Umm, how're gonna charge it during SHTF? You need to have some solar panels, batteries, etc. Also, you better hope that the "S" isn't an EMP, or the electronics part of that solar set up (and, probably, the chainsaw) will become junk.
By doing just that—having some solar panels, batteries, also an adaptor to charge off a car battery...but having a regular old sweat-operated saw as a backup couldn’t hurt. :-)