# How big of a battery would

1. Oct 3, 2012

### Flyingwing12

How big of a battery would....

How big of a battery would it take to power the average sized home for 24 hours?

Considering basic kilowatt-hour consumption with AC. Would it even be possible to power a home off a DC source?

I would hypothesize that you would have to change all of your existing AC appliances to DC.

Which would take some serious work.

Just a question I have had for a while.

2. Oct 4, 2012

### davenn

Re: How big of a battery would....

do some calculations and see what figures you come up with

work on....
a number of lights at X watts each for X hours / day
look for some info on a DC fridge/freezer and get its power consumption in Watts
same with your cooking gear ... toaster, stove, jug for boiling water etc

add it all up for the number of total kW/hrs

as far as appliance type goes ... AC or DC
well you have 2 choices of supply, you could leave it all AC and use an inverter off the batteries .... inverters are available at the kW level and are getting more and more efficient

or you could do as you said and convert the housee to DC and cut out the DC to AC conversion losses.
But if you do that, you need to consider the DC losses at running gear from probably 12 or 24V DC and running that throughout a house at high current levels is going to be VERY lossy compared to the higher voltage of AC 110/230V and lower current

Dave

3. Oct 4, 2012

### sophiecentaur

Re: How big of a battery would....

An affordable, typical car battery will give you 100Ahr (probably half that, if you don[t want to break it). Thats 100X12 Whrs or about one unit (1kWh). How many kWh would you estimate that your home would use in a day? Sounds to me that you'd need quite a few car batteries to do it that way!

If you are considering alternative energy supplies then you need to think more radically. For the heating part of your demand (the greatest, by far for most homes), storing the energy as heat from solar heating panels would be much cheaper and longer lasting. Use PVs and batteries only for the electronic equipment, lighting and the motors. Have a low voltage system for all the small electronic stuff that uses mains adaptors and for LED lighting with a low power inverter only for the stuff that really needs mains voltage. That would modify considerably the battery capacity that you'd need.