The first major question one would need to answer is: How long do I plan to be without power? Less than 12 hours? More then 12 hours?

If you answered less than 12 hours – Solar backup generator.

If you answered more than 12 hours – Regular backup generator.

I am not going to talk about regular generators. We want to know more about a solar backup generators. What do I need to make one? How much will it cost? What can I power with it and for how long?

Let’s start with the last question first. To begin with, this system will only run a few lights, a TV and a laptop. This will not run your entire house. Just likeĀ  most store bought generators will not either. I, personally, would like it to be able to power my refrigerator for 4 continuous hours. In addition to two lights and a small laptop for 4 hours. The refrigerator uses 160 Watts while running. Two lights are 25 Watts and my netbook charger use about 15 Watts. That is equal to 200 watts. For a total of 800 Watt hours. I would use a 12 Volt system for this small application. 800/12×2=133 Amp Hours of batteries. I would round this up to at least 150 amp hours and purchase a battery close to that number.

Now for the solar panel. Since this system will only be use intermittently, I can get away with using a simple solar rule. 1 Watt panel power for every amp hour of battery. No charge controller is required. I would need a 15 Watt Solar Panel.

What does this cost.

Cheap Wal-mart batteries x2 = $100

20 Watt solar panel (No 15W Availible) = $200

Cheap AC/DC inverter 600W =$60

All total for less then $400. No gas, no fumes, NO CARBON MONOXIDE.

Xantrex XPower Portable Powerpack 1500

Xantrex XPower Portable Powerpack 1500

Or you can buy this. All ready to go. For almost the same price. Only problem, no solar panel and smaller battery. On the positive side. Very nice inverter! Nice cart!

Sure, this will cost more then a regular generator. But, your fuel is free. In a pinch, you could always hook the inverter up to your car battery. Then start you car when the battery starts to get low. Not the best solution but good in an emergency.