Originally Posted by chriscowles
My wife and I both use CPAP and have done so when dry camping. Rather than use an inverter to change the 12v DC to 120v AC, we have 12v adapters purchased from the CPAP manufacturer. It's more efficient because the CPAP actually runs off DC.
We have 2 g27 12v deep cycle batteries in trolling motor battery cases from Wal-Mart. They're our power source when dry-camping in the trailer. When not camping the 12v adapters described above come in the house with us and the batteries live on our back porch, plugged into a Battery Tender Junior to maintain the charge.
If we suffer a power failure, they're our backup power system for the CPAP. The battery cases have carry handles and cigarette lighter sockets which fit the CPAP power adapter plugs.
A Honda 2000eu is our recharge power source. We've only used it when camping but, if the home power outage were prolonged (we live in hurricane territory) it would serve that purpose at home, too.
I checked on CPAP.com and I cannot get a DC power cord for my unit, I guess it's too old..
No issue with backup power at home on the farm, we have to have power to pump water for the stock, heat the barns, power the shop and house so I own a 25 KW diesel, skid mounted standby genset, plumbed into my bulk diesel storage tank (1000 gallons). It's on an automatic vacuum transfer switch that is rated for 250 amps inductive load at 220 volts, plenty enough to run the place. The only thing I have to do is start it weekly and make sure the batteries are good... dang batteries again. They have a constant trickle charge and are flooded cell starting batteries. 15 seconds after we loose line power, the genny starts and 45 seconds after that it assumes the full load. When the unit senses stable line power, it cycles out and shuts down.
So, if I'm sleeping, my machine barely misses a beat. If we loose power at night the only way we can tell is the clocks are blinking. The genny is out by the barn, you cannot hear it in the house at all.
I didn't wire it, like I said, I'm electrically deficient. I had it wired by a certified and licensed electrician. I did the mechanical install however. It was a government surplus unit, has a John Deere turbocharged diesel engine and a Westinghouse generator head.
I have one of those Champoin 2000 watt inverters for the camper. Nice little unit, real quiet, super light, starts one pull and runs a whole weekend off an on, on about 1/2 gallon of gas. I'm very happy with it, Best part was it was 449 bucks new, delivered to my front porch.
I would have bought a Honda or a Yamaha but the price scared me away and the Champ has excellent reviews. I have a Honda engine on a garden tiller thats been a constant PITA from day one and I had a Honda engine on a pressure washer that threw a rod and not from me not changing the oil either. With that, I'm pretty much done with Honda powered stuff but the Yamaha and the Honda are way overpriced (compared the the Champion). Was a slam dunk for me.
I looked at the battery monitors mentioned in the above posts. It looks intimidating with shunts and all, for me to put in, not sure I'm capable and not sure if the cost ($150.00) justifies the end.
If I'm 'murdering' my present deep cycle and it pukes next year, I can get another for less than 100 bucks and go another year or 2 or get into 2 6 volt golf cart batteries when this one pukes.. Lots of options. I do need to physically measure how much room is available, it is a truck camper so room is at a premium. Something I'll get into this winter. The camper will 'sleep' in a heated equipment shop with my truck. I winterized it last weekend and then scratched my head and asked myself why I did that. The camper will never be below freezing, I keep the shop at 60 all the time.... oh well.
I see they now have a mount where you can physically mount a second battery under the bed of the truck, on the truck frame but in my view that could be an issue maintenance wise.
I do like the idea of keeping heavy items (like batteries and water tanks) as low as possible. Keeps the Cg low and adds to the stability of the camper and truck.