long camping trip

[Scoutcamper]

Chaperoning a 7 day canoe trip with my sons scout troop in Canada this summer and need to find a way of powering my cpap. Is there a source for renting multiple lithium batteries to get me through most or all of the nights? When I camp at home I rely on a deep cycle battery for a couple of nights but that isn't an option for this trip.

[Sleep87]

One option might be to get some smaller sealed lead-acid or AGM batteries such as those used in uninterruptible power supplies. They won't be quite as light as lithium, but they're much cheaper. Battery Station has a 12V, 9Ah battery for $16. You'll need more than one, but you can at least scale the number carried to the length of trip, with the possible downside of needing to get up during the night to swap batteries.

Maybe you can do a trial run at home to test actual power draw and run-time.

The CPAP you're using may also make a big difference in power draw, as could its settings -- make sure to turn off humidifiers and the like.

[Sleep87]

What sort of machine are you using?

Some data: using a Transcend machine set to a fixed relatively low pressure: a 12V, 9 AHr AGM battery such as what I cited above lasted about 7.5 hours when attached to a mostly-blocked hose (no human), using Transcend's own 12V transformer (since the machine runs off of 18V). When it failed, the single battery was at 10.73 V, and the transformer and CPAP were power cycling on and off pretty rapidly. A different transformer may have been able to eke more runtime out of the battery. I did not try it with running multiple batteries in parallel, though I speculate that runtime off of two batteries in parallel might be better than twice the runtime on one battery.

One thing I have noticed about every machine I've looked at: power draw is far from steady, even through a single breath cycle. From that, I predict that the specifics of the machine and power arrangements may matter a lot.

[Cowboy Casey]

I have used a SLI group 31 deep cell battery from batteries plus connected to a true sine wave converter and it ran my ASV for 4 days... if you have a car or truck to charge the battery once or twice it would work great for you.. just so its not a surprise, this battery is not light, its about 80 pounds

https://www.batteriesplus.com/battery/m ... m/sli31mdc
http://www.amazon.com/gp/product/B002I04A74

When it comes down to it, this is just a HUGE battery backup.... When connecting the battery and inverter, use at least 2/0 gauge wire like the link below but go to your local stereo shop and have them build you a red and black 2 foot cable to connect them..
http://www.amazon.com/0b-20-Gauge-Power ... ref=sr_1_2

[Sir NoddinOff]

You got some good replies but try typing in the search box below the CPAPtalk logo the term:

batteries camping

a baziillon nicely targeted hits appear as if by magic.