I connected my battery tender to my battery over the winter. Didn't disconnect the battery. Just installed the "pig tail" and hooked it up. No problems.
The same situation for me since many years on manu mikes. Never seen something like blown rectifiers (that is what they're afraid of).http://www.powerletproducts.com/product/battery-tender-yuasa-charging-cable/261
This plugs in to the power outlet under the left side of your seat (assuming your riding an ST) and will trickle charge your battery. I've used it for the past three years. Maintaining battery charge couldn't be easier with this adapter.