I too purchased a set of heated gloves from powerinmotion. This is my second season using them and they are great. I also bought one of their heated vest ( with 2-16V batteries) in December.
Through that past cold snap I was wearing both vest & gloves for coyote hunting. Even on those -35C / -45C WC mornings, the vest only seen the "low" temperature setting. Not sure when I would use medium or high. The gloves were usually on the medium settings.
For the vest, they claim you will get 22 hours of run time on the low setting, with two 16 V batteries ( 44 hours with 4 batteries). I kept track of usage over 5 days and at 18 hours, I charged the batteries. They may have made the 22 hours but I wasn't about to chance it
It did however take 14 hours to charge the batteries.
Both vest & gloves are a great Alberta product coming out of Calgary.
The gloves come in different sizes but the vest is suppose to be a "one size fits all", however anyone with a chest size larger than 44" would find it too small.