I'm using my Hitec X1 charger to balance charge the LiFePO4 batteries in my 50cc plane; 2.0A charging rate. The batteries are 3850 mAh for the RX and 2200 mAh for the Ignition.

The ignition charges fine - After a little flying on Wednesday it took 4m 15s to put 72 mAh back into the battery.
The rx, however, is what's weird. It charged for 120m 00s, at which point it exceeded the safety time limit. 317 mAh were put back in.

On a small Lithium battery tester the ignition reads:

#1 -3.44
#2 - 3.45
All - 6.82

The rx reads:

#1 - 3.57
#2 - 3.36
All - 6.86

The rx battery doesn't appear to be properly balanced.

Questions:

1. Why is this happening with the rx battery?
2. What should I do about it?

Cheers!