Putting My CPAP on DC

A few weeks back we had a power failure at night and I had to use my back-up cans of O2 since my concentrater could not be used.  I did not want to go out to the RV because would have taken a couple hours to warm it up.  So I am setting up a DC pack to run my CPAP off a Motorcycle battery.  I checked my CPAP to verify I can use with a DC cord, it can.

 

All I will need to do is unplug the AC plug top left and plug in DC cord. I have a battery and have ordered a DC cord for my CPAP and will give it a try soon.

I got my DC cables!

Here is my battery and DC cable I added the battery clamps.  It all fits into about a third of a shoe box.  I made sure I bought the correct cord for my CPAP they are not all the same.  I hooked it up to my CPAP yesterday at bed time and it ran for just over 6 hours, than shut down.  (Battery was about 85% charged when I started).  I was happy with this! I can buy a bigger battery but I wanted to keep it basic and under 80 dollars total.  I also can plug into a car or RV DC plug if needed.  

I intend this only as a one night back up.  If power is out longer I would have time to fire up the RV propane heater or generator along with 2 electric space heaters.  I have enough fuel to run the generator for 4-5 days depending on temp.  Enough propane for 2-3 days with solar and battery bank for medical equipment.  Plus I have 3 standard O2 tanks for back-up.

I also have a 50 watt portable solar panel to recharge this battery and to maintain our house battery when off shore or generator power.  Our 200 watt solar on our roof is dedicated to our 300amp battery bank which is used only for my medical equipment.

Final Note/recap.

Went back and looked at the battery chart I have the smallest battery.  So it has a max of 30 amp hrs to empty.  If I add an inverter to the system there is not enough instant power amps to run the CPAP. But if I plug in directly as I did above with the DC cord I get 5-6 hours before shut down.  This tells me my battery no-longer has enough energy to run my CPAP after this time.  So I draw it down to about 40% before recharge is required.  With this heavy draw down and since it is not a deep cycle I probably will only get a half dozen uses max, but since it is only an emergency back up it will be fine.

Below is how I store my battery and cords.  The container is a old tupper ware 1/2 gallon ice cream holder and a lunch box the top and handle are out of the photo so you could see everything else.