LiPo - Cell Voltages

I would welcome opinions on following:
Turnigy 3S - LiPo 3,300 mAh had little use and stored at 3.85V per cell when not in regular use
and always balanced charged.
Despite several attempts at Balance Charging it records cell voltages of 4.20 , 4.13 & 4.20.
Decision to be made, bin job or use ?
Thanks
Colin.

Since you've charged it you might as well use it. After the flight check voltages again to see whether you're right to be worried.

4Pedalsfly wrote: I would welcome opinions on following:
Turnigy 3S - LiPo 3,300 mAh had little use and stored at 3.85V per cell when not in regular use
and always balanced charged.
Despite several attempts at Balance Charging it records cell voltages of 4.20 , 4.13 & 4.20.
Decision to be made, bin job or use ?
Thanks
Colin.

In addition to reduced cell voltage, you verify a cell has deteriorated by checking its internal resistance. Many modern chargers have this capability. A new cell should be ITRO 2/3 milli ohms and a cell will continue to work well up to 10 m/ohms. You will notice a significant performance drop > 20m/ohms

I can check your internal resistance Colin with my charger Colin.

If resistance is within reason keep using it and get as much use out of it as possible.

Thanks Kevin, I didn't know about internal resistance and measuring it. Wish I'd known before, I've just taken four LiPos to the tip!

I checked Colins lipo and cell 2 was at 12 meghom with voltage 1 volt down. Bin job like my two 6 cell lipos for the Beast.

PhilF51 wrote: I checked Colins lipo and cell 2 was at 12 meghom with voltage 1 volt down. Bin job like my two 6 cell lipos for the Beast.

12 Megohm is as near as dammit open circuit. Sometimes the balance wires fall out of their jst-xh connector pins and the repair is just to fit a new pin or connector.
The battery would have no voltage atall on the main connector if the cell was really open circuit!
I suspect there is nothing wrong with the LiPO except for a broken balance connector or one of the balance wires itself is broken.

in the case of the Beast Lipos John they had ballooned for some time, but squeezed as much life out of them as possible and I knew I had duffed them earlier for reasons I won't go into here. In Colin's case there was the voltage difference and mid cell high resistance. He had said it was no longer performing as expected.

I had to bite the bullet and buy two more 6 cell 60C Lipos. Tried the new one yesterday on the Beast bipe. Now it's a performer!

JRI, I think Phil has his Mohm and mohm mixed up.

MikeSeale wrote: JRI, I think Phil has his Mohm and mohm mixed up.

:lol: Yep! meant My Mum.