Originally Posted by tmex
Measure the current draw with the ignition off. I would be curious to see what you get. Why speculate? It is an easy measurement to make. Maybe I have two bikes with CPU problems - seems unlikely, but it is possible.
I would speculate that the "typical" later model GS's or HP2's would have about three weeks to a drained battery incapable of starting the motorcycle. To avoid this situation you MUST use a tender.
Please make the measurement, I am very very curious why your bike seems to be so special.
Twice I killed my battery. Once by leaving my GPS on for 3 days, and once by leaving my parking lights on for 12 hours. Both resulted in the inability to start the bike. Both times I jump started my bike. I ride only 1.5 miles to work each day, and a similar distance for lunch each day. Long trips on the weekends. 32K miles in 18 months, 110° to 8°, rain and sun and snow.
I'll be happy to test the voltage of my battery, but I see no reason why my bike, and my GF's 2 year old R1200ST with 19K miles on it, should be any different than anyone elses. I have never done any battery maintenance on it, and it wouldn't have any need for it anyhow.
I still say, as have many, that there is no need for a battery tender for the average rider. Unless you park your bikes for weeks on end, and rarely ride it, you should never have to worry about it. Hell, my car is more likely to need a jump than my bike I drive it so little.
PS Just out of curiosity, what background do you have for speculation on battery life and the apparent absolute need for a battery tender? Are you a mechanic, electrical engineer etc?