direct dc or inverter

[nbf]

For car camping, I'm wondering whether it is more efficient (longer run time off the car battery) to go directly from the battery (using the dc cables to the cpap machine, which my machine can to) or using a small inverter. I would think it would be better to avoid the energy conversion with the inverter and just stay with the dc. I don't want to buy the 12v dc cables or the inverter just to try it out. Anybody know?
Thanks,
Jim

[chunkyfrog]

Inverters do lose some power; how much depends on the model.
edit: I mean efficiency.

[Goofproof]

Running off D/C is the most efficient way to run off portable power, using a inverter adds anpther level of power usage cutting down on the batteries run time. If you have A/C it's cheaper to use it, because of no power loss to recharge a battery, but straight D/C is the most efficient for portable use. Jim

[nbf]

Thanks for confirming that to me.
Jim

[Goofproof]

Thanks for confirming that to me.
Jim

It shouldn't be necessary, but having a jump starter battery unit is a good backup plan. You never know when a battery will decide to fail. Jim