2 cells won't charge....

[Engan01]

Hi!

I have some problems with my 3s lipo batteries. I have four and three of them won't charge properly.
I don't know if it's the batteries itself or the charger that is the main problem.

When the battery is fully charged (one cell reach 4,2v) the other two cells are usually between 3,8-3,9v each.

Please look at pictures for reference.

Any ides what's wrong here?

Thanx!

***EDIT***
Worth to mention is that I usually have all my lipos fully charged, even over longer period of times (about a week).
Is it possibly this is the cause of these fault readings? anything I can do about it?

From what I have read this is not the correct way of storing the lipo if Im not using them for a few days....

 

[thongbong]

It might be your balancing lead adapter, if its 3 out of 4 batteries showing the same cells depleted. Make sure the connections are tight and there aren't any cold solder joints. Have you tried discharging your lipos for storage down to 3.8V/cell?

Leaving a lipo fully charged for a week isn't the best idea, 2 days max is what I go by. But I can't see why that would kill off 2 cells.

 

[ElGuano]

0.15v difference between cells is already a large discrepancy, 0.31v is huge

If it's happening to 3 out of 4 of your batteries, the charger probably has something to do with it, either reading wrong or balancing wrong. Can you plug your balance leads into the charger without the use of the breakout board? Or better yet, can you double-check the actual voltages of the cells using a lipo checker/low voltage buzzer or a multimeter?

I've kept my batteries fully charged for over a week before. It's not best practice, and will shorten the overall life of the pack, but shouldn't result in these huge swings in per-cell voltage.

 

[Engan01]

0.15v difference between cells is already a large discrepancy, 0.31v is huge

If it's happening to 3 out of 4 of your batteries, the charger probably has something to do with it, either reading wrong or balancing wrong. Can you plug your balance leads into the charger without the use of the breakout board? Or better yet, can you double-check the actual voltages of the cells using a lipo checker/low voltage buzzer or a multimeter?

I've kept my batteries fully charged for over a week before. It's not best practice, and will shorten the overall life of the pack, but shouldn't result in these huge swings in per-cell voltage.

Im afraid I can't connect the balance plug of the battery directly into the charger. I have also tried with two different balance boards, but still gets the same results.
I have checked my batteries with both a lipo checker and my low voltage buzzer. Still the same values..... :/

 

[ElGuano]

How do you typically run your batteries? What do you fly them to and how do you handle storage and charging?

It's sounding like your charger may be faulty, but just making sure you're not doing anything strange during use...