C-Pap power usage

[Vintage465]

So, I have been using my 12v(6.6 amps) C-Pap machine for a few years in my Creek Side. Now..........my wife is using a C-Pap. So far I have had my wife use my home unit(same exact one as in the trailer) on her side of the Queen size bed. The pressure on my unit is just a hair higher then hers is set for. With both units running all night without the humidifiers running has a very minimal affect on our 2-6v series 200a battery set up. Well, she wants her own, not mine. So hers is a 24v unit that uses 3.7 amps. Again, mine is a 12v @ 6.6 amps. Thinking when I get the converter to jump the 12v up to 24v it will double the amp draw? That would be something like 7.4 amp. Which in reality is not much more then what I have going on now. Is my thinking right?

[SidecarFlip]

Vintage465 wrote:

ktmrfs wrote:

Vintage465 wrote:

SidecarFlip wrote:
Interesting reading. I use an S8 in my TC, running 2 Trojan 6 volt batteries and an AIMS power remote switching PSW 1500 watt and after 8 hours continuous use my SeeLevel battery monitor still shows 80 percent capacity in my batteries in the morning.

I use a passive (air over) humidifier, not as heated one.Hard to find but worth the trouble.

I also use the S8 on hunting trips running off a Lithium Ion battery pack and a MSW 500 watt inverter (passive again) and 2 Li packs run the machine for 3 8 hour nights and charging is a cigarette lighter plug away.

I have no issues in the TC or in a tent.

I am running two cpap machines. That is why I may be using more. But with two machines, if I only tug it down to 75-80% of capacity, my solar always packs me back up by noonish.

even with two machines, not using humidifier, it sound like a higher than expected draw. my one machine, the airsense 10 draws at most 8AH/night, actually closer to 5AH. so even at 10AH/night each, that's 20AH total, or not quite 10 percent on a pair of golf carts. you should be staying above 90 percent if that's all that is drawing current. I suspect things like your fridge, CO detector, propane detector, stereo even in off is really standby, are all drawing as much or more than a CPAP machine.

and trying to determine battery SOC by only looking at battery resting voltage is difficult.

Yes I was thinking all the little green and red lights all over the trailer would be adding to the drop

Because I have a TC and not a trailer, I can keep the parasitic losses to a minimum. The only green light I have is the CO detector and 3 amber led's on the fridge. No nightlights on either. Just pitch black and sleeping.

No TV and no stereo. I use a C Crane Solar Observer am/fm NOAA weather radio for entertainment and it's solar powered.

Every light bulb inside and outside are LED.

[SidecarFlip]

Why I use a passive hunidifier. Keeps the power consumption lower.

[ktmrfs]

MEXICOWANDERER wrote:
This morning:

Respironics BiPAP

14.0 inspiration

11.0 expiration

Duration: 7 hours 09 minutes

Without humidifier

6.62 ampere hours. 12.00 volts lab power supply input.

Allow me to demonstrate a sample 🙂

A 12 watt fan would stir papers at six feet. And with BiPAP fan disabled, the BiPAP unit electronics draws .09 ampere. LCD display lamp off.

your daily AH is consistent with my resmed air sense CPAP without the humidifier, and also consistent with a resperonics unit I had previously.

[MEXICOWANDERER]

This morning:

Respironics BiPAP

14.0 inspiration

11.0 expiration

Duration: 7 hours 09 minutes

Without humidifier

6.62 ampere hours. 12.00 volts lab power supply input.

Allow me to demonstrate a sample 🙂

A 12 watt fan would stir papers at six feet. And with BiPAP fan disabled, the BiPAP unit electronics draws .09 ampere. LCD display lamp off.

[Vintage465]

ktmrfs wrote:

Vintage465 wrote:

SidecarFlip wrote:
Interesting reading. I use an S8 in my TC, running 2 Trojan 6 volt batteries and an AIMS power remote switching PSW 1500 watt and after 8 hours continuous use my SeeLevel battery monitor still shows 80 percent capacity in my batteries in the morning.

I use a passive (air over) humidifier, not as heated one.Hard to find but worth the trouble.

I also use the S8 on hunting trips running off a Lithium Ion battery pack and a MSW 500 watt inverter (passive again) and 2 Li packs run the machine for 3 8 hour nights and charging is a cigarette lighter plug away.

I have no issues in the TC or in a tent.

I am running two cpap machines. That is why I may be using more. But with two machines, if I only tug it down to 75-80% of capacity, my solar always packs me back up by noonish.

even with two machines, not using humidifier, it sound like a higher than expected draw. my one machine, the airsense 10 draws at most 8AH/night, actually closer to 5AH. so even at 10AH/night each, that's 20AH total, or not quite 10 percent on a pair of golf carts. you should be staying above 90 percent if that's all that is drawing current. I suspect things like your fridge, CO detector, propane detector, stereo even in off is really standby, are all drawing as much or more than a CPAP machine.

and trying to determine battery SOC by only looking at battery resting voltage is difficult.

Yes I was thinking all the little green and red lights all over the trailer would be adding to the drop

[ktmrfs]

Vintage465 wrote:

SidecarFlip wrote:
Interesting reading. I use an S8 in my TC, running 2 Trojan 6 volt batteries and an AIMS power remote switching PSW 1500 watt and after 8 hours continuous use my SeeLevel battery monitor still shows 80 percent capacity in my batteries in the morning.

I use a passive (air over) humidifier, not as heated one.Hard to find but worth the trouble.

I also use the S8 on hunting trips running off a Lithium Ion battery pack and a MSW 500 watt inverter (passive again) and 2 Li packs run the machine for 3 8 hour nights and charging is a cigarette lighter plug away.

I have no issues in the TC or in a tent.

I am running two cpap machines. That is why I may be using more. But with two machines, if I only tug it down to 75-80% of capacity, my solar always packs me back up by noonish.

even with two machines, not using humidifier, it sound like a higher than expected draw. my one machine, the airsense 10 draws at most 8AH/night, actually closer to 5AH. so even at 10AH/night each, that's 20AH total, or not quite 10 percent on a pair of golf carts. you should be staying above 90 percent if that's all that is drawing current. I suspect things like your fridge, CO detector, propane detector, stereo even in off is really standby, are all drawing as much or more than a CPAP machine.

and trying to determine battery SOC by only looking at battery resting voltage is difficult.

[Vintage465]

beemerphile1 wrote:

Vintage465 wrote:
...I may have to look into one of the little "Mr. Heater" Free Standing Catalytic heaters for real cold nights.....

FWIW, I don't believe Mr. Heater produces any portable catalytic heaters, only blue flame heaters. The Buddy line of heaters are all blue flame heaters.

Gonna say I need some schooling on this then! I will look further into these. I was thinking by the looks, they were catalytic heaters.

[Vintage465]

SidecarFlip wrote:
Interesting reading. I use an S8 in my TC, running 2 Trojan 6 volt batteries and an AIMS power remote switching PSW 1500 watt and after 8 hours continuous use my SeeLevel battery monitor still shows 80 percent capacity in my batteries in the morning.

I use a passive (air over) humidifier, not as heated one.Hard to find but worth the trouble.

I also use the S8 on hunting trips running off a Lithium Ion battery pack and a MSW 500 watt inverter (passive again) and 2 Li packs run the machine for 3 8 hour nights and charging is a cigarette lighter plug away.

I have no issues in the TC or in a tent.

I am running two cpap machines. That is why I may be using more. But with two machines, if I only tug it down to 75-80% of capacity, my solar always packs me back up by noonish.

[ktmrfs]

SidecarFlip wrote:
That is a good presentation for sure. Now I know why my +90 condensing furnace (in out house running on propane) makes so much water and why the exhaust develops a lot of ice around it in the winter time...all water. I was considering a Wave heater for my next unit. Reading that, I think I'll stick to a forced air unit and deal with the amp draw.

and these furnaces get quite a bit of extra efficiency and heat out of condensing water from vapor to liquid. water releases a great deal of heat when it goes from a vapor state to a liquid. Conversly it takes a great deal of energy to get water from a liquid to vapor, notice how water will sit near boiling for quite a while before coming to a full boil.

[SidecarFlip]

Only thing I know about 'Buddy' heaters is that I use one in my hunting blind in the winter to take the chill off.

I also have a Coleman catalytic heater that uses Coleman fuel. Both work well in the winter.

[beemerphile1]

Vintage465 wrote:
...I may have to look into one of the little "Mr. Heater" Free Standing Catalytic heaters for real cold nights.....

FWIW, I don't believe Mr. Heater produces any portable catalytic heaters, only blue flame heaters. The Buddy line of heaters are all blue flame heaters.

[SidecarFlip]

That is a good presentation for sure. Now I know why my +90 condensing furnace (in out house running on propane) makes so much water and why the exhaust develops a lot of ice around it in the winter time...all water. I was considering a Wave heater for my next unit. Reading that, I think I'll stick to a forced air unit and deal with the amp draw.

[JimK-NY]

ktmrfs, thanks for the info. Nicely presented. I am not going to convert my camper to a cat heater, but I will be using one 24 hrs per day to heat my garage/workshop. I expect to burn about a gallon of propane a day. Getting some humidity into the air will actually be a plus.

[ktmrfs]

MrWizard wrote:
please point me to some reference that says one gallon of propane produces 3 quarts of water

if all much hydrogen is used from the LP (hydrocarbon chain) to combine with oxygen in the air to produce water,
what is producing the heat, and where did the carbon atoms go

heat comes from breaking down the propane into free hydrogen and free carbon and the hydrogen combining with oxygen which equals water plus heat and carbon combining with oxygen producing CO2 plus heat.

The breakdown begins when the propane comes in contact with a heat source hot enough to start the reaction.

The equation for the combustion of propane is:
C3H8 + 5 O2 = 3 CO2 + 4 H2O + energy
for Complete Combustion...

However, you do not get complete combustion, you get some CO
2 C3H8 + 7 O2 = 2CO + 8 H2O + 2CO2 + energy

In either case burning 2 moles of propane will produce 8 moles of water.

1 mole of propane is 44 grams and 1 mole of water is 18 grams.

44 grams = 0.0970024 pounds
18 grams = 0.0396828 Pounds X 4 = 0.158731 pounds

0.09070024 / 0.1587312 = 1/x

x= 1.75 pounds of water for each pound of propane

For water, 1 gallon = 8.33#

For liquid propane, it varies according to temperature. At 77 degF, it is 1 gallon per 4.11#

so buring 4.11 lbs of propane equal 7.19 lbs of water or .86 gallons of water, more than 3 quarts of water.

thats why you see so much water vapor in cold air from burning hydrocarbon fuels, it's all the water as a byproduct of combustion condensing as it cools below the dew point.

plust lots of heat, about 90,000 BTU per gallon of liquid propane burned.

you can do the same calculation for burning natural gas, diesel, gasoline, oil etc. you get heat, water and C02.

when buring coal, which is almost completely carbon, virtually no hydrogen you get heat plus C02, and very very little water.

you can do the same set of calculations to determine how many lbs of C02 are produced.