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Old 05-02-2012, 08:03 PM   #14
AKat777
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Join Date: Apr 2012
Posts: 104
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Quote:
Originally Posted by Ran D. St. Clair View Post
As far as electrical, can you give us more of a hint. Does this thing need to boondock, meaning run on batteries? If so you need batteries, a battery charger/inverter, and probably a transfer switch. If it's more of a plug it in design then the electrical is more of an elaborate extension cord, or cords, probably with some circuit breakers. You might still need a transfer switch, or you might keep things simple and manual, like plug it into shore power or plug it into a generator.

Lots of people in the RV world would recommend a power management system that checks for miswired inputs, high voltage, low voltage, etc. Some will also recommend an auto-transformer that boosts low voltage to avoid blowing things up with motors and compressors like refrigerators or air conditioners. You probably know how good or bad your power sources can be.

Speaking of such. Will you have an air conditioner or possibly 2?

Modern high efficiency residential AC powered refrigerators are suitable for RV use. For short trips you can just keep them closed while you travel. For longer trips you would need batteries and an inverter.

You can run some things off of the 12V truck starter batteries, but that's problematic. Starter batteries are not deep cycle batteries so if you draw them down much powering an inverter you will soon be replacing batteries. That and you can easily find youself unable to start the truck. Depending on just the alternator to charge the starter batteries when they are also the house batteries is probably not going to work unless you drive a lot and pull current from the batteries very little.

The possabilities are many, so give us more information about your off grid needs.
Part of why I am unsure of what components I will need is because I am still deciding what I want to do. While at the show, I have basically unlimited shore power. And I know about the quality of the electricity.. I maintain the generators (total of 3) that supplies the RV's and the show itself..hehe. Away from the show is when things start to get really murky. I could get a set of 4 (6?) deep cycle marine batteries and some sort of a switch at the breaker box to choose input. But that would require an inverter, a switch (forget what it's called at the moment) in between the truck batteries and the 'house' batteries to allow the house batteries to help with starting the truck, and charging the house batteries while the truck is running. The switch prevents the truck batteries from being drained, so even if you kill the house batteries you can still start the truck, and recharge the house batteries. (there is always the car charger I have in storage as well, lol).

At the moment I am leaning towards a house on wheels that relies on shore power. I dont plan on doing a great deal of travelling with it. On the other hand, halfway through the project I might decide to toss 4 panels on the roof, and a battery rack under the truck for free power. I can certainly survive on less in the house, but the workshop in the back just isnt practical to try to run on batteries. Most of my work tools run on a *minimum* of 7.5 amps out to 12-15amps for the good stuff.

I think I am going to put an AC unit in, but a small one. 15' of living space that will be super-insulated (I think I will be trying spray foam. Worst that happens it does not work and I scoop it out to put in rigid foam) wont take much to cool off.

The workshop and the house will be running off separate shore cords. As I said previously, the workshop is an electricity sinkhole.

As you can tell from my random rambling thoughts, this truck is being built with a fairly narrow specific use in mind. I should consider other things as I move forward, but I know what I intend to use it for. It will be parked in the show, or it will be parked next to whatever residential rehab problem (oops I meant rehab project..lol) I am working on at the time. So I am thinking shore power 95% of the time, 5% travel time, which I can plan for, ie empty the fridge. Or a small pack of batteries and an inverter to run the fridge from place to place. Which would require almost no additional work.
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