Trolling motor or battery problem
The Guest brand charger I had at the time reported them charged, but only one was.
I also had a battery that reported charged on a single MinnKota charger this spring that would turn my 55pd on small boat about 30 seconds then die.
I'd check the wiring/fuses first, see if you have 24v at the socket with a multimeter, then try the batteries with multimeter for 12V each. Good luck with it- hate this kind of stuff.