battery multitracker

Hi, I need some advice,
I'm going into the Bighorns for a week or so and was wondering if anyone had a fave battery powered multitrack recorder. Really only need two inputs at a time but need phantom and overdubbing. I haven't tried recording in the wild so don't know what to expect as far as battery life or even what's available. I want at least four tracks but eight would be even better. I can get a lot of batteries but don't know what recorder to look at. Prefer XLR in X 2 if possible. Would like to spend under 400 if it's doable.

Thanks,
Jick