Ive got a few battery powered tools , lamps that I want to convert to use a few 18650 batteries, One thing that is confusing me is the charging, Ive see these little charging / management PCB but none have any meter or LED to indicate what state the battery/ies are in.
I have a few pieces of equipment, lamps, phone, laptop and even the cheapest lamp has a green/red charging-charged LED indicator
Is there anything I can add to these charging / management PCB ?