Sofirn 2 Bay 18650 Charger

Hi there i am new to lights and chargers. I bought a 2 bay Sofirn charger with 4 18650 batteries directly from Sofirn. When I plug in the charger the led lights up green right away without even a battery inserted. When I put in the batteries the led stays green. How do i know when its charged? I have an Efest single bay charger that is behaving the same. I know there is another new thread on chargers for these batteries, I guess i am looking for a 4 bay charger that can do 18650 and 26650 batteries and is a quality effective piece. Thanks for your time I just dont know what to make of a charger that glows green with no batteries in it when its plugged in? The light i am using is the BLF Q 8 that has just arrived from Sofirn and has 4 18650 batteries. Thanks

From the Sofirn web page, charger standby has green Led. Inserting a battery would light red if charging, else green if battery is fully charged.

From the picture from one reviewer, standard behavior. Only when charging does the Led turn red.

Perhaps your batteries are fully charged?

Thanks for your help and reply appreciate it

just realized that Sofirn puts a white sticker on the negative terminal. it is hard to see and I was not aware. I guess a new guy mistake . All is well with batteries and charger