I had to figure out how to power a CPAP while camping. Some thoughts:
- The article says to use a 12-volt marine deep-cycle battery. Recommend using an AGM battery instead, no need to deal with refilling electrolyte and easier to transport. Also the 35 amp-hour U1 size is only about 22 pounds and fits in a small cooler or tool box.
- Most of the modern machines (Philips or ResMed) have DC-DC power adapters available. Philips is great because you can get a $30 cigarette lighter cable, connect that to a cigarette->alligator clip, and plug that directly to a battery. ResMed's adapters seemed more expensive (they use 24 volts), but at least it's an option. AC inverters are obviously inefficient.
- Not using a humidifier would probably double your battery life. With a 35 AH battery I could get about 3 days with humidifier/heated hose on. 3 days without humidifier left about 40-60% battery life. Of course, this depends on your pressure settings. The humidifier also works passively if not powered, flow of air through the water tray still does some humidification.
My next project, trying to figure out how to add a portable solar panel to the battery.
Unless the cigarette lighter plug has a clip to hold it into place, it seems like a bad connector to use to power a life-safety device since they are easily dislodged (in fact, the spring at the terminal at the end is actively trying to push the plug out of the socket)
I'd probably use something like Anderson power poles if it were me.
Yeah that looks more secure, unfortunately Philips added a DRM-like protection to force everyone to use their cigarette adapter. Basically there is some sort of circuitry that identifies an official cable. Someone on a CPAP message board said it was only a resistor across a 3rd pin in the power plug, but can't find the link.
I plugged an "unofficial" cable, as well as an 18v lithium-ion plug, and got a "Check Power" message on my Dreamstation. The unit was powered, but it refused to start until it detected the "official" cigarette cable.
That seems like an awful use of DRM -- by forcing users to use a substandard connector. It does nothing to protect the device since, as you've done, you can put a cigarette lighter socket on anything.
That's just awful. I might understand ink cartridges, but here afflicted patients suffering from sleep apnea disorder rely on these devices to help them breathe at night, and if you lose the official cable, you are up a crick. We need regulations a la "Right to Repair" against abuse of DRM in this manner. This is literally just screwing over people with disabilities (I have severe sleep apnea myself). I remember having to order a massively overpriced proprietary "smartcard" reader from China to retrieve my patient data from the older Respironics CPAP that I used to have.
- The article says to use a 12-volt marine deep-cycle battery. Recommend using an AGM battery instead, no need to deal with refilling electrolyte and easier to transport. Also the 35 amp-hour U1 size is only about 22 pounds and fits in a small cooler or tool box.
- Most of the modern machines (Philips or ResMed) have DC-DC power adapters available. Philips is great because you can get a $30 cigarette lighter cable, connect that to a cigarette->alligator clip, and plug that directly to a battery. ResMed's adapters seemed more expensive (they use 24 volts), but at least it's an option. AC inverters are obviously inefficient.
- Not using a humidifier would probably double your battery life. With a 35 AH battery I could get about 3 days with humidifier/heated hose on. 3 days without humidifier left about 40-60% battery life. Of course, this depends on your pressure settings. The humidifier also works passively if not powered, flow of air through the water tray still does some humidification.
My next project, trying to figure out how to add a portable solar panel to the battery.