I've discovered that it takes about 15 hours to full recharge, and also you need to keep it plugged in. It quickly loses its charge if left unplugged. The charger is 'smart' and turns itself to 'standby' when not actually charging.
It seems to work quite well. On the lowest level of heat it will last all night, but at its highest it only lasted 3 hours. The choice of 3 settings depend on the temperature outside, and if you want to 'feel warm' or 'not feel cold'. There is probably a tendency to turn it higher than it needs to be.
The jacket has several extension strips and straps if you need to accommodate a larger body.
There are various jackets by different makes. The variables are the number of of heating panels, and the wattage, and battery size.
This is the make and model I bought, but there are other models and makes.https://www.arrishobby.com/arris-rechargable-heated-warm-vest-size-adjustable-for-outdoor-use-p-3803