acdii

I bought a new Life pack for an RX, 2400 mah. When I hooked it to the charger, first thing I looked at was cell voltage, one cell was ~2 volts the other 3.3, I balance charged it and the timer kicked off before the charge finished. Not a good sign. I connected the pack to my RX and did some setup with my plane I am building and the voltage seemed OK. Yesterday I took the pack and checked voltage and the cell is at 2.5 volts. Sounds like a bad cell. Am I right? IIRC once these cells go below a certain voltage, they dont recover. Since this will be in a plane with at least $1000 sunk into it, I am taking it back, but just want to confirm my thoughts too.

aeajr

My Feedback: (2)

I would agree with you, but would question how the cells got that far out of sync. Is it the pack or are you not balancing the cells during or after charging?

You say you are using a balance charger but is the balancing working? Did you have it set for LIFE or LiPo?

Are your other packs coming off the charger in balance? I would check.

flyinwalenda

My Feedback: (5)

As mentioned, if indeed it is that far out of balance out of the box then there is something wrong with the pack.
However, you need to provide more info as to what kind of charger , is it set-up for LiFe voltage, are you using the balance charge mode, ?
When a pack is that far out the charger (when set-up correctly) takes a VERY long time to complete the charge and balance cycle as it tries to drop the one cell voltage and bring the other up.
DO you have a hand-held LiXx checker that will show pack and cell voltages when plugged to the pack?

acdii

I returned the pack. It had a bad cell out of the box, had nothing to do with my charger. I put my low battery alarm on it when I pulled it out and it read below 1 volt on one cell and beeped like mad. I tried a balance charge and it charged up and held a charge for a while, but after a few days was back to under 1 volt. they accepted the return after checking it out themselves, but didn't have another one of the same size.

I have several LIFE packs and have no issues with them, also several Lipo without issues, have a decent charger, Thunder 650 that does a pretty good job keeping all my batteries in peak condition. I even was able to recover some 12V Nicads for my starter with it. It just seemed unusual to have one cell that low right off the shelf, might have been sitting too long in the package.

aeajr

My Feedback: (2)

Well good for you for checking. Not everyone does.