I have a three year old R1200RT LE.
The battery has begun to show signs of heading for failure - it starts the bike but, in doing so, the display returns to default settings - background goes to RT logo and any heated grips / seat will return to zero. Of themselves, irritating but not the end of the world.
When in for a service at 35,000 miles, the battery was checked by the tech who reported it showed 83% which was acceptable but might be improved by an overnight charge. I declined, since the bike has spent most of it's garage time hooked up to an Optimate 4.
I'm going to replace the battery next Spring before any foreign trips and I've done some initial searches on line to see what is available. I would prefer not to pay BMW prices but I'm willing to pay for a better battery if I can be convinced there is such a thing.
One of the first sticking points is that I want a battery which is as close as possible to the dimensions of the current battery. I can pull the battery and take my own measurements but has anyone else measured the OE battery and could share the L x W x H ?
Once I'm sure of dimensions I may come back looking for recommendations on more technical details.
