Consumer Reports-like rating system on portable batteries used for CPAP machines?

What resource is available to determine what high quality batteries specific to CPAP machines are available in the marketplace?

Hi... i am concerned on my bigger trips it wouldnt be able to keep up with my phone and a6000, and gopro. i plan on using one of the anker 5000mah or less batteries paired with the suntactics solar charger. those batteries can typically charge a phone one to two times. ill leave the panels out every day while away from camp and be able to alternate charging devices to whichever actually needs it.

It's a hard thing to know. I'm sure the CPAP-specific batteries (Freedom, Medistorm, etc) are very well built, and they should be considering the high prices. I know the ResMed power bricks, for example, are built to very high spec from the teardowns we've seen of them - much higher than a similar "consumer" power supply of the same rating would be.

Unfortunately those batteries are so expensive I doubt anyone is interested in buying one for the purpose of tearing it down. If anyone has pictures of the internals or a dead one to donate for an autopsy, I'm happy to give a general opinion on it (I have a degree in EE and do a lot of hobby electronics stuff, though it's not my profession and you should take my opinion with a grain of salt).

Most 12V deep-cycle batteries are fine, that's old technology and any of the standard brands are going to put out a decent, safe product (especially if you get a sealed AGM battery). How you rig them up to connect to AC charging and the CPAP device is of course variable in quality and safety. Here's my example: http://cpaptalk.com/viewtopic/t173238/F ... ackup.html

For third-party 12V/24V lithium backup batteries (for example: https://www.amazon.com/100-Watt-Portabl ... 01M3S00H0/) it gets pretty sketchy. Lithium is more volatile in general, plus it's a small market and often these are generic devices rebranded by no-name brands. The quality could be anywhere, and without a teardown and electrical testing, it's hard to be sure.

I’ve tried 2 different batteries. The Freedom battery which lasted one night. They say 2, but that probably depends on the type of mask you have and other variables. The one I really like is the Maxoak K5 power bank which lasted me 5 nights. You can find both of these on Amazon.
If you want consumer report, Maybe you need refer to the reviews on Amazon.
By the way, why need report?

Chuck Connors wrote: ↑

Tue Oct 23, 2018 7:56 pm

What resource is available to determine what high quality batteries specific to CPAP machines are available in the marketplace?

It would be nice, but since there are only a couple of vendors and not that many customers, its not likely. Frankly they all seem fairly nice but greatly overpriced unless you specifically need a lightweight pack for airline travel or mountain climbing. And most users only use them them a few times, the anecdotal reviews aren't worth a lot.

So I'll widen the question to why aren't there reviews of other packs that might be useful for cpap users?

There are two types of batteries commonly used- AGM and Lithium Ion. The AGM batteries are pretty generic and I've almost never seen a review of the specific manufacturers. I often recommend Universal Battery because they seem to set the standard and have generally high marks, but frankly I don't know if some other brand like "Mighty Max" is actually better. I do wonder about batteries that are selected by vendors of low end jump-starters - they do not have the incentive to pay extra for a long lasting battery. BTW, I use a high quality brand (Trojan) for my boat batteries, but they are getting cycled a 100 times a year, and I expect the to last at least 6-7 years. My cpap backup battery might get used once or twice a year, so there's no need of paying double when there's almost no chance I'll see any benefit.

Lithium Ion is more complicated. The cells are pretty standard - many of the packs use the same 18650 size cells found in a Tesla S or X, but there are many different parameters to choose from - fast or slow discharge, fast or slow charge, long shelf life, etc. This means that pack designer has a lot of freedom to select cells for their purpose, it clouds the issue for consumers. If a pack is advertised as being able to jump start a V8, does that mean it will last 8 hours with a cpap? (Hint: cranking a car for a 10 seconds is about 1 amp-hour.) So while it might be nice to have a good impartial review, the market is so fragmented we're not likely to see one.

Another problem is that the battery (or cells) is only part of the problem. Lithium packs are almost always wrapped in a package with electronics that are necessary to manage the cells. There are many packs that look nice, but if they are designed for charging cell phones and tablets they may not be the best for a cpap. This, of course, makes room for the several vendors of cpap specific packs. AGM batteries don't don't need the cell management of lithium, but they are often sold in jump starters where the issue becomes the quality of the charger and other components.

So what about all those web sites that list the "10 Best Whatevers!!!" I look at them on occasion, but you have to take the with a large grain of salt, especially if they provide helpful links to Amazon. That "Best Mattresses" website is getting a 5% kickback from Amazon for purchases through the links! And of course when you see a review for a battery pack in a camping magazine you'll also see an ad for it. Coincidence?

So what to do? For AGM uses (home backup, car camping, boating or RV) I recommend assembling your own system with a battery with good Amazon reviews and a quality small charger (such as BatteryTender). If you like to get fancy you can put it in a box with plugs and sockets, but all you really need is to bolt on a cable and put some tape over the connectors. For a lithium pack (airline travel, hiking) you can go cheap with a pack designed for charging tablets or pay the higher price for one of the packs designed specifically for cpaps. If you must go with a mass market product, the best guide it probably the Amazon reviews where a bad "5-star/1-star ratio" means you don't want this product for a medical device backup.

Thank you for the very helpful replies.

I consider the captain an expert on off-grid power for pap use.
AFAIK, he is the ONLY resource we can trust.
Thank you to CapnLoki for awesome service.