Yeah, that's the math I was needing. It's a 1/3 hp motor, it works very well - it drains the sump in under 60 seconds, and in the tropical storm, it was running about every 5 minutes, so I was planning on a fairly large battery system (I have access to a large number of 71 amp-hour AGM batteries, more than enough for what I need). The key need is to be able to keep the pump going for a 24 period of intermittent on-off, about 10 minutes run time per hour under the heaviest flow conditions we can reasonably expect it to manage. Now all I have to do is pick something that won't set me back $700 for the inverter. Thanks.