A follow-up. Gil, NN4CW, suggested the Blackberry 8330 battery charger for the Tecsun PL-380. I ordered one but the vendor shipped the wrong model. They shipped the correct one right away and didn't ask for the wrong one back, and I got it yesterday. It does indeed plug in and charge the radio, but it generates a LOT of RFI (radio-frequency interference). The noise only shows up when the charger is plugged into the radio. Switching supplies don't get serious until you give them a load. Wrapping the charger-radio cord around and through various ferrites didn't help enough to be worthwhile on MW, SW and many FM stations, so use this gadget for charging and disconnect it for listening. The Garmin GPS USB cable, OTOH, only introduces a little noise on MW, but my desktop PC is pretty noisy to start with.
I got an OEM Blackberry charger, their part number ASY-12709-001, or model number PSM04A-050RIMC . If you use your search engine to look for both numbers it will return a variety of outfits that sell them, all over the world. This charger is specified for 100-240 Vac input, 50-60 Hz, 5-Vdc output at 0.7 A.
Radios with clocks and alarms are continuously drawing power from the batteries. Having a charger that isn't dependent on the PC is handy. I got mine from an eBay seller, skymaster28, whose price was better than any I could find from an online retailer.