Saturday, July 30, 2016

Noggin scratchin' time?

Arriving in the bus this morning, the CPU fan was purring away nicely. The Walmart fan had stalled and was not spinning. After flicking the blades, it began to spin nicely. Needless to say that could probably be cured by adding a capacitor to the brew. Having said that, once a capacitor is added then I also need to add a diode so I'll skip that for now  not that I don't have copious supplies of both.

Out of interest, I tested both the Walmart and the CPU fan by holding a plastic Walmart bag over the vent. The CPU fan filled the bag rapidly. The Walmart fan, less quickly. That was my cue to replace the second fan with a CPU fan. Now I have a pair of 12V 120mm CPU fans powered by sunlight, extracting air from the bus.

Looking into what's actually happening, while air is being extracted imperceptibly, nothing much is happening in terms of internal temperature. Indeed the galley was 100F and the bedroom was 92F at 11:30AM. I turned on the floor fan to see if under bus air made a difference. That is, of course, battery powered.

Thinking about ventilation for the galley, I'm opposed to putting a roof vent due to strikes from low hanging branches and potential leaks. I did measure the open window at exactly 24 inches by 11 and 1/8. I'd had a thought about possibly putting a piece of Formica cut to that size with Peltier elements inserted and heat sinks on each side as a DIY air conditioner. Now though, my mind is wandering around potentially putting extraction fans in a similar form factor. Having said that, it's a temporary solution to a permanent problem.

I am most definitely not keen on the existing hole in the bedroom floor. That, I want to fill as it represents a loss of valuable floor real estate. Similarly, if I have stinky drips on the ground from my waste tanks then I'll be breathing all those lovely bacteria. Not good!

I looked at the charge controller that arrived the other day. The mount is totally broken. I didn't even see pieces in the envelope so I assume the yellow peril in China sent it ready broken. Needless to say, I did notify them but have received no response. I'm betting, looking at all the other complaints about non response when something arrives broken that I never will. I'm not sure with a broken mount whether it's usable.

The old plan had been to put the solar panels to charge a battery and run the fan. Given the minuscule power from those panels, the new plan is just to leave them hooked up to the fans and forget about trying to harvest more power simply because there won't be any spare power. They barely run the fans and that's one CPU fan per 10W panel.

The new plan is to connect the charge controller to the bus battery via the control panel. Then to hang my 5W solar panel in the window. That might help to keep the batteries fresh or the controller might use more power than the panel produces.

Looking around the bus, I need to do a lot of cleaning. I need also to find some place to store my unused supplies and tools. It's getting to the point where I'm going to have to retitle it as the registration expires in a couple of months.

For fun, I tried my 5W panel, aimed squarely at the sun on my Peltier cooler. Indeed, it worked. The cooling effect was minimal but there was a definite cooling effect. With a few more unshielded 5W .panels I'm sure a small cooler could be kept cool. I wouldn't want to keep more than a cooler the size of a coke can cool with that though.

I set to and painted the aluminum of the solar panels and their mounts, getting most of it done and dried before a sudden rainstorm. After everything had dried, I went back and painted the rest. It was welcome to note that the CPU fans kept going during the rainstorm.

The back compartment of the bus always gets very hot. Putting my hand on the metalwork, I discovered the compartment where the lights used to be becomes very hot. I'm thinking therefore of squirting insulation foam inside. In an attempt to ward off heat, I put a piece of foam board inside the one rear window that's not painted black. It will be interesting to see if that makes a difference.

Thinking more on Peltier coolers, the big killer is not the cost of the element nor the glue but big aluminum heat sinks seem to be terribly expensive not to mention heavy. It's looking very much as though a cooling fan introducing cooler outside air is probably the best bet. A quick and dirty solution would be a piece of plywood or PVC planking popped into an open window with one of my battery powered fans installed and set to blow or suck dependent upon requirements. Realistically though, I'd prefer a permanent vent that didn't take away my light.

In other news, I removed the big mirror in the cab today. It was just a dirt magnet that served no useful function. It was designed to observe bus passengers and of course I have no passengers unless somebody chooses to ride the toilet! The no guns sign is now about 2/3 gone.

As with the rear bulkhead at the top, the front bulkhead is very hot. I'm thinking that the sides where the 8 way flashers used to be could easily be filled with insulation. The middle can't be filled as its a wiring conduit. I might be able to work around that somehow.

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