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Snoopy
01-28-2017, 10:02 AM
Hello, is it a good idea to recharge LIPO battery every time after use? How often should we do it?

jwatte
01-28-2017, 08:50 PM
A LiPo should not be discharged below 3.2V per cell.
It also has a slow self-discharge, so if you're not going to use it for many months, giving it a charge so you know it won't go below 3.2V is helpful.
Charging all the way to full (4.2V / cell and only a small current remaining) will wear the oxide in the cell, though, and thus "consume life" of the cell. Charging it up to a lower voltage will damage it less.

Thus, a good idea might be to charge to 3.9V or 4.0V per cell, use a trickle charge like 0.2C, and cut off the charging once it gets there. This will pad against self-loss, and also make sure that the battery is at least 70% or so ready to be used if you need it immediately, yet not wear it out too much. (This is what I generally do.)

Note that you'll need to use a charger that lets you set the voltage. Personally, I use a high quality benchtop power supply, and charge the full stack (without worrying about balance.) I set the current limit to something small, and then keep an eye on it, and when the battery draws less than the current limit, at the target voltage, I call it done.
Once I want to charge it full, I use a balance charger to make sure the cells are in "harmony," but you really don't need to do that every time you charge.

Zenta
01-29-2017, 03:31 AM
Some chargers have an option called "Storage charge". About 50% capacity is ideal if you are not going to use it immediately.

Snoopy
01-29-2017, 08:44 AM
Thanks jwatte and Zenta. I bought a SKYRC iMax B6AC version 2 AC/DC Dual Power Professional Balance Charger/Discharger. Have not used it before. Is there a step-by-step guide on how to do what you suggested using this device?

Zenta
01-30-2017, 02:40 AM
I did a fast search on you charger and found that it has the option for "Storage charge" :

"Store" setting will charge the battery at approximately a 50% charge for long term storage. This prolongs the useful life of the battery pack.
I recommend reading the manual.

Snoopy
01-30-2017, 03:59 PM
Some chargers have an option called "Storage charge". About 50% capacity is ideal if you are not going to use it immediately.

Thanks. Assuming that I do a 50% storage charge now and when I need to use the battery again, should I recharge it more?

jwatte
01-30-2017, 06:30 PM
Yes, that would be optimal.
If you know that you will use the battery within a week or two, though, just charge it full right away.

TXBDan
11-14-2017, 01:29 PM
I've had a couple LiPo packs sitting for a couple years... in terms of safety, what should I do with them? attempt to charge? dispose somehow?

jwatte
11-14-2017, 08:12 PM
Put a voltage meter to them. If the voltage is 3.0 volts per cell or better, you should be able to charge them and use them. If it's much less than that, it's probably better to throw them out.