That's a definite possibility.
But the saga continues! Last night I decided to go ahead and pull the jump starter out of my truck. I figured, if it's not working there's no reason for me to carry it. It still shows as being "charged" and since it has 2 USB ports it will absolutely function as a way to keep cell phones/etc charged or powered. So I took it into the garage.
View attachment 715839
Now I should point out that this type of charger has the battery (of course) and it also has some kind of transformer or controller that connects to the battery and has the jumper cables on it. This module has a voltage sensor that is there to protect the battery in the event that you accidentally connect to the wrong terminals on the battery. There is a little LED light that flashes on the module, which you can see in this picture:
View attachment 715840
When I checked the voltage on the clamps with the jump starter powered up, it was all over the place: 4v, 9v, 6v etc. So I think you are right: the "brain" in the connecting module was trying to "sense" the voltage (it probably sensed the voltage of the 9v battery in my voltmeter.)
So instead, I pulled the module out, and connected the volt meter directly to the battery. This was the result:
View attachment 715841
Showing 16.5v! So clearly the battery seems to be able to hold it's charge (which is impressive to me, since the charger sat in my truck all Winter, and there were a number of times the temperatures got well below freezing and stayed that way for days.)
What I'm thinking now is that the connector module has a little "brain" in it that is seeking a specific voltage, and it may not be sensing enough voltage from the motorcycle battery to charge it up. I'm not sure.
However, I WILL be keeping the Beattit charger in the garage from now on, and not in the truck, unless we are going on a trip somewhere.
But it also makes me think that for a longer trip, it might be a good idea if, instead of this small, lightweight "smart" charger and lithium battery, I bring a bigger, heavier, 'dumb' jump starter with a simple AGM battery setup. Yes it would be bulky and take up more room but it seems it'd likely be more reliable as well.