What amp are you charging it at?
Have you checked the cells to see if it needs maintenance?
Have you checked the connections to make sure they are healthy?
Are you using a TM with 5 speeds forward or is one with percentage of thrust?
Put it on the lowest amp setting on your charger....relax for a day... pop the cover and add distilled water to the bottom of the plastic tube....fish...if it don't satisfy you add some aspirin....repeat....if it don't satisfy buy a new battery or two preferably the biggest group you can find/afford....fish for two years...repeat...
Tight lines
Chad
Sent from my SM-G975U using Crappie.com Fishing mobile app