Need some small bits of battery advice

Hi all!

Thinking ahead to the inevitable ice storms of the winter, I broke down and bought a deep cycle marine battery (and appropriate adapter) for my ResMed S9. I've attached some pictures to make everything crystal clear. My current pressure setting is 15. I've tested the setup for a few minutes, and everything seems to be working fine.

I'm aware of the subtleties of deep cycle batteries—checking a charge, maximizing battery life by not using a humidifier/heated hose—but need one or two pointers.

1) According to the ResMed literature, I needed a battery with 74 amp hours to get an 8 hour night's sleep out of my machine. However, the smallest one for sale at the battery store was 615 (?!? — see pic). I went ahead and bought it—does this just mean I'll get more time between recharges?

2) Speaking of recharges, I am aware of the benefits of getting a meter to check on the charge, and of having a dedicated monitoring system to plug the battery in to keep the cycle going—but since I'm primarily wondering about how I will recharge the battery in the event of a power outage. Everything I've read hereabouts suggests hooking it up to my car battery for 20 minutes—is that really it? Just pop some jumper cables on and go?

Any input is helpful. Part of me would love for someone to have just come in and said, "Here's a guide, follow these instructions and everything will be okay"—but it seems like it's every man for himself!

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  • gadlengadlen Posts: 1
    edited September 2018

    The battery you bought has, according to this site 75AH. So you'll get just one night's use out of it. Sorry :-(

    The "615 MCA" is how much power you could get out of the battery if you were trying to start an engine... 615 "Marine Cranking Amps". You don't really care about that number.

    A battery will only charge so fast. Hooked up to your car, it would take 2-3 hours to get it mostly charged. 5 hours to get it fully charged. It'll work though!

    All the best to you!

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