Join Date: Apr 2015
Location: North Central WV
Oh no doubt on it keeping on with the keeping on, and .4 or .5 is fine, but at some point there will be another .1 where it won't be ok, especially if it's super cold or super warm. A 12.3v battery is a pretty discharged battery---it's not the percentage of the whole, it's the percentage of the operating delta, and you're at the bottom of it.
Edit: Actually, on these little engines, I don't know when it will be come a problem. I know on boats, and in cars, a battery below about 12.1-12.2 won't turn it over, and on LED driven flashlights, you'll stop getting light pretty fast at .5v below "fully charged".