2000mAh added to a 2200mAh lipo

[Don223]

Hi guys,
I'm finding some good info here about lipo batteries. I have a 2200mAh 3S 15c battery that has been charged 6 times. I'm doing light hovering on my mini Titan in the basement. Four of the charges added around 1800mAh and two charges added 2000mAh. I didn't hear the timer and lost track of time. I stopped flying when the ESC dropped the headspeed indicating the voltage reached 2.9v per cell. When I put it on the Cell Pro it said the lowest cell was 3.3v

Did I greatly reduce the life of this pack?

I just charged it again, flew for 5 minutes, and put it on my Cell Pro charger. It said it was at 49% and then it added 1047mAh.

What are the signs that a battery is near its end? Won't take the full mAh amount anymore?

Thanks Guys!
Don

[WayneBrown]

I'd say you were getting your money's worth.
Cut your flight times a bit shorter and you should be fine. 5 min for 1047 is actually pretty good efficiency.

[Efliernz]

you will find if you overdrive them that they do not hold their voltage well. They also won't take full charge.


I stopped flying when the ESC dropped the headspeed indicating the voltage reached 2.9v per cell. When I put it on the Cell Pro it said the lowest cell was 3.3v


The cell voltage leaps up in a matter of seconds after you stop drawing current. Either stop flying earlier to prevent useage over 80% or use a low-voltage alarm. An alarm will warn you if a cell is dieing early. A stopwatch won't!!!

I set my alarm limit to 3.33 per cell on my 3-4S and 5-7S alarms. When the lights come on, it is usually around 78-82%. It will vary depending on temperature of the day, but it is better than a 90% drain. That will damage your packs long-term.

[Pinecone]

The basic answer is yes, you shortened the life of the pack. How much? Probably not that much, but don't keep doing it.

Timer PLUS lipo alarm is the way to go.

[Don223]

I've gone thru 5 more charge cycles today with my timer set to 6 minutes. Charging from here adds around 1200mAh. One thing I've notived is that the last 2 charges finished balancing at 4.18v per cell where all previous charges gave 4.20v per cell.

Is this normal?

[bullaculla]

I have a few evo6s 4900 packs for my trex600 and today when my Lipo alarm (good stuff from Efliernz) went off I landed. Much later in the evening I charged it and the pack read 3.5 volts per cell before charging, but after 100% charge, it took back in 4500mah! thats 90%! I gotta use a timer too, but i'm still a noob and i'd like to keep the heli in the air as long as possible to get more stick time.

[WillJames]

Shortening of life from what I have seen and been told happens a lot worse at high current draws of the pack. In other words, if you are flying a super HOT setup that draws mega amps, then discharging to 90%+ can shorten the life of the pack more quickly than if you are running a setup that is low amp draw and easy on your packs.

Not sure if this is how it works out scientifically, but is is how it seems to work at the field from what I have seen. Others have commented on this as well.

[kgfly]

bullaculla,

Those are expensive batteries which you probably want to work for more than 30-50 cycles. If you don't want to time your flights, try turning your alarm threshold up by 0.1V per cell. That will give you a better safety margin.

[bullaculla]

Yeah, I turned it up to go off at between 20 and 21v. It was right at 20v.
Thanks.

I wasn't doing anything crazy. just hovering and a few loops and rolls. So it wasn't hot, just drained.