Solar AC power

[ironhat]

I have my home properly wired to plug in a gasoline generator - the proper switch panel connects some of the home's circuits. Anyway, I came across this and am now thinking of solar electricity. Do these folks have a good, pre-thought out product or just a good-for-them-thinking-to-make-a-buck, rip-off? Will a local electrical contractor do a better job. Remember, I'm pretty rural and there's likely going to be a learning curve for the professional around here.

[LCHIEN]

personally I think that ad is hucksterism. I would not trust those guys. Lost of exaggeration.

For $2000+ they will sell you an 90W solar panel, a 1800 W inverter and a battery.
They say it weights 65 lbs I'm not sure if that's the whole thing or just the battery that weighs 65#.
Assuming generously its the battery (which would make it a bigger battery) 65# is probably a bit bigger than your average car battery which I'm guessing offhand weigths about 45# and stores about 60 Amp-hours of energy. So a 65# battery lets say generously that it holds about 100 A-hrs.

That will run an 1800W inverter about an hour and a half. BTW, an 1800W inverter provide less than half the power of your average $800 4000W portable gas generator which will run for 6-8 hours on about 5 gallons of gasoline producing around 2000 W or 3-4 hours producing 4000 W.

To charge the battery fully, it will take a 90W panel about 10 hours of bright direct overhead sunshine. Maybe 20 hours of sunshine if its optimally pointed at the noon sun while the sun moves across the horizon and more if you aimed it last fall and its now spring - more than a day in any case.

So they talk about running out of gas... how about if you use up the battery in 1.5 hours and it takes 2 days to charge the battery with that puny solar cell array?

Anyway, what they are selling seems way expensive for what you get and not even suitable for purpose. A good array and a bigger battery and a larger inverter are necessary to approach the performance of a cheaper generator and will likely to be much more expensive.
As it is, it would be suitable for helping ride out a brief power outage with a couple of *small* appliances.

[gsmittle]

Hmmmm… Personally, I don't find the web site terribly convincing—something about the typewriter font and the looooong page that's short on details and long on hype. What's a "Solar Generator" anyway? A battery?

I've never seen a whole-house solar power unit in person, but from my reading (yes, I read a lot) I get the impression that the battery part of the solar power unit is pretty large and heavy. I can't see an 1800 watt battery (what is that, maybe 50 amp-hours?) powering a refrigerator for very long.

My 5500 watt generator will just power the refrigerator, freezer, furnace, and a couple of electrical outlets.

I'm sure Loring will weigh in with much more detail and actual facts.

g.

[LCHIEN]

...

I'm sure Loring will weigh in with much more detail and actual facts.

g.

you're right - I already did!

Anyway if you want to wire your house for solar you'd better contract with a professional solar panel installer. The batteries to power the house through a nighttime outtage let alone a few dark and/or stormy days or upper lattitude winter days is going to be ginormous and expensive. The panels will cover your whole southern facing roof and to help pay for it you will need to become a co-generator and use your power to intentionally back feed the power grid to help pay for the system on sunny days. Seriously.

Most people will install solar panels in sunny low latitude climates to generate power during the daytime and co-generate the excess (sell it to the power company) and then draw grid power during the night and other times when the panels don't produce. They don't even pretend to be able to afford the batteries and accompanying problems as a backup solution.

I guess the original question was for an alternative to a small gasoline generator (although you did mention a transfer switch to power the house wiring). Its a matter of scale... the solar requirement to replace the gas generator is more expensive and more problems. For the same reasons gas is great to power cars we won't be seeing practical solar cars in my lifetime.

[ironhat]

Thanks, Loring!

That's just what I needed to hear - the most simple terms of why this wouldn't work. Thanks, bud!

[DrChas]

I have put in solar electric power. What I did was use an installer with a good reputation in our area. I priced out solar panels in advance and did the homework. The installer insisted on supplying the panels, which was fine by me since his prices were competitive. It was not cheap, although frankly I don't remember the costs at the moment. I put in a 3.6 KW system, which supplies all my electrical needs in the summer, but not in the winter (I heat my shop with electricity, there isn't so much sun in the winter, and on days like today the panels are completely snowed in).

It is NOT an emergency backup electricity system. It is fully grid connected, and when the grid goes down it cuts out power from the panels (to prevent back-feeding and electrocuting repair people). I could add batteries a new panel, inverters etc. and make it a backup system, but that would be quite expensive. Frankly it would be a lot less to just buy a generator.

I recommend looking into solar power. It is long-term cost effective, and will likely be more so as electricty prices go up. However, it is a lot of up-front cost, and it takes a lot of solar panels to run a house. In no sense is it the cheap alternative. I put mine up one year when I got a short term unexpected increase in salary. My thought was to look for something that I could do with the money that would leverage that windfall into the future.

[dbhost]

I would be greatly concerned about it. The BBB has no rating report on this business, and they are not BBB accredited... Caveat Emptor...

[Mr__Bill]

A while back I read an article about retrofitting an electric car to output 110V AC and to be used as a generator. It runs off of the batteries until they get low and then the car starts and charges the batteries. As I remember, it used less gas than a stand alone generator, was all automatic and if you left it on outside it was hard for someone to just pick it up to steel. It seemed like a good idea especially if you have an electric car or another good reason to get one.

Bill
over here on the sunny left coast at 42 deg. north latitude.

[gsmittle]

you're right - I already did!

Wow, we must have been typing at the same time!

Thanks for the cogent explanation—sometimes I know this stuff empirically but don't have the background to back it up.

I do know that several full-time RV'ers use solar and batteries, with a generator for backup.

g.

[cwsmith]

Well, I certainly wouldn't "go there". I've looked at "solar" systems and components to make my own, just for Amateur Radion use, and that single solar panel probably wouldn't take care of our annual "Field Day" power needs.

I think Loring stated it best with his technical details, but just seeing little statements like "up to" 1800 watts, makes me wary ("up to" is probably maximum power on a nice early July at noon in Phoenix, AZ). So too are the needs for solar power on an absolute worst-case scenario, that the rather creative writer points out. (He of course doesn't mention how those solar panels, if permanently mounted outside will get covered in snow and thus rendered useless; or, that during such storms we generally do not have bright sunny sky's!)

I hope this helps,

CWS

[jdon]

It seems that the OP concern was using solar power as an emergency power source.

In my experience, power outages almost always occur in conditions not amenable to solar power- at night, stormy, and/or overcast, so it could be a long time after the battery is drained before charging restarts. Also, IIRC, PA is not in the Sunbelt!

[ironhat]

<snip> Also, IIRC, PA is not in the Sunbelt!<snip>

It's not??!