CPAP Camping Rig

B_4 wrote:OK, I am about to purchase a camping rig. This is not my primary CPAP but I am going to use it one weekend a month and one full week a year camping with boy scouts. $$ matters as it will be out of my pocket.

CPAP - Respironics DS250 - Compliance only but it has CFEX I can purchase for $250
https://www.cpap.com/productSearch.php?query=ds250

Battery Pack - Respironics 1028869
https://www.cpap.com/productpage/respir ... e-kit.html

I can get about 3 full nights on the battery CPAP combo. The battery pack weighs about 12.5 lbs.

So for just under $500 I can have a full 2nd rig (no humidifier) with battery for camping and power emergencies. My S9 Autoset has no DC power option and I don't want to put my primary CPAP at risk in a tent in the wilderness subject to cold, heat and weather.

Thoughts?

B_4 wrote:Thoughts?

carbonman wrote:

B_4 wrote:Thoughts?

I don't know what the "official" battery pack is......
I just got an Optima Blue top.
I got the "official" Mseries adpt. from cpap.com and the
cigarette battery adpt. at Radio Shack.

~$230 total.

GumbyCT wrote:billbolton has mentioned a number of times that Resmed's S9 would have a DC option.

Histarch wrote:I just went the Orwell 266 lithium ion route because it was slightly cheaper, lighter weight and I can charge it off my motorcycle aux plug while riding.
I bought the Resmed 12v converter for my S8 Autoset II and was told I can turn my humidifier off and use in a passover mode.
I also have an Aeiomed Aura 2 but unfortunately did not buy the battery pack before they were discontinued. I would prefer to use this machine for travel but have read somewhere that there is no way to turn off heat to the humidifier and this will greatly reduce run time per charge. As this machine is made to run off 12v does using the 12v charger reduce run time the way an inverter/converter would?
If there are any electrical experts here, would you know which machine with their respective converters would last the longest?
Regards,

B_4 wrote:I am going with a PR System One DS250. Does turning CFLEX off save power?

nomoore wrote:I calculated I could get three 8hr nights with my 16ah battery and be down to about 20-25% state of charge. You don't want to drain a lead acid battery more than that.

billbolton wrote:You should not discharge even a "deep discharge" type lead-acid technology battery below ~50% of rated capacity if you want a reasonable service life out of it.

Cheers,

Bill

Cycles vs Life

A battery "cycle" is one complete discharge and recharge cycle. It is usually considered to be discharging from 100% to 20%, and then back to 100%. However, there are often ratings for other depth of discharge cycles, the most common ones are 10%, 20%, and 50%. You have to be careful when looking at ratings that list how many cycles a battery is rated for unless it also states how far down it is being discharged. For example, one of the widely advertised telephone type (float service) batteries have been advertised as having a 20-year life. If you look at the fine print, it has that rating only at 5% DOD - it is much less when used in an application where they are cycled deeper on a regular basis. Those same batteries are rated at less than 5 years if cycled to 50%. For example, most golf cart batteries are rated for about 550 cycles to 50% discharge - which equates to about 2 years.

Battery life is directly related to how deep the battery is cycled each time. If a battery is discharged to 50% every day, it will last about twice as long as if it is cycled to 80% DOD. If cycled only 10% DOD, it will last about 5 times as long as one cycled to 50%. Obviously, there are some practical limitations on this - you don't usually want to have a 5 ton pile of batteries sitting there just to reduce the DOD. The most practical number to use is 50% DOD on a regular basis. This does NOT mean you cannot go to 80% once in a while. It's just that when designing a system when you have some idea of the loads, you should figure on an average DOD of around 50% for the best storage vs cost factor. Also, there is an upper limit - a battery that is continually cycled 5% or less will usually not last as long as one cycled down 10%. This happens because at very shallow cycles, the Lead Dioxide tends to build up in clumps on the the positive plates rather in an even film. The graph above shows how lifespan is affected by depth of discharge. The chart is for a Concorde Lifeline battery, but all lead-acid batteries will be similar in the shape of the curve, although the number of cycles will vary.