I have a Battery Tender Junior and a voltmeter with me.
A lady in town offered to take the battery home with her to charge overnight (we are tenting and had no electrical outlet available). She brought the battery back this morning and said it was fully-charged. I installed it and tried to start, but there wasn't enough cranking power. I placed it on the charger after because, since I hadn't personally charged it the night before, I wanted to make sure I had a fully-charged battery.
After a few hours, the battery tender indicated fully-charged. I attempted to start, but there wasn't enough cranking power.
I have a Lithium-Iron battery - Shorai.
I am suspecting a bad battery since it didn't crank over with it fully-charged, but I will charge it again, and measure the fully-charged voltage. If it doesn't start, I'll need to get a boost and, when I do, I'll measure the output of the rectifier regulator. I'll have to look at the wiring diagram, but I guess this will be applied directly to the battery terminals when the bike is running?
In the meantime, if it is a bad battery, is it safe for the rest of the motorcycle to get a boost while we try to get to Reykjavik to get a new battery?