Full-time battery backup

First, I want to thank JohnBFisher for inspiring a lot of this. You can read his thread on battery backup design here: viewtopic/t89123/Battery-Backup-Design-V2.html

I wanted to do something similar, but running the CPAP off of the battery full-time so power outages wouldn't wake me, as well as be able to use it for light camping. The only major change this required was to seriously increase the size of the battery tender (4A unit), so it could keep the battery near full even with a full load applied (high pressure, humidity, and heated hose).

First, a couple pictures. The unit showing the 15A-fused cigarette output (the Resmed DC converter is rated for a max of 13A) and the SAE connection for the battery tender:


Inside (note the second cigarette socket fused at 5A in case I need to charge something while off the grid):


The battery itself is also fused at 15A using the fused connection that came with the tender. Safety first!

I've been running off of it nightly with no issues, and the tender keeps it fully charged even with the load applied. Links in next comment.

Items and links if it helps someone:
Battery - just a standard U1-size AGM battery
Battery Box - this was a tight fit with the sockets. You may consider getting a box for a bigger battery. If not, mount the sockets as high as you possibly can. I messed up the first time (you can see the covered holes in one of the images above)
Battery Tender - 4 Amp version
Fuses - inline automotive fuse holders for the cigarette sockets
SAE Splitter
SAE Panel Mount Socket
SAE connectors - connected to the sockets (with a fuse inline)
Cigarette Lighter Panel Mount Sockets - don't order cheap ones on Amazon/Ebay/etc, they are very loose and I had one pop apart as well. Source good ones from a reputable supplier, too much junk out there

Although pricey, I am using a Medistrom Pilot Plus 24 and Co-Pilot as my full time battery backup on an Airsense 10 Autoset.

Dave

juaquin wrote: ↑

Sun Oct 07, 2018 7:27 pm

Items and links if it helps someone:
Battery - just a standard U1-size AGM battery
Battery Box - this was a tight fit with the sockets. You may consider getting a box for a bigger battery. If not, mount the sockets as high as you possibly can. I messed up the first time (you can see the covered holes in one of the images above)
Battery Tender - 4 Amp version
Fuses - inline automotive fuse holders for the cigarette sockets
SAE Splitter
SAE Panel Mount Socket
SAE connectors - connected to the sockets (with a fuse inline)
Cigarette Lighter Panel Mount Sockets - don't order cheap ones on Amazon/Ebay/etc, they are very loose and I had one pop apart as well. Source good ones from a reputable supplier, too much junk out there

Nicely done!

I ordered a Medistrom Pilot 12 last year, the first part of September, knowing we were going to get bad winds from a downscaled hurricaine. The Pilot came two day delivery, just in time. Power was out for two days, and I used my APAP, without humidification, for two nights we were in the dark. Work had power, so I would take the Pilot to work, recharge, and bring it back home. Best money spent to have piece of mind knowing I can sleep using my machine should power go out.

juaquin wrote: ↑

Sun Oct 07, 2018 7:27 pm

Items and links if it helps someone:
...

Very nice build! I'm tempted to upgrade my box.

I compliment the workmanship. This setup looks very professional.

TheDuke

I also have the Medistorm 24 + Co-pilot