Originally Posted by terry735001
1 24v 1 thats why you see 24v in alot of high end RVs it 1 to 1
The reason for 24V systems in cars is to reduce current in long runs of cable. Moving up to a 24V system reduces amperage exactly in half versus a 12v system. This means for long runs of cable you can run a smaller diameter cable(higher gauge). Also for large diesel motors, you need a 24V starter because the higher voltage starter will have more torque. This extra torque is needed to turn a large diesel motor in the winter due to cold heavy oil.
I think in your math you are going by RMS current(0.707 X Peak). But even if you are going by RMS you should always calculate based on wattage. Even then, you are still looking at about 7 amps (12vDC) for every 1 amp of 120AC. Keep in mind that most inverters only have 90% efficiency, so if you are using 100W of AC power, calculate the DC amperage for 111W of power.