ktmrfs wrote:
if you don't need the humidifier, turn it off.
This.
And.....when it comes time to replace the CPAPs, get one that actually runs on 12 V and get the appropriate power cords to do that.
As for charging the extra battery, if you are parked at a campsite that has power service, it likely has 30, 50 and 15 amp outlets.
Get a charger in the 15 to 20 amp range and plug it into the 15 amp outlet.
Not only will that solve the recharging problem but then you will have a charger for other things when you need one.