Master Battery Cut-off Switch

[Ken A Hood]

Are these the same? Besides the top one being for 2 batteries? My wife found out she also needs a C-pak machine, so I'm trying to plan ahead; and get a switch that (if needed later on) I can just add another battery dedicated to her machine...

[rainjer]

I have a C-pap machine. I am going to use the kind in the lower picture. I will have 2 batteries & have them wired in parallel & put the switch on the mail lie to the fuse box. I will also have a 30amp in line fuse before the fuse box.

[Chris C]

My girlfriend has a C-Pap machine. It's supposedly going to use about 45 amps a night to run. Based on that, we'll need at least 2 Group 27 batteries to make it two nights. Don't know for sure, but the first picture looks as if you can choose between using one or the other, or both batteries at the same time. The second picture is just a standard battery cutoff switch.

[rainjer]

My girlfriend has a C-Pap machine. It's supposedly going to use about 45 amps a night to run. Based on that, we'll need at least 2 Group 27 batteries to make it two nights. Don't know for sure, but the first picture looks as if you can choose between using one or the other, or both batteries at the same time. The second picture is just a standard battery cutoff switch.

Chris, I have a group 27 115ah Walmart Everstart battery. I think I payed $60 for it.
I have gone 5 night on a single charge. Three of the night where in a tent at below freezing temps. The other 2 night where at home a few days later when the power was out after a wind storm. (I did not get a chance to charge it before the storm.)
I plan on putting a second battery so I can go 4-5 day without thinking about it.
I will also carry my battery charger with me.

What model C-pap does she have?

[Chris C]

Like I mentioned, my girlfriend's C-Pap machine eats up 45 amp hours in an 8 hour night. That is close to half the capacity of a group 27 battery. From what I've learned on this site, it will damage a battery to repeatedly have more than half of its capacity consumed before recharging. That's why I'll have to have 2 group 27 batteries in the trailer to make two nights without charging.

I'm not sure of the brand, but it has a humidifier built in, which just compounds the problem. To make matters worse, the Tech department of the company that makes the machine told us we had to use a pure sine wave inverter or they wouldn't warrant the machine. That means not only having to buy two batteries, but an expensive inverter. Oh well, thank God she's worth it!

[rainjer]

Mine will run directly on 12 volt. I just cost me $60 for the power cord & a fuse.....

[Chris C]

I know. Shame, isn't it? It's not my machine, and he's not my Doctor. She refuses to "insult" him by asking for a more convenient machine. He's so "sold" on this one. Hey, you know how it is..............if Mamma ain't happy, ain't nobody gonna be happy! I'm not complaining. Like I said...........SHE'S WORTH IT!!!!!

[Nitetimes]

The first one is a typical boat battery switch for multiple batteries, the second is just an on/off switch for power cut.

[fornesto]

I used the bottom one. Mounted onto the cover of my fuse box (I used a Radio Shack project box). I can turn the power on and off real easy. I shut her down when towing, or storing.