I guess if you don't have the means to recharge sure, but I routinely charge them using a 12V plug for the charger in my car. I have never had a single issue with one of my batteries. I think making the comparison between NiCad and Li Ion is not accurate. I agree Ni Cad are not the best. Li Ion batteries are much stronger, more powerful and they last right up until the end, at which point the voltage cutoff will drop out and the light turns off.
With the run times of these lights, even on high, you's have to be in that smoky basement a helluva lot longer than your oxygen tank to outrun a battery. That's one of the things I like about rechargeable, I always have the ability to have a full battery.
Being off the grid doesn't mean you cant recharge batteries, unless you are literally off the grid for months and not driving anywhere, I'd just use the drive to town as a chance to charge all the batteries.
BTW where are you in NH? I grew up in Maine and love going over to the Conn lakes fishing
We're not out here to rough it. We're here to smooth it. Things are rough enough in town.