Thread: If a Solar panel is used a house do you..?

If you use a solar panel in a house how is it wired? Does it need to have an inverter and a battery? Are there better ways to store it? Is it plausible to say that solar pannels pay for themselves in a short time? So how does a solar panel get wired is my main question. I want to know if it has to be wired to the battery? Then if it does have to be wired to the battery then how is the battery hooked up to the house? Thanks in advance

Solar panels are DC, mostly in 12V. You can either use the electricity that way in a house wired for 12V, store it in batteries, or using a power inverter to convert it into 110V AC for use either with your house or to sell back to the utility Co. Solar collectors do not pay for themselves in a short time even under the best conditions, compared to standard utility company cost, it will take many years.

You can have a solar power system without storage batteries. It is called a grid-tie inverter and allows you to use the existing electrical grid for storage.
Grid-tie inverter - Wikipedia, the free encyclopedia
In this way, your electrical utility has to make up the difference when there is no solar power coming into the grid, and cutting back their generation when lots of solar power is being generated. There is only so much solar generation that can be installed on the grid before grid stability issues arise.

Such a system does not give you any independence from the power grid, if a power outage should occur.

Originally Posted by Harold14370

There is only so much solar generation that can be installed on the grid before grid stability issues arise.

Thank you both for the responses they were exactly what I was looking for! Extremely helpful and informative and I really appreciate the link. However your comment Harold, brings me to a question and this quote in specific is what made me think about it.... So my question as obvious as it might be is, What stability issues are you talking about? If it is possible to be more specific I'd love a response but if it isn't then just tell me where i can go to read more about these issues.

I also want to know if you wired it too batteries, do you loose a lot off the power int he transfer?

Any time you invert or move power you're going to loose some. Most inverters of the house size are in the 90 to 95% efficiency range, the rest being lost as heat. Also, unless you use particularly thick wiring moving the 12V from the panel to battery or into the home, you'll loose power there as well.

Originally Posted by Fmp2491

Originally Posted by Harold14370

There is only so much solar generation that can be installed on the grid before grid stability issues arise.

Thank you both for the responses they were exactly what I was looking for! Extremely helpful and informative and I really appreciate the link. However your comment Harold, brings me to a question and this quote in specific is what made me think about it.... So my question as obvious as it might be is, What stability issues are you talking about? If it is possible to be more specific I'd love a response but if it isn't then just tell me where i can go to read more about these issues.

I also want to know if you wired it too batteries, do you loose a lot off the power int he transfer?

The grid stability issue isn't something you would have to worry about as a homeowner. It's more of a problem for the electric utility. If a large percentage of the generation in an area is solar, and if the weather turns bad, all of a sudden that power goes away. The coal or nuclear plants running on the grid may not be able to handle the extra load, which could lead to cascading blackouts.

I have a shed that I have a small solar cell on. I keep a 12 volt car batter charged with it, and use 12 volt RV lights inside. Works great, but that all I'm going to spend money on.

ok so the small solar pannel is about strong enough to power for about a Small Shed's worth of electricity? Im trying to essentially figure out how long one lightbulb would take to drain a whole car battery if it was during the day when the solar pannel was also exposed to sun? So as it was discharging to supply the bulb with power the solar pannel was recharging it. An exact specific number is not necessary I just want to know a ballpark figure.

Thanks

A 12 volt car battery with an amp-hour rating of 75 could supply about 75 amp-hour*12 V = 900 watt-hours so it could power a 100 watt light for 9 hours. That's without recharging. A 50 watt solar panel like this one http://www.solarpanelstore.com/pdf/SLP050-12.pdf would supply half the load when the sun is shining.

Wow ok that was a lot better of an answer than I expected given my vague question. Lol thanks I appreciate it!

The calculations aren't that hard. I've got a similar set up with a 60W solar charger and a deep cycle battery that's powering up a shed for a couple hours a week running two CFC lights, an eliptical machine, small TV and will soon power a fan from a solar heat storage box.

An inexpensive book you might like is "the 12Volt bible," which though written with boats in mind, has all the important materials on wiring size, average loss, consumption calculations etc.

Well, I think there are two ways to store energy first one is battery bank and second grid inter tie, both are efficient in storing energy but in battery you can use charger controller to control the extra energy level if there is overloading situation coming. I saw that mostly home solar panels user use battery, it’ easy and cheap method..

Is it plausible to say that solar pannels pay for themselves in a short time?

Depends where you live to a large extent. Solar power in USA is about twice the cost of that in most European countries. (No idea why.)

For individuals at the retail level, some countries or local authorities have much better incentive schemes than others. Regions like mine with very (very) hot summers are very keen to reduce peak loads during hot afternoons. The subsidies paid for the solar installations offset the exorbitant costs of generating or buying in extra power during the periods when solar PV generates maximum power - as well as the all day, every day, benefit of reducing transmission losses. (Also a larger benefit in places like South Australia where you need long transmission lines from centralised power stations to quite small populations in scattered townships.)
So my own solar system cost us less than $2500 six months ago and has already returned $300. No better investment available. (I might add that the rate has already gone down for new installations, but so have the prices. Some home improvement companies are offering systems as freebies for renovation contracts.)


But if you're interested in using batteries rather than treating the grid as a battery, Lynx is right about pursuing boating as a good resource for solar info. They've been doing it for years.