30 W Solar panel - can it charge a generator?

daviddschool wrote in news:e35a378a-671d-473e- snipped-for-privacy@eb6g2000vbb.googlegroups.com:

1:no.(you cannot charge a generator, you might try a battery) 2:no.

Ok, how about this:

ale=3Den This is a battery like you suggested. Could this be trickled charged to run things constantly? And thank you for the quick reply

You need to do a little detective work.

How many watts does the lamp in your bedroom use? How many watts does your computer use? How many hours per day can you get 30 watts from your solar panels? If you put 30 watts for one hour into a battery how many watts will come out? Hint; It won't be 30. What is the efficiency of converting 12 volts dc to 120 volts ac?

After you have some idea about the answers to these questions.you can answer your own questions.

Mikek

I don't know a lot about batteries for renewable energy, but that battery looks suspicious. First it's $300. You need to find a better battery source. It's rated at 1 amp for 100 hours. Typically, batteries are specified for 20 hour discharge. I'd look at the curves before buying one.

You shouldn't have to pay $3/watt for solar panels.

Don't buy solar stuff from a tire store.

Do some math. Add up all the loads you want to run for how long and calculate the total number of amp hours per day at 12V.

You need at least that much solar power accumulated per day. Problem is that solar panels are rated for power output at noon on a sunny summer day in the lower latitudes.

Do some googling and you'll find maps of average insolation history at various locations.

You'll find that, for most of us, The total solar power you're gonna get to charge your batteries on a cloudy winter day approaches zero.

You need a LOT bigger array and a lot more batteries than you might think to do anything useful. Typically, you want more power when the sun ain't shining.

Bottom line is that solar power is not even close to cost effective, or green, for most of us.

I can think of two cases where solar power is beneficial to the end user...

1) where power is not available at all or costs way too much to acquire. If you have a traffic sign with lights on it, the cost of the solar array and batteries is often WAY less than the cost to dig up a street to route power from a source right across the street 100 feet away. 2) where you can get someone else to pay for it...government subsidies. For the record, I'm NOT interested in paying for YOUR solar system.

It makes almost no sense to pay $100 for panels and $300 for a battery plus another $$ for the inverter to get, maybe 50 watt hours on a winter day. This assumes that you're in Canada and not Arizona.

Even if your system is 100% efficient and you lived in a place that was never cloudy, you're gonna get a couple of hundred watt hours/day.

You're gonna be into this sytem $4-500 by the time you buy the wire and brackets and inverter and connectors and nuts and bolts and .... If you save 2.5 cents/day in electricity, the payback period is

50000/2.5 is over 50 years. If you count the cost of investing the money, the payback is...never. And that assumes your battery lasts 50 years.

Stated another way, the carbon footprint of you driving to two stores to pick up the battery and panels is probably bigger than all the carbon you'll ever save by using them. And that ignores all the carbon costs of making the stuff in the first place, shipping it around the world and disposing of it when it's done.

To recap. Not cost effective. Not green.

Are we green yet?

can

So my question is why would anyone buy a solar panel then to run a battery inverter?

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As stated above, in places where the alternatives are more costly and/ or less 'green' than setting up an effective solar system. You suggest that you have a generator and they can be cost effective, but are certainly not 'green'. A micro hydro plant would likely be more costly but can be exceedingly 'green'.

Neil S.

In Oregon, any hydro plant using any stream water must be licensed by the state. May be true in other states, as well.

Paul

Putting aside all the tech stuff and the well made point of the cost at the tire joint, if you run your stuff on 12v (LED lamps and use a computer that will operate off 12v) it can be done and plenty of people are doing that. It will however take an initial capital outlay of more than the $99 level :-)

Cheers ....... Rheilly P

That's obvious, but I'll say it anyway, the device they are using is designed for 120 volts ac input. Hmm... maybe you mean the whole concept of solar panels for household use. If we were starting from scratch, efficiency would be a very important criteria. Our devices would be designed to run on DC and would probably use a voltage higher than 12 volts to reduce I^2R losses in the household wiring. We would also be very stingy with what is on and for how long. Mikek

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Thank you everyone for the breakdown. I really appreciate it. So, if Canadian Tire isn't the place to get it, how about a starter kit for myself where I can work up to a more feasible solution? Any suggestions? Any manufacturers? Any websites? I know I am not going to be turning my entire house into a solar mecca, but I would like to start.

daviddschool wrote in news: snipped-for-privacy@b18g2000vbz.googlegroups.com:

The problem with a solar panel of of any power is, that on a normal day you are lucjy to get 30% of the specification, wich is very optimistic, and is not even reached for high noon desert sun. That leaves you about 5 wats per panel, and you sure need a lot of panels to reach any usable power. Storing that is no problem, but soring only imroves, what peak power you can draw. Example:

5 watts in ~12 hours is 60 watthours. Withdrawing it leaves you with about 80% efficiency, or ~50WH. Using a 100 watt device will drain the batteries in 30 minutes. To be usefull at all, you need big panels. A neigbour of mine, in high summer and 30 square meters of panels, gets peak 1700 Watts, and about a mean of 800 watts during 12 hours on a sunny summer day. Now in winter it gives about 200-400 W during about 7 hours. That kind of equipment might give a household a usefull daily ration of power, provided bad weather stays away. He has a 600 volts converter, and feeds it back into the 240 volt household power. You can sometimes see his meter running in reverse, but most of the time he can directly use the power.(He runs a gas station, and the pumps and computers run(almost) for free). Location:Netherlands, not a very sunny country, about like England. Batteries are only advisable, where normal power is not available. Good batteries are VERY EXPENSIVE. Dont use the China ones. And get a computer controlled charge unit, or even the expensive batteries give up the ghost in short order. For batteries:DO NOT OVERCHARGE, and , DO NOT TRICKLE CHARGE, and DO NOT DEEP DISCHARGE. Those three things kill batteries quickly. Or: Stop charging when they are almost full(~14.8 volts for AGM). Stop drawing power when almost empty(~10-11 volts). I hope this info is useful. :)

In the UK, the government have been scammed into paying well-off householders handsome amounts if they drive their meters backwards with their expensive and over the top solar PV arrays. Meanwhile other residents have to pay higher energy bills to make up for the shortfall.

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Adrian C

same here in france ... I pay for the neighbour's pv panels ...

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Kripton

the ESR Repository @ http://kripton2035.free.fr/esr-repository.html
the Geiger Repository @ http://kripton2035.free.fr/geiger-repositor.html

Is that to suggest that government would take taxpayers hard earned money and spend it in wasteful way? Mikek

Of course they do - they are government - but it's also redistribution of wealth to the greedy. Wrong, stupidly wrong. :-(

Having access to funds over 14,000 pounds is the entrance fee to join this 'Green' weeze, and some have been tempted to get themselves in debt to join the club - or even sign over their roof space for preditory vultures to sit on. Payback is 25 years, and it's not for certain that the panels and connected equipment will actually last that long.

And we have the traditional British weather, the sun does not come out that much ...

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Adrian C

Why should it? It's seen England in daylight once. ;-)

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You can't have a sense of humor, if you have no sense.

I use mine to charge my battery chickens.

Sylvia.

Still too lazy to use the good, old fashioned wind up chickens? ;-)

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You can't have a sense of humor, if you have no sense.

A true Brit would always prefer steam powered hens