Batteries

Deep cycle batteries are measured in amp hours not cold cranking amps like car and truck batteries.
Car and truck batteries will not last very long for alternative power usage as they are not meant to be cycled (drained).

Batteries are DC not AC.

An amp hour is a measurment of how many amps are available in the batteries for use.
It means 1 amp used for 1 hour - if a battery has 270 amp hours it has 1 amp available for 270 hours. Although this is technically true, it is best not to remove more then 80% of the amp hours from the battery at one time..ideally it is best to use no more then 50% to make the batteries last a long time.

In a backup power situation having 370 (AH ) amp hours available would mean:

From full to 80% discharge you would have 296 (AH ) amp hours available to use.
From full to 50% discharge you would have 185 (AH) amp hours available to use.

To calculate how much power anyone item you wish to power needs in battery storage:
If its a AC device that you are trying to figure out how many amps it uses in DC....

A TV that uses 200 watts for instance = 200 watts AC divided by 12 volts DCbaueryvoitage = 16.66 amps DC/hr. If you have 185 amp hours available (500/0) in your 370 AH battery you can run the TV for 11.10 hours.
185 AH divided by 16.66 amps DC = I I. I 0 hours.

The electrical equation I'm using above is :
Watts = amps X volts.

you can use it like this too:
amps X volts = watts.
OR
watts divided by amps = volts.
OR
watts divided by volts = amps.

By knowing 2 of the 3 numbers in that equation you can find the third number easily. Most appliances, TV's, radios etc have at least 2 of the numbers available on the silver sticker on the back or bottom of its outer casing.

If a fan uses 5 amps @ 120 volts AC you would:
5 amps X 120 volts = 600 watts / hour

In battery power that would :
600 watts AC divided by 12 volts DC (battery voltage) = 50 amps DC / per hour / consumption..

If you have low watt lighting:
14 watts AC, divided by 120 volts = .11 amps/per hour.

With that in mind if you want to calculate the consumption of 10 - 14 watt lights you would do so like this:
.11 amps X 10 lights (14 watts) = 1.10 amps. (for 10 low watt lights on for I hour).
1.10 amps X 120 volts = 132 watts.

In battery power that would be:
132 watts AC divided by 12 volts DC(battery voltage) = 11 amps DC / per hour / consumption
independent
A 370 amp hour battery using up to 50% discharge( 185 AH ) could power those 10 lights for:
185 AH divided by II ampsDC = 16.8 hours. (The lights could run).

To make sure you have enough battery capacity to get you through an extended period of time without charging, use the formulas above to estimate your consumption along with the estimating your consumption pages. You should be able to estimate how much power you will need to produce to see you through any rough times or to figure out your total consumption needs if you are considering being total energy independent.

Using the above formulas and estimating your possible usage on the calculating your comsumption page, you should be able to estimate how much power you will need to produce to see you through any rough times or for your total consumption needs if you are considering being energy independent.

If you have further questions please contact us