After scouring the internet I came across a regulated DC converter that increases ~ 12 volts to 16.3 volts and can handle up to 6 amps. The device is sealed and is available on Amazon at a reasonable price. Here is the back of the device.
Here is the front of the device. I've used wire nuts to connect a 12 v accessory power plug (cigarette lighter plug) to the input wires. To the converter outputs I've used wire nuts to connect the Gemini power plug with the 2.1 mm right angle plug.
Here is the finished unit attached to the side of the pier with heavy duty Velcro.
I'll be curious to see if my G-11 performs any differently and if I get the RA or Dec Heavy Tr warning messages.