A question about solar panels

[Guest]

Wow, that seems like really inexpensive systems, and if for real, seems like a no brainer.

What kind of wattage could that support ? Ive read that the average family does about 1600 watts a day ? I could be wrong..

[Delta9r]

I am far from being an expert, I've just got years of personal experience coupled with that of friends and neighbors.

My power usage is frugal compared to most folks who've never had to rely on a stand alone system.

How much can I run? The amount is limited by my inverter, which peaks at 2000 watts. I've never ran it at full load for any length of time, and I don't run heavy loads when the sun isn't shining.
I can use the rice cooker any time, day or night, and the refrigerator is always powered on.
For me the refrigerator is the most important appliance and I've been much happier with this regular fridge than any of the propane units I've had in the past.

I have about $1,500 into my batteries, which I purchased new from Pahoa Battery & Propane.
The inverter is a 2000 watt Xantrex I bought from a friend for $350 after he bought a new Outback rig.
The panels were also purchased second hand several years ago, and I bought them over the course of a few months @ $300 apiece.
Add in a cheap charge controller for about $150, as well as wiring and battery cables, and my total cost has been less than $5k.

Not sure what a "normal" family uses.

"Life is labor, and all that is good in life comes from that labor..."

[ericlp]

Thanks for sharing your specs and info Delta9r. What is the model number on your inverter? Maybe I should try a cheap 2000Watt before spending 2500 on a 2500 outback one. Hmmmm... Do you think you could run a washer with your setup?

[Guest]

I have a extra large flat screen, a computer surround sound system and my music equipment....speakers etc...

Its just me and my wife and my dog. So not a big family, but a good amount of electrics.

What type of system would I need ? I would love to be off grid if possible.

Getting a propane dryer for when we cant hang out our clothes and on demand water heater all seem like good substitutes for those things.

[Delta9r]

Washing machines have high inductive load engines, so I have never considered running one from my setup, but I do believe than a propane dryer would work.
My inverter is one of the cheaper modified sine wave types, so you might not want the same model.
The more costly inverters usually come with a charger/charge controller, and I'm currently saving up for a better unit.
High wattage stereos will also take your batteries down quickly, as will guitar amps, so I run such items from my genset when the need arises.

As someone mentioned earlier, if you're gonna wing it on your own, starting small and building up as you go will lessen the learning curve as well as ease the financial burden, but if you've got the money then a professional installation is definitely the way to go. Me, I'm not so flush with cash flow...

Good luck.

"Life is labor, and all that is good in life comes from that labor..."

[Guest]

Pro install for my needs has to be 12-20K, yes ?

[MarkP]

I figure I have about $3,000 to $4,000 into my system which consists of nine 240 watt nominal 24 volt panels, a 45 amp morningstar mppt charge controller, a re-purposed APC SmartUPS 3000 for an inverter, eight 6-volt costco golf cart batteries hooked up in series for a nominal 48 volt bank, and the miscellaneous wiring, disconnects and overcurrent devices to hook it all together. The SmartUPS 3000 is a true-sine wave inverter that will supply 2,700 watts continuously (3,000 volt-amps). It was not designed for off-grid applications but it is working so far.

My experience is similar to Delta9r's. I put my system together over time, waiting for good deals. The whole concept of "This is my power bill at my Waikiki highrise. What system do I need to provide that much power at my off-grid container house in Puna" just does not compute. If you are asking that question you are almost certainly doomed to disappointment. There are certain things you need like lights and refrigeration and water pressure and a big screen TV. Everything else is a luxury. Keep in mind that while watching the big screen TV you don't really need the lights and water pressure and the heat from the TV will help keep you warm and control humidity, so you see it is all about priorities.

[PaulW]

How much power (kwh, or days of usage) does the typical battery bank store?

[MarkP]

If I get through the day without abusing my batteries too badly I am doing well. I have a generator for back-up so if it has been cloudy I run the generator in the evening while doing laundry, making dinner, etc. Once the generator is on there is no downside to using power at night other than the fuel consumed. With my UPS setup the generator is supplying all power needs and the UPS is slowly charging the batteries. Otherwise, whenever possible I do laundry in the morning, ideally late enough that the batteries are mostly charged and the charge controller has switched to "topping off" mode which means it is limiting the charge going to the batteries and is throwing energy away.

I have a Bosch Nexxt 300 front loading washing machine. It has fancy electronic controls and does not have a high start-up surge so the UPS is fine with it.

[peteadams]

We're entirely off grid with 2.6 kw of panels installed in 2005. We've had several L16 battery replacements since then. Back when I was measuring our daily usage I found we averaged about 4 kw per day. One does have to be frugal with electrical consumption off grid. Our major loads are refrigeration and a 1 hp pump that usually runs on and off over a period of about an hour per day. After asking any number of on grid people, local and mainland, what their usage is (many of course didn't know), it seemed to range from 10-20 kw a day. I once read an article about a couple in Portland, OR who were trying to go green and they stated they had whittled down their consumption to 7 kw per day and found that a bit onerous. After one of our common very gray days here in Puna it's always a good idea for us to run the generator in the evening to pump the batteries back up a bit.