How do you interpet amps per hour?
How much difference is there between a 12v/12amp per hour, 12v/14amp per hour and a 12v/18amp per hour battery?

 

I'm no battery expert, but my guess would be at 12v a device will consume 12 amps per hour. It doesn't make sense to me that it would be descriptive of batteries, but devices instead. Batteries will put out much more than 12 amps in an hour! Now, my digital camera batteries say on the side of them 2100mah (milliamp hours). That means they will put out more amps at any one instance than a battery listed 1800mah... Which is good for digital cameras. In cars, the batteries are balanced on Cold Cranking Amps and Reserve Capacity. Either the battery is made to put out lots of current (ie high CCA) or it is made to store lots of current and divy it out in smaller amounts (ie golf cart batteries).

Where are you getting these figures? Maybe that will help to understand. The only other interpretation I can think of is that a battery can drain 12 amps in an hour without losing its ability to hold the voltage at 12. A battery that can do more amps per hour than 12 would seem to be a high reserve capacity battery,,, much like a golf cart,,, but maybe not so good for things that need to see high amounts of current NOW (ie winches),, but would be very good at starting your engine after running the lights for a long time.

 

I think its the amount of power available, 12 volts x 12 amps is 144 watts of power available, 12x18 is 216 watts available. If you have alot of acc. like handwarmers,winch,etc. all on at once could deaden a lower rated battery.