I did pretty much what you said except for the recording and measuring
part.Â* My ClearNav and my Dynon D10a each have a volt meter displayed
and, though they had slightly different readings, they seemed to track
pretty well as I turned each device in turn.

For now, I'm gonna go with charging the lithium battery for a longer
period after the green light comes on, probably over night each time.

Thanks for all the good advice!

On 10/16/2019 1:50 PM, Charlie M. (UH & 002 owner/pilot) wrote:
Good thoughts posted thus far.....

My $0.02....with even an inexpensive DMM/DVM.....start at the "common buss" on/near the panel with all batteries fully charged.
Measure D.C. Voltage at the buss main input with a battery connected....
Switch things on, read voltage....write it down....
Key mic and do other load things...record voltage under load.
Repeat with the other battery.....
If the large battery shows a bigger voltage drop.....work through connections back towards battery with same test....see where the voltage drops lessens....in between good vs. bad/poor voltage drop is likely a poor or bad connection.

Could be a bad crimp, poor solder joint, loose/poor screw connection, maybe even small wire gage (although not likely unless waaayyyyy tiny...).

--
Dan, 5J