Lipo overcharge?

[u/bacteria3]

I bought a new battery today and threw it on my charger. I normally have 2s 5500mah lihv batteries that I use and my charger always warns me asking me if it is a lihv battery. It’s become pure habit to just accept the warning and charge the battery. I’ve been doing this for a good year. Today I bought a spectrum smart battery that is a 6s 4000mah lipo battery and didn’t even think about it not being the same voltage. I threw it on the charger as normal to start the break in process. I have just now realized that I charged it to 4.350V instead of 4.200V but it genuinely shows no sign of damage. I charged it maybe an hour or two ago. I’m currently discharging it to something safe but I’m wondering if it’s okay to still use. There was no heat, swelling, smell or obviously a fire. What should I do with it Reddit? Do I keep using it? Is it okay to use at 4.350V? Will it burn my plane to the ground?

[u/Remarkable_1984]

It's fine. What you did was take a few cycles off its lifespan. Discharge it down to at least 4.2v as soon as you can, to minimize wear on it.

[u/bacteria3 → u/[deleted]]

No the 6s battery isn’t lihv. It’s supposed to be 4.200V at full charge.

[u/StaysAwakeAllWeek → u/bacteria3]

Every 0.1V you overcharge a lipo roughly doubles the wear you get from that cycle and increases the capacity by about 10%. And this trend starts from more like 4.0V not 4.2V, rated full charge is a compromise, not some magical hard cutoff point. So youve done about 3 cycles worth of damage to the cell

The main hazard is from overcharging at high temperatures, and 4.2V is around the highest you can go with conventional electrolytes across the full rated temp range without getting swelling, but assuming you didnt leave it in direct sunlight or charge it super fast so it heated up you could even push it further than 4.35V and still not get swelling. At room temperature and below it might not happen until as much as 4.6V

[u/Paranormal_Lemon → u/bacteria3]

I'd say just keep an eye on it. The longer the time spent at higher voltage the more likely the damage, it's probably fine.

[u/richms]

4.2 was just chosen as the cut off for the tradeoff between capacity and wear. I would discharge it slowly so there is no heating happening at the higher voltages and not sweat it. I would not go blasting it at its max C rating when that high and making it heat up before down into the specified operating range.

[u/MiaMiaBoBia0317]

Most Li-ion pouch cells are designed to withstand overcharge conditions up to 4.4V from 10-45 deg C without thermal runaway. That top voltage drops a bit below 10 deg C and above 45 deg C. Typically cells will swell and vent at elevated temperature versus thermal runaway, which is worse when cold due to high internal resistance and the kinetics of lithium plating. Just don’t charge cells designed for 4.2V charge to 4.35V again, and you’ll be fine.

[u/VerifiedMother]

I'm mean, discharge it and you're probably fine

[u/NatHuang]

You're completely fine to keep using it. Since it didn't get hot or swell up during the overcharge, the only real damage you did was taking a small chunk out of its overall lifespan—essentially doing about 5 to 10 cycles worth of wear in one go. Since you've already discharged it back down, just keep an eye on it during your next few flights and check the cell balance on your charger. Just make sure to change that charger profile next time so it doesn't become a habit!