I just got the Battery Tender Jr. for Christmas. It comes with the battery harness so it makes it easy to access once installed.
I simply connected the harness to the battery and then ran the connecting wire through the area under the side panel and down the front part of the frame. I ran it on the left side so I could hide it in the wires that already run in that area.
The connection is now easy to get at it and it's hidden.
I've only used it once however it worked excellent. The light on the power pack stays red until the battery is charged, at which point it turns green. You can leave it plugged in as long as you want though cuz the tender will not overcharge the battery.
My was almost completely dead (bike would turn over but the battery didn't have enough juice to start it) and it took about 6 hours to charge (until the light turned green).
I don't know how much they are in the States, however they are about $80 up here. Good investment in my mind.
I picked up a Battery Tender Jr from my dealer for less than $40, (X-mas discount) the Plus was about $60. I've seen the Jr cheaper ($30 @ www.ridegear.com, for one), but I didn't want to wait.
I can't speak to the install on the V-Rod; the dealer installs the quick disconnect lead on every new bike now. I am going to use the one included in the kit for my Road King, since it doesn't get much road time any more. I was told it is as simple as fehrc describes above.
I just bought the Global Battery Tender $69.95 -10% discount. It is better than the junior if you are impatient like me. More powerful and will bring the battery up to speed quicker. You can leave it hooked up if you want. It automatically adjusts the voltage depending on the amount of charge needed.
I use one that was given to me from a buddys diesel.It's called an Ever Start.Seen um at Auto-Zone.I just hook up at the starter solenoid down by the radiator.I use it for alot of equiptment. Oh yea it's only 1.5 amps.
Have had the jr on 3 bikes. A short battery pigtail is installed, then a quick disconnect is used that plugs into the wall. If you read the literature it says that a battery that is maintained everyday using the BT will extend the life of the battery by a factor of 2. Meaning the battery will last 2x as long as a battery that isn;t on the BT everynight. They explain that the BT charges the battery to 14.8 v and that process of getting it back up to that level keeps the plates clean and willing to accept a full charge.
Had a 5yo battery on my Valk
Had a 4yo battery on a smaller VLX
have a 2yo battery in the Vrod