I use the mega charger from tw so I have to use the adapter for them. I have 3 adapters but one doesn't seem to work. If you are familiar with their chargers, when you screw on the battery the little green light will turn red and after a bit will flash green to indicate charging then turn solid green when charging is completed. Problem is with one of the adapters as soon as it's screwed on it immediately turns red, even without a battery or a fully charged battery, then it will never flash green and won't charge the battery at all. This a problem with the adapter or what? They sell them in 5 pks so I can only assume they might go bad. Any idea?