Posted: 11/12/2010 8:36:44 PM EDT
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I have no idea why the hell I want to do this, but here is an idea that I want to make into a reality.
I would like to know if it's possible to do the following: Get a small solar panel and set it up to charge a large battery during the sunlight hours of the day. At nighttime I could disconnect the battery, bring it inside, hook it up to some kind of an inverter, and use it to power small items such as the tabletop fan that I run all night as noise to help me sleep. According to my Kill-A-Watt the fan uses about ~.40kWh a night. I know it's not much but it ends up being about 12kWh a month. I figure if I can power it for free with solar, why the hell not? What kind of a cost would I be looking at to do this, if it even is possible. |
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That's 400 watt hours over perhaps an 8 hour period, meaning that the fan is drawing about 50 watts?
A quick back-of-envelope calculation is that would represent about 4 amps from a 12-volt sealed lead-acid battery. 4 amps over 8 hours represents 32 amp hours of battery capacity (however you don't want to completely discharge the battery, so double that to approximately 60 amp hours capacity to ensure some breathing room. A 60 amp hour battery will probably weigh around 50 pounds, so it's not going to be the most portable thing to lug around, but it is do-able. As a rough guess, a solar panel that could recharge such a battery during a cloudless day might have a size on the order of six to ten square feet (assuming that it is fixed in place rather than tracking the sun) - larger is better if you want to have reserve capacity for cloudy days. While that's not large enough to be impractical, it's not trivial either. So, my guess is that you could probably put together a system to power the fan, and it would probably run you something like $300 to $400 to build it. I could be off by a factor of two, though (considering losses in the battery charger and the inverter). So, you wouldn't really be powering it "for free"... It could take you ten years or more to recoup your investment by offsetting power utility charges (depending on the per-kWh rate that you pay). |
| There are small companies that make make small scale solar power panels that directly hook up to your main power, they also offer optional battery back-ups. Not only that but there is a federal rebate of 30% or some such for doing that. Some states also offer tax incentives for going green. If I owned a home, I would look into it. I don't think investing into solar panels for the barracks is very cost effective, lol. |