Thursday, October 09, 2008

Solar powered station

My long-term plan for my "station" (which doesn't really exist yet) is to power the 12V equipment (which these days is just about everything) from solar power and batteries instead of line power to the maximum extent possible.  What I'd like is to have a system where the 12V bench power is fed from a battery rack which is itself being charged by solar panels.  In the event that the battery level drops below a certain point, however, I want the system to also bring in a regular line supply to provide backup charging so that the batteries don't go completely flat during an extended period of low sun (which can happen here in the storm season, or in the winter if the panels get covered by snow).  I don't want the batteries to charge from line current just any time the sun isn't out, though; I plan to engineer the battery pack so it has enough reserve to get through the longest of winter nights without needing an emergency boost. 

I've found plenty of power controllers that will keep batteries charged from line power, and controllers that will buffer solar with batteries, but I've yet to find one that can do both at once.  I suppose I'll have to homebrew something.  Probably a good idea anyway.

I'm still trying to work out the state table and transitions, but I'm certainly not up to trying to represent that in HTML in a blog post, so that'll have to wait.