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What Size Battery Would You Need to Power Your House?

Discussion in 'All other topics' started by ireland, Feb 13, 2015.

  1. ireland

    ireland Active member

    Nov 28, 2002
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    What Size Battery Would You Need to Power Your House?

    It seems like Tesla might be making a battery for your house. Would that be cool? I think so. But why would you need a house battery? I can think of a couple of uses:

    • For an off-grid house you might like to power it with solar or wind power. Unfortunately, neither of these two sources provide constant energy. If you could store the energy in a battery, you could use this during the night or calm weather.
    • Many people keep a gasoline powered generator for their house. I have one that I don’t use too often, but it’s awesome when you need it. What if you had a battery that you could use for your house in times of power outages? That would be cool.
    • It seems like the power company would like everyone to have a battery. With a house battery, you could reduce power spikes on the grid. When you turn your air conditioner on, it draws a large current for a short period of time(here’s an explanation of why the current spikes). With a battery this current demand could be leveled out (I guess).
    But that’s not why you are here, is it? You want to know how big of a battery you would need. Let’s find out.

    Battery Size
    We need some starting values. First, how long do you want to run your house on a battery? I think Elon Musk (from Tesla) said one week. Got it. The next big thing is the power usage. I think a fair assumption is a constant 2000 Watt power usage. Clearly a house would need more than 2000 watts at some point in the day. However, at night you wouldn’t need much power such that the average for the day could be 2000 watts. If you don’t like that value, you can put your own numbers into the calculations.

    If I know the power and the time, I can use the definition of power to calculate the energy stored in the battery.


  2. whiskey99

    whiskey99 Regular member

    Aug 9, 2010
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    HI,Ireland,I had a small single wide mobile home set up on solar power and this is what ended up with.
    (1) 2000 WATT modified inverter,1000 amps of battery storage @ 12volts,(4) 55watt solar panels.this was 30 yrs. ago.
    If i were to do it today i would have the following (1)8000 watt pure sine wave grid tied inverter,about 4000 watts of solar panels of which you would get only about 80% of that i.e. 3200 watts net.battery bank would be the fly in the ointment,but try to keep from using no more then 20% of amperage at anyone time.
    The 3200 watts of solar panels is per hour.
    Here is approximate costs of this setup (inverter $4000.00,panels about $4000.00,battery bank about $ 4000.00 plus all the wiring & installation,if you get the right inverter it should have generator lock out built in to keep from sending back up grid line and hurting utility workers,the other fly in the ointment will be the 240volt items in the house i got around that switching propane for cooking,drying clothes,and heat,hot water.

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