nosambos wrote:I have two Wagan Powerdome units for my cars. 400W, 600A peak cranking power, 18A hour DC.
First, from what I've been reading, it seems that nearly all manufacturers of sealed lead acid batteries have gone to absorbed gas mat (AGM) which (from what I understand) offers similar functionality to deep-cycle batteries. The capacity-per-volume or per-weight is less, but they're sealed.
Second, crunching some numbers on the size, 18 amp-hours at 12 volts is 216 watt-hours. Figuring half that for safe measure, you've got about 100 watt-hours in each unit. The Wagan site has their vacuum listed at 90 watts, so one hour with the vacuum and you're done. You might be able to get away with not charging your toothbrush for a while, but it looks like counting on about 50 watt-hours a day would be a practical bet. Unfortunately this means you'll need to recharge at Burning Man â€”Â if your consumption was much lower, it's likely that you wouldn't need to charge at all.
Given that there's about 5 hours of usable solar energy each day, that works out to 10 watts for those 5 hours, so with losses and such, you should bank for a 15-watt panel.