Building A Solar Generator on Wheels

Building a solar generator – by Bill Brooks

As many of you know, I recently completed my tiny house on a trailer. I plan to travel to a few locations beginning this winter. I built my tiny house to be self contained, since most of my time will be spent in places without services (electricity, water, etc.). Since batteries will supply the house’s electrical power, I will need to recharge them often. While I will have a propane generator, I plan to use solar power for most of my needs. This should allow me to get power, and keep the costs down by not buying propane as often as if I was using the generator.

Often, trailers have the solar panels mounted on the roofs. This allows the panels to charge the batteries as long as there is sunlight available. The problem with this set up is you need to park your trailer in the sunlight. While this might work well in some locations, others will have trees and other obstacles that can block the sunlight. Also, certain locations might result in parking the trailer facing away from the sun, hence lowering the output of the solar panels.

The finished solar generator on wheels

Originally, I decided to place the solar panels on a cart. This would allow me to move the panels into the sun, reposition them as needed, and provide storage for the panels. As a further enhancement, I added a solar controller, battery, and inverter to the cart and turned it into a solar generator. That way I could have power available in almost any location I plan to go. With this set up, I can use both AC and DC items, such as a microwave, and even a refrigerator all powered by the sun.

The Solar Generator Parts

First, the technical details for those who are interested. The solar generator (which I call the SolGen 160) has a four major components. The 2 solar panels are rated at 80 watts each, for a total 160 watts. The solar charge controller is rated at 30 amps. The battery is a marine deep cycle model, and is rated at 210 amp hours. The inverter is provides a steady output up to 1100 watts of AC power, with a peak output of 2200 watts.

Ok, so what does all that mean. Based on the manufacture’s solar panel ratings under ideal conditions, the SolGen 160 should provide approximately 460 amps of power each week to charge a 12 volt battery. While you never want to discharge a battery completely, the output is enough to fully recharge the battery in 3 to 4 days. If you use only 25% of the battery each day, the solar generator should be able to fully charge it up during the next day. With this set up, it can power a number of appliances, such as a small microwave, TV, laptop, or even some power tools. All the comforts of home can be available wherever the cart is located, in a campground, a forest, or even the desert.

How was the cart assembled

I used 2×3 lumber as the framing for the cart, and enclosed it with the T-1 siding. The overall size of the cart is approximately 4 feet wide by 4 feet long by 4.5 feet tall. I began by building a wooden frame that fit around each panel. I then built two L-shaped pieces for each panel to hold the panels at a 45 degree angel. The L-frames were cross braced to provide a solid base for each panel. Then the two panels were attached together by screwing the frames together. Next I added the T-1 siding to enclose the cart, and a piece of plywood to form the cart floor. After that, I built doors on the back to allow access to the battery and components inside the cart. Finally, the cart was painted and caulked to prevent leaks, and wheels added to make it mobile.

Here is a video slideshow of the building process…

Cost of Materials

The SolGen 160 cost approximately $1500 to build. The cost breakdown is as follows:

Solar Panels – $ 850
Battery+box – $ 180
Solar controller – $ 100
Power Inverter – $ 70
———-
Subtotal – $ 1200

Cart – $ 300
————
Total – $ 1500
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The major portion of the cart expense was for the T-1 siding and the 2×3 lumber. The wheels, hardware and paint were a small additional cost, and purchased locally. While they lumber was purchased locally, the solar panels, controller, and inverter were all purchased from Amazon.com. While this configuration was designed to fit my needs, buying fewer or less expensive solar panels and components would reduce the cost of the cart.

Several people have expressed interest in the SolGen 160 since I posted it on Twitter and Facebook. I am considering selling a set of plans so people can build their own solar generators. See the form below.

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Category : Blog

6 Comments → “Building A Solar Generator on Wheels”


  1. Bill

    Nov 04, 2011

    Thanks for the posting Steven. Great job on the video too!

    Reply

  2. Maria Martin

    Nov 10, 2011

    I would like to obtain the plans of the Solar Generator on Wheels, so I can have someone make it for me, I have Muscular Dystrophy, I depend on several machines that batteries need to be charge up, it would be handy for emergencies, wish I’ve been there, and for near future, with this unstable economy that we don’t know what holds for us.
    Thank you, Maria.

    Reply

  3. Robert

    Dec 17, 2011

    Might I suggest for the same $800 of panels you can purchase
    KD235GX-LPB 2 235watt solar panels and obtain 470 watts peak output.
    Triple the output and would allow for more storage batteries and use of a 12v fridge,lighting,tv,and more.
    The cart would need to be a bit larger 5×6 however you would no longer need to limit your usage to 500 watts a day.
    On a budget note Costco has 100 watt panels on sale for $250 each. High efficiency when used with an MPPT charge controller from suppliers like morningstar etc.

    Very nice design,it almost looks like if it had a small electric motor and a front window it could drive to the next location!!!!
    Robert

    Reply

  4. Keith Levy

    Jan 08, 2012

    Hi Bill.
    How do you plan to transport your solar-cart from one location to another?
    I imagine the two batteries and the panels weigh around 150 kilograms.
    I can’t imagine you pulling it inside your tiny house every time you move.

    While it’s a nice idea, you have if you don’t mind me saying, taken a simple idea and complicated it. I use a tracking panel on The Flying Tortoise and having an angled panel is a very effective way of gaining power, however the regulator and batteries are all in the ‘mother ship’ where I can see them at all times and it’s a simple matter of taking the 90watt panel out in the sun on cloudy days which adds to the two 125 panels input affixed to the roof…

    Kind wishes…

    Reply

  5. Solar Panels

    Apr 18, 2012

    This seems like a good concept, but it may be far too cumbersome to build and transport. Still needs work, but a great start.

    Reply
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