How many solar panels (PV) for a 1500 sqft off grid home?
We use about 400 to 500 kwh per month. We have a tv, computer,microwave, and of course fride, washer/dryer, and back up water heater. (solar water heater is the main one)
Also how much would such a system cost, including batteries and inverters? Rough estimate okay.
I try to use very little energy, and those are the figures on our current electic bills
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You need to consider if you’ll be tied to the grid or off for starters. Here is a source with some ready pricing to give you and idea.
Another source for some off grid solutions.
I’d like to give you a balpark but so much is dependent on actual usage, location other variables.
This is something you really need to do your homework on or you will get ripped off or end up with something that isnt doing what you wanted
Check in with Lowe’s they are going big with GREEN this year
First off, are you really really sure you only use 400kw/h per month that figure is incredibly low compared to typical usage. I would say our household which is about the same size as yours uses 4 times as much, and we have solar heating, energy saving bulbs and efficient appliances.
Last time I did the maths for a complete conversion for our place, it came in at about 30-40k for reliable 2Kw constant usage (1440kw/h per month) for an AC based system with battery and inverter.
It probably makes better sense to buy DC appliances and spend out on energy efficiency at the point of use i.e. laptops instead of desktops and so forth.
When you come to work it out there are some good rules of thumb to help you.
1 square metre of PV will produce about 200W of power. (0.2 Kw/h per hour of sunlight)
You need to store about 5 Kw/h for every 1 you plan to use with a battery.
Inverters waste energy, check the efficiency.
Look at your whole household when you make the shift, it is cheaper usually to reduce consumption than increase supply.
I use about 500 kWh a month and have a 1600 sqft home. It is two years old.
500 kwh divided by 30 days is 16.6 kwh a day. I don’t know where you live so I can’t say how many peak sun hours you get so lets just use five.
16.6 divided by 5 = 3.3 kwh in solar modules. You said the home was off grid so $30,263.70 for parts. Add in 10% to 15% for the install and you got it .
Really there is no way to know without asking you a lot of questions.
What is the total wattage that will be on the system at any one time.. (tv set, freezer, coffee pot and hair drier and a few lights) that will tell you how big of an inverter you need. Then you will need a battery bank that will only be drained by 50% by the end of the day before re-charging. Which you can find because you know you use 16.6 kWh per day. 16.6 divided by 48 volts battery bank is 345 amp hours in battery power plus like said above you need to double that so 700 AH should do it.
There is still more to it because you need to make sure that the 3.3 kWh in solar power will give you a 5% to 10% rate of charge. At 48 volts you would have about 68 amps so you are close to 10% so all is good so far.
If you plan to do it all your self you should start out by buying the parts for a small system and teach yourself all about it. Or talk to a dealer.
Here is a good info page to help you out.
http://www.oynot.com/solar-info.html
And here is a price list of complete systems. http://www.oynot.com/solar-grid-tie-backup-by-array-size.html
http://www.infinitepower.org/calc_pv.htm
this is a link to a solar cost calculator
you need to know: how much electricity you use
how many hours of sunlight in your area