Dead battery ... probably?

[asp125]

Well it happened. After years of reliable service it happened, our Spyder is dead.

We recently moved and the battery tenders got packed into boxes. I last rode it two weeks ago from the old house to the new place. It has been sitting unplugged from the tender since then. I did start it one time to move it from one side of the garage to the other, but otherwise it sat.

We've had the same battery in it for probably 5 years, most of the time on a Battery Tender (tm). It's not our regular ride, so it sits more than it gets ridden. But I do use it a few times a month just to run errands or a two up ride. Fast forward to Friday when sweetie wanted to use it for a grocery run. She turned the key and the dash cycled through it's boot up sequence, and then went blank. Not even the "click" of the starter solenoid.

I plugged in the Battery Tender and a few hours later attempted to start it, same results, one cycle of boot up and then nothing, even with the Tender plugged in. The fender running lights glow dimly before flickering out. Tonight I hooked up the big charger, and set it to 25A starting amperage, figuring if that could jump start a car it should start a Spyder. Turned the key, fender lights glowed faintly, the dash lit up through the boot sequence, and I heard a click of the starter solenoid, but then everything went dark again. This is the troubling part, since most vehicles it's possible to at least get the motor to turn over while jump starting. Is there a special trick to jump starting a dead Spyder?

I haven't unpacked my multimeter yet, so I can't take a voltage reading across the terminals. I do know that the battery doesn't seem to hold a charge, not even for one start. As soon as I unplug the charger it doesn't even have enough juice to cycle the instrument boot sequence. Battery terminals are tight. So I am assuming a completely dead battery. Hopefully that is the only issue and not something like a fried regulator/rectifier/stator. (998 Rotax twin Spyders don't have alternators do they?)

Anyone been through this?