The tender I have comes on when the charge on the battery reaches a low point. It is basically "topping off" the battery and not supplying a constant charge. It came with a quick connect that mounts to the battery full time and the plug comes out from under the seat to connect so you don't have to remove the seat to plug it up
I like to take the battery out of my bike and charge it with my auto charger. Only takes a few minutes to get it out of the bike. That way I can physically inspect the battery and fill it with water when it's finished charging. I make sure the overflow is hooked up properly, and that the connections are clean and tight. Even my 79 Suzuki doesn't have a kick-start, so the battery is very important.
The tender is good because it keeps the charge up and shut off when its done. If you leave the battery sit in the cold and completly die and just charge it in the spring, you could cause damage to the cells or they just go bad because the battery went stone dead. If you don't want to deal with the tender or chargers, just take it out of the bike, put it somewhere in the house or garage that stays room tempature. Don't put it on the cold floor, I've heard that kills them too. Just my
If you leave the battery sit in the cold and completly die and just charge it in the spring, you could cause damage to the cells or they just go bad because the battery went stone dead.
This is why battery tenders are a good thing. Everytime a battery is "dead" then recharged, it loses some life. A battery that is kept at full charge (from frequent use of the bike, or with a tender) will last longer.
A battery tender IS a charger ... just a really low amp one. It monitors the battery's charge, and when it drops below a certain point, it kicks on and charges it back up (then stops and goes back to just monitoring). The combination of low amperage charging and keeping the battery at full charge extends the life of the battery.
If you install the permanent leads that come with it, it's really a snap to use - you just plug in the connector when you park the bike.