12volt inverter, will it run my CPAP machine,

[Matchless]

When I look at electrical things my brain fogs over! I need to take my CPAP machine away with me in my caravan on Thursday, no mains hook up at the rally, will any of these (screwfix) inverter s run my machine for 6 or so hours non stop off my caravan battery, looking at duty cycle etc. some seem to only work for an hour at a time,

 

[Dee J]

At face value your CPAP seems to use less than 50 watts in operation (0.16x240= 38.4 watts) despite it's power supply having the capability of much more. So on that basis would seem do-able. The tripping points are whether the power supply would be happy with the modified sign wave (probably OK) and how the duty cycle is calculated for the inverter (more info needed). Then allow for losses overall (unknown) and the capacity of your battery (with sensible discharge limits)...

 

[GRW]

I think the input (looks like 2.1A, which is just shy of 500 watts) would mean you'd need at least the 800 watt model because of duty cycle.
This would draw though approx. 42ah off your leisure battery, so it'd be flat in an hour (at 50% Discharge for longevity).

The draw though as said above - is way less than the 2.1A input suggests - it ought to need (24v @ 2.5A to AC 230v) no more than about 0.35 Amp input (assuming about 90% efficiency for the power supply) I think.

If 0.35A proved to be the actual draw, then that's only 7-8 Amps per hour off the 12v leisure battery - no problem.

 

[hotponyshoes]

I'd think a couple of 12v battries rigged up in series would run that for 6hrs no problems

Or get a 12v to 24v converter.

Either of those methods would be more efficient than taking 12v upto 230v then back down to 24v again

 

[GRW]

I'd think a couple of 12v battries rigged up in series would run that for 6hrs no problems

Or get a 12v to 24v converter.

Either of those methods would be more efficient than taking 12v upto 230v then back down to 24v again

A buck converter 12-24v would be great... though he'd then have to faff sorting a connection lead between the buck & his device.

 

[ukracer]

I used to run my cpap when we raced, and I was in the middle of a field, using a 150watt model.
I would then run the genny next day to top up battery and be able to charge race batteries.
I used to sleep from 2am to 8am .

 

[Kram]

They should work but a 24v battery or, 12v to 24v boost converter would likely be a better choice if you havent got the inverter yet.

 

[Seadog]

Skynet?

It's started...

 

[voipio]

On paper, the 150W inverter should be easily capable of running the CPAP. However, in the past, I've had experience of switched mode power supplies that run off one inverter type, but not another. The only way to find out is to buy the inverter and see if it works with the CPAP power supply. The 150W inverters generally aren't megabucks to buy. They should be able to run at 100% duty cycle at the load specified, without any problems.

 

[m_c]

As has been mentioned, switch mode power supplies can be temperamental on some inverters.
I'd look for a pure sine wave inverter.
Something in the 2-300W range should run the machine.

 

[hotponyshoes]

I've got some smallish pure sinewave inverters if you are worried about it.
They are decent ones as I fit them for vets to run medical equipment etc. I've got some used ones at sensible prices but I don't really see the point in using one to ultimately just provide 24v dc.

If you have any cordless power tools I wouldn't be surprised if you could even run from an 18v battery.

Even of the plug into the unit is some sort of fancy custom connector I'd be chopping the cable and putting some common connectors in-line.

 

[CompoSimmonite]

I've run my CPAP on a decent 150w inverter and leisure battery numerous times

 

[Matchless]

I'd think a couple of 12v battries rigged up in series would run that for 6hrs no problems

Or get a 12v to 24v converter.

Either of those methods would be more efficient than taking 12v upto 230v then back down to 24v again

I agree but I have not yet found a plug the same as the machine uses, around 5.5mm od (from memory) but with a small centre pin, one advantage of the inverter is that the machine is using it's genuine power supply and that would probably smooth out and problems with the inverter supplied 230v??

 

[Matchless]

I've got some smallish pure sinewave inverters if you are worried about it.
They are decent ones as I fit them for vets to run medical equipment etc. I've got some used ones at sensible prices but I don't really see the point in using one to ultimately just provide 24v dc.

If you have any cordless power tools I wouldn't be surprised if you could even run from an 18v battery.

Even of the plug into the unit is some sort of fancy custom connector I'd be chopping the cable and putting some common connectors in-line.

I have to take the machine back to the hospital every few months for them to download the data, they may not like me chopping their leads! I did think about doing it though!!!!

 

[GRW]

The image of the Skynet data plate suggests that the dc connector is a pretty common "Jack" plug with a centre +ive & an outer -ive (which is typical polarity for Jacks).
Chances are it's one of the standards rather than a one-off.

You used to ge able to get universal laptop chargers that came with an array of interchangeable common jack ends... so I wonder if you could get:
- a 12vdc to 24vdc travel type charger with the right jack option,
Or
- at least a lead with the right Jack (as then you could get a cheap 12-24vdc Buck Converter, and put the lead on it).

 

[Matchless]

The image of the Skynet data plate suggests that the dc connector is a pretty common "Jack" plug with a centre +ive & an outer -ive (which is typical polarity for Jacks).
Chances are it's one of the standards rather than a one-off.

You used to ge able to get universal laptop chargers that came with an array of interchangeable common jack ends... so I wonder if you could get:
- a 12vdc to 24vdc travel type charger with the right jack option,
Or
- at least a lead with the right Jack (as then you could get a cheap 12-24vdc Buck Converter, and put the lead on it).

most have a centre hole of varying size but this one has a solid small dia pointed pin, I will go with an inverter for now and investigate a 12-24v conveter when I get a bit of time.

 

[hotponyshoes]

I expect its a 5.5x1mm
Plug should look like this?

 

[Matchless]

I expect its a 5.5x1mm
Plug should look like this?View attachment 410667

That does look like it,

 

[Tom O]

Skynet?

It's started...

View attachment 410599

Hello Mudda Hello Faader here I am at camp Regada!

 

[ukracer]

I have to take the machine back to the hospital every few months for them to download the data, they may not like me chopping their leads! I did think about doing it though!!!!

Which one do you have? Mine had a recall 3 years ago but they don't have enough stock to replace it.