I have had a 'spare/old' battery I haven't used for 8 months Although I have charged it regularly it has failed I charged it 12 hours ago and charger gave the green light as fully charged at 12.6v This morning I noticed a deformation in the case and voltage drop to 12.2v Time to get rid and replace, I have ordered a Motobatt MBTX12U for my 2010 Speed Triple Images of the failed battery, hopefully you can see the deformed case where the cell has expanded Edit' it is the original Yuasa battery, over 10 years old I have been using a Lithium battery over the summer, but they do not like the cold, hence why I have gone for Motobatt AGM with high CCA The Shido Lithium Ion battery holds a higher voltage at 13.4v, mustn't charge over 15v so needs specialist charger It is 2/3 the size and 1/8 the weight