Sunday, August 20, 2017

I'll have to do better than this rat's nest!

Today and yesterday I worked on my wiring for the magic box. Yesterday though I didn't blog about it, I did test my magic box and wiring before I fastened the wiring to the wall. A good job too because one connection had come undone. I also had an interesting issue with a crimp connector that absolutely refused to crimp. I've never seen anything like it. In the end I resorted to using a vice but got it so tight that the wires simply snapped off.

Currently I'm charging my phone via my magic box. That's running off my 5AH Radio Shack battery which in turn is being charged via my 15W Harbor Freight solar panel. I think I've proved my system works. The voltage dropped quickly from an initial 13V before I connected the phone to 12.5V which is where it's staying. My meter connected directly to the battery is reading 12.7V so I can see my charge controller seems to be maintaining 12.5V as a norm.
 I can say I'm very happy with the initial few minutes of my test. Everything seems to be working within predicted parameters. Ignore the adjustable spanner in the photo above. That's just there to hold the rubber flaps away from the USB charging ports in order that the blue LEDs show nicely. My USB charges came with detachable rubber flaps but I left them in place.
Wiring in the control area is a bit of a rat's nest. I'll have to sort that out. At the moment everything is running off a pair of Radio Shack lead acid batteries. One is 10AH and the other is 5AH. I have a brand new Harbor Freight 35AH battery waiting for fall to be installed underneath the bus.

The plan is to remove the charge controller at the rear of the bus and to use solely one charge controller - the one in the picture directly above. One cable pair will head out from there to the battery. That cable will probably be fairly hefty. I have two 0.5A fans, a 2.5A fan and a magic box with two 3.1A sockets and a pair of meters at say 0.5A each. That all totals 10.7A. Add in the timer that I have yet to install and I'll say a good safety margin is 20A. I can therefore use a 20A cable. That's actually rather good because the controller purportedly is 20A. Solar input is 35W or about 3A maximum. I can't honestly see any need for any more than that but I will add a supplementary input for supplemental solar or wind power.

I had a go at reversing the ventilation fan simply by switching the leads. While the breeze from the intake was impressive right by the intake, I didn't find it that great to be honest. I'm not sure whether that means I need to double up on bilge blowers and change the air ducting or whether I shall just stick with what I have. Needless to say, I've come to the point with ventilation where the thing that works best seems to be to open a window and put a screen in place.

I looked around at portable air conditioning units and found several interesting candidates. I looked into mounting a window unit under the bus and it just ended up looking like an awful lot of work. Looking at the dryer section in the local hardware store I found there are detachable drier connections. Those combined with draft excluding flappers and perhaps some marine vent covers look like being a good solution. I can put air outlet plugins for AC in the bedroom and the galley. Clearly they'd need caps but that looks like one way forward. Of course, that would work only while plugged in. For travel, it seems the only solution is to simply not be inside when it's ludicrously hot.

In terms of cost, portable AC units do run more expensive. I don't think there's a great deal of difference between them though. The case sizes range tremendously with none actually matching my ideal dimensions of 10" by 15" by 26". Now those dimensions would fit quite well in through the door of a spare cupboard on the bus. That's 10" wide by 15" deep by 26" high.

I did consider making an AC unit. Initially I considered a Peltier unit but when I tried Peltier stuff it turned out not to be that great and costwise it worked out too expensive. All an AC unit really is, is a loop of tubing with a reduced tube in the middle of one side and a pump in the middle of the other side. The pump expands the gas on one side and compresses it on the other. The compressed gas radiates heat and a fan blows the heat away. The expanded gas absorbs heat and a fan blows air over the tubes, causing heat to transfer from the room to the expanded gas from which it is lost when the gas enters the compression cycle. Even ordinary air can be used as a refrigerant though the water vapor in it will freeze at low temperatures.

The problem with self build is that it takes time and experimentation when usable units just aren't outrageously expensive. Looking online they seem to go for between $200 and $400. Quite pricey but not outrageously. Recommended solutions such as mini-split and rooftop units have other issues. Cost is the main for mini-split and rooftop would raise the height of the vehicle unacceptably.

I've come to the point where everything extra that I want to add or do involves a trip underneath the bus. The only thing that does not is reconfiguring my rats nest. For that I might just get a piece of plywood, paint it the same color as the wall and lay everything out tidily then just come in and make the connections. Speaking of that, I found my Radio Shack glass filter holder has a problem. It seems to want to let go of my spade connectors. It's supposed to attach via spande connectors but they slip off rather too easily. Despite not wanting to go to blade fuses, it looks like I might just as well switch over to blade and replace the few glass fuses in my control panel with blade.

Just as I wrote that, my extraction fan cut in and I could been a really strong breeze from the window with the mesh over it. The temperature dropped a couple of degrees. It looks like the mesh in combination with my extraction fan might well be doing what's needed.

I saw online some screens with built-in fans. Those ran of 120v which made them interesting. I'd rather have some that would run off lower voltages though. I did build a window unit that runs off D batteries but it wasn't a great success in that it was very hard to mount securely in place. It worked really well though the batteries drained quickly. What I might need to do is to try to get one of the ready-built units to try. Although I've considered AC units, I really don't want to have to use AC units.

Maybe... I should just become a snowbird... Drive to Canada in summer and the Mexico in winter? That would be the best of both worlds. I'd get the good, low-priced and free social healthcare in Canada and the great food in Mexico.

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