DC Adaptor for 2 CPAP machines

[DT6]

Hi - We have two ResMed11 CPAP machines (actually I think they are SPAPs, or APAPS, but whatever) that we have been running off of AC current using the inverter all night.

I recently ordered DC converters for each which consist of a cigarette lighter plug connecting to the DC power source.

We had wire drops put in our 21C so we could easily access electrical lines for something like this.

My question is that since we have two CPAPs, can I power both from a single DC female cigarette lighter receptacle that I attach to the wire stubs in the cabinet?? I plan on using a splitter receptacle that would plug into the female cigarette lighter and then it has two female receptacle's that I can plug the two CPAPs into.

Is there anything wrong with that setup, eg. using a splitter to power two CPAPs off the same DC line?? Each machine appears to draw about 7 to 8 Ah or so in a typical 8 hour sleep cycle, and maybe 13 Ah each at max based on our settings (w/no humidifier).

Secondary Information for others who may have a ResMed:: They do supply some tables that show recommended battery sizes if you are going the DC route. I called and they told me that although the ResMed AirSense 11 is not listed, power draw will be similar to the ResMed AirSense 10. [URL="https://document.resmed.com/documents/articles/198103_battery-guide_glo_eng.pdf"]. However, we have plenty of battery power (currently 200Ah, but will be switching to either a 270Ah BattleBorn or possibly two 206Ah SOKs).

[Vermilye]

Over 10 amps for a long time is pushing the capability of the typical 12V receptacles. You might consider switching at least the combined connector to Anderson connectors.

[DT6]

Originally Posted by Vermilye

Over 10 amps for a long time is pushing the capability of the typical 12V receptacles. You might consider switching at least the combined connector to Anderson connectors.

Would it be better to attach an Anderson PowerPole with 2 or 3 open connections and then cut the male cigarette lighter end off of the CPAP DC Adapter and attach Anderson connectors?

[Vermilye]

In my opinion, I'd replace all of them, but if replacing the connectors on the CPAP machines voids some warrantee issue, at least replace the Escape receptacle & the one on the splitter. Both of those will be carrying the combined current of the two machines which may be too much for the typical 12C connector. You might mount one of these to the Escape provided drop. It takes a 1 1/8" hole saw to mount it.

[richm]

I just did a quick test of my ResMed Airsense 10. With the humidity set at max, and the heated tube set at max temperature, I measured 4.3 amps at 13.4 volts consumed by the ResMed 10. Judging from what is discussed on the ResMed forums, version 10 and version 11 are very similar.

I imagine that power consumption would increase for a minute or so during an apnea occurrence while one is sleeping, as the unit adjust pressure to overcome the obstruction. But at the moment I have no way of measuring that during sleep. I measured 5.3 amps briefly during startup, so my wild guess is that it's possible the maximum is somewhere in that range.

You can cut the power consumption in half by turning off the humidifier and heated tube, but I find I can't tolerate it without the humidifier. If you decrease the humidity setting, and/or decrease the temperature setting on the heated tube, it will definitely conserve power.


I run mine nightly from the cigarette lighter plug ETI installed above the bed, and I haven't seen any issues. As far as I can tell the wiring and the plugs seem normal temperature to the touch. So running a single ResMed via the cigarette lighters definitely okay in my experience.

[mfschu]

I find that if I leave water in the humidifier but leave the control setting at off it works fine for me, not too dry of air and doesn't use the power to heat the water, but I believe you get some moisture just from the air movement about the water.

[C&G in FL]

Years ago, Reace told me that the wiring for the 12 volt outlets was “marginal” and that he did not recommend using a plug in inverter that produced AC voltage that exceeded 150 watts. I ended up installing a 12 volt outlet with 12 gauge stranded wire. I’m not sure that the rule of thumb on 12 volt outlets results from the capacity of the outlet itself. I am inclined to believe it is more related to the wire size feeding it.

[DT6]

Well, it looks like Jon's recommendation for Anderson connectors is the way to go. I did this for my astronomy gear several years ago in order to better control all of the cables and also to improve the power connections, so I have the equipment. I'm just not sure I want to take it on myself.

Since this is a critical item for us, I'll probably consult with the electrical repair guy at our local Camping World repair shop. They just did an outstanding job repairing several warranty issues, some of which were electrical, and the guy seems to really know what he is doing. I do know that once you get the Anderson connections setup, they work great.

Thanks for the help everyone!

[Hawkeye Ed]

I totally agree with richm. The actual draw from my ResMet CPAP is way less than the maximum specified in the documents even when the humidifier is on. Before you go to lots of trouble and effort, why not try it? You can always put your hand around the "cigarette lighter" plugs and receptacles to see if they get warm. I'm betting that they won't.

[alanmalk]

Originally Posted by DT6

Well, it looks like Jon's recommendation for Anderson connectors is the way to go.
...

If you have made your decision to go with Anderson then I highly recommended the proper crimper for the "15/45" series of connectors.

I once tried to assemble the connectors by hand, but with the tool I stopped wasting 2/3rds of my parts and got more reliable connections.

https://powerwerx.com/tricrimp-power...-crimping-tool
Current price - $45.