PC Power Supply Conversion
I'm sure your radio says it requires 13.8VDC, however it will run just fine on 12VDC too. Power supplies are expensive and, if you are like me, you have plenty of spare parts laying around. I had three Dell rack mount server power supplies in my basement. These power supplies are rated at 495 watts. That's more than enough to run most two way radios. The information here may be specific to mine, so you will have to do your own research if yours is different, but you should get the general idea.
Dell D495E-S0 power supply mod
If you're an electronics hoarder such as myself, you'll probably have some PC power supplies laying around. The server power supplies in particular are nice and compact. I had three of these that I'd probably never use for an actual server, so why not use the 12V output to power my radios. I've been using these for months non-stop with no issues. Even when transmitting, the voltage only drops to about 11.8 or 11.9.
The problem is that these power supplies don't just turn on by themselves. If you hook them up to 120v, they will just sit there and do nothing. Luckily, we can trick them into turning on by shorting out two pins on the connection at the back. These pins vary from power supply to power supply, so make sure you know what you are doing before you connect these two pins. I soldered mine together permanently and just turn it off by unplugging it.
Once you have it "always on", break out your multi-meter and verify which of the large connections are +12v and gnd. Solder on your wires and you are all set. I put a set of Anderson powerpole connectors on mine so that I can quickly change between radios if needed, but you can put pretty much anything on here.
Like I said, I have been using these for months with no issues. The power is steady and clean, but YMMV.