Odd Apple iPod Classic battery problem

[Lorenzo_1]

I have a couple of iPod Classics - one bought original in which I've replaced the motherboard and clickwheel and the 2nd bought as a replacement in case the other dies.  Both have new batteries PAB-616-0183 3.7V 700mAh.  Both have the same issue - work perfectly if I ensure the battery doesn't run completely flat (or at least to it's low V cut-off protection voltage) but if let either go flat the iPod shows a failed battery logo when I plug it into power again.  I can recover them fine with a few hours at 100mA or so and 4.2V on power supply.  Can't understand why they won't recover after the protection circuit kicks in.

When the original first died, I ordered a replacement from China and had this problem.  Assumed it was bad manufacture issue. Replaced the batteries for both units recently with Oz-sourced units (which look like the same manufactured items with a sticker over them) and they behave the same way.  There are no problems with charge capacity on the new units - they'll run for hours and recharge fine if not flat.  When I stripped and tested the control circuit on the problem China-sourced battery, I couldn't find any fault with it.  So I'm completely foxed. Seems unlikely both iPods have developed the same charge system fault and am wondering whether perhaps there's some mismatch in the control circuit where the iPod voltage detection system is looking for a voltage different from the low V shut-off in the battery's control board and signalling a battery failure erroneously?

Wonder if anyone's encountered this problem and found a cure.  It's mainly nuisance value having to extract the battery repeatedly and trickle charge it for start-up.  A permanent fix would be nice if anyone knows of one.