Time for me to think about installing solar power...

[lawrocket 3]

Saturday topped off at 109 here in Fresno on Staurday. Same yesterday. We're in the midst of a decent heat wave here, and today is supposed to top out at 105-110, same tomorrow, with nothgin under triple digits until next weekend at the earliest.

This led to some misery, I tell you. On Saturday at 3:50 p.m., power went out. It came on for a few minutes here and there, but was not totally restored until around 7:00. It sucked. Yesterday, power went out at about 3:20 and was not restored until after 8:00. Sure, we could cool off in the pool, but spending five hours in a swimming pool with an 11 month old ain't the best idea.

It was a bitch! Worst was an 11 month old boy who had be be pretty hot, but he was a little trooper. I'm concerned that these outages are going to continue. Now I'm thinking that it would be useful to actually buy some of those solar power cells. How nice would it be to, on a hot as hell fucking day with power out to be the house that has some AC going?

How much does it cost to set up a solar unit that would be enough to:
1) Power the AC;
2) Power the refrigerator;
3) Power my kegarator (even the beer got warm, dammit!); and
4) Power a television.

My wife is hotter than your wife.

[billvon 3,102]

>How much does it cost to set up a solar unit that would be enough to:
>1) Power the AC;
>2) Power the refrigerator;
>3) Power my kegarator (even the beer got warm, dammit!);
>and 4) Power a television.


Well, make sure you're solving the right problem first. If losing power on occasion is the problem, a cheap generator and a transfer switch is going to be your cheapest solution. If power bills are the issue, a grid-intertie (with no backup batteries) is going to be more cost-effective.

But if you want both, and you don't mind dealing with batteries, then solar backup can work. You'll need the following:

1. Batteries. About $50 a kilowatt-hour.

2. Inverter. Best price point right now is the Outback GTFX2524 at about $1500. Good for 2500 watts, which is a small A/C, an efficient refrigerator and some entertainment (TV, computer etc) 3600 watt version is $1700.

3. Solar. Running around $4/watt now.

4. Charge controller. $150 for a cheap one, $500 for an excellent one.

5. Misc - solar mounts, wiring, new breakers, DC fusing etc.

One good option is to get the GTFX inverter, the batteries, and wait on the solar. For $2000 you can get about 8 kilowatt-hours of ridethrough, which means two hours at full power or all day with minimal usage (i.e. just refrig, TV, fans, lights etc.) Then you can add solar later with not too much fuss. You can also do clever things like load balancing, which saves you money if you have TOU metering.

[lawrocket 3]

Bill, I'm interested not only in backup power, but also in saving money in the long run.

I plan on being in this house for at least ten years. Goodness knows, Fresno has enough sunlight - it's why we are the raisin capital.

I understand you actually put power back into the system. It's something I'd certainly be interested in doing.

So with the inverter and the batteries, does that come down to taking the power off of the main system and storing it for emergency use?

My wife is hotter than your wife.

[PhreeZone 20]

So how would you figure the number of batteries and size of solar grid you'd need? Say your average monthly usage is about 900kwh with a peak of 1500 and a low of 480?

My calculations puts the max load at about 32kwh per day, is that the number to shoot for?

I'm looking at getting a house and if I could go off the grid when I buy it all the better!

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[wildblue 7]

CA is one of the best places for solar... you guys get like 4 times the kWh/m^2/day (something that that) as we do here. And a ton of incentives from the state. Bastards - more reason to hate you.

Quote

My calculations puts the max load at about 32kwh per day, is that the number to shoot for?

Put money into being energy efficient first. I read somewhere that for every $1 you spend to increase efficiency, you'll save $2 on the solar stuff. EDIT: Bill says $5-$10... we'll go with that.

it's like incest - you're substituting convenience for quality

[billvon 3,102]

>So with the inverter and the batteries, does that come down to taking
>the power off of the main system and storing it for emergency use?

Basically yes. The batteries are charged once (when you first power it up) and are then 'floated' forever. Floating is a very, very low level of charge that makes them last as long as possible. If you add solar, the batteries still float; the inverter sends the excess power back to the grid. If you don't have permission to feed power back, you can run off the batteries (and charge them via solar) and then fall back on the grid only when the batteries get low. That's hard on the batteries though.

>So how would you figure the number of batteries and size of solar
>grid you'd need? Say your average monthly usage is about 900kwh
>with a peak of 1500 and a low of 480?

Peak of 1500 watts? That sets the size of the inverter; a 2500W would be fine.

900kwh is about 30kwhr/day, so the first step is to reduce that to about 8-12. You can get there pretty easily. For every $1 you spend on efficient appliances (refrigerators and A/C mainly) you save $5-$10 on the solar system, so that's the first target. We got down to 4-5kwhr/day before we started with solar.

Once you get to say 10kwhr/day, then you divide that by the available direct sun hours per day (5-6 in sunny areas, 2-3 in the northeast.) So in Arizona you'd need 2000 watts, which will come to about $8000.

[PhreeZone 20]

Yeah, what kills us here is the heaters for winter. Its hard to heat a house when its 10 degrees out on 8kwh per day My max usage in May - October is less then 600kwh per month. Thats about 20kwh per day and I'm pretty sure that I can get lower once I can get rid of some of these cheap appliances they put in apartments around here.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[billvon 3,102]

>Yeah, what kills us here is the heaters for winter.

Don't use electric heat! It's the most expensive form of heat there is. Natural gas, oil and wood are cheaper even with current fuel prices, and of course more insulation always brings prices down. For rentals, you can get catalytic heaters that run off propane or natural gas.

Solar hot water is a very cheap way to save on electric power if you're using electric DHW (and you can make the changes of course.) Systems can run $1500 or less depending on climate, roof and current system. Payback is usually under 5 years.

>Its hard to heat a house when its 10 degrees out on 8kwh per day.
>My max usage in May - October is less then 600kwh per month.
> Thats about 20kwh per day and I'm pretty sure that I can get lower
> once I can get rid of some of these cheap appliances they put in
> apartments around here.

Unlikely; cheap appliances are inefficient, which means more heat given off. Get more efficient appliances and you'll need more electric heat.

[wildblue 7]

bill -

what do you think about using waste heat for DHW? Seems to be cheaper than solar, maybe more invovled installation though? I haven't looked into that much, but it seems your AC might work better/longer. Wouldn't work all that well here, but seems like it might be a decent way to go for people in the bottom part of the country.

it's like incest - you're substituting convenience for quality