Hi All,

Need help understanding how to restore a lipo battery. I have accucell 6 which shows that the battery is 2S on the confirmation screen but when I select 2S battery it shows charged as it reaches 7.4 volts immidiately now when I select 3S 11.1 volt it shows as 2S and if I start charging it shows 2 cells as 3.6 volt and one cell as 1.26 volts and after 2 mins it gives low cell voltage error and stops charging  any solutions?

HellyFlyer

Use "trickle" charging to try to revive it.  What I do is to charge it as something like 0.1A for some time (basically the lowest your charger supports, but not more than like 0.3A to be safe, which is a self imposed rule, not certain about absolute limits and not particularly for this mAH) and watch the lipo if it is getting heated up. Unless something was really wrong with it, it should slowly build up the voltage.  Stop charging like this when you have enough voltage for the cell count to be correctly detected.  After that, I charge at 0.5C again watching the temperature.  I will also be careful when I use that cell the first time after reviving.

Trickle charging is usually defined as charging at 10% (some say 5% or even lower) of the rating of the pack.

Is there a seperate mode in this charger called tickle charge or by that you mean just bring down the Amp to 0.1 and try charging. If that's what you mean then I tried doing that and that's when I got the error message as "low cell voltage" and it stopped charging

Hellyflyer

On the chargers I tried with, I just brought the charging rate to 0.1A; and they did not complain (Align, Turnigy, IMAX, MRC Brain). 

See if you can bypass this by NOT connecting the balance connector.  As you are trickle charging anyways, there is no additional risk, but do watch the temperature as suggested earlier.

Ok thanks willl try that

Thanks Anwar it worked without the balance cable and now my battery is showing all cells above 4.1 V

Cool

Be careful the first time you use it, try to discharge it only like 50% (I guess it is just a mental way of saying sorry, more than any technical reason )

Also, time your flights so that you can avoid getting into this.

BTW, Why 4.1 ?  Is it more like 4.19 ?

Yeah I stopped charging it ans went off to bed when it reached over 4.1 volts ...LOL so will complete it today once I reach home from work.

Hi,

I had 3s 1450mah  Tx  battery, and one of the cell was dead and it did not show up in the charger and showed only 2 cells. After going through many forums i charged one cell alone , by cutting the wire and connecting it to a Nokia 6v 600 mah charger. Even after five hours it was showing 0.07 v not more than that. After a day it would not come back to life.

So  cut and threw away that 1 particular cell, resoldered the others and now i have 2s 1450 mah lipoly pack.

Between, have i done something wrong in charging that 1s. Can somebody let us know one more time clearly what should be the charging voltage and max amp for one cell..while trickle charging..
(weekend is spent going through forums to get answers...have not gone to the field for 2 weeks..getting mad  )

Regards,
Ramkumar G

If you had a good charger, you should have tried trickle charging, like above.  I have had about 70% success on this so far (others give me their "misbehaving" lipos, so I get to do this often), so it could be that your pack belongs to the other 30% (totally dead).

For trickle charging of a 1450mAH cell, I believe you will need something like 5v at 100mA. Requesting comments from people who are closer to these.

Quote from: ramjin82 on March 21, 2010, 03:37:25 PM
After going through many forums i charged one cell alone , by cutting the wire and connecting it to a Nokia 6v 600 mah charger.

I would'nt experiment with the charging of lipos...

hi guys,
I have a few 3s batts.................so if one goes down on one cell I leave it for a few days and it generaly 'self ballances' from the other 2 cells, if not then its the bin job.
once a lipo cell dies or discharges quickly its a sign of 'soon be gone'
regards
don