Power up on battery only gives wrong percentage left

[dave-at-axon]

Running Android on an A20 I have found that if I power up with external DC connected, the batter shows the correct charge percentage.

If I disconnect DC and run on the battery and put it into standby with the power button or let it go to sleep itself, it wakes up with the power button and show the correct battery charge.

If I power it off and then power up with only battery and no external DC the battery state is wrong. Like today it was 78% when I powered off. After power up it was 18%.

If I put it into standby and then bring it back out, the charge shows 78%. If I let it sleep again and power up, it again shows a different reading when back on and this time it was 32%.

After a power off and back on after a few mins, it now shows 81% so something is clearly wrong with the AXP209 code somewhere.