I had read about the polarity issue (you guys are so awesome) so I bought a usb charger for the 510. Question on that, now that I'm thinking about it. Can you use ANY usb wall charger with a usb batt charger? For instance, I have a handy dandy iPhone wall charger that takes the usb.
The polarity issue still exist with the USB charger. Not only will you fry your battery for sure, but you might also fry your charger or computer. DON"T
If you look carefully at your charger, you should see a little diagram like this: +--(0--- - That's the polarity diagram. Look at the charger that comes with your battery or the battery specs and you will see the same king of diagram. They HAVE to MATCH!
I have fried 3 batteries in less than a couple of hours using a USB and learned my lessons
