Installing an accessory fuse box

This is currently not visible to the general public, so make as many notations as you'd like. My comments or questions are in bold italics

I still need to insert woot's comments about the trailer-hitch connectors.

Why? My bike already has a fuse box

Yes, it does, but it's not really set up for the use of accessories, or farkles, as they're often called. A new fuse box will allow you to connect other electronic bits such as GPS, radio, or heated gear and have each unit fused individually. This also reduces the possibility of damaging the main fuse box.

Defining terms

You will see auxiliary power supply boxes labeled 'distribution blocks', 'auxiliary fuse boxes', and most likely several other things. The important thing is you want a fuse box, or panel, that will allow you to have a separate fuse for each accessory. That way, if one gets overloaded and the fuse blows, you won't lose everything else.

What kinds of boxes are there?

There are a few different types of fuse boxes/panels. Some treat each attachment point as a separate entity, requiring that power be sent directly from the battery to each connection point on the box (individual circuits) like the Centech AP1. In this case you can daisy chain (make very short connections) the power wires from one connection to the next, instead of running a wire from the battery for each. This article does not cover this type, as it's more difficult to do.

The Eastern Beaver FB-4 also works this way, but it comes in a kit with everything wired for you. This is the easiest reasonably-priced box to use if you haven't done this sort of thing before.

Other fuse blocks have only one connection to power; this connection powers all terminals after the main connection receives power (aka common bus). This is what is used in the photos for this article, the Bussman 15600 Series ATC Fuse Panel. This is still relatively easy to wire up, looks 'cleaner', and is cheaper. Having someone who knows something about electronics to hold your hand is a good idea if you do this, though.

There are some advanced boxes that let you wire some things hot all the time and have others that only get powered when the key is on. The Centech AP2 is one of these.

Finally, if you're scared about hooking everything up (you don't really need to be) the Fuzeblocks FZ-1 comes with an internal relay, constant or switched power choices, and only needs a few connections.

Things to buy

All these items should be available at Autozone-type parts stores or electronics shops such as Radio Shack.

• A fuse box, naturally. See above.

• A 30 amp, four-pin relay. Numbers on the relay pins should be 30, 85, 86, and 87. Pay no attention to the #87a pin on the relay in the pictures, although a five pin relay can be used without worry, as long as nothing is attached to the 87a pin. Bosch, Omron, and Hella are all good quality.

• An inline fuse holder and 10 amp fuse.Take the fuse out of the holder and don't connect anything to the battery until everything is in place.

• Several feet of flexible stranded copper wire. 14 gauge is generally recommended. Positive/hot/+ is usually red. Use a different color for ground (negative). Always use stranded wire in auto/moto applications. Pictures show stranded (left) and solid (right) wire.

File:Solid wire.JPG

• Crimp connectors

• Heat shrink tubing (optional, but a good idea for covering splices)

Or the kind of connectors that already have heat shrink on them.

• Dielectric grease - again optional, but a very good idea.

• One machine screw/bolt for the new ground post. Make sure that the ring terminals you plan on using fit over the bolt.

• 1-4 lock nuts, including Nyloks and k-nuts.

• Mounting bolts, nuts & washers

Finding a mounting location

For the purposes of this article, we will be following the installation of the Bussman 15600. If you are using one of the Eastern Beaver units, hook the relay up the same, then follow their directions. Mounting will be virtually the same as with the Bussman. In fact, you can use this as a basic guide for any fuse box on most any motorcycle.

The first thing to tackle is finding a place for your new fuse box. In order to know how long to make the wires you really have to figure out where to mount everything, but read the whole article first, OK? This does not mean that you should mount the box yet. As always, try to test everything before mounting, in the interest of saving time if something gets hooked up wrong.

You can mount the fuse box anywhere you want. Our man determined that the best place for him was on the left side, in between the coolant reservoir and the CDI.

The mounting location is on the wheel well. There is nothing on the other side to hit with a drill, and you can reach around to tighten the lock nuts on that side. It would be wise to use Nylok fasteners, or something similar, and blue Loctite.

The Buss provides four mounting holes. Only two were used, and the box was mounted diagonally.

Find a convenient point to mount the relay. Remember that 'finding a place to mount it' and 'mounting it there permanently' are two different things. So, don't affix it permanently yet.

You can put the relay just above the stock fuse box, where it's close to the horn circuit and the battery, and not taking up room on the other side. A simple zip-tie will suffice for mounting. The black plastic underneath is the airbox. Absolutely do not drill any holes in the airbox. If that position doesn't work for you, underneath the seat or anywhere on the bike will work. Remember that the shorter the wires the better.

Hooking it up

This diagram needs a few more details; Ryan says "It could use the pins that you need to attach to and where the wires are going".

kinda like this, version 2

File:Aux fuse box diagram-3.gif

First, wire up the relay. Why a relay? With a relay, you use the OEM wiring to power the relay, and then put in new wiring for the fuse box. The relay uses a small amount of power (the horn circuit) to turn on and off a bigger amount of power (the new heavier wire) to the new box. This is true for bigger headlights or any other higher-current-draw accessories you want to add to your motorcycle.

Relay terminals

• 30 positive from battery
• 87 new positive to fuse block
• 85 positive from horn circuit
• 86 ground to the battery negative terminal

Details

• The main power comes from the battery, through the new in-line fuse holder, to the #30 pin on the relay. The fuse holder wire might not be long enough to reach the relay. If so, crimp in a longer wire. Always keep the unfused portion of a wire as short as possible, so try to hook the fuse holder directly to the battery, then run the longer wire to the relay (after the fuse).

• Terminal 87 gets hooked to the main positive connector on the Bussman box.

• Terminals 85 and 86 are the 'trigger' circuit. This is what makes the relay fire. When a circuit is made through this pair, by turning the key on, a switch on the pair 30-87 is toggled from open to closed. When this switch is closed, 30-87 are connected; this connects the battery to the new fusebox and powers your accessories. For this install the positive side (85) was taken from the horn circuit at the stock fuse box. The ground (86) goes to the battery ground (negative).

Installation of the Bussman box

The Buss doesn't provide a 'ground' terminal on their unit. So, you can add a ground post (lower right corner) to compliment the power lead. This is not strictly necessary, but it does make the install safer and cleaner. For your accessories, you could ground them all at different locations around the bike. By putting a ground post on the Bussman you can run hot and ground leads to each device next to each other at the same time, and have them both hook to the fuse box.

Find a location on your fuse box that will be easy to access and where the bolt won't get in the way of anything. In the example here, the grounding post is in the lower right hand corner. Drill a hole in the plastic that is just large enough for the bolt to pass through. Feed the bolt through from the back side, so the head of the bolt is on the back side of the fuse box, and secure with one of the Nylok lock nuts on the front side. You want the long end of the bolt sticking out, so you can add your individual grounds later.

After you mount the fuse block to the bike, put a wire going from this post back to the negative terminal on the battery and secure it with a k-nut. You can then put all of the accessory ground leads on this post. You can put a couple of accessory leads between k-nuts, assuming the wires don't break from extreme mounting angles.

Use the Nyloks for the body attachments and the top nut on the grounding post because they hold VERY well in a harsh vibrating environment, like on a bike. The k-nuts are good for the middle of the grounding post (holding the ground leads down) because they're metal and grip well on the ring terminals.

Add additional k-nuts as needed (keeping only about 2 ground leads per k-nut) and top it all off with a nylok.

Connect the positive lead from the relay (pin 87) to the positive terminal on the Bussman (red wire).

Sealing the heat shrink connectors with a small torch, instead of the usual butane lighter.

Next comes the fun part: cutting into the wiring harness at the OEM fuse block. Consult the schematic to determine which connection to tap into. Don't use the unused 'accessories' fuse because those two connections are always hot. This also goes for the OEM accessory wires. The horn was the circuit tapped into, since it has minimal draw when not in use. The schematic showed the wire needed to tap was the lower harness brown/white wire. Double-check this by testing voltage outside the sheath, then pulling the fuse.

define sheath; yeah, I know what you mean, but I can't explain it.

>>Ryan - The sheath is the plastic coating covering the wire strands and is also known as "insulator". This would be a perfect time to introduce Posi-taps for those that may be a bit squeamish when it comes to cutting into the factory harness. http://www.posi-lock.com/posiplug.html

Ok, obviously I've never used a multimeter. Is there a way to test voltage on a wire that isn't bare?

>>Ryan - How to find a trigger wire: Using a multimeter set to a 20V scale, take one of the probes and poke it into the wire in question. You don't want to go all the way through the wire, just break through the sheathing into the wire core. Take the other probe and touch it to a ground (negative battery terminal, frame, etc.). With the key off there should be zero volts measured. Now turn the key on; there should be ~12 volts (-12V is fine). This means that wire is only getting power when the bike is on and this is what we want for this project. If this isn't the case make sure the probes are where they should be and/or try another wire.

>>Ryan - With the Bussman, all negative leads from the accessories are connected via ring terminals to the grounding post that was installed in the lower right hand corner. Two ground connections are visible in the following picture.

The final product. Two accessories are already hooked up, with the 5 and 10 amp fuses. Two more are pre-wired for future farkles.

Make sure all the connections are connected, mounting points tightened, and you're done. Our home mechanic says, "My Bussman setup cost me about $15, including the relay, wiring and end connections. I've been very happy with it. I've had no averse weather issues with its 'open' design. The two factors that have helped make that occur are its location and the use of dielectric grease."