# Convert $/Ah to$/kWh

1. Jul 10, 2014

### km011

It has been years since my college physics class and I'm struggling to get an answer that makes sense. I'm trying to convert the price of battery cells from $0.76/Ah (for a 2.8-3.0 Ah battery cell) assuming 3.6 V to$/kWh.

This is likely really simple, but I really want to understand how to do this.

Thanks!

2. Jul 10, 2014

### cpscdave

Amps are Coulumbs/sec (so Ah would be a measure of columbs)
Volts are Joules/Coloumb
so to get KWh (which is joules) You'd take Ah*V

3. Jul 10, 2014

### jim hardy

there's an unaccounted for "kilo" in there somewhere ?

4. Jul 10, 2014

### meBigGuy

Also realize that the voltage is not a constant 3.6V. Look at the discharge curves for the batteries you are considering. Also, the Ah rating is at a particular specified discharge rate only. (and temperature)

5. Jul 11, 2014

### jbelectric777

amp hours are used for volume of a battery. ex: 9v Duracell = 500ma/hr. which only means the battery will produce 500ma for one hour. or 100ma for 5 hrs. you had dollar signs so I can only take that as what would the cost be in dc battery output compared to alternating commercial supplied current. using 500ma is too small so figure a couple 50AH car batteries. last time I checked one kwh (AC) was about ten cents a kwh. so your 100AH batteries deliver (12 x 100) = 1200 or about 12 cents per hour. By the time the trickle charge was done you probably would have spent 3 times that amount. and that doesn't account for what bigguy said about curves, drop, etc.

6. Jul 11, 2014

### cpscdave

Opps there is indeed :) Only off by 10^3 thats a good day for me :D