Watt-seconds?! awesome. Also in terms of a DIY open-source solution take a look at this project: http://www.solarnetwork.net/developmentGuides.php built using Java on Linux and defines interfaces already implemented for the Cent-a-meter and a bunch of major solar charge controllers and grid-connect inverters. And listens to the weather, the grid electricity price...very extendible, enterprise level code based on OSGi.

There's an open source EV project called the Tumanako Platform - take a look at what's going on: http://www.tumanako.net/

http://knol.google.com/k/john-gorman/talking-sensibly-to-a-computer-maven/1iimid3vxo7fe/1#

an open source solar generation and home consumption logging project: http://www.solarnetwork.net/architecture.php this device might be helpful!

no need to burn a lot of coal to save some octane. what about this: http://www.solarnetwork.net/

in NZ you should check out: http://www.greenstage.co.nz/ an open-source LiFePO4-based racing vehicle.

good point. a DIY open-source solar project possibly suited to small offices: http://www.solarnetwork.net/