Bought FXR heated gloves last year and a second set of batteries.
I've ridden in -50C temps, for 12 hour rides, for a few different years so I got to try different setups.
Had quality gloves, native made mitts over them, with chemical heater packs jammed inside.
High end mitts only and thin gloves, with heater packs.
If you have the ability to get the heated FXR gloves, they do work, well.
We'd stop and need to do something that meant your hands are exposed to the outside for some time. I'd dial the gloves up to max while off my hands, and they'd heat up and warm the fingers up quickly once back in the gloves. A little bulky, but a good trade off.
They are 110V to recharge. I found a 12v to 110v inverter that fits in the skidoo glovebox and charge the batteries, but didn't need to use it as the batteries lasted until we got to the next hotel.
When I was 30 I could keep my hands in the snow all day long and still be fine.
At 50 my fingers are not so forgiving.