power supply / UPS

[a64pilot]

I'm new here but have been lurking for awhile. My question is referencing power outages etc. I see plans of $300 and more for basically a homemade UPS, but unless I don't understand what is going on why can't I simply pull a deep cycle battery out of my boat or go to Walmart for one and while I'm there get a battery tender and a lighter adapter, order the power supply cable for my particular machine and run the CPAP off the battery permanently with the battery tender keeping it charged? Way less than $300 and if there is a power outage, nothing happens as I'm running off the battery anyway?

[Tech Guy]

As long as your power supply is 12 volt a deep cycle should work. Recently picked up a 29D at pep boys. Will wire in a 3.5 mm plug and should work through the night. Have not tested this yet and have the battery as an emergency power source in case it's needed. Some others are running 24 volt supplies which is why the extra effort is required.

[CapnLoki]

That will work fine - the power cable for your PRS1 is straight through and costs about $25. I would recommend an AGM deep cycle battery for indoor use since its the least likely to have spill/venting issues. Use a quality trickle charger like a Battery Tender; make sure the terminals are protected against accident shorts (a box or at least terminal boots); and a fuse would be nice.

The $300 seems high but when you add up the items, maybe throw in an inverter or voltage converter for pumps that can't run on 12V, maybe oversize the battery so you can run a humidifier for a number of days, etc. you can easily get to $300. Also there are other threads on travel batteries, lightweight Lithium packs that are good for one overnight plane flight, which cost about $300 or more.

[kwikwater]

I've used an off the shelf dry cell, deep cycle marine battery for the 8 years I've been on CPAP. I've always had a Respironics so it's 12V already. I had a battery and solar panel I carried on river trips already, so all I did was put a fuse in my positive lead to the cigarette plugin I already had. Then it was a PR cord for the cig lighter to the machine and I was in. I don't use the humidifier to save power and I get 4 nights from a full charge. Never really determined how good my solar panel is, but it lived through a 18 day Grand Canyon with out ever going down. I use it around 20-30 nights a year. It all fits nicely in a 20MM ammo box so durability and (UGH) carrying it is pretty doable. I set my "nest" up closer to my boat since CPAP. Those batteries are HEAVY!!!

[a64pilot]

OK, thanks. Pretty much exactly what I thought. So if you have a 14V machine, then any neg ground 14V supply is fine, most RV's have a female 14V plug for TV's etc., automobiles of course, pretty much any motor vehicle.
Seems like a machine that uses 14V DC might be something better to have than one that needs 120V AC, inverters being inefficient and something else to break.
I have a dream of sailing the world in a few years when I retire, and being diagnosed with sleep apnea recently had me worried that I might not be able to make that dream.
I assume my machine draws a little less than 60W with the humidifier as that is the size of the power supply, I assume most of that draw is for the humidifier, anybody know the actual current draw without the humidifier?

[CapnLoki]

I assume my machine draws a little less than 60W with the humidifier as that is the size of the power supply, I assume most of that draw is for the humidifier, anybody know the actual current draw without the humidifier?

The load will depend on the pump pressure. My PRS1 draws about 0.5-0.7 Amps at under 10cm pressure, but it can go up over 1 Amp, with higher startup draw. I don't bother bringing the humidifier to my boat, though it did get a little dry when a cold front came through with 40 degree nights. BTW, my AHI numbers run about 2.5 on land, but are usually below 1 on the boat.

[hueyville]

A64 pilot. If you are ever on the north side oc atlanta I have tons of new agm deep cycle telecom batteries. If you want to pick one up price is free. Mosf are 28 amphour but some are the 150 pound 165 amp hour monsters. I do battery backup systems for a living but found it easier to go to big box computer store and buy a 1,300 VA UPS. Reliable, looks more elegant in bedroom and costs less than building one.

[DaveMunson]

My plan is to use (either) the car battery and a powerful enough inverter. I have a 100 ft power cord set aside to run from the garage to the bedroom. I turn off the heat on the S9 heated humidifier and go to sleep. I got a couple nice alligator clips for the battery terminal and have the cable from the battery to the cpap fused. I've used it twice so far this year and 2-3 times last year. For storage I wrap the inverter + cables and extension cord in saran wrap. A full night's sleep using this drops the battery to 12.5 volts (the battery is 5-7 years old and 6 or so hours does not seem to drain or damage it at all). In the case the power outage lasts forever I would use for night the wife's car than the diesel tractor's battery.

The thing to watch for is to make the cables idiot proof. It's the middle of the night and all you will have is a flashlight. Secondly, protect the setup and have it ready to go. In the morning I usually hook up the trickle charger but from the voltage readings the battery is fine without (it will charge on the drive to work).

I see plans of $300 and more for basically a homemade UPS, but unless I don't understand what is going on why can't I simply pull a deep cycle battery out of my boat

[squid13]

Here is a good post for building a battery backup system. viewtopic/t89123/Battery-Backup-Design-V2.html Since you have a S9 all you need is a battery and this https://www.cpap.com/productpage/DC-Con ... hines.html