Thursday, October 14, 2010

Here Comes The Sun...

Well, actually, the days are getting shorter. What I mean is here comes our solar power. We have a plan for powering our little gypsy home and Jamie has been explaining it to me. He's the electrician so he makes the plan. Now let's see if I understand it enough to explain it here...

Jamie says that travel trailers and mobile homes are the best situation for converting to off-grid power because they have separate light circuits and appliance circuits. The trailers we are living in are even better because the lighting is already 12v DC power rather than 120v AC. The solar panel system will be generating and storing power at 12v DC. When we convert 12v DC to 120v AC it creates heat and wasted energy and electricity. So with this we can save energy by using 12v DC as much as possible (lighting, cell phone charging, etc) and only doing conversion to 120v AC when we have to.

Ok, so the guest house has about 160-170 watts of 12v power with 450 amp hours of storage. This is what I am currently plugged into to power my laptop, charge my cell phone and mifi internet, run my sewing maching and occasional plug in a power tool. All of my lighting is battery powered lanterns and flashlights. (So far this has been sufficient for one trailer during summer). The solar panels we are looking to get are each 60-150 watt 12v. We probably only need 250-300 watts total, but Jamie has a goal of 350-400 watts. The higher the wattage, the faster the batteries are charged, which will become very important in the winter. We currently have enough batteries collected for 350 amp hours of storage. This should be ok for now, but we would like to have more.

(Now here's where we get into stuff that I have to copy and paste from his email as I am still working on understanding all of this.) Besides solar panels and batteries, we need a Charge Controller. It would be best to start out with a bigger one than we need so that as we expand we don't have to buy a second one. Jamie would like to get a 12 volt/ 45 amp charge controller with a digital display. The digital display allows for better monitoring and the size would allow us to someday expand to 500-600 watts. We are all about the long-term plan with how we're designing things here. The best source for acquiring this is going to be eBay.

We'll also need an inverter. This is what allows us to convert to 120v. For now a 600 watt automotive unit will work. When we have a more real house, we'll need to get a different one.

Other materials needed for putting the system together are things that Jamie has been able to salvage from construction site waste or has ways of getting. But everything I have mentioned is stuff we are trying to save up to buy. We can start putting the system together with at least one solar panel. This is a big project where we could use all the financial help we can get. I'm not certain of total cost and we are still doing a lot of pricing research. I'm sure I have forgotten something here that Jamie can fill in or elaborate on in comments.

1 comment:

  1. Looks like I should chime in right about now.

    Rhi, I am impressed! You have absorbed more than I thought, I sometimes go to deep into technical details and end up with people staring at me with the "glossy eyed" look.

    The plan of attack is to start small and add to the system as we go. The solar panels and batterys can be added to, increasing the potential of the system as we can afford pieces. The Charge Controller and the Inverter are items that can not be added to, if the first ones we buy are insufficient, then we have to replace them with the right size later. The idea is not re-buy these components. The Charge Controller, monitors the power that the solar panels are creating and monitors the charge of the batterys and decides what the batterys need. A quality unit will last a long time and protect the batterys, which will help us get the longest life possible from them. A good quality Charge Controller is going to cost us $90-200.

    The plan of starting small and adding as we can afford, allows us the flexiblity of starting with less money. As we add to the system, we are able to do more with the power. To start we are looking at:
    (1-2)80-90watt solar panel --> $200-300 each
    Coleman Air C160 Charge Controller --> $175
    Batterys (350 amp hours) --> donated ($500)
    Inverter --> already acquired ($100)

    The Coleman Air Charge Controller is a little overkill, but it will be more than sufficient in the long run and is top quality. It also is designed to handle a wind turbine system and solar system at the same time! I have had an interest in building a small wind turbine to create power, but I am trying to focus on the more important projects, first.

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