06-21-2015, 11:31 PM
(This post was last modified: 06-21-2015, 11:35 PM by Oldguide.)
Attached is a first crack at a spreadsheet that lists alternatives for CPAP camping. The list is not intended to be totally inclusive, but takes the various types of battery suggested by different folks and provides examples. I created two columns. Being a numbers person I was curious about the cost per amp hour of different devices. Nothing new here in terms of what is known, but the differences are more dramatic than I had thought. The other column just highlights if the device has been tested for CPAP. This was based on whether there was a post somewhere from someone who had used the device successfully.
As we all know different manufacturers' machines have different requirements. This table is based on 12v machines which seem to be the most common. As Starr and I found out--and as long time users of this board know--we also have different CPAP requirements. The "successful" users I found tended to not have extreme requirements in terms of pressures, etc. As I believe Sleepster noted, the higher your pressure the more power you will consume. Finally, all were based on going without the humidifier.
As they say on TV, consult your doctor if you are planning a wilderness trip.
As one who has spent much of his life in the woods, I wanted to do something that will allow others to enjoy such experiences if at all possible.
Please add comments, corrections, etc.
MANY thanks to all the folks who contributed to this project. I just put your ideas into spreadsheet form.
Being a newbie I am not sure if I have done the attachment right. Seemed to make the most sense as a jpg image. I hope the size is ok, but I had to cut considerably to get in under the quota. JPG seemed best because it can be enlarged easily.
.jpg image.jpg (175.34 KB)
06-22-2015, 01:14 AM
(This post was last modified: 06-22-2015, 01:29 AM by GWild.)
As for trying to make a distinction between a single cell battery and a multi-cell battery ... wow. I need pop corn. In this case, it is similar to the difference between a single-cell jail and multi-cell jail. Cell is synonymous with room, partition, etc. They have dictionaries for that issue. Hint hint, nudge nudge.
-- ps: thought I'd ad the fact that cell became popular when manufacturers needed to describe the case size of say a 1.5 volt carbon-zinc battery. You couldn't just tell someone to get a 1.5v battery for their new widget. So folk used the term F-cell, D-cell, C-cell, AA and down for AAAA and 2/3 A, N, etc. to describe the battery case size.
So I wonder -- is a 9v transistor battery a cell? Not really, it has six cells in it. Transistor was another term used to help the public understand what they needed, and was common in early transistor radios... and a fad name was born... the battery certainly has no transistors in it.
06-22-2015, 06:18 AM
(This post was last modified: 06-22-2015, 06:18 AM by OMyMyOHellYes.)
Magazine vs. Clip
<<pull pin, lob over fence>>
I am quite interested in this thread as I am also researching battery options for camping, including canoe camping. Oldguide, I'm not sure you have accounted for the differences in amp-hour ratings as a measure of energy storage when amp-hours are quoted on different voltages. That is, a battery rated at 12 AH at 12 volts has 3 times the energy storage of a 12 AH battery rated at 4 volts. Some of the lithium batteries with multiple voltage outputs are quoted based on the lower voltage. Thus when run at a higher voltage, the available AH are proportionately less.
This is a great start on a Wiki article, but I don't see anyone on this thread that's a wiki contributor. OldGuide's spreadsheet should be wikified and put up there for reference.
06-22-2015, 10:07 AM
(This post was last modified: 06-22-2015, 10:21 AM by Oldguide.)
I was trying to quote 12v ratings for AH, but some were not clear. If I have some wrong let me know. Feel free to PM me and I will change the table. We would not want someone to purchase an item and then have it last only a few hours.
I also left out warranty info in part because I was running out of columns. Most seem to be for one year.
I also figured people would could find that.
Thanks again for all the help!
(06-22-2015, 09:08 AM)BKeeper Wrote: I am quite interested in this thread as I am also researching battery options for camping, including canoe camping. Oldguide, I'm not sure you have accounted for the differences in amp-hour ratings as a measure of energy storage when amp-hours are quoted on different voltages. That is, a battery rated at 12 AH at 12 volts has 3 times the energy storage of a 12 AH battery rated at 4 volts. Some of the lithium batteries with multiple voltage outputs are quoted based on the lower voltage. Thus when run at a higher voltage, the available AH are proportionately less.
Adding to that: The permissible % of discharge needs to factored in.
Just because a battery is rated 12 A-Hr, does not mean on can pull all 12 A-Hr out of it. Lacking that information, one may undersize a battery.
INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
Good point on discharge. I think ordinary lead acid generally shouldn't be discharged past 50% for best battery life, while the newer lithium iron phosphate, can be taken way lower - don't know how far. Old guide, I didn't check your AH numbers until now - on the Pilot lithium quoted at 32 AH, by looking at the first review, I'm backing into a number of abut 8 AH (at 12v) based on the first reviewer's numbers (using the watt hours in a given iPad, divided by 12v times the number of recharges possible). I looked at this battery last week, all excited, until I surmised that the AH were quoted at a lower voltage. Someone correct me if I am wrong, please.
06-22-2015, 01:22 PM
(This post was last modified: 06-22-2015, 01:26 PM by GWild.)
While a Wiki article sounds good - the data will go stale in a matter of months and the data upkeep would be a challenge. On the other hand, there is enough good data available from manufacturers to allow fair evaluation by those actually interested in it. And those that aren't more than likely can't evaluate the technical data well enough to help, anyway.
Ignoring things like silver or air batteries and not-so-common tech...
Carbon zinc: one time use, cheaper.
Alkaline: one time use, cheap.
NiCd: multi-use: 100x, not so cheap. Requires effort to maintain.
NiMH: multi-use 200x. Average. Requires less work to maintain.
LiIon: multi-use 400x. Average plus. Requires special chargers to maintain.
LiFePO: multi-use 800x. Expensive. Requires special chargers to maintain.
LiFePO+: multi-use >2000x, up and coming technology. Very expensive. Easy to maintain, sometimes requires special charger.
- + indicates internal equalization electronics
Heavy, wet technology:
Lead-acid (lead-calcium plate alloys): multi-use 20x. Not so cheap. Heavy. Think car old battery maintenance.
Lead-acid (lead-calcium plate alloys) AGM: multi-use 20x. Not so cheap. Heavy, but kind of dry. Think car new battery maintenance.
Lead-acid (lead-antimony plate alloys): multi-use 800x. Getting expensive. Heavy. Think car old battery maintenance.
Lead-acid (lead-antimony plate alloys) AGM: multi-use 500x. More expensive. Heavy. Think car new battery maintenance.
Lead-acid (lead-antimony plate alloys) gelled electrolyte: multi-use 650x. Even more expensive. Heavy. Think car new battery maintenance.
Lead-acid (lead-antimony plate alloys, advanced paste compounding), wet electrolyte: multi-use >2000x. Very expensive. Heavy. Think car old battery maintenance.
ps - that last one once was the primary reserve your land line phone runs on when the AC goes out.
The other side of this coin is how well the device in use treats the battery. A device that draws a battery down without regard for minimum voltage can damage a battery. The new LiFePO batteries with built in electronics guard against over discharge ... as well as having all the charge protection. Combined with the fact they have extremely low self discharge (aka - long shelf life), appear to be a perfect reserve battery for xPAP.
Again - the typical user doesn't have the skill set to maintain a battery - while cheap, an 18AH SLA can die sitting on the shelf if not maintained; so whatever the solution is, it needs to be fool proof. So that's a +1 for the latest Lithium tech. Expensive yes, but there is serious value in what the internals provide, and has a better chance of lasting a few years in a typical household.