I believe the battery is two 18650 Li-ion cells. They measure about 18 mm diameter by 65 mm long. They are wired in parallel and the open circuit voltage is 3.94 v, while the output when the light is on (steady) is 3.88 v. (Straight out of the box, with no recharging.)
We keep our teardrop in that garage, and have a solar panel to maintain the battery. So, one thing I can do is to plug it into the cigarette lighter style outlet in the galley of our teardrop. In that case, the teardrop battery will keep it charged, while the solar panel and charge controller will keep the teardrop battery maintained.
But I'd also like to use this in the garage while we have the teardrop up in New York for the Summer. The charger claims it takes 12-32 volts input, so it is evidently a charge controller of sorts itself, and I should be able to connect it directly to the solar panel output. But, the claim by the manufacturer is that the cells have about a 6 hour life between charges, so I'd be deeply discharging it every night, and it might stay that way for hours, to days if we get cloudy weather.
So my question is: Is that a bad thing to do to lithium ion batteries? And how bad? If I left it for a Summer, would I have to replace the cells, or might I come back and find the thing started a fire? Or at least cooked the rest of the electronics?
Informed replies preferred, but hey, I realize beggars can't be choosers!
Seriously, thank you for any insight!
Tom