Lipo Issue Question

[lcc014]

I have a few GenAce 6s 1200mAh 40C batteries. They all exhibit a same symptom at about 20 flights. They all lost charges so fast. I just spooled up my heli and before talking off, ESC started to beeps. I could hear the head speed started to decrease.

I measured individual cells in these batteries. Most of them have 1 cell with much lower voltage. For example, 3.7V vs 4.01V. I did recharge one of them back to around 25.2V using iCharger 20B - Lipo Auto Balance Mode @ 1C. That took more than 2 hours to complete the charging. I always charge batteries at 1C and never over-discharge these batteries.

What is the reason for having losing chargers fast ? Do I get a bunch of low quality batteries or else ?

Is there any method to fix this issue ?

I have Nano-Tech battery too, it has not lost charge "fast" yet and it has the same number of flights as the GenAce batteries. Only complain about Nano-tech battery is "puff" early. Otherwise, it is good.

Thanks.

[pctomlin]

From what you described in the second paragraph your battery has a bad cell.

[lcc014]

Originally Posted by pctomlin

From what you described in the second paragraph your battery has a bad cell.

So, how to fix this bad cell, replace it with new cell or else ? This happens to more than 1 GenAce batteries. They all were brought around the same time.

Thanks.

[Slyster]

I would guess it must be a bad batch? tis very unusual for Gens Ace. I would say toss the packs and buy new ones.. or contact seller (if resonably recent purchase) for exchange.

Charger working fine with other 6s packs? (just to rule out charger issue)

[lcc014]

These packs have been used for about 20 flights, so exchange is impossible. Most likely, I need to toss them all out

Charger is "new", less than 3 months old. So, I think that I could rule out charger issue. I have no problem with Nano-tech and Voltz batteries using this same charger; only the GensAce batteries.

[kirby_]

Originally Posted by lcc014

These packs have been used for about 20 flights, so exchange is impossible. Most likely, I need to toss them all out

It's not impossible. A bunch of bad cells isn't expected after only twenty flights. Especially if it hasn't been very long. Contact the store who sold them to you and tell them what's going on and tell them you think the batteries are defective.

[lcc014]

Originally Posted by kirby_

It's not impossible. A bunch of bad cells isn't expected after only twenty flights. Especially if it hasn't been very long. Contact the store who sold them to you and tell them what's going on and tell them you think the batteries are defective.

20 flight counts are from 1 or 2 flight per week spreading over the whole summer of this year. So all the batteries were purchased early this year. I don't think the seller: HobbyPartz.com will do exchange .....

[wingsnwheels]

two things come to mind,
1) You run them too low (I usually go down to about 30-40% and they last for years)
2) You store them fully charged (even 24 hours is too long IMO !!)

[CrashNburn420]

Try some pulse packs. You can pick them up at helidirect which is right near you in Boston.

Are you leaving them fully charged all the time? Or over discharging them?

[lcc014]

Originally Posted by CrashNburn420

Try some pulse packs. You can pick them up at helidirect which is right near you in Boston.

Are you leaving them fully charged all the time? Or I've discharging them?

I leave them fully charged at all times. I had similar experience with Pulse 850mAh. That stopped me buying Pulse for a while....

[Slyster]

Never store charged over 24 hours. That's your issue. Always store at storage chage levels (charger has that setting) of around 3.8v/cell.

Lipo basics
https://www.helifreak.com/showthread.php?t=336421

[lcc014]

Originally Posted by Slyster

Never store charged over 24 hours. That's your issue. Always store at storage chage levels (charger has that setting) of around 3.8v/cell.

Lipo basics
https://www.helifreak.com/showthread.php?t=336421

Got it. I will change my Lipo usage habit.

Thanks.