I had a Varta on my bike too... it didn't last 2.5 years. despite the bike being used daily.. with no power hungry gadgets.. hell.. I hardly use the heated grips as my winter gloves make em superfluous. So in my opinion those batteries are junk. (sorry to be blunt - but I expected better)
I replaced it with an Exide Gel.. the OE battery for these bikes.
just a few days ago a chap posted about a 19 amp Lucas Gel.. for £50 + £3.95 postage.
thats an excellent price. linky -
http://www.mdsbattery.co.uk/shop/pr...entName=Motorcycle+Batteries&DepartmentID=155
A little late coming for me.. I paid almost £20 more for the Exide. never mind eh. However I fully expect it to last anything up to 10 years.... certainly a LOT longer than 2.5