I would highly suggest that you put in a bit of money like around $35.00 & purchase a Battery Tender, true it is a TRADE NAME, though it is probably the best on the market since around the early 80s. Only charges with 1.25amps which is ideal for small batteries like we have on our bikes. It has two idiot lights & will start of reading RED meaning it is on Charge then once charged properly the red light is dropped & on comes the GREEN light saying the charger is on STORAGE meaning it is not charging, yet will start up on its own once the battery drops in full charge.
You can put the bike away & just hook up the Battery Tender to it all winter & come Spring just disconect & all should be ready. Still that would be with a non-servicable battery or jell battery while a normal battery has to be watched for the level of fluid & sometimes tilled up during the 3 or 6 months of storage.
I have my three sportbikes hooked up to said chargers & have done this for the past 3 or 5 yrs.
Also in the hot days of the summer & with short runs, continual starting, & the heat the poor battery suffers as the most drain is when starting SO use the BT to again keep up the battery. Fact is I advise ALL that have a m/c with an electronic starting system should have a BT.
Problem with some commercial charges is that they are with 2, 4 , 6, 8 or even more amps & that is pure 'ell to a small battery so reason BT only has 1.25 amps for SMALL batteries on the various things like riding lawnmores & who knows what else PLUS our m/cs.
Lastly if you battery is very low on the fluid, before you try to charge it up then best to raise the fluid level by using distilled water.