Enough Power?

Submitted: Tuesday, Nov 12, 2019 at 19:20
ThreadID: 139309 Views:1005 Replies:12 FollowUps:8
I have a Phillips C Pap machine and just purchased the 12v lead for use in the van. I have 2 x 120 AH Deep Cycle batteries and would like to know if I have enough power for the night plus running a ARB 60 ltr fridge and the van fridge? Thanks in advance
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Reply By: IvanTheTerrible - Tuesday, Nov 12, 2019 at 19:47

Tuesday, Nov 12, 2019 at 19:47
Done a few that are running a single battery. Best bet is to set it up and try it at home
AnswerID: 628623

Reply By: Allan B (Sunshine Coast) - Tuesday, Nov 12, 2019 at 19:56

Tuesday, Nov 12, 2019 at 19:56
Poppy, quite possibly your batteries will handle the overnight load provided that the batteries start off being fully charged and in good condition. But the only way to be sure is to try it out in practice. Fire up the fridges and sleep in the van with the CPap overnight before you leave on holiday.

Realise that it all depends on how much demand you put on your fridges, the ambient conditions, any additional loads such as lights TV etc, and whether you CPap is running a humidifier function.

Other than performing a test the question is very conjectural.

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AnswerID: 628624

Reply By: Gbc.. - Tuesday, Nov 12, 2019 at 20:37

Tuesday, Nov 12, 2019 at 20:37
My old boy’s 24 v unit running through the inverter crueled my 360 ah bank each night on our last camping trip. It took some managing.
AnswerID: 628626

Reply By: Member - Murray R (VIC) - Tuesday, Nov 12, 2019 at 21:14

Tuesday, Nov 12, 2019 at 21:14
My wife uses a resmed cpap machine which we run off 12v which draws 5 amp with humidifer. The bushman frig running all day plus the cpap at night runs my 100 ah battery to 50%. Battery recharge is by 180 watt solar panel or driving the next day as we are mainly touring.
As the others have said do a test run before you go. Remember that what ever power you take out of your batteries you need to put much back in the next day so that your batteries are fully charged for the next nights sleep.
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Follow Up By: Keir & Marg - Friday, Nov 15, 2019 at 16:00

Friday, Nov 15, 2019 at 16:00
Concur with Murray R's figures. My wife has a Resmed10 running on a Resmed DC-DC converter which outputs 19v and the plug also fits the Dell which needs 19v to charge the computer if required. We use a maximum of 60Ah (i.e 5A for 12 hours) overnight with the Resmed on auto humidification and a heated tube. You can reduce the power consumed by doing one or more of the following:
A. Put a blanking plug in place of the humidification tank;
B. Change the auto humidification setting to a manual low number;
C. Rather than cold water, fill the humidification tank with water at about 40C;
D. Reduce the tube temperature or turn the tube heating off altogether; and
E. Wake the wife up at dawn so she doesn't get 12 hours sleep!!!!

Option E is not recommended - even a nice cup of tea doesn't seem to resolve the anger issues.
FollowupID: 903135

Follow Up By: Member - Murray R (VIC) - Sunday, Nov 17, 2019 at 18:33

Sunday, Nov 17, 2019 at 18:33
optian E doesn,t work after 10 hrs sleep either LOL
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Reply By: poppy2 - Tuesday, Nov 12, 2019 at 23:00

Tuesday, Nov 12, 2019 at 23:00
It makes sense to do the test at home before going on the road. Thanks for your responses
AnswerID: 628631

Reply By: Member - Cuppa - Tuesday, Nov 12, 2019 at 23:43

Tuesday, Nov 12, 2019 at 23:43
Test at home advice is good.
I use a Devibiss Intellipap 2 Dv64 cpap, which runs natively on 12v & uses pulse dose humidification. This makes it ideal to use on the move as current draw, on the lowest setting humidification averages only around 22Ah per night, less without the humidifier. The battery set up you have would easily cope with that, but unfortunately most Cpaps & humidifiers use a lot more.
AnswerID: 628632

Follow Up By: Member - Cuppa - Wednesday, Nov 13, 2019 at 19:02

Wednesday, Nov 13, 2019 at 19:02
Just thought (for anyone else in the position to be needing to buy a machine to travel with who may read this) I'd add that I tested my machine at home with my battery monitor before heading off on the road full time two years ago. Plugged into a 12v socket maximum draw at my pressure setting was 2.1 amps with the humidifier turned on at level 1 (of 5). However this fluctuated with breath, different breathing in than out with the pulse dose technology (even though there is still a heated water chamber) so in reality average current was a little over half the max figure, so in round figures say about 1.5 amps. For an auto machine which is does all a Resmed Airsense 10 for example, can do, including it's quietness there is nothing else available which uses less power. Downside is that you have to buy it direct from the USA because the Devilbiss distributor in Australia still, years after the Intellipap2 was released, only has the older (& slightly noiser) Sleepcube models without pulsedose.
FollowupID: 903097

Reply By: eaglefree - Wednesday, Nov 13, 2019 at 00:23

Wednesday, Nov 13, 2019 at 00:23
Hi Poppy

My first van I had 120w solar, 100ah agm battery. Have a devil ids cube cpap and small 18litre waeco chest fridge+ tv. Not enough.

Second van I built has 400w solar (this should be minimum) 130ah battery, 30 litre drawer fridge, laptop, phone chargers,tv, cpap, diesel heater. All good. Battery drops only to 80% charge at worse. Charges up very quickly in the morning in fact I’ve dropped my idea of buying a generator!

A good smart charger for when you have access to 240v is a good move.

I think your solar is not enough. I hope that helps.
AnswerID: 628633

Reply By: Michael F20 - Wednesday, Nov 13, 2019 at 08:52

Wednesday, Nov 13, 2019 at 08:52
I have a Resmed machine which I use in conjunction with a heated tube (on each night winter and summer)
I run mine through a 12v/240v inverter and it does basically nothing to my battery, Check with Phillips as to what your machine will draw and from then on it is easy math. I reckon yours will draw next to nothing . Cheers mike11_
AnswerID: 628634

Follow Up By: Malcom M - Wednesday, Nov 13, 2019 at 09:28

Wednesday, Nov 13, 2019 at 09:28
Its certainly doing something to your battery.
My Resmed Autoset 10 pulls 4 amps at 24v so figure 8 amps at 12v (I use the 12-24v adapter).
Thats like having a couple of extra fridges running...

I usually turn the tube heater off when camping to minimise the current.
FollowupID: 903085

Follow Up By: Member - Odog - Wednesday, Nov 13, 2019 at 16:59

Wednesday, Nov 13, 2019 at 16:59
Pretty sure, all resmed machines are 24volts... I use an S9, but when camping van or tent, I don’t use the humidifier, the humidifier uses heaps of power, and just a standard hose, just run the hose in the sleeping bag with body heat.. works for me.. I do know that some machines, including some resmed models, you can’t disconnect the humidifier, which is why I went with the S9.. sweet dreams.. Odog
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Follow Up By: Malcom M - Thursday, Nov 14, 2019 at 08:05

Thursday, Nov 14, 2019 at 08:05

FYI , with the 10s you can get a blanking module to replace the humidifier if you don't need it.
The humidifier only adds 50 or so mm to the length so not really a problem
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Follow Up By: poppy2 - Friday, Nov 15, 2019 at 18:38

Friday, Nov 15, 2019 at 18:38
I have removed the Humidifier as it is not needed so no problem.
FollowupID: 903139

Reply By: Batt's - Wednesday, Nov 13, 2019 at 17:28

Wednesday, Nov 13, 2019 at 17:28
You didn't mention the size and type of fridge in the van is it 12v compressor or a 3 way which would help. Adding solar panels would also help for extended periods staying in one place. It would also help to talk to someone local who deals with solar set ups, add up how much power you consume and what would suit if your going to do a lot of travelling so you have no issues along the way.
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Reply By: poppy2 - Wednesday, Nov 13, 2019 at 18:36

Wednesday, Nov 13, 2019 at 18:36
I forgot that I run the van fridge on gas and I do not use the humidifier and the fuse in the 12v lead is 8amp and had a look in the book and the machine draws 6o watts . So I will have the CPap machine along with the ARB 60ltr Fridge/ Freezer already cooled and possibly a 12 volt fan. I have a 160 watt Solar panel hooked up to the van and all the lights are LED. I have an inverter . So what does everyone think? enough power or use the inverter?
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Follow Up By: Batt's - Wednesday, Nov 13, 2019 at 19:45

Wednesday, Nov 13, 2019 at 19:45
That will help the van fridge is on gas, as others have mentioned give it a go at home if you start with fully charged batteries note the voltage then check next morning after running things like your away on a trip see how much power you consume. I would then see how much power the solar panel puts back into the batteries at the end of the day still running the ARB fridge etc. Then you should get a rough idea how many days you may get out of the batteries.
FollowupID: 903098

Reply By: poppy2 - Saturday, Nov 23, 2019 at 08:08

Saturday, Nov 23, 2019 at 08:08
Last night I did the test at home . Batteries were reading 13.4V, turned off 240V power.
Had the ARB 60 ltr pre cooled and a 24 pack of water and temp was set to 3C.
At 6.30pm I connected the ARB fridge/freezer and the160 watt foldable solar panel and set it up to catch the morning sun.
I turned on the exterior light and 2 sets of internal lighting (all LED)
At 9.30 pm batteries were reading 12.8 V. I plugged in the CPap machine and turned it on and went to bed.
At 1 AM batteries were reading 12.7V, at 4AM batteries were reading 12.6 V. It is daylight here by 4.30AM and sun maybe up by 4.45 - 5.00 AM.
Got out of bed at 6.45 AM and batteries were reading 13.4V...
Very happy with the results and thanks everyone for your input and hope this helps someone also.
AnswerID: 628762

Reply By: Jarse - Saturday, Nov 23, 2019 at 13:52

Saturday, Nov 23, 2019 at 13:52
The heated line uses more power than the humidifier on a Resmed. The heated line is there to stop rainout. One thing to consider is getting a cloth hose cover, which stops the line rubbing on your skin, and insulates at the same time, so the heated line isn't cycling as much. Another is a stand to suspend the line a couple of feet above your head. I got one because I ended up almost strangling myself with the line during the night. A side advantage is that most of the line is on the other side of the stand, and there is no rainout as a result. So I just turn off the heated line nowadays.

The humidifier should be able to be switched off in the menu (it is on the S9) if you want to disable it. I can't go without humidification, so I just turn it down a bit when camping,
AnswerID: 628768

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