BL-5J external charger pinout?
 

So, it finally happened, my USB port has said its final goodbyes.

I was checking ebay for external chargers, and all of them seem to only have 2 pins (link) whereas the battery has 3 pins, the third supposedly being the BSI pin (http://www.cpkb.org/wiki/Nokia_BL-5J_battery_pinout).

Are these cheap chargers ok, or will I end up ruining my battery charging with one of these?