Quick mention about any motorbike related gear (mostly warm and light) there's a site I receive regular emails from who have the most amazing prices on top branded gear. MotoOutlet.
I haven't searched for whether they do the electric jackets, I mostly ignore the emails because I don't currently have a registered motorbike but friends who have told me they use the site have mentioned they can't be beaten for prices.
I have no affiliation with the site, I just get the emails and occasionally browse in the form of being a "Forever Dreamer"
I'll have a motorbike one day, the new MV Agusta Super Veloce excites me, I'll have to win the lotto to buy it then these old bones won't bend up into that race seating position but, "forever dreamer".
The following is a site/seller in the UK I'm guessing but they know about cold and motorbikes.
While pricing won't be correct for our market it does show a couple of heated vests and there use including battery/voltage supply requirements.
Code:
https://bikerrated.com/gear/clothing/heated-motorcycle-vests-jackets/
Another of my stupid thoughts about staying warm.
Now I'm going to make a coffee and put a slug of OP rum or brandy in it!
Oh, that works too but don't put a big slug if you're getting behind the wheel or stumbling around in the dark.