Powering S8 From 12 Volts

[danricketts]

Hi Guys,

I'm due to go camping in a few weeks time and will be taking my S8 with me however the site doesn't have an electric hookup.

I intend to use a leisure battery connected to a pair of solar panels to provide power but would rather run the unit at 12 volts instead of using an inverter (more efficiency meaning more hours use) but begrudge paying out for the Resmed DC-12 converter.

So my question is does anyone see a reason why the unit couldn't be powered using a 12v voltage regulator? I have the electronics knowledge to build a suitable circuit, it's more a case of whether or not I'll damage the unit (although I can't possibly imagine how!).

Thanks

Dan

[leswaller]

Hi Guys,

I'm due to go camping in a few weeks time and will be taking my S8 with me however the site doesn't have an electric hookup.

I intend to use a leisure battery connected to a pair of solar panels to provide power but would rather run the unit at 12 volts instead of using an inverter (more efficiency meaning more hours use) but begrudge paying out for the Resmed DC-12 converter.

So my question is does anyone see a reason why the unit couldn't be powered using a 12v voltage regulator? I have the electronics knowledge to build a suitable circuit, it's more a case of whether or not I'll damage the unit (although I can't possibly imagine how!).

Thanks

Dan

Give Resmed a ring on +01235 862 997 and see if you can speak to Steve who is one of the service technicians, he is very helpful and I am sure he will know the answer

[TimBarnacle]

camping

I camp a fair bit, and power is a bit of a problem - i have a remstar auto M series and have tried a power pack from maplin

http://www.maplin.co.uk/Module.aspx?ModuleNo=224871

which gave about 2 hours of power max. any suggestions?
Thanks
Tim

[James @ Intus]

Hi Tim, welcome to the group.

It depends a bit on your budget. We do a high end Polymer Ion (even lighter and more safe than Lithium Ion) universal CPAP battery pack. It runs REMstar units directly, and ResMed units with ResMed's DC-12 adapter.

On a full charge with machine pressure around 10 you can get close to three nights out of it.

[TimBarnacle]

Ok Thanks, had the machine since Oct 08, and like the results so much, I dont want to be without it even for one night

[GrumpyBiker]

Hi Tim, welcome to the group.

It depends a bit on your budget. We do a high end Polymer Ion (even lighter and more safe than Lithium Ion) universal CPAP battery pack. It runs REMstar units directly, and ResMed units with ResMed's DC-12 adapter.

On a full charge with machine pressure around 10 you can get close to three nights out of it.

I have one of the Super CPAP Battery packs and so far I am impressed. I initially bought it as an aid to camping by motorcycle - Leisure batteries and the like are a non-starter due to size and weight.

The Super CPAP battery is rated at 266Watt-Hours, divide 266 by the wattage of your machine to get absolute maximum duration. A word of caution however, as an Electronic Engineer, I would not recommend fully discharging a Lithium Polymer Ion battery, and try to keep mine to at least 1/4 charged. With my Remstar M series APAP, I can easily get two nights without humidifier. I have now started taking it with me on business trips - I leave the power brick at home as I can then pack battery, mask, hose and pressure source into the Remstar's carry bag.

Starting tomorrow, I am off on a 10-day camping trip with electric hookup every third night. I will report on how the battery pack coped when I return.

Andy

[James @ Intus]

Hi Andy, thanks for the feedback, sounds like you're making great use of it, perhaps more than planned initially.

It's a very nice pack indeed. It's shape also easily goes into a suitcase, between a stack of clothes for example. Not too heavy and looks quite Apple-like gadgety too, something almost cool to have

I look forward to hearing about your camping trip experience.

[GrumpyBiker]

Well, I'm back - trip shortened to 9 days due to missing home comforts, but 3,000 miles covered and apart from travel fatigue, feeling fine.

The battery pack is a gem. Small enough to easily pack on a motorcycle. I removed the supplied 12v lead and adaptors as I have the Resmed filtered 12v supply lead. The resmed lead went into my Auto-M series carry case, together with the pressure source but not humidifier (partly to reduce the electrical load, but mostly to save space).

The battery pack looks good, with a standard 'Cigar lighter' type socket and a coaxial input socket. Between these is a bank of LED's one red (fault) and four green, indicating state of charge.

My APAP machine is set to 10cm low, 17cm high and I have a 90% reading of around 16.5cm. Since being on APAP, I am back to my long-lost regime of 11pm to 6am sleeping, giving seven hours a night. I am fortunate in that I have never had a problem keeping the mask on - partly being determined not to remove it, partly having worked as a flight-test engineer (electronics, not pilot!) and had worn military aircraft oxygen masks for hours on end when younger.

I set up my Auto M-series in the carry case, with the battery on the open case lid, to keep everything out of any possible condensation. I then loosely covered that with a section of nylon cut from an old breathable waterproof coat.

Short story - the battery worked like acharm. After the first night, the charge indicator had dropped from 4 to 3, as usual. On checking the second morning it was still on 3! The third night I had electric hookup and re-charged the battery. When we returned from our meal at the pub, the battery was charged - so less than 5 hours charging.

Owing to limited pitch availability I had an extra night of hookup after the 6th night, so decided to try for three nights. The battery pack was able to achieve this, dropping to one green light after three nights of approximately 6.5 to 7 hours each.

Yes its expensive, but it is very good and well worth considering for compact power for weekend trips or as a backup if you live in , or visit, an area with unreliable electric supply. As I said before, I am using mine for business trips to avoid trailing leads in strange rooms at night - a real trip hazard.

Andy

[threewheelweave]

Top Report Again - Thanks Andy

Hi Andy

Glad you had a good trip and looks like the battery pack is a top bit of equipment! Giving you so much power for three nights without recharge is fantastic!

You said you didn't use the humidifier - any idea how long the battery lasts while you use both?

Thanks again for great feedback!

TWW
UK

[GrumpyBiker]

I have not tried the battery with the humidifier yet, I have always removed the humidifier to keep the setup compact for travel.

I will try it tonight to see how much power is used.

Andy