Camping Battery Setup for an Resmed S9 Autoset

I got myself a new camping battery setup for my ResMed S9 autoset. It was quite expensive to get the lithium Ion Battery and the 12V adapter for my machine, just shy of $380. I love to ride motorcycles and I love to camp for me this is the price of freedom. The battery is a Super CPAP Battery Pack-266 and the 12v adapter is the ResMed required adapter. This item fits in its own convenient carry bag and it was the only one that I found that said you could use the 12v power supply to recharge the battery without an inverter. I did see these batteries offered else where but the company that I ordered from told me they had them built specifically for them to be able to charge from the 12v direct. The company was Best CPAP Price. Their name was no lie as this battery was as much as 100 dollars cheaper then the others and again when I called each supplier they were the only ones that said theirs would support 12v direct charging without the inverter.

I got the package in three days with no delays. They were extremely helpful on the phone and the guy I chatted with had one that he himself had used. When I got my battery I charged it up and put it to work to "test" it before I had to rely on it camping. It worked flawlessly and ran my CPAP for two nights at a total of 15.5 hours and still was showing a 3/4 charge left in the battery. It really looks like this unit will easily power my machine for three nights. I have my machine set for a high pressure of 12 and low pressure of 8 with it hovering most of the time right around 10. I will let you know how it charges on my motorcycle at the end of 4th of July weekend.

cbrxxcess wrote:I got myself a new camping battery setup for my ResMed S9 autoset. ... When I got my battery I charged it up and put it to work to "test" it before I had to rely on it camping. It worked flawlessly and ran my CPAP for two nights at a total of 15.5 hours and still was showing a 3/4 charge left in the battery. It really looks like this unit will easily power my machine for three nights. I have my machine set for a high pressure of 12 and low pressure of 8 with it hovering most of the time right around 10. I will let you know how it charges on my motorcycle at the end of 4th of July weekend.

I'd be very interested to hear how this goes for you. Are you also powering the humidifier or just the main unit? I have a friend who does camps with kids for a week (we're talking tents here) at a time and said he can't find a good solution to power both the main unit and the humidifier, so he doesn't take anything (which makes no sense to me but it's his choice). If your solution works, I'd like to recommend it to him. Looking forward to your post-holiday weekend review.

Sorry that I forgot that important piece of info. No I did not have the humidifier hooked up to the unit. I am sure it would drastically cut into the battery life. I may give it a shot when i get home just to see how long it would work that way. I would not take the humidifier with me while on the motorcycle anyway I need the room. To me a good nights sleep is to important to leave the machine if the humidifier does not work. I am just jacked that I am going to be able to not worry about having a campsite with electricity. In fees alone I should be able to pay for this in no time at all.

Don't put a lot of faith in the "3/4" full indication. Figuring out how much charge is left in a battery is very difficult to design an accurate circuit for.

Good luck with your camping trip.

Archangle is correct, the indicator isn't accurate. In theory, the battery is capable of powering the S9 with no humidifier for around 2 nights only, though you might just get 3 short nights if using a medium pressure. Using a humidifier can increase the current draw by as much as six times, depending on settings and whether you use a heated tube or not, so you wouldn't get even one nights use from the battery.

But glad it works for you.

archangle wrote:...Figuring out how much charge is left in a battery is very difficult to design an accurate circuit for.
...

Actually, that isn't strictly true. What is almost impossible is to create an inexpensive circuit to accurately measure remaining charge. http://ztsinc.com/ makes several testers that are accurate to within 10%, but the price isn't cheap. And they wouldn't help in this particular case.

I do get a chuckle out of the cheap "battery guages" that are, in reality, just dumbed-down voltmeters. Voltage doesn't drop linearly, especially in LithIon cells, so it isn't a good indicator of remaining charge. Heck, voltage and capacity are 2 totally different properties. That's like trying to determine the humdity with only a dry bulb temperature reading. The only accurate way to measure remaining charge without actually draining the cell is to measure the current under a known load when the nominal capacity of the cell is also known. Even then, variance in internal resistance makes very accurate measurements (< 10%) impossible even with moderately-priced testers.

I can tell ya it run it for two full nights without the humidifier at approximately 10cm. As for the accuracy of the gauge who knows? Once I am back I will see if I can get a third night but I just wanted to make sure one was possible. It does that easily.

I too, am looking to do some motorcycle camping. I found a battery, with built in inverter usb and dc outputs and can be charged by ac, solar and dc power outlet. It's around 13 pounds and I ran it 10 hours last night. Battery was $129 plus $38 for the adapter for charging from dc. The battery indicator looked to have 20% left. I don't know how accurate that is, but I intend to charge it everyday when I am on the road. The manual says that it takes 5 hours to charge.

I forgot to add that I am using a resmed dc converter with a resmed Autoset 8.

I look forward to your report. I have the DC adapter for use in my motorhome and considering the battery for when I am off in a tent somewhere. A couple of nights holding a charge is not sufficient for me. However, I see that the battery can be directly charged from a solar array. I am considering a Brunton 56 foldable array but now we are talking real money. Anyone else use solar to charge a battery pack?

goldfinch wrote:I look forward to your report. I have the DC adapter for use in my motorhome and considering the battery for when I am off in a tent somewhere. A couple of nights holding a charge is not sufficient for me. However, I see that the battery can be directly charged from a solar array. I am considering a Brunton 56 foldable array but now we are talking real money. Anyone else use solar to charge a battery pack?

It might not hurt to go to http://www.goalzero.com. They sell portable solar panels to charge the unit that I have. They also have other storage units as well.

BTW - I only heard of this company four days ago at our local Costco. They have been doing roadshows to promote their product according to the salesman that I spoke with.

Good luck.

Thanks. I'll check these out. With solar and battery pack it looks like I am going to be around a thousand bucks. <sigh> But useful for my "lifestyle."

It can be difficult to make the solar charging system meet your needs. Your machine will use a certain number of watt hours a night. Your solar charger needs to produce enough watt hours per day to stay ahead of the CPAP machine discharging your battery.

How many hours charging do you need to charge your battery after a night of CPAP? If you're changing campsites, how early in the day will you be able to set up your solar array? Will you have a spot to set up the array that gets sun for enough hours a day? Will you get enough power on cloudy days?

Remember that morning and evening hours don't count as much as noon hours. If a solar panel is specified as 10 watts, that usually means 10 watts at noon, on a clear day, with the panel directly perpendicular to the sunlight. Most parts of the US get 4 to 6 effective hours of sun per day.

I'm not saying it can't be done, just that it takes some calculations and may take more panel and battery than you want to haul around.

I figure 10 watts is not near enough for the reasons you mentioned. That is why I was considering the Brunton foldable 56 watt. The use would be base camps away from shore power.

I'm going to charge mine with DC power from my motorcycle. The battery is supposed to charge in 5 hours for a full charge. I got, at home, about 15 hours run time on the battery with my DC-12 converter with my S8 autoset/without humidifier, before the machine shut down. So I will have to charge it every day.

So far, I like the design of the battery as it is housed in a water resistant case, includes an inverter, DC out, USB out, battery gauge, and a carrying handle. It is an AGM battery rated for 150W output. I also purchased for $8 a LED light (very compact) that can be plugged into the USB port. So I can use it as a lantern in the tent as well.

Solar is alluring, but not practical for every application as mentioned in the prior posts. It won't work for me.

But the battery should work fine as you can charge off of your well charged motorcycle battery. Provided you are riding every day, yes?

I am curious as to how long my xPAP is going to run off of the motorhome batteries. I have a generator but I hate running it and won't at night, at most I will run it to recharge the house batteries. Right now I am plugged into shore power so it is a non-issue. By late next week I will be boondocking so it will be a good test. I might even experiment with and without humidifier.