I need adive buying a battery

[Pesser]

I need help buying a good battery. I think that this battery is powerful enough to handle the humidifier. Has anyone tried this:
https://www.cpap.com/productpage/respir ... d-kit.html

Some battery packs have fans to cool them. These make noise and are likely to wake me up. I am hoping that the battery above does not have fans! In addition I think that the battery above is more powerful than the CPAP.com one, shown here:
https://www.cpap.com/productpage/cpap.c ... cable.html

I live in an area where power outages are frequent. If I had a good battery I would simply go to sleep with it, when there is a reasonable risk of an outage occurring, and also when an outage has occurred.

[Julie]

Just sent you a PM.

[archangle]

My S9 draws around 30 watts with humidifier. At 12V, this would be 2.5 amps.

That battery has a 14 amp hour rating. 5-6 hours run time with humidifier.

If you're not going to be traveling with it, you could make a system on your own from a marine battery for $150 or so. It would have 50-100 amp hours, or 20 to 40 hours of run time with humidifier.

Actual power draw, battery capacity, and run time will vary a whole lot in the real world.

[Pesser]

My S9 draws around 30 watts with humidifier. At 12V, this would be 2.5 amps.

That battery has a 14 amp hour rating. 5-6 hours run time with humidifier.

If you're not going to be traveling with it, you could make a system on your own from a marine battery for $150 or so. It would have 50-100 amp hours, or 20 to 40 hours of run time with humidifier.

Actual power draw, battery capacity, and run time will vary a whole lot in the real world.

Thanks for the help! Are you referring to the CPAP.com battery or the Respironics!

[archangle]

Thanks for the help! Are you referring to the CPAP.com battery or the Respironics!

Didn't notice the second link, sorry.

Looks like the second link (cpap.com) is only 6.7 amp hours, so it has about half the capability of the first one. It is, however, much lighter, since it's a lithium ion.

[Pesser]

Thanks for the help! Are you referring to the CPAP.com battery or the Respironics!

Didn't notice the second link, sorry.

Looks like the second link (cpap.com) is only 6.7 amp hours, so it has about half the capability of the first one. It is, however, much lighter, since it's a lithium ion.

You're helping me a great deal. I have no idea how to calculate the power requirements of my machine. One thing is certain....the power calculator at the bottom of the page on CPAP.com is to be used with great care. It clearly agrees with you; that using a humidifier reduces the length of service greatly. Do you have a quick formula for calculating amp requirements? Or maybe you already know what amps I use with humidifier! Thanks a lot!

[Pesser]

I guess the solution in the battery world is not to use a humidifier!!!!!!!!!

[archangle]

Thanks for the help! Are you referring to the CPAP.com battery or the Respironics!

Didn't notice the second link, sorry.

Looks like the second link (cpap.com) is only 6.7 amp hours, so it has about half the capability of the first one. It is, however, much lighter, since it's a lithium ion.

You're helping me a great deal. I have no idea how to calculate the power requirements of my machine. One thing is certain....the power calculator at the bottom of the page on CPAP.com is to be used with great care. It clearly agrees with you; that using a humidifier reduces the length of service greatly. Do you have a quick formula for calculating amp requirements? Or maybe you already know what amps I use with humidifier! Thanks a lot!

Real battery usage and lifetime varies a lot even with the same machine. There is some info from ResMed on their machines in the links section of my signature line. As a wild guess, 2.5 amps/30 watts with the humidifier, and 1 amp/12 watts without. Most users of an S9 or PRS1 machine will probably be less, but no guarantees.

I guess the solution in the battery world is not to use a humidifier!!!!!!!!!

Not necessarily, but if you use the humidifier, you need to plan for it with a bigger battery, or plan for a shorter run time.

[Pesser]

Where can I find the amp usage of my machine. There's a lot of info on the back. At fixed voltage it looks like 100 watts (like a computer desktop usage) is equal to: 100(watts)/115(volts)=.8695amps. With a battery producing around 7 amps it looks like it can supply power. Now the only problem is....for how long? Have I got this right?

[Bama Rambler]

Your math is correct if the battery put out 115 volts. In order to get the amp draw at 12 volts you need to replace the 115 volts in your equation with 12 volts. Then multiply that by number of sleep hours. Then you need to add some excess to account for losses, etc..

[bwexler]

On my PRS1 960TS with heated hose it requires an upgraded 80 watt power brick. So I would use 80 watts per hour at 12 volts or 640 wat hours for an 8 hour night. divide the by 12 volts and you would have about 5.33 amp hours fro one night.

There is a major difference between the 2 units. The PR unit is a sealed lead acid battery with 14 amp hours. Lead acid batteries should not be run to less than 50% charge or 7 amp hours useable.
The CPAP unit is Lithium ION which is much lighter and can be discharged to about 100%.
Therefore both batteries have about the same usable run time, but the CPAP one weighs a lot less (easier to carry) and will usually last longer, more charge discharge cycles.

[archangle]

Where can I find the amp usage of my machine. There's a lot of info on the back. At fixed voltage it looks like 100 watts (like a computer desktop usage) is equal to: 100(watts)/115(volts)=.8695amps. With a battery producing around 7 amps it looks like it can supply power. Now the only problem is....for how long? Have I got this right?

First off, that number is AC amps at 115 volts. If you run it off 12V DC, the number of amps will be about 10 times higher. 1 amp at 115V is a lot more energy than 1 amp at 12V. 100 watts at 12V is about 8 amps. Your CPAP probably won't actually draw that much, especially not when averaged over a night's usage.

Any rating printed on your machine will be a maximum rating for safety purposes, not the actual consumption. It will also not be the average usage over several hours. Actual usage will vary with pressure, the leak rate of your mask, unintentional leaks, your breathing patterns, settings like EPR and Flex, humidifier usage and settings, humidity, room temperature, how clean the air filter is, etc.

I haven't seen any good power usage documents for Respironics, but the ResMed document I mentioned may give you some ideas.

There may be a guide somewhere to power usage for PRS1 machines. I measured mine using a device called a "Kill a Watt" that measures power on the AC line. My 30 watt measurement is a several hour average. The power on the DC side would have to be somewhat less than that on the AC line, but it's the best estimate I've got.

[Pesser]

My S9 draws around 30 watts with humidifier. At 12V, this would be 2.5 amps.

That battery has a 14 amp hour rating. 5-6 hours run time with humidifier.

If you're not going to be traveling with it, you could make a system on your own from a marine battery for $150 or so. It would have 50-100 amp hours, or 20 to 40 hours of run time with humidifier.

Actual power draw, battery capacity, and run time will vary a whole lot in the real world.

I have a 1500W battery setup for power failures. I don’t need it for power failures because I am install a power generator(Subaru7500W). My wife doesn’t like sleeping with the generator on. I am thinking that while my 1500W “deep cycle” battery setup is ten years old, it still produces a significant amount of power. I think I’ll try using this. It has a loud fan system but I can run a long extension cord and put the unit in another room while sleeping! Do you think this might be a possible solution to running my APAP with my humidifier? Thanks for all your help! Also thank you…..everyone for your help.

[Guest]

I think I’ll try using this. It has a loud fan system but I can run a long extension cord and put the unit in another room while sleeping! Do you think this might be a possible solution to running my APAP with my humidifier?

You just need 12V so connect right to the battery, you don't/won't need a fan. Use the humidifier in bypass mode for the time you are on battery.

[CapnLoki]

On my PRS1 960TS with heated hose it requires an upgraded 80 watt power brick. So I would use 80 watts per hour at 12 volts or 640 wat hours for an 8 hour night. divide the by 12 volts and you would have about 5.33 amp hours fro one night.

There is a major difference between the 2 units. The PR unit is a sealed lead acid battery with 14 amp hours. Lead acid batteries should not be run to less than 50% charge or 7 amp hours useable.
The CPAP unit is Lithium ION which is much lighter and can be discharged to about 100%.
Therefore both batteries have about the same usable run time, but the CPAP one weighs a lot less (easier to carry) and will usually last longer, more charge discharge cycles.

Sorry - you have a factor of 10 error - 640 divided by 12 is 53.33 AmpHours. However, the 80 Watt rating is the maximum power it can pass, not the average. the brick is usually oversized by a large margin (factor of 2 or more) to handle worst case and start up situations. Its very unlikely to total draw could be that high - 15 to 30 AmpHours is more likely with the humidifier running.

I generally agree with the advice that lead acid batteries should not be discharged below 50%. However, the affect of running down to 20% is to greatly reduce the number of usable cycles. In other words, if you run it down to 20% every day you might kill it in a few weeks or so; if you do it once a year you might never notice the difference.