Camping with CPAP

Rainier

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I wired in a voltage regulated relay and put a spare battery in the frunk. Bought the ResMed 12v adapter.
Battery charges while riding. The relay feeds the battery when voltage is above, uh, 13?
I tested it for two nights without charging and could have probably done three.
I love wiring, so this was a fun project. The ResMed piece was the single most expensive item..
Used it on a couple 7-9 day camping trips without a hitch.
 

Afan

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And 4 years later still "in development" :(

"... The Airing micro-CPAP device is currently in development and not yet available. The timing of the development of complex and innovative technologies is difficult to predict precisely. Delay in achieving one milestone affects the remaining development process..."
 

Afan

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I wired in a voltage regulated relay and put a spare battery in the frunk. Bought the ResMed 12v adapter.
Battery charges while riding. The relay feeds the battery when voltage is above, uh, 13?
I tested it for two nights without charging and could have probably done three.
I love wiring, so this was a fun project. The ResMed piece was the single most expensive item..
Used it on a couple 7-9 day camping trips without a hitch.
Hey Rainer,
Can you please post more info? Some pictures too?
Thanks.
 

Rainier

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Let me find some time. I'm a university prof finishing the semester on line, which I detest. Huge time sucker. Don't have any pics but I can tell you what I did. It does work well for me.
 

Afan

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Let me find some time. I'm a university prof finishing the semester on line, which I detest. Huge time sucker. Don't have any pics but I can tell you what I did. It does work well for me.
No problem. Thanks.
 

Rainier

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Sorry to be so late in doing this. Moving to a new state. Broken ankle slow to heal. Obviously my priorities are screwed up!

Let me begin with a few requirements. First, my sleep apnea is both physiological (screwed up pipes) and neurological (the ol’ brain is sending the wrong signals.) I HAVE TO USE A MACHINE. Surgery and oral appliances are not an option for me. Second, buying another CPAP isn’t in my budget. If I had the money, I’d buy a travel version. I’d still need a battery though, so I went with a 12 volt adapter as described below.)

Here’s a description of parts and procedures for installing an extra battery for my ResMed CPAP appliance.

Get a deep charge battery, 12 volt. I found one on either eBay or Amazon for around $40. Pick one that is sealed.

Get a “VSR” a “voltage sensitive relay.” This is a relay (switch) that measures incoming voltage. When it reaches X volts, it opens, sending power to, in our case, the extra battery. Voltage drops (from alternator/engine) the switch closes: no power to extra battery.

Here’s where I decided to go cheaper. BEP sells a DIGITAL VSR starting at $90 on Amazon and eBay. Go with a mechanical version and you’re looking at around $40. And there are clones out there for a few dollars less.

It’s a relay not a NASA space shuttle CPU. Most (all?) of the other relays on our bikes are mechanical. Not a problem. I can’t justify putting a digital relay in there, but if you’ve the money go for it!

BEP is a good brand and their stuff is waterproof out of the box. Here’s a PDF of how to wire their VSR: (any VSR will wire similarly). See below for an excerpt from this page.

https://www.bepmarine.com/en/~/media/inriver/329437-25323.pdf
(or download the attachment)

Get whatever adapter your CPAP requires to operate from a 12-volt source. ResMed will sell you one for, if memory serves, $120 on Amazon. Doctors with an Amazon account get a discount; my brother is a doctor, but he doesn’t have an Amazon account. Ask your doc?

I picked up a waterproof toggle switch and LED so I could turn the charging system on or off and know if it was on. I have a small “dashboard” fabricated out of steel mounted to the handlebar. It holds a voltmeter, a couple of switches and my heated gear controls. The switch and LED went there.

I mounted the VSR in the right “vent” compartment. You could easily do left, but I have other things in there. I put an SAE socket (female) in the frunk bulkhead and wired the storage battery with a male plug.

(My practice is to ALWAYS mark the positive terminal on SAE plugs or sockets with red tape. One mistake taught me that. Your experience and practice may be different.)

Wire as the diagram in the PDF above. (Download the attachment.) Test everything before final mounting. There’s an LED on the VSR that lights when voltage is passing through. Check that now, ‘cause you won’t see it when it’s in the “vent” compartment.

The VSR is held in place with that 3M super heavy duty Velcro-like stuff.

The battery sits at the front of the frunk and I added a plastic box/tray to keep it snug and organize the other frunk stuff. I had a spare voltmeter to which I attached an SAE socket. I can plug the battery’s SAE cable into the voltmeter and get a reading whenever I care to. That’s the same cable that plugs into the socket mounted on the frunk bulkhead.

In camp the battery comes out and I attach one lead from the ResMed transformer to the battery and the other to my CPAP machine. As I said earlier, testing at home I got two nights out of the battery without charging it. I’m fairly sure three was in reach.

Traveling at highway speeds for 3-4 hours will charge the storage battery. (That’s a guess; could be more could be less. What I know is each day ended with the storage battery fully charged.)

Total cost was less than $200.00. I like doing electrical work, so I didn’t count the time. I have lots of wire in different gauges and used heat shrink solder butt connectors which work a treat. (Look on eBay or Amazon for “heat shrink solder connectors” and you’ll see what I’m talking about. This is a clever, easy and waterproof way to make wire connections. A heat gun comes in handy.)

+. +. +​

Note on the wiring diagram below. I ignored the three isolators but did include fuses and the switch + light.
You'll need to open the attached PDF for the diagram. Or grab the BEP instructions mentioned above.
 

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  • Charging a CPAP battery while riding.pdf
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GregC

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FYI - there’s a huge thread over at Adv Rider covering this with lots of adaptions folks have figured out.
 
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