Originally Posted by
tankme
What bugs me about my LiPo batteries is all the information/disinformation out there about them. I am fully aware they can catch fire if handled improperly. I bought a set of them for my 1/6th scale tanks last year. What concerns me is that they are not that old and have only been charged a few times, but are "puffing up". One seems to be more puffed than the other.
This is them:
https://hobbyking.com/en_us/zippy-fl...-30c-xt90.html
They seem to run fine and I can't tell if there is any capacity loss since it seemed to puff up after the first charge. I charged them both on a iMAX B6 RC Lipo NiMh NiCD Battery Balance Charger at what I thought was low amps (1A). The balance plug was used during charging. I read that the puffing isn't a good thing. They are 6S as the tanks were originally spec'd to run on 24V. I would prefer not to start my 1/6th scale KV-2 on fire by using a battery at risk, but I also don't want to go back to 12V lead acid batteries which is what was in it before. I was drawing so much current from the smaller 12V 7AH batteries that the cases were warped and bulged from the heat.
Obviously you are not an amateur.
A "packet" lipo will puff when discharged heavily.
This is not usually a bad thing, if they swell where the covers are overly tight then swapping out the cell might be wise. You don't have to write off the whole pack for one poor cell and using a balance charger is a good idea.
You have to switch the charger into balance mode, just plugging in the lead does not balance the cells.
As those packs represent a significant investment I'd revisit the balance mode again.
Dump the packs to 3.3v/cell
Put them on the charger and select the LiPo charge option.
When you see the usual select V and A press the + or - key without the flashing Volts and Amps and it will cycle through several LiPo charging options
usually the first is the balance option.
I'd do a full balance and dump then with a slight load, a lap around the block with some pause should do it and then recharge with balance. Maybe shoot some slow moving doggies on the way.
A balance charge will often take 2 or 3 times as long, don't sweat it but just ask you doggy to keep an eye on it.
If you don't have a doggie don't trust your wife to do it, do it yourself and set the timer on you iPhone for about 15 minutes and you'll see the changes. On most chargers pressing the up and down will give a per cell reading if you'd like to see it.
A stop watch is your friend, without definitive data our perceptions will distort facts.
Get facts and time everything, there is no other way of empirical judgement.
To be honest I would have gone for a LiFePo4 battery solution.
The weapon of choice for Solar and wind systems and far more stable than even Pb packs
https://www.aliexpress.com/item/Original-32650-3-2V-5500mah-rechargeable-Li-ion-battery-32650-LiFePO4-5C-discharge-battery-for-Backup/32868030150.html? See if this works.
I use a similar cell set for my motorcycle battery and the battery in my 18hp Ride on Mower so there is no doubt they can deliver enough current but I would make a series/parallel pack and you'll never buy a battery again.
Don't worry too much about the swelling, but never charge your packs whilst they in the vehicle.
Hope this helps and please let me know how you go.
Happy Doggy Stalking.
Bill