I had problems, until I installed a Motobatt 'Absorbed Glass Mat Technology' from wemoto.com - as it says ...
MotoBatt is an AGM battery, a type of Sealed Lead Acid (SLA) battery. Get all the benefits of a gel battery at a sensible price. Each Quadflex Battery has 4 terminal (2+ and 2-) and when necessary includes spacers, enabling the battery to function in multiple applications (I didn't need them!)
. No electrolyte or harsh acids to deal with, Motobatt Batteries are sealed and require no maintenance. Charged and ready to install directly out of the box.
It has a terminal at each corner - how good is that, such a simple idea means it fits bikes with cables in any configuration.