What he said! I ran the cables/pigtail from the battery box towards the wishbone and down near the seat post tube. I also have the pig-tail on the righ hand side above the starter. I wanted to keep it away from the passenger peg.When in doubt - use one more zip-tie!Not sure what bike you have (model, year) but on most bikes you can run the pigtail down either the right or left hand side down tube. Zip tie it to the down tube and leave enough free towards the end so that you can easily grab it, move it, rotate it etc. so that it's not a pain to connect your tender. So take the pigtail out the front side of the battery box and run it down one of the down tubes.
Knowing the bike helpsSorry, I have a 2017 Road Glide Special, You don't use the factory Pigtail under left side cover? doesn't seem long enough to reach seat post tube.