Camping battery Cpap set up

[SuperSleeper]

I wouldn't use any type of inverter for a newer ResMed CPAP/Humidifier combo... unless you have large capacity batteries and cost is no factor for you. Like Arch says, you need a pure sine wave inverter (more expensive than the usual consumer-level modified sine wave inverters) and you're still going to lose power in the inversion process.

By the time you spend that money, you probably would have been better off purchasing a ResMed converter unit that's specifically designed for your machine. That's what I did and it works great. Less worries and less power consumption tham going the inversion route.

[Sleepster]

I wouldn't use any type of inverter for a newer ResMed CPAP/Humidifier combo... unless you have large capacity batteries and cost is no factor for you.

And there's really no reason to use an inverter on a Respironics machine as they run directly off 12-volt DC electricity.

[SuperSleeper]

And there's really no reason to use an inverter on a Respironics machine as they run directly off 12-volt DC electricity.

Yep, that's the one nice thing i liked about my old pre-2007 REMstar Pro with C-Flex... had a simple cable that attached directly to the 12-volt battery.

[Crog Welly]

Sorry for delay is responding and many thanks for input from everybody.

PaulaO2 .
I have used this set up before. I have been able to get 7 hours out of it in the past.

SuperSleeper
I am not using a humidifier. I think that I have probably run the battery down to a low state of charge in past camping usage as you describe. Last time I used it was 5 days in a row at a campground charging the battery up during the day. I lost ground each day as the battery came back with less and less charge at the end of the daytime charge cycle. I bet it gradually dug deeper and deeper into the battery charge level and maybe did permanent damage to the battery. The Booster Pac ES2500 has its own ac wall charger and circuitry that allows you to keep the battery charging 24/7. I think these engine starter batteries do not have the right design characteristics and are probably not optimized for a 2amp 8 hour draw.

Bryank1
Yes indeed current draw without humidifier is 1.4 Amps at 12v dc per SuperSleeper ResMed battery link. So it should be possible to get 10 hours out of it. But I think SuperSleeper is right I need a new bigger battery.

ArchAngle
It is a MSW inverter but I am not running the humidifier.

So I will take your collective advice and get a ResMed DC converter and get a new battery.

So much for the Li-Ion 7.8 Ah camping battery packs I guess they will hardly run the machine for anything like long enough. These deep cycle abtteries are heavy so I am just going to have to lose weight and go out without the machine for a few nights.

Thanks everybody.


Crog

[PaulaO2]

I think these engine starter batteries do not have the right design characteristics and are probably not optimized for a 2amp 8 hour draw.

And there is the problem. You can't use an engine starting battery, like what is in your car or truck. You need a "deep cycle" or "marine" or "wheelchair" battery.

[Sleepster]

I think these engine starter batteries do not have the right design characteristics and are probably not optimized for a 2amp 8 hour draw.

And there is the problem. You can't use an engine starting battery, like what is in your car or truck. You need a "deep cycle" or "marine" or "wheelchair" battery.

For occasional use you can use your car battery. It just won't hold up as long as a deep-cycle battery if you keep discharging it too far.

The only difference is that a deep-cycle battery has thicker lead plates.

[archangle]

Last time I used it was 5 days in a row at a campground charging the battery up during the day. I lost ground each day as the battery came back with less and less charge at the end of the daytime charge cycle. I bet it gradually dug deeper and deeper into the battery charge level and maybe did permanent damage to the battery. The Booster Pac ES2500 has its own ac wall charger and circuitry that allows you to keep the battery charging 24/7. I think these engine starter batteries do not have the right design characteristics and are probably not optimized for a 2amp 8 hour draw.

I think the charger that comes with the battery is optimized to not damage the battery, not to recharge quickly. Normally, you use the jumper battery once in a great while and have plenty of time to recharge it again before you need to recharge it. Also, you usually won't run it down that far before recharging.