12V Deep cycle batteries: Learn Me!

Hey,

I am going camping in about a month.

The kicker is that I use a CPAP machine for sleep, and out here in the boonies, there is a limited number of campsites that have 120V power.

I can connect my machine with a battery box, a 12v deep cycle battery, and that's about it. My current machine totally drains my battery box in about 9 hours.

So....can someone recommend a suitable battery, and a good place to buy it? I checked O'Reillys and they have several batteries that can be ordered.

All tips and comments are appreciated!

TIA,

Rog

Not sure you budget but a lithium battery will weigh less than half as much and probably have more than twice the usable charge. Only downside (other than cost) is that you shouldn't charge it in freezing temperatures. 

How about a solar panel charger for the battery box you already have?

My BIL went camping all the time with his CPAP, any old generic group 27 car battery and a 25 watt solar panel to charge it during the day. Seemed to work fine,