After connecting the battery directly to the board I’m still getting 0.25 in serial monitor.
Board shows no life on battery alone.
Unlike normal D61 tests, board does not even continue running on battery alone if booted and started with USB then USB disconnected.
Where else does it go other than through D61 and to Q7?
What does the multimeter say if you measure between GND and BATT+?
If the multimeter shows the right value, but serial monitor shows 0.25, then I think it has to be a problem with Q7.
The fact that some boards can be “kickstarted” from USB and then keep running is really weird though. I don’t quite understand why that’s happening. It’s as if D61 is only mostly dead. If D61 was truly dead, or removed, then I would expect the board to turn off as soon as USB power is removed.
Remotely helping a guy. He has no meter, but the known fully charged battery is directly wired to the board to test, so very likely that would just read battery voltage.
Q7 is now suspect I guess.
It is odd. Maybe it fails in a half open state or something?
It could also be that the battery protection circuit is busted.
May I ask which components comprise that circuit?
How should I know? Ask the battery maker.
oh duh. I read that as reverse polarity protection on the board.