Help with Clock Battery Replacement

[BKDCRCKR]

Hello all.

I have 2 controller port boards that I took out of my DCs and brought to work to have a coworker solder new clock batteries on. Very odd though. One of the LEDs is on.

Mind you these are Not connected in the consoles and I did buy the ML batteries, the correct ones. How come the LED is powering on?

Thank you.

[Umbrella$$Dreamcast]

probably battery powered