Charge cord for Wireless cam

Hey Guys, I think I have a Gen1 wireless camera.

Is there any charge cable that I could plug straight into the back of the camera to AC plug or an external battery power bank? It’s a bit of a pain to keep recharging the battery all the time.

I see there’s a small rubber plug on the back but can’t tell what it’s used for.

thanks!

Might that plug be for a solar charger?