Thor Forums

[Chance]

Originally Posted by 16ACE27

So confusing! You can't talk amps or amp-hours without including volts.

For example:

A 400 AH battery bank at 12 VDC will run a 10 amp 12 volt load for 40 hours.

A 400 AH battery bank at 12 VDC will run a 15 amp 120 volt air conditioning load for 2.67 hours.

To keep it simple and straight forward, and avoid confusion, I believe it’s best to keep power numbers (in Watts) separate from battery ratings (in Amp-hours). Unless it’s specifically mentioned otherwise, 400 Ah is just that — regardless of voltage. What that 400 Ah can and can not accomplish obviously depends on voltages, but that’s a more complicated analysis involving other equipment because they are not 100% efficient, hence math is a bit more complicated. In this case it is implied an inverter would convert 12 VDC battery power to 120 VAC power required by an air conditioner, but that’s jumping the gun because more and more motorhomes are making use of both 12 and 48 VDC air conditioners.

Obviously 400 Ah of battery capacity at 48 VDC is a lot more energy than 400 Ah at 12 VDC, but both are still 400 Ah. That part of rating doesn’t change.

I’d stick to basics or confusion will be off the charts.


Without additional explanation, the number he listed are just wrong. And if goal is to power an inverter to then power an air conditioner, more information and calculations are needed.