One battery solution and some stats

I recently asked for help figuring out some stuff for a battery for camping. I received some great help and I just wanted to report the results and findings in a less cluttered fashion so that it may (hopefully) benefit someone in the future.

First: THE STATS. THESE WILL BE UPDATED AS I CONDUCT MORE TESTS.
These usage hours are all using a Phillips Respironics PRS1 50 series APAP Pressure range 14-15 with a humidifier. I'm testing the usage hours for various humidity settings with the battery setup I chose. You can see the equipment further down this post.

Humidity setting of 5: 11 hours of usage
Volt readings:
13.2 After full charge by battery tender
12.0 After first night (5 humidity setting) 6 hours of use
6.5 After machine died in the middle of the second night. (5 humidity) 5 hours of use before dying.

Humidity setting of 3: 16 hours of usage
Volt reading - Notes
13.2 - Fully charged right after taking it off of the battery tender charger
12.3 - After first night at 3 humidity setting - 7.5 hours of usage
(forgot) - Second night of usage (3 setting) - 7 hours of usage (DIDN'T DIE ON SECOND NIGHT LIKE IT DID AT A 5 SETTING)
6.4 - Died - (3 setting) - Died after 1.5 hours of usage

Humidity setting of 1: (test not conducted yet - will be updated later)

Humidity setting OFF (test not conducted yet - will be updated later)

THE SETUP
I bought this 12V 35Ah sealed deep cycle battery. It weighs about 24 pounds. I liked that I didn't have to worry about it leaking. I bought it mainly on CapnLokis recommendation. So far I've been pretty impressed with it.

You can buy it here $69.90

I then got the Battery Tender plus to charge it with and to use its cable system. It comes with a fused quick connect wiring system that I attached to the battery and will leave connected.

You can buy it here $44.99

I got this cigarette adapter quick connect that is compatible with the Battery Tender system

You can buy it here $8.15

I got the official respironics DC cord. THIS ONE IS NOT COMPATIBLE WITH THE 60 SERIES, so if you have that, don't buy this one. One thing to note, it comes with 3 fuses. a 3Amp, 5Amp, and 7Amp. It comes with the 3Amp one pre-installed. When I attempted to use my machines humidifier with that 3Amp fuse installed, it blew the fuse. I've been using the 5Amp one without any problems, even at full humidity settings.

You can buy it here $24.95

I'm using this thing to check voltages even though I know its a poor indicator of actual Amp Hours left/charge level. (Its pretty much all I have and I cant really afford better alternatives)

You can buy it here $2.76

And finally, I bought a male to male Cigarette socket cord in hopes that I might be able to connect the battery to my cars plug while driving around during the day to add some sort of beneficial (although probably minimal) charge.

You can buy it here $7.33

All in I spent 162.55. You could spend less if you already have a battery charger and the various cables and such.

Anyway, I hope this helps someone. I'll post more results as I do more tests and I'll update this post. Please let me know if you have any comments, suggestions, recommendations or whatever that may help other people. (or myself)

My 35 amp-hour deep cycle AGM battery was a bit cheaper on Amazon Prime. $63.99
I opted for the 0.75 amp Battery Tender Jr for $27.69 on Amazon Prime. I have a 3 amp/10 amp battery charger if I need to recharge the battery faster.
The ResMed 12v to 24v DC-DC converter is stupid-expensive. The best I could do was $84.85 with free shipping.

I have not tried to collect any power consumption data. I've just been going by the ResMed battery guide
http://www.resmed.com/us/dam/documents/ ... lo_eng.pdf

I'm good to go for a night in case of a power failure running the humidifier and ClimateLine hose. With an unheaded SlimLine hose and no humidifier, I should get 3 days on the boat.

Try to never run the battery down below 10.5 volts or so. Once it hits 10 volts or so, it drops off rapidly, so you don't get much more usage. Deep discharge like that doesn't hurt a deep cycle battery as much as a regular battery, but it is still harmful, and 6.4 is into the severe harm range.

I understand you're trying to determine the practical limits of the battery, but deep discharge is harmful as Archangle said. Thanks for reporting the results. How much does the Motobatt 35ah battery weigh?

GeoffD wrote:My 35 amp-hour deep cycle AGM battery was a bit cheaper on Amazon Prime. $63.99 ...

The MotoBatt has a "perpetual" 15% discount code so the price is actually about $60. That's the reason I chose this battery (plus I like the yellow color). Right now its on my workbench testing new boat instruments. (I had a hidden agenda in this purchase.)

blakepro wrote: I'm using this thing to check voltages even though I know its a poor indicator of actual Amp Hours left/charge level. (Its pretty much all I have and I cant really afford better alternatives)

You can buy it here $2.76

This is a great idea. I have one of those coming from Amazon. For $2.80, it's good to have as part of the power failure kit since my multimeter is always buried in the garage or basement somewhere in a tool box. I'd like to see what the voltage drop is after one overnight on the boat.

The ResMed DC-DC adapter has a male cigarette lighter connector and a separate female connector with alligator clips. I need to cut off the alligator clips and permanently attach the female connector to the battery terminals. Then use a couple of shrink wrap wire sleeves or electrical tape to cover the battery terminals and secure everything with tie wraps.

I'm toying with getting a PowerFilm rollable solar panel. They come in 7, 14, and 21 watt sizes. 14.5" wide and 22", 42", or 62" length. I can just lay it on the dodger on the boat and keep the batteries topped up if I'm anchored somewhere for a few days.

Wow very imaginative of using a battery to power the pap machine thank you for the knowledge

A voltmeter doesn't tell you that much about how much capacity is left, but it's pretty good in helping you avoid overdischarging the battery.

Here's a chart, but take it with a grain of salt. Don't let the battery discharge to too low of a voltage.

I use 12V 20A deep cycle batteries for river rafting. I take along a really simple battery tester. Green/Yellow/Red lights. As soon as it hits yellow, I switch to the next battery. So far, no issues. I top off my batteries once a month while not in use. I chose a slightly smaller battery and bought 4 of them. They each weigh 13 lb. My rafting trips are 3-8 nights, so I bring the number of batteries I need for the trip. I get 2 nights per battery on average. No humidifier, pressure 15-17.

I am currently putting together a system for kayak touring. The 13 lb. batteries are a no-go for those trips. I need lighter & smaller. I would like to use a C-100 Li Ion battery. I have a follow-up with my sleep Dr. next week to evaluate my pressure needs, and maybe adjust downward a little. Sleepyhead shows that my average pressure is 14-15 and my 90% is 16. So I may be able to adjust a tiny bit? Anything will be helpful so that I can use a C-100 battery for 2 night kayak trips.