Battery charging problem

I have a battery problem… These are 2x LiPo Zippy 30c 3s in series (so 6s).

For charging I use:

And Imax b6

I seems that every time i charge it one of the cells reaches 4.20 and others decrease on every charge. So after 3-4 the lowest is on 3.98 and others are not much higher.

Please advise me wise senseis

Only thing I can think of is;

Check the LiPo balance plugs are inserted correctly into the harness. Check the 6s harness plug is inserted correctly in the charger. Or, maybe the wiring is incorrect in the harness thingy.

Do the packs charge perfectly on their own?


I would charge each pack individually, at 3s, to see if that resolves the issue. If so, it’s a problem with the series connection, balance leads or balance adaptor. If not it’s most likely an issue with the charger.

@dedinski how old are your batteries?

I will try your suggestions and report.

My batteries are 2 months old and I used them for a week.

I checked each battery on their own and after several hours (much more than I expected), they charged completely.

This is what they say for the harness on HKing: “Compatible with our Accucel chargers and TURNIGY, Flightmax or Rhino batteries.” My Imax is from ebay, maybe its not compatible?

Since the harness leads directly from the batteries, and the turned out allright I guess it must be the charger (or the harness), do you agree?