If you are riding every few days, ride or charge and make sure it starts.Remove the ground terminal from the battery while the bike is not used. Reconnect and try to start the bike. I have had automotive regulators, and the diodes in the altenators fail. This drags the battery down. Most testers did not find this failure. Batterys do intermittantly fail under load, but most fail completely soon after.
A quick check after a short ride on my 01 origional battery.
Switches off 12.6 vdc.
Ignition on, FI lamp off, dip beam 12vdc.
Starter, dropped to 9.85 vdc.
Running, idle of 1200rpm, charged to 14.6vdc.
You may want to look at the electrolite level. I have found that my Magna will over charge enough to lower the level below the plates. If you catch it soon enough, distilled water will give you a few more months.
If you need to compare, I am near Tifton, Ga. And if I ever get this new chain staked correctly could ride down.