V-465
2013 GMC 2500HD Duramax Denali. 2015 CreekSide 20fq w/450 watts solar and 465 amp/hour of batteries. Retired and living the dream!
so maybe 7.8 amps at 12v
I can explain it to you.
But I Can Not understand it for you !
....
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CPAPs can chew through a lot of battery power. According to the OP, his 12 volt model uses 6.6 amps. For 8 hours of use, that would be 53 amp hours. Two units running for a night would deplete the 200 AH batteries to less than 50 percent. The 6.6 amp draw sounds high and is probably the maximum with the humidifier running. My wife's unit pulls about 3 amps without the humidifier. Anyway, CPAPs pull a lot of power and if you are going to run a CPAP solely on battery power, you will need a substantial battery bank and you will need to run a generator or have a suitable solar system and plenty of sunlight.
There are some new travel units that require minimal power, but you would need to go back to your sleep doctor to discuss the suitability.
ktmrfs wrote:
I'm going to guess her's is a resmed. battery power solutions makes a great 12V to 24V DC to DC converter for these units.
I'm going to guess her's is a resmed. battery power solutions makes a great 12V to 24V DC to DC converter for these units.
Yes, I have ordered the Resmed 12v DC/DC to 24v converter. I am pretty sure the only thing I will need to do to get it fired up is fabricate a pretty stout 12 gauge, 12v extension cord to get from my side of the bed to hers.
JimK-NY wrote:
I think a few added comments might be of help for anyone who is not familiar with RV CPAP issues. First, Res Med makes CPAPs designed to run on 110 volts and also other units designed for 12 volt use. The 110 units seem to use a lot of power and for battery use they would also require an inverter which loses additional power in the form of heat. The 12 volt units comes with a transformer and can be used with 110. I found many of the providers do not understand the difference. So you might actually need to research the Resmed offerings and give the provider the appropriate part number.
CPAPs can chew through a lot of battery power. According to the OP, his 12 volt model uses 6.6 amps. For 8 hours of use, that would be 53 amp hours. Two units running for a night would deplete the 200 AH batteries to less than 50 percent. The 6.6 amp draw sounds high and is probably the maximum with the humidifier running. My wife's unit pulls about 3 amps without the humidifier. Anyway, CPAPs pull a lot of power and if you are going to run a CPAP solely on battery power, you will need a substantial battery bank and you will need to run a generator or have a suitable solar system and plenty of sunlight.
There are some new travel units that require minimal power, but you would need to go back to your sleep doctor to discuss the suitability.
I think a few added comments might be of help for anyone who is not familiar with RV CPAP issues. First, Res Med makes CPAPs designed to run on 110 volts and also other units designed for 12 volt use. The 110 units seem to use a lot of power and for battery use they would also require an inverter which loses additional power in the form of heat. The 12 volt units comes with a transformer and can be used with 110. I found many of the providers do not understand the difference. So you might actually need to research the Resmed offerings and give the provider the appropriate part number.
CPAPs can chew through a lot of battery power. According to the OP, his 12 volt model uses 6.6 amps. For 8 hours of use, that would be 53 amp hours. Two units running for a night would deplete the 200 AH batteries to less than 50 percent. The 6.6 amp draw sounds high and is probably the maximum with the humidifier running. My wife's unit pulls about 3 amps without the humidifier. Anyway, CPAPs pull a lot of power and if you are going to run a CPAP solely on battery power, you will need a substantial battery bank and you will need to run a generator or have a suitable solar system and plenty of sunlight.
There are some new travel units that require minimal power, but you would need to go back to your sleep doctor to discuss the suitability.
I am thinking that the Amp draw on the labels that I posted are with the Humidifier in use. Since running two machines(my trailer unit and my house unit) w/o humidifiers on drops me to say 12.4 volts. 12.6 volts is 100% charge right?
per hour, without humidifier.
Voltage is a very poor indicator of battery state of charge. A good battery monitor will tell you what is going on.
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Next, if at all possible turn the unit to Airplane mode AND either turn off the humidifier or use the humidifier bypass plug unless you really need the humidifier, and also turn OFF the heating to the tube. If you do these, the power draw drops dramatically.
doing this I can run my resmed for 2 nights on a 250WH battery pack, that's about 8AH per day. so figure about a 1A draw from the battery. Using humidifier, you will draw 3 or 4 times that. It won't make it one night using the humidifier.
JFNM wrote:
Most likely. Most CPAP/BiPAP machines consume around 1 amp @ 12VDC,
per hour, without humidifier.
Voltage is a very poor indicator of battery state of charge. A good battery monitor will tell you what is going on.
Most likely. Most CPAP/BiPAP machines consume around 1 amp @ 12VDC,
per hour, without humidifier.
Voltage is a very poor indicator of battery state of charge. A good battery monitor will tell you what is going on.
I did a lot of research and could not find any ResMed units under 3 amps even without a humidifier. I sure would like to know which models only pull about 1 amp.
Yesterday I took a 900 watt liquid heating coil
Stuck it into a glass water glass. 16 oz. A wide tumbler.
Dialed in 40 watts AC, a resistive load.
Ambient air temp 66F
Within 25 minutes the HALF QUART of water was at 133F. Too hot to touch. I am not aware of any single or bi-level device that holds one half quart in the humidifier reservoir.
My Respironics unit is a Bi-Pap. Therefore the inspiration cycle which is set at 14 draws more watts than the expiration cycle which is set at 10.
In cool weather the humidifier heater draws more power. I found through a study that about 40% of the additional needed heater power is used when compensating temperature via the unit's humidifier thermostat.
Medical suppliers sell insulating tubes for breathing apparatus cannula. Significantly reduces ampere hour accumulation.
In addition, I have very loosely covered the Respironcs unit itself with a section of SPACE BLANKET. Yes I thoroughly monitored heat buildup (none) and after EIGHT YEARS on the same machine I can say the covering has had no negative effects. There is not enough inherent power consumed by the machine to radiate heat.
The heating pad beneath the reservoir has an enormously safe thermostatic system. Not only primary heating but a safety shutoff
If you really want to get snotty about saving energy, apply a dab of vegetable cooking oil between the heating pad and reservoir tank aluminum pad. This increases heat transfer significantly.
There is no arguing with meters. Any breathing apparatus that draws 50 watts of power continuously will either catch fire or melt the ice inside your igloo.
The subject of powering a breathing apparatus via an RV 12 volt system has omitted one vital fact.
DISCONNECT THE DEVICE BEFORE STARTING THE ENGINE in a camper or motorhome. The unit primary protection is contained within it's medical grade switched power brick. Contact ResMed or Respironics about the particulars of this. Starting the engine is a big no-no and for good reason.
By the way my BiPap draws 3.34 amperes max setting of 5 on the humidifier, with a 30% on duty cycle in 60F ambient the remaining 70% draws 13 watts.
With insulated cannula and space blanket the duty cycle drops to 20% with 50F ambient. This has no effect on the pressure unit wattage draw.
JimK-NY wrote:
I did a lot of research and could not find any ResMed units under 3 amps even without a humidifier. I sure would like to know which models only pull about 1 amp.
JFNM wrote:
Most likely. Most CPAP/BiPAP machines consume around 1 amp @ 12VDC, per hour, without humidifier.
Most likely. Most CPAP/BiPAP machines consume around 1 amp @ 12VDC, per hour, without humidifier.
I did a lot of research and could not find any ResMed units under 3 amps even without a humidifier. I sure would like to know which models only pull about 1 amp.
Years ago, I had a ResMed Escape S8, I can't remember the exact number but it consumed something just over 1A @ 12V per hour. My current BiPAP, Phillips System One BiPAP Auto, consumes almost exactly 1A @12V per hour. Both were measured using a Kill-A-Watt meter over several nights use. No humidifier, as noted above.
Maybe take a Kill-A-Watt with you to your next appointment and measure some of the options there?? Be sure to actually measure the power consumption, the documentation is always higher than actual.
MEXICOWANDERER wrote:
The power calculations do not fit.
The power calculations do not fit.
I agree. I suspect "published" numbers are being reported and not measured numbers OR with and without humidifier is being confused.
MEXICOWANDERER wrote:
The subject of powering a breathing apparatus via an RV 12 volt system has omitted one vital fact.
DISCONNECT THE DEVICE BEFORE STARTING THE ENGINE in a camper or motorhome. The unit primary protection is contained within it's medical grade switched power brick. Contact ResMed or Respironics about the particulars of this. Starting the engine is a big no-no and for good reason.
The subject of powering a breathing apparatus via an RV 12 volt system has omitted one vital fact.
DISCONNECT THE DEVICE BEFORE STARTING THE ENGINE in a camper or motorhome. The unit primary protection is contained within it's medical grade switched power brick. Contact ResMed or Respironics about the particulars of this. Starting the engine is a big no-no and for good reason.
I'm not sure why one of these devices (or inverter) would be connected to the starting battery but I suppose every coach is different so it is possible. Mine is connected to my house battery and I rarely ever disconnect it. Not a problem in several years of full-timing.
Da chassis battery be connected to da alternator and starter
You are fortunate. I have talked to several people who had their machines go dark.
I suggest deferring to ResMed or Respironics about disconnecting the machine. Inside the BiPAP or CPAP is a pathetically small amount of deviant voltage protection. The companies rest all their laurels inside the medical grade power brick.
Any problem is compounded when using a non medical booster for 24 volt operation. The toroid and caps = LC harmonics. Check with the machine manufacturer. Thank god I have transient voltage supplies and the knowledge how to construct circuits.
MEXICOWANDERER wrote:
Da house battery be connected to da chassis battery wid a relay
Da chassis battery be connected to da alternator and starter
You are fortunate. I have talked to several people who had their machines go dark.
I suggest deferring to ResMed or Respironics about disconnecting the machine. Inside the BiPAP or CPAP is a pathetically small amount of deviant voltage protection. The companies rest all their laurels inside the medical grade power brick.
Any problem is compounded when using a non medical booster for 24 volt operation. The toroid and caps = LC harmonics. Check with the machine manufacturer. Thank god I have transient voltage supplies and the knowledge how to construct circuits.
Da house battery be connected to da chassis battery wid a relay
Da chassis battery be connected to da alternator and starter
You are fortunate. I have talked to several people who had their machines go dark.
I suggest deferring to ResMed or Respironics about disconnecting the machine. Inside the BiPAP or CPAP is a pathetically small amount of deviant voltage protection. The companies rest all their laurels inside the medical grade power brick.
Any problem is compounded when using a non medical booster for 24 volt operation. The toroid and caps = LC harmonics. Check with the machine manufacturer. Thank god I have transient voltage supplies and the knowledge how to construct circuits.
Kind of off topic but you must be refering to YOUR specific setup. They are not all the same.
Energy does not disappear. It has to translate to motion, heat, magnetics, etc.
A programmed positive pressure fan, plus 30 watt heating resistance cannot "magically" consume a surplus of amperage. Any difference between a 300 dollar unit and six thousand dollar unit would be minimal. Say 120%.
"My humidifier uses more power than your humidifier because the wattage knows my unit costs more money?"
The PROM and energy management system within a BiPAP is minuscule compared to a non medical system.
Any finally
Look at the max power rating of your unit's power brick. My Respironic brick is rated for 5 amperes at 12.00 vdc.
In your wildest dreams, do you think Respironics would choose a MEDICAL power supply rated at or near maximum potential?
At full output on a cold* day, my brick heats to near 40c 104F.
*Do you sleep in 45F temperatures?
Measuring not guessing is the key to knowledge and meaningful planning.
I have a four thousand dollar Respironics unit apart. It failed when the owner tried powering it with an unregulated 7 ampere brick. The 5.0 volt logic system power supply chip failed. Perhaps (?) a 5.0 volt TO220 reg can be substituted but the board is 100% wave soldered.
JimK-NY wrote:
I did a lot of research and could not find any ResMed units under 3 amps even without a humidifier. I sure would like to know which models only pull about 1 amp.
JFNM wrote:
Most likely. Most CPAP/BiPAP machines consume around 1 amp @ 12VDC,
per hour, without humidifier.
Voltage is a very poor indicator of battery state of charge. A good battery monitor will tell you what is going on.
Most likely. Most CPAP/BiPAP machines consume around 1 amp @ 12VDC,
per hour, without humidifier.
Voltage is a very poor indicator of battery state of charge. A good battery monitor will tell you what is going on.
I did a lot of research and could not find any ResMed units under 3 amps even without a humidifier. I sure would like to know which models only pull about 1 amp.
I have a resmed airsense 10. I can run it for two and half nights, sometimes 3 off a 200WH Lithium Ion battery with it in airplane mode, humidifier off, and hose heater off.
Assuming I draw the battery down to near 0, possible with a Lithium ion, 24 hours works out to about 2A average draw or less, depending on how far the battery really gets drained. More likely average draw is in the 1.5A range or less, that is using a 12 to 24V DC to DC converter with it's losses.
earlier, I goofed and said 1A, brain fart in mental calculations, but the 1A number is probably closer to reality than the mental 2A calculation assuming 100 percent battery discharge. The CPAP will shut off when battery voltage gets below a certain voltage, likely well above full discharge.
Be carefull about mfg ratings. the current draw will be the max current draw for a given configuration. current draw is highest at startup as it ramps up the blower etc. until it senses you are sleeping. And it also will likely assume max pressure, and max air volume.
So each user is likely to experience different average power draw.
He and some respondents are off-the-rails with his energy assumptions. You are fortunate with not having problems with your unit. All assisted breathing apparatus comes with an instruction booklet. Inside that booklet you will find specific reference to unplug the unit from 12vdc before the vehicle engine is started. Capiche?
Actually looking with your own personal eyeballs at CPAP and BiPAP circuit boards will show an absolute minimum of transient voltage protection. If you want to risk your personal equipment, that is your concern. I am reporting what I see.
12 to 24 volt boosters.
I have actual experience with this unit and it is surprisingly efficient, durable, and long-lived. The aluminum shell is SEALED. Submersible and a great heat sink.
Ripple is .06 vdc at 50 watts output.
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Input voltage
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C 12V(10-20V)Output voltage
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And please remember amperage at given wattage is HALF that of 12 volts.
I run the unit through a ProWatt 2000 inverter and use the humidifier every night.
Average use is 7 hours per night. Battery bank drop per night is about 22 Ah. This includes inverter and conversion losses.
Not a big power hog in my book. Easily made up by the solar power system.
Yes, I could buy a 12 - 24 booster, turn off the humidifier and save 10 or 12 Ah per night, but at this point no need.
2007 Tundra DC 4X4 5.7, Alcan custom rear springs, 2009 Cougar 245RKS, 370 watts ET solar,
Rogue MPT-3024, 440 AH GC2 bank, ProWatt 2000,100% LED lighting
12thgenusa wrote:
Personal experience. I have a ResMed AirSense 10 with the 90 watt brick, 1-1.5 Amp input at 115 volts with 3.75 amp output at 24 volts.
I run the unit through a ProWatt 2000 inverter and use the humidifier every night.
Average use is 7 hours per night. Battery bank drop per night is about 22 Ah. This includes inverter and conversion losses.
Not a big power hog in my book. Easily made up by the solar power system.
Yes, I could buy a 12 - 24 booster, turn off the humidifier and save 10 or 12 Ah per night, but at this point no need.
Personal experience. I have a ResMed AirSense 10 with the 90 watt brick, 1-1.5 Amp input at 115 volts with 3.75 amp output at 24 volts.
I run the unit through a ProWatt 2000 inverter and use the humidifier every night.
Average use is 7 hours per night. Battery bank drop per night is about 22 Ah. This includes inverter and conversion losses.
Not a big power hog in my book. Easily made up by the solar power system.
Yes, I could buy a 12 - 24 booster, turn off the humidifier and save 10 or 12 Ah per night, but at this point no need.
OK, 22AH over 7 hours is about a 3A average draw on 12V. that would be 1.5A on 24V and about 0.300 A on 120V.
I wonder where ResMed is coming from in thinking/publishing/advertising that "engine startup electrical disturbances" superimposed on a circuirt with two or more large storage batteries in it will somehow get those disturbances past those batteries' (capacitors') terminals and then through a DC to DC converter into the guts of a CPAP machine?
![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/scratchead.gif "scratchead")
and ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/huh.gif "huh")
We operate one ResMed off an inverter and one ResMed via a (too expensive) ResMed DC to DC converter accessory. They draw between 1 to 1.5 amps each from the coach batteries - which was a pleasant surprise in how trivial their draw was.
2005 E450 Itasca 24V Class C
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MEXICOWANDERER wrote:
Again stick your finger onto the starter motor power terminal crank the engine release the key then scrape yourself off the wall.
Again stick your finger onto the starter motor power terminal crank the engine release the key then scrape yourself off the wall.
It first - takes voltage (higher than 12 volts), then second - adequate current driven by that voltage for a person to get plastered to the wall.
I understand that the necessary current is available, but where is high voltage coming from during the engine starting procedure? The alternator of course is a source of relatively high AC voltage when it's spinning, but it's hardly doing that during engine start.
* This post was edited 06/15/17 12:50am by pnichols *
pnichols wrote:
It first - takes voltage (higher than 12 volts), then second - adequate current driven by that voltage for a person to get plastered to the wall.
I understand that the necessary current is available, but where is high voltage coming from during the engine starting procedure? The alternator of course is a source of relatively high AC voltage when it's spinning, but it's hardly doing that during engine start.
MEXICOWANDERER wrote:
Again stick your finger onto the starter motor power terminal crank the engine release the key then scrape yourself off the wall.
Again stick your finger onto the starter motor power terminal crank the engine release the key then scrape yourself off the wall.
It first - takes voltage (higher than 12 volts), then second - adequate current driven by that voltage for a person to get plastered to the wall.
I understand that the necessary current is available, but where is high voltage coming from during the engine starting procedure? The alternator of course is a source of relatively high AC voltage when it's spinning, but it's hardly doing that during engine start.
Induction in the starter motor or solenoid coils when the circuit is broken. Recall that an inductor is the complement of a capacitor; it tends to prevent changes to current (rather than voltage) by supplying or sinking voltage (rather than current). Open the circuit, and the current immediately goes from many amps to zero, and the response of the inductance of the coils causes the voltage there to spike. For this reason, coils on relays etc. often have snubber diodes or resistors to provide a path for these transients to discharge.
That particular voltage spike oughtn't make it back into the 12V system since it's on the disconnected side of the circuit, but there are other sources of probably lesser voltage fluctuations when the vehicle is started. Car and truck electrical systems are not particularly clean or stable supplies.
DrewE wrote:
Induction in the starter motor or solenoid coils when the circuit is broken. Recall that an inductor is the complement of a capacitor; it tends to prevent changes to current (rather than voltage) by supplying or sinking voltage (rather than current). Open the circuit, and the current immediately goes from many amps to zero, and the response of the inductance of the coils causes the voltage there to spike. For this reason, coils on relays etc. often have snubber diodes or resistors to provide a path for these transients to discharge.
That particular voltage spike oughtn't make it back into the 12V system since it's on the disconnected side of the circuit, but there are other sources of probably lesser voltage fluctuations when the vehicle is started. Car and truck electrical systems are not particularly clean or stable supplies.
pnichols wrote:
It first - takes voltage (higher than 12 volts), then second - adequate current driven by that voltage for a person to get plastered to the wall.
I understand that the necessary current is available, but where is high voltage coming from during the engine starting procedure? The alternator of course is a source of relatively high AC voltage when it's spinning, but it's hardly doing that during engine start.
MEXICOWANDERER wrote:
Again stick your finger onto the starter motor power terminal crank the engine release the key then scrape yourself off the wall.
Again stick your finger onto the starter motor power terminal crank the engine release the key then scrape yourself off the wall.
It first - takes voltage (higher than 12 volts), then second - adequate current driven by that voltage for a person to get plastered to the wall.
I understand that the necessary current is available, but where is high voltage coming from during the engine starting procedure? The alternator of course is a source of relatively high AC voltage when it's spinning, but it's hardly doing that during engine start.
Induction in the starter motor or solenoid coils when the circuit is broken. Recall that an inductor is the complement of a capacitor; it tends to prevent changes to current (rather than voltage) by supplying or sinking voltage (rather than current). Open the circuit, and the current immediately goes from many amps to zero, and the response of the inductance of the coils causes the voltage there to spike. For this reason, coils on relays etc. often have snubber diodes or resistors to provide a path for these transients to discharge.
That particular voltage spike oughtn't make it back into the 12V system since it's on the disconnected side of the circuit, but there are other sources of probably lesser voltage fluctuations when the vehicle is started. Car and truck electrical systems are not particularly clean or stable supplies.
yup. Put a scope on many of the power lines in a car and you may be suprised what kind of spikes are there as relays switch etc. and the starter motor being a DC motor with brushes and comutator is particularly bad for putting big spikes on the 12V lines.
I've found several aftermarket accy for a car that would die pretty quick and prematurely. In all the cases, I found they had no snubber diodes on the supplies to prevent voltage spikes from getting into the circuit. And when your looking at logic rated at 20 or 30V destruct limits, it isn't very hard at all to kill stuff in short order with the voltage spikes running around in the car.
voltage across a capacitor can't change instantaniously, current through an inductor can't change instantaneously. So when you interupt these circuits you get big voltage or current spikes.
A good example is the arc you likely have seen when disconnecting somthing like a hair dryer while running from an outlet. that voltage spike is related to the inductance and interupting the supply quickly. The result is a big voltage spike.
Note that disconnecting a resistive load doesn't give any noticeable arc.
When solenoid contacts open voltage in amplitude jumps the gap between receding contacts. Look at solenoid contacts sometime. The erosion is not hypothetical. A 1Kv transient can bridge quite a distance. Mercury filled relays are not for the heck of it
![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/smile.gif "smile")
Finishing up from my perspective..........the one thing I am not good at is unplugging the unit from the 12v for traveling. I have logged quite a few miles with it plugged in, but I will need to get better. These things are a bit too pricey to be irresponsible with!
Inspiration cycle uses significantly more watts than expiration with a BiPap.
Use something like a Kil-A-Watt meter with the power brick connected to it. Multiply accumulated kWh fraction x 90% for a reasonable guess as to what to expect. A tubing insulation sleeve available from your medical supplier will SIGNIFICANTLY reduce humidifier accumulations because you will set the humidification to a much lower number.
(Above derived from experience not guesswork or assumptions)
MEXICOWANDERER wrote:
Checking amp draw accumulations must be done with meters not by assumptions from reading an instruction book.
Inspiration cycle uses significantly more watts than expiration with a BiPap.
Use something like a Kil-A-Watt meter with the power brick connected to it. Multiply accumulated kWh fraction x 90% for a reasonable guess as to what to expect. A tubing insulation sleeve available from your medical supplier will SIGNIFICANTLY reduce humidifier accumulations because you will set the humidification to a much lower number.
(Above derived from experience not guesswork or assumptions)
Checking amp draw accumulations must be done with meters not by assumptions from reading an instruction book.
Inspiration cycle uses significantly more watts than expiration with a BiPap.
Use something like a Kil-A-Watt meter with the power brick connected to it. Multiply accumulated kWh fraction x 90% for a reasonable guess as to what to expect. A tubing insulation sleeve available from your medical supplier will SIGNIFICANTLY reduce humidifier accumulations because you will set the humidification to a much lower number.
(Above derived from experience not guesswork or assumptions)
I will just turn the Humidifiers off on both units..............way less amp draw. Gonna say, more than likely I will do this by trial and error.......AKA seat of the pants. I will run them both with the Humidifiers off and see if it works. If it doesn't, then I will purchase a lower amp draw unit.
Vintage465 wrote:
I checked the amp draw on both of the units. The amp draw must include the Humidifier. If it didn't the two units would use 106.72 amps over an 8hr period. That would have taken my to 50% of their capacity. That has not happened. I have used the two Phillips Respironic units quite a few times. The Resmed unit uses about 1.25 amp hr. more. I am thinking with my Phillips Respironics and the Resmed unit both running w/o Humidifiers on would be just about the same(it will draw 10a more over night) as the two Phillips units w/o the Humidifiers on. Thinking it will be OK.
Finishing up from my perspective..........the one thing I am not good at is unplugging the unit from the 12v for traveling. I have logged quite a few miles with it plugged in, but I will need to get better. These things are a bit too pricey to be irresponsible with!
I checked the amp draw on both of the units. The amp draw must include the Humidifier. If it didn't the two units would use 106.72 amps over an 8hr period. That would have taken my to 50% of their capacity. That has not happened. I have used the two Phillips Respironic units quite a few times. The Resmed unit uses about 1.25 amp hr. more. I am thinking with my Phillips Respironics and the Resmed unit both running w/o Humidifiers on would be just about the same(it will draw 10a more over night) as the two Phillips units w/o the Humidifiers on. Thinking it will be OK.
Finishing up from my perspective..........the one thing I am not good at is unplugging the unit from the 12v for traveling. I have logged quite a few miles with it plugged in, but I will need to get better. These things are a bit too pricey to be irresponsible with!
and with the humidifier, the current draw is NOT a constant function of time. It is high initally to heat the water, then will drop way down and the heating unit will cycle to keep the water at a constant temperature. How much cycling and how much current will depend on air flow rate, and air temperature as well as outside temperature and how much water remains in the reservoir. as water level drops energy needed to keep it at a constant temperature decreases.
But the spec's are for worst case max draw conditions, likely full reservoir, highest airflow rate, lowest outside temperature, very low humidity and line voltage that will draw max current. Then a safety factor added to that.
Having designed test equipment to meet UL spec's one NEVER NEVER EVER wants to ship a unit that draws more current than the nameplate spec. That will get you in big trouble with U.L.
Probably even worse for medical equipment.
So. I'd take the nameplate current draw as a serious absolute worst case operating condition.
I've found the easiest way to estimate the actual AH draw is to read my trimetric before going to bed and in the AM to see battery SOC and then calculate AH useage. Need to do that in the evening when everything else is off and in the AM before turning on the heat etc.
And I've run mine off a 200WH Lithium Ion battery pack and seen how many hours till it quites. Usually sometime in the third night. That works out to between 1 and 1.5A, consistent with what I get from the trimetric.
It's not peak Amps you care about it's the Amps integrated over the time it is on.
MEXICOWANDERER wrote:
Checking amp draw accumulations must be done with meters not by assumptions from reading an instruction book.
Inspiration cycle uses significantly more watts than expiration with a BiPap.
Use something like a Kil-A-Watt meter with the power brick connected to it. Multiply accumulated kWh fraction x 90% for a reasonable guess as to what to expect. A tubing insulation sleeve available from your medical supplier will SIGNIFICANTLY reduce humidifier accumulations because you will set the humidification to a much lower number.
(Above derived from experience not guesswork or assumptions)
Checking amp draw accumulations must be done with meters not by assumptions from reading an instruction book.
Inspiration cycle uses significantly more watts than expiration with a BiPap.
Use something like a Kil-A-Watt meter with the power brick connected to it. Multiply accumulated kWh fraction x 90% for a reasonable guess as to what to expect. A tubing insulation sleeve available from your medical supplier will SIGNIFICANTLY reduce humidifier accumulations because you will set the humidification to a much lower number.
(Above derived from experience not guesswork or assumptions)
Mex makes a good point on use of an insulation sleave for the tube. At least for resmed, they are inexpensive and reduce the need for tube heating and condensation. And along the way will reduce AH useage.
Unit: Resmed Airsense 10 powered from 12V DC via the Battery power solutions 12V-24V DC converter
Power source: Battery power solutions 250WH Lithium Ion battery pack. 250WH I estimated to be about 20AH.
I turned off the humidifier, the tube heat and the wifi
Results
3 and 1/2 nights of operation 8hrs each night before the converter determined the battery voltage was to low.
So, 28 hours of operation consumed 20Ahrs or less, not knowing how low it discharged the battery. Or figure around 6AH/day, which works out to less than 1A average current draw.
For reference, the BPS website lists the runtime for this CPAP machine as 1-2 nights on the 100WH battery pack they now sell. So my run time of 3.5 nights on a 250WH pack is very consistent with their data.
These results are also consistent with the data I had from my previous CPAP unit a Remstar unit, which would run 3 nights on the same battery pack.
Also, I've run the resmed unit with humidifier on and can barely get 1 nights use. Consistent with the BPS website which states runtime can be reduced by 60 percent or more when using the humidifier.
Conclusion: a CPAP with humidifier turned off, is a minimal current drain on a trailer battery. With humidifier turned on current draw can easily triple.
Mel
Vintage465 wrote:
So the results are in! With my Phillips DreamStation and the Resmed AirSense 10 running w/o humidifiers, Hose heaters and WyFy we would suck the batteries to 12.4 to 12.5 volts. So we had something like 75-80% left. This is pretty easy to work with. However, it may not leave enough battery to keep a furnace on all night and keep the trailer @ 55-60 degrees in the winter. I may have to look into one of the little "Mr. Heater" Free Standing Catalytic heaters for real cold nights. My wife doesn't really like Catalytic heaters as they tug on your oxygen levels. But these new ones have low Ox. shut down and Tip-Over shut down too, so I may be able to sell this idea.......Real easy to store when not in use and sets up in a hurry!
So the results are in! With my Phillips DreamStation and the Resmed AirSense 10 running w/o humidifiers, Hose heaters and WyFy we would suck the batteries to 12.4 to 12.5 volts. So we had something like 75-80% left. This is pretty easy to work with. However, it may not leave enough battery to keep a furnace on all night and keep the trailer @ 55-60 degrees in the winter. I may have to look into one of the little "Mr. Heater" Free Standing Catalytic heaters for real cold nights. My wife doesn't really like Catalytic heaters as they tug on your oxygen levels. But these new ones have low Ox. shut down and Tip-Over shut down too, so I may be able to sell this idea.......Real easy to store when not in use and sets up in a hurry!
I'm suprised at the results and how the battery is being discharged. I have a resmed airsense 10 and with the humidifier off, wifi off, and hose heater off, I can run it 3 1/2 nights on a 250WH (20AH) BPS lithium battery pack using a BPS 12-24V converter. If on the forth night I use the BPS sine wave inverter I can get to 4 1/2 nights, since the sine wave inverter shuts down at a slightly lower battery voltage. Don't know if it discharges it 100 percent but even if it did, thats around 7AH each night, for a current draw of less than 1 amp average, and if we go for 4 nights, that's only about 5AH/night. unless the phillips is a real power hog this setup should hardly put a dent in a pair of GC batteries in one night.
furnaces are a big power hog. we turn ours down to 45F at night, keeps the furnace from waking us up, and set the furnace come on about an hour before we get up to get the trailer warm.
one downside of the cat heaters is the water vapor from combustion and possible condensation issues. for each gallon of propane burned from your stove, ovenm or portable cat heater, you will put about 3 quarts of water into the air since the combustion air is not vented outside.
Not an issue with a furnace or WH since the combustion air gets exhausted outside.
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.
2015 Backpack SS1500
1997 Ford 7.3 OBS 4x4 CC LB
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
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
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.
* This post was edited 06/26/17 10:07pm by ktmrfs *
Vintage465 wrote:
...I may have to look into one of the little "Mr. Heater" Free Standing Catalytic heaters for real cold nights.....
...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.
Build a life you don't need a vacation from.
2016 Silverado 3500HD DRW D/A 4x4
2018 Keystone Cougar 26RBS
2006 Weekend Warrior FK1900
I also have a Coleman catalytic heater that uses Coleman fuel. Both work well in the winter.
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.
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 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.
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.
beemerphile1 wrote:
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.
Vintage465 wrote:
...I may have to look into one of the little "Mr. Heater" Free Standing Catalytic heaters for real cold nights.....
...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 wrote:
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.
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.
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.
ktmrfs wrote:
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 wrote:
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.
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.
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
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.
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.
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.
Vintage465 wrote:
Yes I was thinking all the little green and red lights all over the trailer would be adding to the drop
ktmrfs wrote:
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 wrote:
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.
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.
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.