Monday, July 19, 2010

Power Shed

The final solar electric components have come in for my friend's off-grid house. The charge controller was back ordered, but now it's in. Currently power is provided from a battery bank charged from a generator. Batteries, inverter, and generator are currently housed in an old shed next to the house.

Next week we are going to build a power shed and move everything to that. What's a power shed? Start with a fairly ordinary shed. For my friends project, we are thinking of something small, like 4 X 8 feet. It's big enough to house a battery box, inverter, and generator. The solar panels will mount right on the roof.

There are some big advantages to a power shed rather than putting everything in the house.

For one, it's a bit safer. Everything is away from the house in an uninhabited structure. The house is in a nice shady area. Very comfortable in the summer and the surrounding trees provide some protection from cold winter winds. It would be a shame to cut them down just to have sun on the solar panels.

It would be possible to put the solar panels away from the house on a pole and keep the batteries and inverter in the house. One of the disadvantages with that is the cost of heavy gage wire from the panels to the house. It's the way my panels and batteries are set up, but I got a really good price on wire twenty years ago. With the panels on the shed roof near the batteries, my friend will save a lot of money. True, we still have a long wire run to the house, but we can use much cheaper high voltage wire since the inverter is in the shed.

The solar shed will be in a nice sunny location. I'm going to mount the battery gage in the window so they can see it as they walk from the driveway to their house. If the batteries charge is low, they'll know about it right away. Monitoring a home system is important. You don't want to wait until the inverter shuts off from low voltage to know you have a problem.

It's important to have good ventilation in the summer to keep the batteries from over heating. In the winter, the battery box and shed will be well insulated to keep it from getting too cold. Cold batteries don't hold as much power as warmer ones. On the other hand, too warm and battery life is shortened. Maybe I'd better put a thermometer in the shed that can be seen from the window.

One the cool things about a power shed is that it can be moved. If they want to relocate the shed to a more convenient spot, they can drag it or load it on a flat bed trailer. Someone could even use a power shed on rented land. Should they decide to move, they can take the shed with them.
In some locations, if a small shed is not on a permanent foundation, it's not taxed. Check your local laws. Often they can be built without a permit. I've heard of people who get a permit for a "garden shed." They even keep a rake and shovel in there, but it's a power shed.

That's next week's project. I'll ask the property owners if they'd mine me taking a few pictures.


1 comment:

  1. That's a sound concept, one used by many of the fishing cabins around the Laguna Madre. The shed is located on the (predominately)downwind side, to carry noise and fumes away, and isolate the cabin from any "mishaps". These are fixed by necessity (cabins on piers). But on land, mobility is a good idea.