[Al Skierkiewicz]

Curtis,
Working backwards from the 55 amp hour batteries, we can expect that the total current is somewhere between 5 and 10 amps when driving. Since the need is intermittent, it might even be a little higher. However, getting the little engine to both supply enough horse power to cut grass and energize the alternator might be asking too much. Remember that the output of the alternator is a function of input power, speed and load. Depending on the size of the yard you want to cut, you might be happier with a simple 24 volt battery system and outboard charger. Two robot batteries in series might give you enough to drive the mower for at least an hour, if that works.