Broken down!

[hl3013st]

When the battery is totally empty then is dead, the car and bike batteries should be remained at 12V. During the winter you should  measure the battery before ignition. if it is 9 to 10V you can charge it and it is fine, if you push the ignition button before you charge the battery, then you just destroyed your battery

[scoot]

I always remove my battery in winter and its put permanently on charge on my optimizer only taken off to start my bike every month.
Ride safe
Scoot 

[Andy]

When the factory battery goes I pay the $10 extra bucks to upgrade to an AGM battery. Running a AGM flat even in the winter is harmless and deep cycling them is also far less damaging then a standard Lead Acid battery. There are many other advantages for AGM batteries, especially in cold climates like we have here. Its all Military and Emergency Services use here.