new lighter batteries, any good?

[rockycpap]

Hi!
There are many new lithium ion battery packs available that promise lots of amp hours at very little weight. My question is if these new batteries are a good idea to power Cpap machines.
Some of the packs state "External portable lithium-ion battery pack for CPAP or other devices which requir 9-12.6V power supply." Which makes me wonder how forgiving the input voltage could be. I have both a Goodknight and M series, both accept 12volt input but is it really ok to give them 9 volts?

[jnk]

Hi!
There are many new lithium ion battery packs available that promise lots of amp hours at very little weight. My question is if these new batteries are a good idea to power Cpap machines.
Some of the packs state "External portable lithium-ion battery pack for CPAP or other devices which requir 9-12.6V power supply." Which makes me wonder how forgiving the input voltage could be. I have both a Goodknight and M series, both accept 12volt input but is it really ok to give them 9 volts?

You mean, like these?

https://www.cpap.com/simple-find-cpap-p ... eries.html

[billbolton]

There are many new lithium ion battery packs available that promise lots of amp hours at very little weight.

The upside of Lithium Ion batteries is that they have a great energy to weight ratio, but the downside is that they degrade chemically at a faster rate than many other battery technologies, and typically have a service life of 3 years, whether they are actively used or not.

Basically that means if you actively use Lithium Ion batteries a lot (as in most mobile phone applications) you get good value for money, but if you use them only occassionally they can be a costly solution... unless weight is a very critical aspect of the particular use you have for the battery.

As an example, I have a battery pack I use with my CPAP kit a few times a year on long duration international airline flight sectors. The pack weighs about 1.8Kg and uses NiMH (Nickel Metal Hydride) rechargable batteries. These batteries will probably last me 10 years or so. If I had gone down the Lithium Ion battery pack route, the pack would have weighed about 30% less but have cost 40% more, and have lasted for about 3 years. For me the weight is not that critical, as it is goes in my carry-on baggage, while the cost differential is significant.

There are some new Lithium Ion based battery technologies that will go into commercial production in the coming year, and these may have different set of trade offs that need to be considered.

On topic of output voltage, the Lithium Ion the pack you are considering probably has a couple of selectable output voltages, so as long as you have it set for a ~12 Volt DC output you should be fine. Most xPAP kit that has 12V DC power option will actually run at voltages down to about 10.5V to 11V DC before getting to the point of running "outside of specification".

Cheers,

Bill

[jnk]

Great info!

Thanks, Bill.

Do you think that Respironics lead-acid pack would be a better solution for me (outages/overnighter) with my ResMed VPAP Auto running at 14/10 bilevel mode?

http://directhomemedical.com/machines-c ... -cpap.html

https://www.cpap.com/productpage/respir ... -pack.html

(Hope you don't mind my borrowing your thread, Rockycpap.)

[datracer99]

I recently purchased 2 x 12v 4500maH Li-Ion batteries off fleabay. They are supposed to be for use with surveillance cameras. They have discharge protection to stop them running at high current loads, and to stop supplying power when they drop to 10.5 volts.

I linked them in parallel and tested them overnight. With the intellipap I got just over 8 hours at 10cm.
These are very light weight (each one is about 170g), and will be ideal when I travel as a fail-safe if the hotel power is poor, or to use on a long flight.
The only down side is that they are slow to charge - this seems to be common with li-ion batteries, and the quality ofthe chargers is poor - only one of them indicates when the battery is fully charged. Not an issue when I charge them together though. I suspect if you had a resmed or an M series you would need 3 of these batteries for a full night.

But if you are not after a battery that is super light weight - i.e if it's just a backup for home use - then a lead-acid battery is goingto be far better value for money as long as you keep it topped up with a trickle charger.

[yardbird]

I think the best battery for home backup.... bang for the buck... no fumes.. long lasting... good power output...safe.... etc... would have to be a Advanced Glass Mat Valve Regulated Sealed Lead Acid Battery Construction (AGM or VRSLAB )

There is never a way to make the acid free to slosh around. This allows for installation at any angle, and has lead to DOT exemption for USPS, UPS, and Fedex.(department of transportation) so... even if you trip over it and it ends up on its side for a few hours.... no acid spill. Since the AGM material has an extremely low electrical resistance it can crank more amps in and out without cost to life. AGM batteries are rated at 100% their capacity for charging and discharging amperage. (compared with roughly 35% for gel and flooded models). Less acid means a lighter battery. Advanced AGM batteries offer exceptional life cycles and are far better than either gel or flooded batteries. This leads to longer battery life and increases your ROI.

The AGM is a bit more expensive than a car battery, but you're keeping this in your bedroom... not under the hood of your car.

If you're going PURELY for light weight? Forget Lithium Ion and get right into Lithium Polymer. Think of 2 teabags having as much electrical punch as a 10-pack of AA Nickel Metal hydride batteries all wired together. I fly electric-powered radio controlled airplanes. My radio is on NiMH 10-pack but my planes fly on LiPo batteries to keep weight down without sacrificing power and endurance.

[rockycpap]

Thanks for your input.
Datracer 99, did you ever check the actual output voltage from the batteries you got off Ebay? What batteries did you get?
Sometimes the voltage stated is just approximate and if these batteries are not regulated then they probably put out 11.1volt. What do the usual machines run on? The Respironics and Puritan Bennett machines both state 12 volts as input but clearly they can take much more since you can run them off the cigarette plug in the car, which gets up to 14.5 volts or higher when the car is on. Does anybody know how low a voltage these machine will run on without a problem?
How important is well regulated DC voltage for these machines?
Thanks...

[ColinP]

even if you trip over it and it ends up on its side for a few hours.... no acid spill.

If you trip over my battery, I can promise you it will not fall on it's side. However, your foot is going to hurt...

Colin

[jnk]

even if you trip over it and it ends up on its side for a few hours.... no acid spill.

If you trip over my battery, I can promise you it will not fall on it's side. However, your foot is going to hurt...

Colin

Maybe cpap.com should stock steel-toed night slippers as a CPAP-related accessory.

Or mayb Pad-a-Cheek can add some pad-a-toe items.

[datracer99]

Thanks for your input.
Datracer 99, did you ever check the actual output voltage from the batteries you got off Ebay? What batteries did you get?
Sometimes the voltage stated is just approximate and if these batteries are not regulated then they probably put out 11.1volt. What do the usual machines run on? The Respironics and Puritan Bennett machines both state 12 volts as input but clearly they can take much more since you can run them off the cigarette plug in the car, which gets up to 14.5 volts or higher when the car is on. Does anybody know how low a voltage these machine will run on without a problem?
How important is well regulated DC voltage for these machines?
Thanks...

The batteries I bought are regulated, so fully charged they put out 12.6V. They drop to 10.6 before shutting off.
The intellipap runs fine down to 10.6V.
The batteries were listed as "4500mA 12V Super Rechargeabl Li-ion Battery For Camera" from credilebuy
They also sell 6500mAH versions as well.
Beause these batteries are protected from high current drain they need to be run in pairs, so that neither battery hits the overload limit.

I looked at a lot of batteries for my travel pack. i would like to have used LiFe or Li-Polymer batteries, but I can't find them in 12v output in the right current cpacities to be useful as a CPAP battery pack.

If you buy anything other than NiMh or a lead based battery then make sure it comes with an approriate charger. It's not easy to get chargers for the newer battery types.

[yardbird]

If you buy anything other than NiMh or a lead based battery then make sure it comes with an approriate charger. It's not easy to get chargers for the newer battery types.

True that. I have one charger that handles regular lead acid, NiCad, and NiMh. But when it comes to the LiPo I have a dedicated charger.

As far as finding LiPo in sufficient output, you probably won't find a single LiPo to do the job. LiPo batteries are assembled into packs based on desired amperage and voltage. They are often connected in various combinations of series and parallel within the same pack. A 4-cell pack may have a designation "2S2P" which means it is 4 cells, assembled as :
2 cells in Series (x2) .... that's the 2S part
with the 2 series packs wired parallel ... that's the 2P part

I have a 4 foot flying wing with a powerful electric motor using LiPo packs in 2S2P configuration that flies at about 85 miles an hour straight and level.

These assembled packs can be ordered with balancing modules to keep all component cells in the pack equalized in terms of charge and prevent overcharging a single cell i the pack. In the hobby we take the LiPo batteries with safety features stripped off... so we're using the "bare" cells. LiPo batteries have many industrial applications but without the safeguards, these batteries can burn violenty if there is an internal short. I charge mine in the middle of the garage floor, inside the cell of a cinder block, with a plastic bag full of sand on top. If a battery goes incendiary while charging, the plastic bag melts and the sand smothers the flames. I know of at least one car lost when a plane's battery pack burned in the trunk.