12 volt invertor

Hi,
I am in need of a inverter to run my daughters Cpap type machine.
Is a bigger capacity inverter more economical to run, ie. uses less power to perform the same function as a smaller capacity inverter?
William
Always planning the next trip. VKS-737 mobile 1619

Member
My Profile  My Blog  Send Message

Back Expand Un-Read 0 Moderator

Reply By: Member - Mark C (QLD) - Monday, Sep 04, 2017 at 21:08

Monday, Sep 04, 2017 at 21:08
Hello William
I run my Cpap from a 12 volt adaptor similar to a computer adaptor from a 12 volt cig plug on a 30 amp fuse from the battery setup in my camper. I bought it when I purchased my Cpap because I asked for a camping setup and wanted to run from 12v not an invertor.
Mark And Helen QLD
Living the Dream

Member
My Profile  My Position  Send Message

AnswerID: 613528

Follow Up By: Member - Mark C (QLD) - Monday, Sep 04, 2017 at 21:09

Monday, Sep 04, 2017 at 21:09
Sorry forgot to mention I run the humidifier version of the Cpap with heated hose.
Mark And Helen QLD
Living the Dream

Member
My Profile  My Position  Send Message

1
FollowupID: 884017

Follow Up By: IvanTheTerrible - Monday, Sep 04, 2017 at 21:40

Monday, Sep 04, 2017 at 21:40
If you do run an inverter then twice the rated power is all you need. If the CPAP isn't AC then a DC to DC inverter is better and will waste lees power. SA waste converting 12 volts to 240 only back down again
2
FollowupID: 884018

Reply By: Les - PK Ranger - Monday, Sep 04, 2017 at 22:19

Monday, Sep 04, 2017 at 22:19
William, I'll send a mate a message with link to here.
He's been running one on trips and only uses 1amp a night, easily run from 12v, though think his is 12v unit with 240v to run at home.
Anyway, he's looked into this a lot so should be able to advise his experiences.
AnswerID: 613530

Follow Up By: Les - PK Ranger - Monday, Sep 04, 2017 at 22:49

Monday, Sep 04, 2017 at 22:49
A bit of info, as mate is a little reluctant to share his story . . .

resmed autoset 10 with dc to dc converter with humidifier on ,heated tube off including my frigde and camp lights .Voltage drops minimal to 12.3 overnight . The tube goes in my sleeping bag to avoid condensation

Hope that helps.
0
FollowupID: 884022

Follow Up By: Les - PK Ranger - Tuesday, Sep 05, 2017 at 17:55

Tuesday, Sep 05, 2017 at 17:55
William, a bit more info from my mate . . . a lot of what you ask and units etc will depend on what sort of condition your daughters needs are . . . mate looked up your unit . . .

ResMed Lumis 150 VPAP ST-A
Ref 28223
$6,500.00
Lumis™ is a non-invasive ventilator series designed for non-dependent patients with respiratory insufficiency.

Mate noted > He might have half a lung Les, not sure if its used for cpap.

Another unit mate is getting soon . . . he comments . . .

A lot of Aussie dont know that you can purchase cpap from the USA for up to 1/3 of the cost no probs with voltage as they all work on 100-240 volt http://www.1800cpap.com/ .An Airmini from resmed http://www.1800cpap.com/airmini-autoset-travel-cpap-machine-by-resmed.aspx fits in palm of hand $1900 in aust . Resmed is an aussie brand

All I can say is for your daughter to check with her medical people and discuss units, ask about Resmed 12v etc and see what they recommend (impartiality may be an issue of course).
0
FollowupID: 884054

Follow Up By: Member - William B (The Shire) - Tuesday, Sep 05, 2017 at 18:46

Tuesday, Sep 05, 2017 at 18:46
Les,
Thank you for your efforts and please thank your mate for me.

The machine my daughter uses is not a CPAP but it is easier to use that name because most people are familiar with that terminology.

Your mate is partially right in his assessment, Emma has a lung disease ..

So the machine is a necessity, her condition will not stop her travelling with us, but we do need to take extra precautions and using the machine helps.

We are in the process of having one supplied and I will be asking all the questions about power supplies.

William
Always planning the next trip. VKS-737 mobile 1619

Member
My Profile  My Blog  Send Message

0
FollowupID: 884055

Follow Up By: Les - PK Ranger - Tuesday, Sep 05, 2017 at 18:50

Tuesday, Sep 05, 2017 at 18:50
William, sorry for taking this off track so much then, obviously the machine she needs is probably going to require the inverter.

Mate, I'd like to wish Emma all the best in her battle, and enjoy the best quality of life she can receive when enjoying the great outdoors / travel with her family.
1
FollowupID: 884056

Follow Up By: Member - William B (The Shire) - Tuesday, Sep 05, 2017 at 19:04

Tuesday, Sep 05, 2017 at 19:04
Les, you haven't taken off track at all, please don't think that.
All the info you and your mate have supplied is exactly the sort of info that I was after.
It still only runs on 24 volt and and uses around 4 amps, it is just a matter of selecting the most efficient method of operating it out bush.
We are heading off late Sept. and will probably use a invertor I already have until we source our own.
William
Always planning the next trip. VKS-737 mobile 1619

Member
My Profile  My Blog  Send Message

1
FollowupID: 884057

Follow Up By: Les - PK Ranger - Tuesday, Sep 05, 2017 at 19:24

Tuesday, Sep 05, 2017 at 19:24
Ah good oh William, just thought it was getting too related to apnea conditions.
Hopefully you can find the best long term solution when you get into the info a bit more.
Enjoy the travels later in the month.
0
FollowupID: 884059

Reply By: Member - Alan H (QLD) - Tuesday, Sep 05, 2017 at 07:33

Tuesday, Sep 05, 2017 at 07:33
I also have a CPAP machine with heated hose. I use 240V at home and when camping use a Resmed 12v inverter. I think the CPAP actually operates at 19V or some similar odd voltage.
I have a 240V inverter but found that using it through this inverter uses a fair bit of power during the night so I went 12V. When camping I usually turn the humidifier off and this saves quite a bit of current draw. (approx 3 amps down to 1 amp)
Cheers
AnswerID: 613533

Reply By: Phil B (WA) - Tuesday, Sep 05, 2017 at 09:27

Tuesday, Sep 05, 2017 at 09:27
I've used CPAP's for 15 + years while camping.

My experience has been different models have differing power consumption rates and if using a humidifier, power increase goes up significantly. Read details on the name plate of your device and if you haven’t purchased one yet hunt down one with lowest power use and preferably with a 12 volt outlet as well as normal 240v.

Also note that if using 240 volt from an inverter, be aware of electrocution risk; this is why I sleep in a tent.

Happy sleeping.


There is a lot of difference between
‘Human Being’ and ‘Being Human’.





Lifetime Member
My Profile  My Blog  Send Message

AnswerID: 613535

Reply By: CSeaJay - Tuesday, Sep 05, 2017 at 10:11

Tuesday, Sep 05, 2017 at 10:11
Wow there appears to be a huge take-up of cpap machines.
Many people on them have been recommended to do so by the agents of the machines and their "free" tests.
"Come in and we will test to see if you should be using one of our machines".
They wouldn't recommend against using one would they?
AnswerID: 613536

Follow Up By: Les - PK Ranger - Tuesday, Sep 05, 2017 at 11:56

Tuesday, Sep 05, 2017 at 11:56
I have a couple of mates that have sleep apnea, it is possibly more common than people think, and leads to many health issues that may not normally be first linked to the condition.
GPs are the most common place for people to discover they have it, not so much the sleep apnea test places, they get people referred to them and the tests are pretty thorough.
1
FollowupID: 884039

Reply By: Malcom M - Tuesday, Sep 05, 2017 at 11:41

Tuesday, Sep 05, 2017 at 11:41
Basically a bigger inverter will be better as its not flogging its guts out generating 240v. Reduces heat etc.
Cheap smaller units running close to their max often start whistling or squealing.
Actual battery power used really comes down to design (quality) of the unit. Cheaper ones tend to use more.

You don't say what make/model cpap.
The different machines offer different features which use differing amounts of power. Sometimes you can turn bits off and save power.
The Resmed AirMini uses very little power but I use a Resmed Autoset 10 with heated hose and humidifier. It consumes some 90 watts at 24v = around 4 amps, my 80L Waeco on 12v uses about 4amps with its compressor running so that effectivly 2x 80L fridges.
Turning off the humidifier and heated hose drops that enormously but its still a very hungry device.
Resmed make a 12 to 24v inverter/adapter which I also have but that still pulls near 8 amps at 12v with all cpap functions turned on.

Using an 240v inverter has some overhead losses. You have to convert 12v up to 240v just so you can drag it down to 24v again via its 240v adapter. Much more efficient to use the 12-24v inverter.
Bottom line is that in this example, you still need to supply at least 90w (8 amps) of 12v plus the inverter overhead.

Are you heading for the bush or powered camping sites?

AnswerID: 613538

Follow Up By: Member - William B (The Shire) - Tuesday, Sep 05, 2017 at 13:53

Tuesday, Sep 05, 2017 at 13:53
Hi Malcolm,
Thanks for your detailed reply.
The machine is a Resmed Lumis 150. (VPAP st)
We intend to mostly bush camping, and have just purchased a Jayco 17.58-3 Outback.
The Resmed is a hire unit at the moment but we will be purchasing one soon.
I hadn't looked at what it actually used in regards power, I see that it is 24v and it uses 3.75 amps.
I will have a look at the Resmed site.
William
Always planning the next trip. VKS-737 mobile 1619

Member
My Profile  My Blog  Send Message

0
FollowupID: 884044

Reply By: Member - Bruce and Di T (SA) - Tuesday, Sep 05, 2017 at 13:50

Tuesday, Sep 05, 2017 at 13:50
Bruce uses a Resmed cpap machine with heated hose and humidifier. He uses 240 volt at home and when we have it away camping he uses a 12volt DC to DC converter available from Resmed. Works a treat and use little power and both of us get a good night's sleep! :)

Di
AnswerID: 613541

Follow Up By: Member - Mark C (QLD) - Tuesday, Sep 05, 2017 at 19:18

Tuesday, Sep 05, 2017 at 19:18
Hello Di

My wife loves my Resmed cpap machine when at home and camping. 240v at home and DC to DC converter when camping, from Resmed as you said. We both have a good nights sleep and my health conditions are less at risk without stopping breathing and snoring.
I specifically asked for the 12v dc to dc converter when I ordered after the trial period. I think it was an extra $150 but well worth it.
Mark And Helen QLD
Living the Dream

Member
My Profile  My Position  Send Message

0
FollowupID: 884058

Follow Up By: Member - Bruce and Di T (SA) - Wednesday, Sep 06, 2017 at 20:05

Wednesday, Sep 06, 2017 at 20:05
They're great. Converters do the job!
Di
0
FollowupID: 884083

Follow Up By: Les - PK Ranger - Wednesday, Sep 06, 2017 at 21:10

Wednesday, Sep 06, 2017 at 21:10
Yes, mate agrees, see the link for the resmed doc link I posted a couple down.
0
FollowupID: 884084

Reply By: Sigmund - Wednesday, Sep 06, 2017 at 12:31

Wednesday, Sep 06, 2017 at 12:31
Don't buy a cheapie inverter; they don't cope well with corrugations in my experience.

If you're going to fix an inverter in your camper keep it away from shock and spring mounts.

Inverters draw a base current when idle and that figure should be available.

Best wishes with the plan.
AnswerID: 613569

Reply By: Les - PK Ranger - Wednesday, Sep 06, 2017 at 16:14

Wednesday, Sep 06, 2017 at 16:14
William, mate just sent this link to the ResMed Battery Guide

Gives a lot of good info . . . they mention 'converters'.

AnswerID: 613573

Sponsored Links

Popular Products (13)