105F in the bedroom

This morning got off to a fairly inauspicious start with my stepping in the dark, barefoot into fresh dog vomit. Then it got more interesting as I picked up some deodorant in my bleary eyed 6am zombie state and found I'd put something called Spring Blossom on that actually smelt more like carbolic soap.

Having returned from work, I did some work toward the solar power system on the bus. The panel to go over the access hatch I cut yesterday got trimmed to a better size. Then it had two coats of paint. At the time of writing, the paint was still hardening.

Inside the bus it was pretty hot. The bedroom was 105 so I turned the fans on and soon got the temperature down. Odd things happened with the temperature though. It rose and fell in different places. Clearly the sun heats different areas differently. The tree shading part if the cus complicates this pattern.

I have very much a feeling that I'm going to have to do something different as regards ventilation. The cool air inlet in the bedroom is a good idea but I think it might be better to have a through flow with an air inlet at the front and a couple of fans sucking the air inward. Those fans will need filters.

The next thing was I looked at where I'm going to put my solar panels. They're going on the back of the bus even though this is not ideal. The rationale is that they won't increase the height of an already tall vehicle. Power produced won't be ideal but it should be adequate. It should - running the fans directly - power them during the brightest and hottest hours. If, miraculously, there's excess power then it might charge some NiMh batteries thus allowing the fans to continue running through the night.

The solar panels look pretty good from the front. They're supposed to be 10W and I have two. My quick calculation for a 12v CPU fan at 160ma is that it would use 1.92W. That does not include the higher starting amperage however.

The back is not so promising. It's all glued together with a rather soft white paste type glue. I fear this will quickly disintegrate in the South Carolina heat. There are no easy mounting places. The screw holes look good but finding a way of mounting the panels could be somewhat challenging. My immediate thought is two pieces of aluminum angle running along long sides of the panel, riveted to the sides of the aluminum of the panel and to the bus.

The panel has some nice looking screw contacts but no apparent diodes. I'll have to put diodes in the circuit somewhere. I'm not really sure that it's going to be worth putting any battery protecting circuitry in with two 10W panels. Assuming I charged AA NiMh batteries at 2000mah, fully charged batteries would power a 160ma fan for 12 hours. Assuming the panel charged the battery and powered the fan during the 8 hours of full sun, it would have to put out an awful lot of power. I can probably do without a battery regulator.

Well, tomorrow is the day the panels will be installed. I drew a level line which probably can't be seen in this picture above which I'll mount the lower bracket. Attaching the bracket to the panel is a delicate operation. Next I'll paint the shiny edges to be the same grey as the bus then seal with silicone sealant. I'm planning to minimize the visual impact of the panels.