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Medistrom battery backup
#11
It looks similar to the C-100 battery for CPAP.
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Lovin' my CPAP since day 1! (January 2015)
If we aren't cleanin' it we're breathin' it!

"Take it as it comes, specialize in having fun"
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#12
The do look similar, and so does the ResMed Power Station II device. Hopefully, someone can give us a first-hand report on these devices at some point.

Dave
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#13
I've done some more investigating.

The Medistrom is a 100 watt hour battery per their specs.

If you have a 100 watt hour battery you divide by nominal voltage to get amp hours. 100 watt hours / 24 volts nominal = 4.167 amp hours.

The ResMed site has battery tables for their machines. My AirSense 10
running with 8cmH20 pressure and the slim line hose needs a 10 amp hour battery to run for 8 hours.

So - 10/8 = 1.25 amp hour per hour of run time.

Now - ResMed states this is with a 50% safety margin. So, if the battery were brand new, and you got 100% out of it, you could get 6.6 hours
out of it with no humidification or heat. I have no idea how realistic that is.

And 4.167 amp hours / 1.25 amp hours/hour = 3.3 hours run time.

Turn on the humidifier set to 4 with the slimline hose and you need 24 amp hours or battery to get 8 hours run time.

So, likewise, 24/8 = 3 amp hours per hour.

And 4.167 amp hours / 3 amp hours/hour = 1.389 hours of run time.

Throw in the Climate Air hose, or turn up the pressure, and run time deteriorates.

So, for me, this battery would NEVER be able to run my machine for a night.
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#14
The highest my 560P used when last tested was about 25 watts PEAK; overnight it averaged under 10 watts set at 7-20cm. So 10 hours for this 100Wh battery seems like a reasonable number... just keep in mind NO BATTERY wants the humidifier and heater on.
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#15
(06-17-2015, 10:46 PM)GWild Wrote: The highest my 560P used when last tested was about 25 watts PEAK; overnight it averaged under 10 watts set at 7-20cm. So 10 hours for this 100Wh battery seems like a reasonable number... just keep in mind NO BATTERY wants the humidifier and heater on.

I run a 100Ah deep cycle battery when camping and it runs my machine @15 with the humidifier on high all night, as well as a box fan and a laptop.
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#16
The majority of you are right in assuming this thing will NOT run for 10 hours. Dave did the math above and he is correct. You cannot fool physics and a 100Wh battery will only allow 100Wh of drain before the voltage drops below a threshold, 1.75V per cell for lead battery, unsure exactly for lithium. There are different ratings a battery can be given also. A C10 rating would be ideal in this case as it will tell exactly how many watts the battery can sustain for 10 hours before exhausting. A C10 rating of 100Wh would mean this battery can truly supply 100Wh of power in one night of use. Who knows what rating it actually has. C1,C5,C10,C24,C100 it could be any of those!

This is designed to run for a few hours of power loss at most.
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#17
Quote:The majority of you are right in assuming this thing will NOT run for 10 hours.

I disagree. I think it may very well power an xPAP for a full 8 hour night.

This is a bit off topic, but a 20 hour discharge rating (C/20) versus a 10 hour discharge rating (C/10) is usually not 50% different. C is the battery capacity... there is no standard that says that capacity number is at C/20, but it is a generally accepted rule. Lithium batteries (weight of the item that is the focus of this discussion suggests it is Lithium- probably LiFePO) seem to have better performance in this regard. Also, we all need to keep in mind battery energy storage in Watt-hours should not be confused with battery capacity in ampere-hours no more than those two have much to do with cranking-amperes.

It is frustrating, but we are left guessing by the manufacturer/reseller of these things as to what they consider intended and acceptable use. Do they expect 100% discharge or only 33% discharge? I expect (or assume) the design of these lightweight battery systems are intended for a single night use, then need recharge. For example, as an airplane carry-on for a 9 hour flight. And, since we all have been 'taught' that 8 hours of battery life is okay (check your smart phone recharge schedule), 8 hours for an xPAP battery makes sense.

Thus, I would expect this battery to run a typical xPAP machine for 8 hours of normal, NON-HEATED use. After all, if it is an emergency, most of us can do without humidifiers a night or two.

As an earlier post said, if you need a single night of reserve for one of those just in case events, buy it and try it on your system. But do check the return policy -- the big South American river in the sky is generally pretty good - even their third party resellers. If, on the other hand, this is for power-out emergencies, you probably want something else - something that can last a few days before you need to seek an outlet to recharge it.

No one has mentioned it, but there are some quiet, small (under 30lb, under 1000W) gas generators that will run for 8 hours on a tank of gas... and they can power more than just a CPAP in those real emergencies. Some even have a 12V socket along with 110 or 220 outlets.

Regardless of theory and guesswork, unless someone already owns one of these specific battery kits, who can say how long it will last -- and even if we did own one, our use probably won't match your use; we are two different people with entirely different breathing patterns.
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#18
Well, those small generators don't exactly have Pure Sine Wave output, for the most part. Heck my UPS won't even charge off one - so I'm not gonna connect my cpap. But they are fine for running a TV and Sat receiver in the field for a tailgate. Smile

And if you can live without your humidifier, good for you! I can't.

I've decided to get an APC BR1500G. Will tide me over for up to 1 hour. Looking at other solutions for whole house generators to extend that run time.

Dave
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#19
And I have asked the manufacturer these questions on the A site where it is sold. No response after 3 days.

No argument that my ResMed at 8 cmH2O with humidity and a Climate hose will be different than someone's Respironics with no humidity at 15 cmH20. That is why I obtained the ResMed Specs, since I have a ResMed unit, and you can do the same if you wish to reference your specific situation. There may well be one that would allow 8 hours with this unit, but it is not mine.

Personally, a night without humidity would pain me more than a night without my cpap.

Dave


(06-18-2015, 01:37 PM)GWild Wrote:
Quote:The majority of you are right in assuming this thing will NOT run for 10 hours.

I disagree. I think it may very well power an xPAP for a full 8 hour night.

This is a bit off topic, but a 20 hour discharge rating (C/20) versus a 10 hour discharge rating (C/10) is usually not 50% different. C is the battery capacity... there is no standard that says that capacity number is at C/20, but it is a generally accepted rule. Lithium batteries (weight of the item that is the focus of this discussion suggests it is Lithium- probably LiFePO) seem to have better performance in this regard. Also, we all need to keep in mind battery energy storage in Watt-hours should not be confused with battery capacity in ampere-hours no more than those two have much to do with cranking-amperes.

It is frustrating, but we are left guessing by the manufacturer/reseller of these things as to what they consider intended and acceptable use. Do they expect 100% discharge or only 33% discharge? I expect (or assume) the design of these lightweight battery systems are intended for a single night use, then need recharge. For example, as an airplane carry-on for a 9 hour flight. And, since we all have been 'taught' that 8 hours of battery life is okay (check your smart phone recharge schedule), 8 hours for an xPAP battery makes sense.

Thus, I would expect this battery to run a typical xPAP machine for 8 hours of normal, NON-HEATED use. After all, if it is an emergency, most of us can do without humidifiers a night or two.

As an earlier post said, if you need a single night of reserve for one of those just in case events, buy it and try it on your system. But do check the return policy -- the big South American river in the sky is generally pretty good - even their third party resellers. If, on the other hand, this is for power-out emergencies, you probably want something else - something that can last a few days before you need to seek an outlet to recharge it.

No one has mentioned it, but there are some quiet, small (under 30lb, under 1000W) gas generators that will run for 8 hours on a tank of gas... and they can power more than just a CPAP in those real emergencies. Some even have a 12V socket along with 110 or 220 outlets.

Regardless of theory and guesswork, unless someone already owns one of these specific battery kits, who can say how long it will last -- and even if we did own one, our use probably won't match your use; we are two different people with entirely different breathing patterns.

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#20
Quote:Well, those small generators don't exactly have Pure Sine Wave output, for the most part. ... snip ... I've decided to get an APC BR1500G.

Sinewave genset with alternator - generally under 10% distortion, even the small ones - versus an modified-sinewave inverter with 90% distortion... hmm.
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