I just installed a new Noco 3 bank charger and ran one bank to each of 3 batteries. Charger is wired correctly LOL

When charging the starting battery, my outboard starts to make a clicking noise. I unplugged the charger and tried a portable charger on the starting battery - same thing a clicking noise from the Yamaha.

The starting battery is 3 to 4 yrs old, maybe a dead dead battery? I unhooked everything from the starting battery and have it isolated and on charge now. Will retry after/if the battery makes it to a full charge status.

Anyone experience this clicking noise from their outboard while charging the starting battery? What was the cause?

Thx