Battery Shed Cooling

[rossw]

Put a 6 to 8" pvc pipe to your battery box, a straight run through the roof, paint the pipe flat black above the roof to create a draft. Place a vent on the side of the building that does not get sun at ground level and cover the vent with screen wire. This should allow a exchange of cooler air for hot air. You can cover the pvc with a chimney cap and seal the ground level vent or vent when it is cold with Styrofoam.

That's very similar to what I did here, back in Jan 2006. It's still going strong....
http://www.anotherpower.com/board/index.php/topic,329.msg2765.html#msg2765