Ive got a twin peak aswell. Did exactly the same on my batteries by not charging them fully, and then i found that the charger cuts out due to "overheating" inside, and it sensed "other perameters" as Guver said. So I took a old hairdrier, stripped it apart and removed the motor with the fan assembly and chuhed the rest. Took some deans plugs and soldered it up and connected it to a seperate battery and just let it run next to or blow into the vent of the charger. Now it work as its suppose to, just by being colled a bit.