To actually add something worthwhile to my lst post, here is something I found on the BatteryTender.com site.
9. How long can I leave the Battery Tender Plus battery charger connected to a battery?
In theory, you can leave the Battery Tender Plus battery charger connected to a battery forever. Like they say, “Just plug it in and forget about it!” Practically speaking, it is a good idea to check on the battery at least once a week. Strange things can happen. Sometimes a battery can have a weak cell that won’t show up until the worst possible time. Of course, that time is usually when the battery is connected to a charger. If something goes wrong, then you have to deal with the question of the chicken and the egg. Which came first? Did the battery fail because it was connected to the charger or did the charger fail because it was connected to the battery?
No matter how good a product is, anything can break. With a battery and a charger connected together, it’s a much better idea to be proactive and anticipate problems, however unlikely they may be. In more than 99.9% of cases, nothing will go wrong. That still leaves about 0.1% where something might. Learn to respect electricity. A little common sense can go a long way.
I use the plain Deltran Battery Tender JR, not the HD labeled unit. My does not have a blinking Green, nly steady Red or steady Green.
Chief
<EDIT>Same goes for regular Battery Tender and Battey Tender JR, forever.</EDIT>