Cpap, Inverter followup

[brenkco]

Well, our first weekend boondocking. Here is what I have learned about the cpap. I acutally have a bipap with humidifier.
I first tried a 140 watt, single outlet inverter plugged into 12v TV outlet (Carl & HamRad's suggestion). Worked fine without humidifier. Humidifier overloaded inverter and shut down.

Second, I tried a 420 watt, double outlet inverter w/ digital display. 12v outlet cord stated do not exceed 100w using this cord. Tried machine without extension cord, humidifier on. I was drawing about 96-103 watts and seemed to run ok. Tried using a 16-3 extension cord to reach the headboard and the inverter over loaded and shut off. Other problem was the inverter was very loud.

I also purchased a 740 watt inverter but didn't bother as the 12v outlet cord had the same 100 watt warning.

I imagine both of the larger inverters might have worked using the direct battery connection but I opted to use the smaller, quiet inverter without the humidifier.

Bottom line is the small, cheap inverter as suggested was the best solution for a few days of boondocking.

I still plan on ordering the 12v cord for the bipap machine itself. The one spec I have found says the the machine draws 5.0a, 12vdc with humidifier.

Thank you to all for your help.

Ken

[7.3Ford]

The 12V TV outlet may not have big enough wire for the inverter, so the voltage drop across the wire is to much.

Not sure, but I think I herd somewhere, that on 12V power you could not use humidifier.

I have wonder about smaller inverters to just run the CPAP machine. My 2500 Watt inverter draws about 120 Watts just being on. Since we have Six 6 volt batteries and solar, we haven't been to worried about it, but last year we dry camped, and never saw the sun for three days (only 15-20 Watts out of solar panels), and had to crank up the generator for 5-6 hours to charge the batteries.

[lasater]

I have a Respironics Series M BiPAP with humidifier. When boondocking, I use a 12 volt power cord plugged into the TV booster panel in our front wardrobe. If I run only the BiPAP machine on 12 VDC, it will pull up to 3 amps max. If I add the humidifier, power consumption goes up to 4.16 amps max.

I also have a 3,000 watt inverter, so any way I want to power the machine, I can. The only impact the humidifier has is that it takes longer for the solar panels to recharge the batteries after I use it all night followed by running a 12-cup coffee pot in the morning. And both devices are essential.

[7.3Ford]

quote:Originally posted by lasater

I have a Respironics Series M BiPAP with humidifier. When boondocking, I use a 12 volt power cord plugged into the TV booster panel in our front wardrobe. If I run only the BiPAP machine on 12 VDC, it will pull up to 3 amps max. If I add the humidifier, power consumption goes up to 4.16 amps max.

I also have a 3,000 watt inverter, so any way I want to power the machine, I can. The only impact the humidifier has is that it takes longer for the solar panels to recharge the batteries after I use it all night followed by running a 12-cup coffee pot in the morning. And both devices are essential.

Brad,

Good to know. You got to keep the coffee pot I think a mod is coming my way. Say 4.5 Amps x 12 Volts = 54 Watts. The inverter will pull over 120 Watts just for being on with no load or 10 Amps. Hasn't been a problem yet, except when there is no sun comming my way for 2 or 3 days.

[7.3Ford]

Ken,

Here is another option for you CPAP machine.

http://www.directhomemedical.com/mac...rsal-cpap.html

[brenkco]

Thanks!
I have the same machine Brad. Looks like the 12v adaptor is a good way to go.
I sure appreciate the feedback!!

Ken

[hookman]

I run my 325 watt inverter directly off my batteries. Then use a piece of extension cord cable to a plug in the bed frame. I run my CPAP with a humidifier with no trouble. This is the inverter I use.
http://www.amazon.com/STP-325-DUAL-O...7308548&sr=8-2