Not sure if my lipos are puffing up. I live in Las Vegas so ik that the heat can really damage the batteries. But not sure if this is the cause. Not sure if the batteries are even useable. Are they?
I put velcro on two sides of the battery as well as electrical tape but don’t mind that.
That definitely looks a little puffy, maybe a capacity check will help assess the severity of the situation?
Try balance charging them to full, then discharging them about halfway and check all your individual cell voltages to see if any are significantly out (More than 50mv or so). That will give you some indication of whether you have any cells that are significantly lower in capacity than others.
they’re puffed. Toss them out.
If they are 6s then throw them out and I can send you some new ones for cheap xD
That is puffy, for sure. Heat is a problem but it’s also the way you treat your cells. Full charging and leaving them sit for a day or two CAN even be enough to puff new cells. Lipos are more finicky in that it’s easier to damage them, but they also have less points of failure and they sag way less than li-ion. So it’s a mixed bag. Another thing that can kill lipos is high discharging. They will say 20c or higher, but never go over 10c if you want them to last and not puff quickly.
May not need to chuck the whole thing. You can find, remove and even replace the bad cell. Some consider it pretty dodgy but I like to get the most out of them. Done it before and will do it again.
I think it’s also a case of draining a cell down below 3.6v. lipo alarms are the best way to prevent that. But they aren’t very accurate. You might see 22v total for a 6s pack but one cell has gone to 2.8 or less got hot and puffy and the others are sitting fat dumb and happy at 3.8v (or whatever it adds up to).
I checked internal resistance. All seem fine. The capacity of the battery hasn’t gone down at all. Do you guys think I should still use them?
Here is a photo of my internal resistance
They can prob still be used for a few cycles (mabye untill you get new Batts? But don’t try to stretch it.), puffed lipos are not nescirally dangerous. If only lipos never puffed.
You should’ve saw my lipo’s… I drained them to 3v every day…
Just use an alarm and keep a close eye on it. If IR is that low they are doing well.
Just a slight correction here. Lipos typically have the same internal chemistry as our 18650’s.
The only difference is that 18650’s will puff (just as easily) but will not get larger and instead build up pressure internally. They both are susceptible to the same amount of damage from the same conditions, the only difference is that lipos will have an indication that they have degraded.
So is the upper cycle limit of a cell referring to the amount of cycles before it enters thermal runaway from increased internal resistance?
Or does it eventually just turn into a paperweight
The upper limit only refers to the capacity remaining. So a manufacturer will spec 500 cycles, meaning that after 500 cycles the cell will only be able to output 80% of it’s initial amp hour rating. I think 80 is the standard.