the 7.4-7.6V area, even 7.8 is probably OK

Question: How low is your battery voltage when you begin charging? Usually I have to discharge batteries to get to storage voltage. I am a believer that running lipos in the car below storage voltage is a cause of puffing. That's a long discussion, but it may be that you are puffing lipos due to high current load at low voltage.

1. Get lipo bag if you're concerned. I've had so many puffed batteries (some severe) but never had explosions (lucky I guess). You can continue to use it no problem based on your description.
2. Storage mode is always slow for most chargers. It doesn't go above 1A. If you plan to use the battery again next day, you don't need storage mode. But like Adamska said, if you overuse the battery, the voltage will be very low and then you will end up losing the battery w/o properly keeping the battery. Just check the voltage after usage. If it's too low, you'd better bring it up close to 7.4V. If it's higher than that and you will use it in a few days again, leave it alone. If you won't use it for more than a week, keep it at storage mode. Just leave it overnight.

It should be fine to use balance mode to get close to storage voltage to save time, but I'd suggest you switch back to storage mode as a final pass.

What is your low-voltage cutoff set to on your ESC? The lower you go on volts the more prone to puffing the pack will be.
If you are going to use the pack within a week or so then storage mode is not critical, and if you do have the discipline to watch the pack on the charger then yes, using balance mode and pulling it off at the right voltage will work fine. On most chargers, if you start a storage cycle with a pack that is discharged it will be quicker than starting with a charged pack since chargers typically always have much higher charge rates than their discharge rate.

So is storage charge quicker than discharge charge? I normally put all batteries in storage mode but it takes like a solid 2 hours @ 1.00amp rate.

I'd expect them to have similar discharge rates. It probably depends on the charger though.

If the battery needs to be discharged to reach storage mode then no, it won't be any quicker in either setting. Storage mode just tells the charger to put the cells at storage voltage, if the cells are over that voltage it will discharge, and if they are below it will charge.
I spend a lot of time flying RC planes, those drain a battery in 5 minutes or less so we take stacks of packs with us. If I'm not going to be flying for a while I'll put them all in storage mode and cycle through them in my office. If they are all drained, I can get through 15-20 packs on a dual charger during the day no problem. If they are charged and need to discharge there's no way I can get through the pile of them in a day.