I had a salvaged 12v 12ah ups battery that had been sitting on the shelf in an unknown state of charge for a year or so, I had used it to test a headlight and it was on the dim side. The battery sat for another year, and was abused by our techs in the normal ways (screwdriver across the terminals, etc). The sparks were pretty weak by then and it wouldn't run my 120v power inverter anymore so I decided to run the empeg off it just to see how long it would last in it's diminished state.

Result: the empeg ran for about 6 hours the first day, then when I hooked it up the next day it ran another 4-5 hours before hitting the powerfail sequence when the drives spun up.

I'd bet a good LI-on laptop battery would last at least 2-3 days if not a week of commuting between charges and be a good deal lighter than the motorcycle battery.


YMMV, quite literally :)