Remove seat 2008 flhrc - 2008 Harley Davidson FLHR Road king

It means your drawing more current than you should be. Check with voltmeter, take it to your dealer. Do you know how many amps its supposed to draw?

throttle cable could be dry or fraid ! try oiling the cable , removing it and working the cable by hand would be best and you can also check if cable is not damaged at the same time !

I have a 2008 Road King Classic (FLHRC) and on mine, both the oil drain and transmission drain is a hex head bolt, 5/8" I seem to recall.

Remove seat.
Release HFSM antenna, move out of the way.
Remove the bolt(s) securing ECM top caddy to the frame.
Carefully lift the ECM caddy up from the battery and rotate the caddy toward the right and set on upper right frame tube.
Disconnect negative terminal.
Disconnect positive terminal.
Grab lifting strap and lift battery enough to grab ahold of.
Lift battery out of frame.

Put in and tighten!

Just a suggestion,no offense.I'd check out how much of the frame top rail that the tanks mount to.you have access to.Drill a hole in the front that will allow you to access the handle bars with speaker wire.Drill another hole in the end,under the seat front.You'd only have to remove seat.Fish the wire thru the frame rail and connect each end to where you want.Places that install sound systems can give you stiff wire to fish with.Check out this possibility before you remove tanks.On the plus side less exposed wires on frame.

http://www.carlsalter.com/motorcycle-manuals.asp

free service manual there, pdf format