I have a Kobalt 40V 12" chainsaw that I use for cutting up the limbs on the trees I've cut down. It's over a year old, and it's done a pile of cutting. I've used it up in trees several times for larger limbs, but I prefer using the 10" folding razor saw aloft.
The 12" Kobalt has been a great saw with one exception. It's so light that it tends to jump forward and up when cutting anything smaller than one inch. The chain takes too big of a bite, and you really need to be ready to hold it in check. I avoid using the top of the blade on small stuff, but it does just fine on anything larger than one inch. Unfortunately, the saw doesn't have a chain brake.
As for the battery, I've always quit because I was tired (usually after several hours) before the it needed recharging. It probably helps that I'll make some cuts, and then spend a few minutes moving cut stuff to the pile before cutting some more. I can't comment on cold temperature use since I'm in south Georgia.