Lipo Use and Care Questions

[terrabit]

Hi!

Like many of us, I've invested heavily in my batteries and I want them to last. But I also don't want to leave anything on the table (capacity or flight time) - I want to maximize the duty cycle without reducing service life.

So ... how far down can I SAFELY discharge them? (FP says 3v. I'm averaging 3.7v on the TP1010c at recharge. Haven't come near 3v per cell.) How hot should they be? (I'm seeing up to 110 degrees F on the 10S.) How cool do they need to be before recharging. (First couple are hitting the charger at around 80 degrees F.) Is it better to charge100%, 95%, Fast Charge (90%) or does that matter at all? What are some of the things you guys do to care for your batteries?

I have FP EVO 25 10S 3700's and 3S 2170's so far. I'm charging with 2 x TP1010C/TP210V combos. I've been attempting to stick to 80/20 based on mAh and charge cool to 95%.

Muchos gracias!!!

[Pinecone]

1) The single biggest thing you can do to get longer life out of your pack is to not overdischarge the packs. According to Kokam, a maximum of 80% depth of discharge can increae pack cycle life "several fold." Minimum voltages are somewhat of a gues, so best is to adjust your flight times to put no more than 80% back into your packs.

2) For most chargers, all those various charging schemes are just terminating the charge beofer the max you can stuff into the pack. The last 10% of the charge take a long time. So to reduce the charging time you just cut it off. Of course you need to modify your timing algorithm to take ito account the lower charge level. So if you Fast Charge (90%) you should only put 70% back into a pack, since the other 10% isn't charged. If you use a 95% charge level, you shouldn't put back more than 75%.

Most references state that charging at not more than 1C charge rate is best, although some makers claim that charing up to 2C or even 3C will not shorten teh pack life of high quality high discharge rate packs. Personally Ihave extra time, so I charge at not more than 1.4C.

[terrabit]

Thank you much! I believe I am in compliance. What about temperature at recharge? Is it critical for the batteries to be "cool", or absolute ambient temperature before recharging?

[Pinecone]

They should be cool. Best would be room temp, but I have charged them once they came down to about 90 using a IR thermometer.

[terrabit]

Thank you!