Anyone know a good resource for information regarding solar panels for home use? We're moving into a new house, and at this time I don't have the money to put up a whole array like I would prefer to. I saw a DIY kit online that says it generates 20W. Looking at our last utility bill, I notice that in the previous month we averaged 16.9 Kwh of use per day. I'm not knowledgeable about such things, but I'm guessing that this 20W system, at around $500 would take about 823 years or so (just an estimate) to pay for itself.

Excuse my mediocre math and logic skills here, but if our daily usage was 20Kwh, and a solar panel was generating 20W per day, does that mean the solar is creating 1/1000th of our daily use?

I need to get educated!

Transformers won’t work with solar panels. Solar panels produce DC voltage, transformers only work with AC. Solar panels are for charging batteries. You need an inverter to convert the battery voltage to AC.


A 20 Watt solar panel is not enough to do anything in a home. A 20 watt 12 volt panel only produces 1.6 amps, while this could be useful for camping, it’s nothing for a house.

To put 20W into perspective...

I use a folding 18W/12V solar panel in one of my portable kits for charging batteries,cell phones, etc. I wouldn't even use a panel that small to charge a car battery unless I had a few weeks of sun to spare and the battery were really tiny.

The stuff for home use is usually at least 60-120 watts per panel.

Check out http://www.backwoodssolar.com/home.htm thew have lots of information.

Good point about the AC/DC issue. The kit that I was...now past tense after these posts...was thinking about includes an inverter.

Figured it was going to be more expensive than the 20W kit...all things in time!

If you get away with $25,000 for a good whole house solar home project I would say you were doing good. Closer to $40,000 or $50,000 to be realistic.


But that doesn’t mean you can’t put in zone solar power, have a panel that runs a few things.


But really your best return on solar power is solar water heating. Water heating is less expensive then solar electricity producing panels and they give a much better return on your water heating bills. Almost eliminating it. Another thing to look into is solar air heaters. These work like an electric heater would, they heat just a room, they are not too expensive $1600.00 for one that produces the same heat as an 1500 watt electric heater would. But they are also easy to make. And I have not seen it done in any that I have looked at, but you can boost their heating even more by putting several 12-volt light bulbs (like an auto stop light) to produce extra heat to warm the air even more. Just run the light bulbs off a 12-volt solar panel. No batteries needed, when the sun goes down the air and electricity production stops. It would be simple to do.


PS you could also use the light bulb idea in a solar water heater to make it produce hot water faster.

You can also DIY it and home make solar water heaters which use black PVC or metal pipes or even recyclables to heat the water...much more efficient than converting it to electricity, then to heat.


Here's an example (there are many out there just like this one)
http://www.kk.org/streetuse/archives/2007/06/beer_bottle_solar_hot_water_he.php

Yes, a 20w panel will produce LESS than 1/1000 of your daily use. A single 60W lightbulb would need 3 20W panels, in full sun, to operate.

Solar is not a "payback" system by any means. Solar is what you use when you decide you'd rather just make your own electric.

You don't start seeing whole-house capable systems - and by whole house, I mean a whole house that uses highly efficient refrigerators, no air conditioning, CFL and LED lighting, no electric stove - until you start spending $15,000 or so.

You can start small. If you have a shed, or a utility area, you can light that with a 20W system and some LED's.

The thing to remember - it's not alternative energy - it's alternative energy sources - as in multiple things at once. We already do this - gas, oil, electric all are energy sources we use, you can still mix 'n match. I heat with wood, but still have an electric hot water heater. So we dropped the oil, but kept the grid-tie electric. And that's OK!

Best of luck.

Have a look at www.homepower.com for a LOT more.

Quite right.

Back in the day, a lot of rural folks used wood fires as their primary energy source. It was fairly cheap (usually free for the taking), plentiful, and reliable. It wasn't the easiest energy source to use, you certainly couldn't use it for cooling a house, but for cooking, heating, and sometimes even lighting, it was acceptable.

Hello Ors,

I have some experience with DIY small solar photovoltaic systems.

Energy consumption is measured in wh (watts-hour). For instance, a 60w light bulb, lighted for 3 hours will use 60w X 3hrs = 180wh.

The same ideia is applyed to energy generation: one 20w solar pannel, receiving full sun for 5 hours will generate 20W X 5hrs = 100wh.


To supply your current demand of electric power (16.9kwh/day), you would need aproximately 3.4 kw in power generation (assuming 5 hours of full sun). It can be achieved with 170 20w panels, 28 120w panels or other similar configuration.

Unless your are very far away from the power grid (or the goverment has some kind of incentive to "on grid" systems), Solar photovoltaic power is rarely the cheapest option. But it is still usefull as an emergency energy source.

My first experience in photovoltaics has been with a 20w solar pannel, small gel cell battery and a charge controller, to feed a ham radio transceiver and two emergency lights.

Now I have a bigger pannel (120w) and batteries, to run a complete ham radio station, wireless internet link, notebook computer and some fluorescent lights.

You can find lots of information about DIY alternative energy (wind,hidro, solar) in this site:

www.otherpower.com

Fabio