Don't think that's what's happening in my case and if it was it should do it consistently which it hasn't. All cells were balanced when connected to PC.
From my test in July: (hope this helps)
Latest EScribe and firmware.... plugged in device to charge and Device monitor showed battery levels at 3.90 v. each... left to charge for a couple hours and when checked batts were at 4.18 v. each and not charging.... unplugged device and plugged back in and it then charged to 4.20 v. on each cell.... replicated this several times... I'm using the default settings for Li-Po's....
Edit: after batts were fully charged to 4.20 v. I left the device plugged into usb of computer and after about 35 minutes I opened Device Manger again and batts showed 4.18 v. each again and batts not charging...unplugged device and plugged in again with Device Monitor open and started charging again up to 4.20 V.
I haven't seen this occur with previous firmware until this one... ??
EDIT2: Watched charging and it peaked at 8.00 Wh for the pack @ 12.6 v.and 4.20v each cell.... left device plugged in.... charging current etc dropped off to almost zero and Wh started dropping off from 8.0 Wh as did the Pack voltage started dropping off from 12.6 v. and cells started dropping off to below 4.20 v. After watching this after about 7 minutes the Wh is now at 7.968, Pack voltage at 12.58 and cells at 4.19. After another 10 minutes the Wh dropped to 7.922 Wh and Pack voltage is 12.56 v. and cell voltage is 4.19.
Watched another 10 minutes (device still plugged in to usb computer port)... Wh dropped to 7.873, Pack voltage dropped to 12.55v., cell voltage dropped to 4.18V...
NOTE: USB Voltage 4.752 v., USB power 0.012 and current 0.003 (varies slightly but not in charging state enough to keep the pack at full charge).
Watched another 10 minutes: Wh = 7.840 Pack voltage = 12.54 Cell voltage = 4.18 each
Watched another 10 minutes: Wh = 7.805 Pack voltage = 12.53 Cell voltage = 4.18 each
Watched another 10 minutes: Wh = 7.769 Pack voltage = 12.52 Cell voltage = 4.17 each
Watched another 10 minutes: Wh = 7.731 Pack voltage = 12.50 Cell voltage = 4.17 each
Unplugged device and plugged back in and charging again at : USB Power = 1.523 W USB Current = 0.334 A USB Voltage = 4.462V. Charged back up rather quickly to 8.0 Wh. 12.60 V. Pack and 4.20 v. each cell... unplugged and will let rest and will check again after being unplugged from USB.
So.... is this due to needing a better usb cable (line loss),,, a firmware tweek, or a computer charging issue??? I'm puzzled..... ??
I asked why???
Response:
This is actually a firmware tweak from the July 9th firmware:
You can see from Mod->Battery->Discharge Curve that 4.18V corresponds to 98% charge. Once we determine that the charge is essentially completed, we now turn off the charger circuitry entirely until it reaches 25 mV below the termination voltage.
This means if you have a LED connected to the charger PWM it will turn off when charging has ceased, so that can be used as an indicator. It should also be better for the battery.
Response #2:
The device does not sleep while plugged in to USB.