AirSense 10 units won't run on an inverter? Screwed again?

theaftermath · Post by **theaftermath** » Sat Nov 03, 2018 6:55 pm

I must be missing something. The DC-DC converters for these are terribly inefficient aren't they? Input is 12v/24v 13A/6.5A with an output of 24v 3.75A!!

palerider · Post by **palerider** » Sat Nov 03, 2018 8:18 pm

theaftermath wrote: ↑
Sat Nov 03, 2018 6:55 pm
I must be missing something. The DC-DC converters for these are terribly inefficient aren't they? Input is 12v/24v 13A/6.5A with an output of 24v 3.75A!!

No, they're not. they're very efficient (> 95%)

chunkyfrog · Post by **chunkyfrog** » Sat Nov 03, 2018 10:49 pm

Electricity--it's all about math.
Basic electrical equations explain it all.
Knowledge is power--especially knowledge of power.

theaftermath · Post by **theaftermath** » Sun Nov 04, 2018 3:50 pm

I guess the reason I'm a bit stumped is because hooking this up to a Killawatt meter it shows about 300wh for about 8hrs of use with humidity and tube turned on but it won't last 6 hours using this converter with 70ah battery? Is the converter going bad?

Snoregone Conclusion · Post by **Snoregone Conclusion** » Sun Nov 04, 2018 4:10 pm

theaftermath wrote: ↑
Sun Nov 04, 2018 3:50 pm
I guess the reason I'm a bit stumped is because hooking this up to a Killawatt meter it shows about 300wh for about 8hrs of use with humidity and tube turned on but it won't last 6 hours using this converter with 70ah battery? Is the converter going bad?

Ah is not the same as wh: power (watts) is current (amps) multiplied by voltage, amps only measures current.

prodigyplace · Post by **prodigyplace** » Sun Nov 04, 2018 4:15 pm

Here is the Resmed battery guide that assumes you are using their inverter to convert 12 V DC to 24 V DC.

https://www.resmed.com/us/dam/documents ... lo_eng.pdf

The amount of current / power used depends on a number of factors. Mask pressure, humidity level, and use of heated hose can all affect how long a battery will last.

theaftermath · Post by **theaftermath** » Sun Nov 04, 2018 4:43 pm

Snoregone Conclusion wrote: ↑
Sun Nov 04, 2018 4:10 pm

theaftermath wrote: ↑
Sun Nov 04, 2018 3:50 pm
I guess the reason I'm a bit stumped is because hooking this up to a Killawatt meter it shows about 300wh for about 8hrs of use with humidity and tube turned on but it won't last 6 hours using this converter with 70ah battery? Is the converter going bad?
Ah is not the same as wh: power (watts) is current (amps) multiplied by voltage, amps only measures current.

I do understand they are different, just showing my results. When plugged into AC the results showed that the machine would easily run off of that same 70ah setup that wouldn't run for 6 hours with the DC-DC converter.

theaftermath · Post by **theaftermath** » Sun Nov 04, 2018 4:55 pm

prodigyplace wrote: ↑
Sun Nov 04, 2018 4:15 pm
Here is the Resmed battery guide that assumes you are using their inverter to convert 12 V DC to 24 V DC.

https://www.resmed.com/us/dam/documents ... lo_eng.pdf

The amount of current / power used depends on a number of factors. Mask pressure, humidity level, and use of heated hose can all affect how long a battery will last.

I did see this and it suggests a 45ah battery for the settings used on the machine but from the kw meter results when plugged into AC compared to not being able to get a full night out of a 70ah battery when using their DC converter something is off?

theaftermath · Post by **theaftermath** » Sun Nov 04, 2018 5:07 pm

prodigyplace wrote: ↑
Sun Nov 04, 2018 4:15 pm
Here is the Resmed battery guide that assumes you are using their inverter to convert 12 V DC to 24 V DC.

https://www.resmed.com/us/dam/documents ... lo_eng.pdf

The amount of current / power used depends on a number of factors. Mask pressure, humidity level, and use of heated hose can all affect how long a battery will last.

The settings of the machine were the same but I don't know about surrounding air humidity or temperature differences.

palerider · Post by **palerider** » Sun Nov 04, 2018 6:33 pm

theaftermath wrote: ↑
Sun Nov 04, 2018 3:50 pm
I guess the reason I'm a bit stumped is because hooking this up to a Killawatt meter it shows about 300wh for about 8hrs of use with humidity and tube turned on but it won't last 6 hours using this converter with 70ah battery? Is the converter going bad?

More likely your battery is bad,

You can get five nights with a resmed converter and a 35ah battery... *without humidification*.

CapnLoki · Post by **CapnLoki** » Mon Nov 05, 2018 1:57 pm

palerider wrote: ↑
Sun Nov 04, 2018 6:33 pm

theaftermath wrote: ↑
Sun Nov 04, 2018 3:50 pm
I guess the reason I'm a bit stumped is because hooking this up to a Killawatt meter it shows about 300wh for about 8hrs of use with humidity and tube turned on but it won't last 6 hours using this converter with 70ah battery? Is the converter going bad?
More likely your battery is bad,

I agree - a 70ah battery should have about 840 watt-hours. The testing with my Philips 560 was around 20ah with moderate humidity/hose settiings. The ResMed is a bit less efficient.

palerider wrote: ↑
Sun Nov 04, 2018 6:33 pm
You can get five nights with a resmed converter and a 35ah battery... *without humidification*.

Five nights might be a stretch - that's 7ah a night with no reserve.

AirSense 10 units won't run on an inverter? Screwed again?

Re: AirSense 10 units won't run on an inverter? Screwed again?

Re: AirSense 10 units won't run on an inverter? Screwed again?

Re: AirSense 10 units won't run on an inverter? Screwed again?

Re: AirSense 10 units won't run on an inverter? Screwed again?

Re: AirSense 10 units won't run on an inverter? Screwed again?

Re: AirSense 10 units won't run on an inverter? Screwed again?

Re: AirSense 10 units won't run on an inverter? Screwed again?

Re: AirSense 10 units won't run on an inverter? Screwed again?

Re: AirSense 10 units won't run on an inverter? Screwed again?

Re: AirSense 10 units won't run on an inverter? Screwed again?

Re: AirSense 10 units won't run on an inverter? Screwed again?

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Additional Comments: 3B Elara FFM