I find I never find batteries and chargers that work together the same way twice.
Sometimes the charger stays red and suddenly goes green when the charge is complete.
Other times the charger light flickers between red and green for a while before becoming solid green.
Sometimes the battery button light flashes several times, and the battery is off when charged.
Othertimes the light flashes, and the battery is on when charged.
There seems to be nothing standard about any of them. Of course not one of them comes with any directions, neither chargers nor batteries.
It makes me wonder what the hell is wrong with them the first time I get something different. But I just leave the batts on the charger for a while and they work.
It doesn't seem like they should, but chargers do go bad. I just had to replace on that had the green light come on in half the time another one beside it did. Both were charging completly dead 350mah eGo batts. When I moved the batt to the other charger it took another 30 mins for that light to turn green.
It's possible the early light charger might still be charging after the light is green, but I replaced it rather than risk having half-charged batteries. Especially since I like the little batts to tote around in a shirt pocket.