Inverter....Overnight Constant Power

[balthaus]

My wife and I both have sleep apnea and sleep with our C-Pap machines EVERY night.
I am hoping...for us (because I would not wish untreated sleep apnea on anyone)...that someone here can relate.
They each draw about 60w (120w total) and I need to keep the machines running all night.
Currently there is a 2.5kw gen in our but running the genny all night is a little counter productive for sleeping, not to mention potential CO2 issues.
I have been looking at 3k inverters but don't know if I can pull that trigger just yet.
Smaller inverter to start ?
Any thoughts ?

[bcassedy]

I actually had a 3kw inverter at one time. That turned out to be overkill (image that said "Overkill Bill"... I have since replaced it with a Xantrex Freedom HF 1000w unit. It offers a detachable face plate that I mounted in old port tach hole on the lower station (installed a FlowScan unit in the starboard hole). We use the inverter for our fridge/freezer. It draws 74w when it kicks in.

The HF 1000w would do for your needs. It's not so much the wattage of the inverter as the storage capacity of the battery/batteries that it draws power from.
This is one site I found that might help with the needed calculation for size/type/capacity battery/batteries you would need:
http://electronics.stackexchange.com/qu ... plications

Bill

[Fastjeff]

We have a 2KW inverter that's NEVER come close to being overloaded. The reason why--as all inverter owners have learned--is that BATTERIES are the limiting factor with inverters.

We presently have up to 4 batteries we can 'cut in' to make it through an overnight stay and still make coffee in the morning--barely at times. A typical load is intermittent 'fridge operation (off all night) TV and VCR for a few hours, and lights. Big deal, right?

The bottom line: Batteries are lousy at storing energy, as electric car owners have found to their disgust.

Jeff

[Supersport18]

I have run my old cpap off of a sears jump start box inverter. Recharge it during the day and it will last all night. Also, new cpap has an 12 v adapter that can connect to a marine batt or cig lighter.

[Supersport18]

http://www.sears.com/diehard-platinum-p ... 871688000P

[balthaus]

Supersport18
Thanks for that info
I will check into that for my wife and I. We both have the same C-Pap machine.
Jump box seems kite a good thing to have aboard anyway.

[Supersport18]

You will need 1 per cpap. It also has a compressor,inflator, emergency work light, and usb outlet.

[Fastjeff]

Okay, but be forewarned that batteries--especially tiny ones like these--have very limited storage capacity.

Jeff

[Supersport18]

Yes,they are limited. But for occasional overnighters on the hook they have worked great. I even took one on a 70 mile run to the Dry Tortugas and spent 2 nights anchored off of Fort Jefferson. No problems and had a great night of sleep. Tanqueray and tonic probably helped,also. Just be sure to fully charge them during the day. Get one and do a dry run with it at home before you try it on the boat.

[TheScottFraser]

I can relate 1000%. I also can not sleep without my machine. Does your machine have a small box in the cord. Like a laptop? Most cpap machines are not 120v at all. Many are actually 12v. I have a marine optima deep cycle battery mounted to the countertop next to the bed in my 39'. I charge the battery while at the dock or the generator with an inexpensive "battery tender" brand trickle charger. It is plenty big to run the machine. Only thing that takes some work is to make a cord or get a cigarette lighter kit for your machine. I picked the optima sealed battery because I didn't want a vended battery next to my bed. If you do not have a 12v machine, look into getting one to leave on the boat. Most insurance companies will help make these things very affordable now and they just keep getting better every year. Sleep tight. Also. They make fitted oral mouth pieces that move your jaw out when you sleep. Crazy expensive but if you got a few grand to invest in a zero power solution you might want to check it out.