[AK]

A diode in the rectifier is a one way valve - if you keep forcing power the wrong way, it can damage it, by constant high ampage and a fluctuating power surge.

Modern gel batteries do seem to need a trickle from an optimate, as they dont do the job as well as the old lead acid batteries - but, unfortunately the positioning of these batteries require a sealed battery, so they do not leak.

Hopefully this should improve soon - but doesnt help your situation now.

Modern stuff is better - but best to use the optimate.

Alan