This seems like the correct thread to ask this question.
My wife recently got a CPAP machine, an AirSense 10 with heated hose and humidification. We have some trips planned this summer where nearby mains electricity may not be available.
I bought an inverter thing, that I attach my lawnmower battery to. The 5Ah/56V battery runs the CPAP great, but only for about 4-5 hours.
Turning off the humidifier and heat should let the pump run longer. First question: how uncomfortable will it be switching from heated and humidified air to ambient air?
I know she could just try turning those off, but conditions could be anything from extremely dry and cool to wet and warm. How much difference will that make?
The second question relates to electricity, so I'm going to hide it under a clicky thing.
The lawn mower battery is 0.28kWh, but I can only get about 0.18kWh of useful work out of it. The CPAP needs 0.25-0.30kWh per night. At the campsite I will also have a 75.0kWh battery available. My question, the lawnmower battery inverter claims to provide a perfect sine wave, and a kill-a-watt shows it as having 60Hz, and a fan I connected it to runs perfectly. The CPAP also runs great off it, until the power runs out.
The 12v inverter I have is from the 90s. I have no idea what kind of wave it supplies. The kill-a-watt says it has “dc” Hz. That result is not in the manual. The fan I plugged into it runs, but does not seem happy. If it were an IC engine I’d say it was “missing”. I didn’t let it run long, because I don’t want to burn out the motor on my fan.
Is whatever weird modified sine wave coming out of my old inverter going to damage the power supply for the CPAP?
It’s a 110-240V to 24V power supply, and I assume it is pretty low quality, because it stays warm all the time, and pulls 3-5 watts even when unplugged from the CPAP.
So three options, which to do?
- Use the lawnmower battery for as long as it lasts each night. Costs $150, but is very versatile, because we don’t always have to be near the car.
- Use the wonky inverter with an AC extension cord. No additional cost, but have to be near the car, and no idea what that will do to the CPAP power supply.
- Buy a 12v to 24v power supply for the CPAP, plus an extension 12v cable. Cost is around $50, and will only work near the car.