How do inverters work?

[most] Cigarette lighter circuits are always hot. Otherwise a bigger inverter (properly installed) will be connected directly to the batteries and always hot except they will have an on/off switch. Only reason you may need to run the truck is while running something large like maybe a microwave, and the inverter may balk at not having supplemental alternator power. But I suspect a CPAP machine should not be a problem for a smaller inverter and without the truck running, but if your truck is configured to run with fewer batteries, you may not be able to run an inverter long before needing to recharge the batteries.

 

Houses are on AC current. Automobiles are on DC. Power converters convert the DC current of autos into the AC currentof houses so you can plug in and run household products.

Be warned,without the engine running, power inverters WILL run the batteries down.

 

Not only this but a lot of tractors have battery protection circuits that will shut it off at a point before enough power is used as to not allow the engine to start.

 

Inverters aren't cheap, if it's ONLY for your CPAP it's probably unneeded as most CPAP's have 12V power supplies. Assuming yours uses the standard 12V 1A connection on the back shouldn't be an issue. Remember ALL electronics run on DC power to begin with so it's only a adapter change when you want to run them from straight 12V.

 

I use a cpap, I run it off a little 175 watt inverter plugged into a cigarette lighter plug, it runs all night with the truck off with no problem, they draw very little power especially if the humidifier is off