You can find power supplies on Amazon that put out the correct 13.8v DC and have a 10 amp accessory port (cigarette lighter) that will work fine for a 20 watt radio. I suggest buying a 30 amp power supply just incase you ever decide to get a 50 watt radio to use as a base station.
Here is one example: 13.8V 30A Bench Power Supply, Analog DC Power Supply with Cigarette Plug, Ham Radio Regulated Switching Power Supply, Noise Offset Control I know its a generic brand, but that exact power supply is sold under various names and has a good reputation.
One thing to remember is that most, if not all, power supplies are marketed at their peak power output. The continuous power output is between 75 and 80 percent of that. SO a 30 amp power supply is really only good for 22-24 amps of continuous use. A 20 amp power supply is good for 14-16 amps continuous and a 15 amp power supply is good for 10-12 amps continuous.
I would love to run longer antennas but I need to be able to park in my garage and also fit into low parking garages at my doctors appointments. I might end up getting another Comet 2x4SR for when out and about.
WRYZ926's post in Radioddity DB20-G for Vehicle&Home Use? was marked as the answer