I have one of the portable jump starters that I carry in the bike on long trips, It has a usb plug and will charge a cell phone pretty quick. The port in the bike takes a long time to charge a phone even with the engine running.

 

That annoys me too. Same in my cars- the 12V sockets are dead unless the ignition is on.
I'd rather they be hot always, and I'll take the risk. Maybe something I'll look into- rewiring one of those sockets to be constantly hot.