[burtonridr]

Ive been searching how to figure out how to calculate how much it costs to charge a car battery at home.

Does anyone know how to figure that out?

How would I calculate how much it will cost to charge a 12v battery with 300 amps assuming that the charger is using a standard 120v supply source?

I know it will depend on how much my rate is per Kw, so is there a way to find out how many Kw it will use?

[SolarDave]

A mostly dead average automobile battery would need about .5 KWh to be recharged - 5-10 cents, depending on where you live.

[Cashmere]

I'm not sure if a charger draws a constant current - it may, but given that the output to the battery drops with accumulated charge, the charger could theoretically draw less current from your 120 supply as the battery charges.

If you would like a rough answer - I'd say pennies to a quarter.

If you want an exact answer:
[web]http://www.p3international.com/products/special/P4400/P4400-CE.html[/web]

[burtonridr]

I'm not sure if a charger draws a constant current - it may, but given that the output to the battery drops with accumulated charge, the charger could theoretically draw less current from your 120 supply as the battery charges.

If you would like a rough answer - I'd say pennies to a quarter.

If you want an exact answer:
[web]http://www.p3international.com/products/special/P4400/P4400-CE.html[/web]

Thanks, that little device is awesome!

[burtonridr]

I have one more electrical question...

I dont know how to figure out how long a device can run on a battery.

I know that the amp hour rating has some significance.

But let say I have a device using 12v and 15amps. If it is running off a battery that holds 600 amps, how long can it run? I was think you would just take 600 and divide it by 15 amps, is that right?

What the difference between amps, cold cranking amps, and amp hours?

[Vegas]

Amphour=amp/time, IE a 12v 600ah batt can make 600a for one hour, or 300a for two. This is misleading though, AH rating are usualy based on a ten hour rate, puekert's(sp) effect makes a higher rate of discharge give a lower capacity. Some batts a one hour rate may only be 1/2 capacity.

Amp is a simple measure of current, the 800 pound gorrilla of electricy. Without a time componet it is a static measurement, like torque, it doesn't tell you much.

Cranking amp rating is the max current that a batt can deliver, peak power, or how big an arc dropping a spanner across the leads makes...


12v @300ah=3.6kwh @$0.10 per KWH $0.36 cents to charge a compleatly dry batt like that. Add ~%20 to that for losses...

[burtonridr]

Amphour=amp/time, IE a 12v 600ah batt can make 600a for one hour, or 300a for two. This is misleading though, AH rating are usualy based on a ten hour rate, puekert's(sp) effect makes a higher rate of discharge give a lower capacity. Some batts a one hour rate may only be 1/2 capacity.

Amp is a simple measure of current, the 800 pound gorrilla of electricy. Without a time componet it is a static measurement, like torque, it doesn't tell you much.

Cranking amp rating is the max current that a batt can deliver, peak power, or how big an arc dropping a spanner across the leads makes...


12v @300ah=3.6kwh @$0.10 per KWH $0.36 cents to charge a compleatly dry batt like that. Add ~%20 to that for losses...

Thanks

That helps clear thing up