quick help on battery break in please

[8000ft]

So I am breaking in a new Turnigy 5000mAh, 40c, 2S pack.
Am I on the right track?

Question: my charger does not have a select-able discharge cut off point, so I'm watching the voltage reading. Is that right?

I'm starting with 4.2 volts per cell with a max discharge end point of 3.2 volts per cell.
I want to discharge the pack to 60% so I think the I will manually stop the discharge at 3.8 volts.

Discharging at 1C = (5Amp)

Another way that I am estimating is that this pack should take 1 hour to discharge so at about 20 minutes it should be at 60%ish.

[8000ft]

Ok I'm a half hour in and reading 4.05

[8000ft]

45 minutes at 3.94v

[Chiphead]

I am not aware of breaking in Lipo packs. I am aware of breaking in NiMH, but I do not believe it to be necessary for Lipo.

I charge my Lipos to 4.15 and set the Low Voltage Cutoff right about 3.2-3.4 (depends on the ESC). I store my Lipos at 3.85. Since adhering to this practice, I've had Lipos last years and dozens of cycles.

[8000ft]

3.85 a 90 minutes.

I will start a recharge now.

[8000ft]

Judging by the time it took to get to 50% it looks like my charger was discharging around 1.5A not 5A like I had expected.

[8000ft]

I think that I will try to build a light bulb discharger with a bunch of 12V bulbs and be able to select how many I put in series to adjust the Amp draw up to 10C.

10C on a 5000mAh pack would be 600W of 12V bulbs. (12x600=5000)


OOPS! I need to wire in parallel NOT series.

[8000ft]

WOW my math is way off. I will recalculate for 2S and 3S packs.

[FloridaCrawler]

You dont need to do this. I would advise against a lightbulb dis-charger.

[Eric0424]

There's no need to breaking-in a LiPo, you're just wasting charge/discharge cycles. The only brands of batteries I see recommending break-in are of questionable quality and it's just to help them reject warranty claims.

[RadioFlyer]

Originally Posted by FloridaCrawler

You dont need to do this. I would advise against a lightbulb dis-charger.

+1 Too easy to forget it and kill your pack. If you're dead set on it at least get a cheap low-voltage alarm so that it will sound off when it reaches the cut-off voltage.

That said, I have a lightbulb dis-charger that I built twentysome years ago. It has 11 automotive 1156 bulbs soldered together in a circular pattern. At 7 volts it draws about 27 amps. I still use it to discharge my NiMh and NiCd batteries (yes I still have some! lol)



Sean

[8000ft]

My only reason for the discharger is that to reduce this 2s pack from full to storage takes 90 minutes and when I have 4 full batteries ( two 2s and two 3s) and at the end of the day if I haven't used them or a couple of them I would like to be able to quickly discharge them.

[Olle P]

Originally Posted by Chiphead

... Since adhering to this practice, I've had Lipos last years and dozens of cycles.

You have that bad result?
A LiPo is expected to last for hundreds of cycles, not dozens.

But then again, with cut-off set that high you won't use much of the available energy and therefore discard the battery too soon.
And if you only need to use each battery a few times a year then time will degrade the capacity more than your use of it.