Such a thing as a PC port-->battery charger?

I am unfamiliar with the uses of a camera's PC port - is it possible, or does anyone make, a cable that would go from a 120v wall outlet to the PC port to keep the battery(s) charged while the camera is just sitting there? Has anyone heard of this? Is it technically feasible? My camera sits on the tripod a lot just waiting for me to take it outside, and I thought that having a 'trickle' charge working on the batteries might be a good idea.

Or no?

Thanks.

The 'PC' port is not an input...it has the two lines which permit the camera shutter electrical contacts to fire a (non-ETTL) flash which is connected to the camera.

In theory the USB port might provide electrical voltage INPUT to the camera, but then the battery of some cameras need to have input higher than 7.4V while other newer cameras need input of higher than 3.7V (USB provides 5v). While the interface cable might be able to supply voltage to the camera during data transfer from camera to PC via USB cable, Canon does not state that it can be used to charge the battery while the 3.7v battery is in the camera.

Wilt wrote in post #15448140
The 'PC' port is not an input...it has the two lines which permit the camera shutter electrical contacts to fire a (non-ETTL) flash which is connected to the camera.
In theory the USB port might provide electrical voltage INPUT to the camera, but then the battery of some cameras need to have input higher than 7.4V while other newer cameras need input of higher than 3.7V (USB provides 5v). While the interface cable might be able to supply voltage to the camera during data transfer from camera to PC via USB cable, Canon does not state that it can be used to charge the battery while the 3.7v battery is in the camera.

Aha. Thank you. Oh well..