Question of Balance

[Bad Raven]

I have lots of chargers.  6 used for daily LiPo recharges beside my computer so they can be watched. three more in garage for when working in there. One in model workshop room again for when in there.

Beng ultra careful of four new batteries, I checked their voltage/balance after first charge, and found first one then the others were all lower on Cell 3.  Verified on three other checkers, cell 3 lower, 4.17x against 4.20x.  All these were charged on my newest charger.

Next charge, I didn't use that charger, and on another they all charged much more evenly.

Next charge, back to the first charger, and yes, cell 3 lower.

Have gradually eliminated the external items like the 2/3/4/5/6 patch board and the short balance extensions (used as the batteries have very short balance leads)

It's the charger, despite it showing 4.20 each cell at end. Its less than two years old. When new it balanced perfectly.  Not now!

As it was colder weather I was assuming the shorter flight times were due that. Instead that lower cell was hitting my 3.6v land point sooner.

More expense................. Its a sealed unit or I might open it up to investigate why.

[ched]

Weird, open it up and have a look but I would guess it's a firmware calibration thing and I doubt you can change it without the correct software.

Oh there might be a dry joint inside the charger!