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Adding accessories to your ride is a “time honored” tradition - knowing how to do it properly will save you a lot of trouble in the long run.
My motorcycles are my primary form of transportation, and I ride practically year-round. As such, they have to accommodate some essential accessories that require DC power.
At minimum, all my bikes have at least four items that require DC power.
The battery gauge gives me constant verification of the state of my charging system.
The USB port is for charging my cell phone or small tablet that travels with me, especially on trips where wilderness camping is an occurrence.
A GPS is an essential piece of my gear, as I travel extensively - sometimes to remote locations - places where a mobile phone just doesn’t “cut it”.
Adding these items requires a proper distribution system for power that an auxiliary fuse block provides, while protecting the motorcycle and it's wiring from common faults and potential fire hazards.
In this post, I will explain how to properly install a fuse block of this type, and how to safely choose wiring and fuses for each application.
The first item that needs to be installed is a proper fuse block. There are a number of these out on the market, but I have found that the model FZ1 from fuzeblocks.com is among the best. The FZ1 has the advantage of having a built in relay and six available channels, any combination of which can be configured for constant or switched use. It was designed exclusively for installation on motorcycles, and as such is built more robustly than most. It has a total capacity of 30 amps, which is more than enough for most motorcycling applications.
Before you start the installation, you need to work out the location for this block. It should be accessible (in case fuses need to be replaced), but also protected from the elements. Most times there is an adequate location somewhere under the seat for this - in this tutorial I will be showing how it was installed on my 2015 Ducati Scrambler.
After deciding on a suitable location, you need to start wiring up all of your accessories. As mentioned, the FZ1 has six available channels, each with it’s own ground and output bus for connections...
Wire sizing for your accessories is an important consideration, as is the choice of fuses, Wire size should be chosen according to the individual current draw of the unit being fused. Wire length is usually also a consideration, but in a application such as this it is less likely to matter as the wire runs will almost always be short (mostly less than 8 feet or so). Most of my intended accessories draw 5 amps or less when in use, so 16 AWG wire is more than suitable.
The one exception is the “DIN” plug connection that is intended to power my heated clothing. In this case, careful consideration must be made to size everything accordingly. In the most extreme case, I will be using a pair of heated gloves (27 watts - 2.2 amps), along with a heated jacket liner (30 watts - 2.5 amps) & a pair of insoles (15 watts - 1.2 amps). The total draw for all these items is 72 watts - and almost 6 amps, so 14 AWG wire, at minimum, should be chosen for this circuit.
Run your wires to the appropriate bus on the block, making sure to tin each exposed end before insertion.
Fusing is another matter, the fuse size should exceed the total draw of the accessory, but not by too much. For the volt meter, I use a 1 amp fuse, a 3 amp fuse is correct for both the USB and GPS, and for the “DIN” socket a 10 amp fuse is appropriate.
The FZ1 has the capability of making any of the circuits “constant” (always on, regardless of the state of the bikes ignition switch) or “switched” only on when the key is actuated. This is accomplished by the position of the fuse for each circuit. Looking at the photo of the unit above, you will notice that each circuit has three “legs” for insertion of an ATM type fuse. The middle “leg” is always utilized, but depending on your choice the fuse will either be installed using the middle and left “legs” (constant) or the middle and right “leg” (switched).
After you have completed the accessory wiring, it’s time to wire the fuse block itself. The FZ1 has a total potential capacity of 30 amps, but my intention is to not exceed 20. As such 12 AWG wiring is sufficient for power connection to the battery. Run a length of wire from the negative battery terminal to the blocks input bus (labeled “GND” in the photo above). Positive connection should also be 12 AWG wire, but MUST include an additional fuse in-line (located as close to the battery terminal as possible) - the fuse size for this should not exceed 20 amps.
All that is left is to run a trigger wire for the relays switched operation. 24 AWG wire is suitable. Simply tap into an existing wire on the bike that is energized when the ignition is turned on - most will choose the wire positive side of the wire going to the tail light, but I chose the wire going to the Scramblers USB connection under the seat. You can make this connection easier by using a “posi-tap” type connector, like shown below...
That’s it, you’re all done. Now go out and ride, knowing that you will so so safely. Here are some additional photos, show the details of my latest installation on the Scrambler:
Fuse Block
Battery Gauge
Waterproof USB
“DIN” Socket
Originally posted on my personal blog, HERE.

My motorcycles are my primary form of transportation, and I ride practically year-round. As such, they have to accommodate some essential accessories that require DC power.
At minimum, all my bikes have at least four items that require DC power.
- “DIN” type power socket
- Small voltmeter / battery gauge
- USB charging port
- GPS power
The battery gauge gives me constant verification of the state of my charging system.
The USB port is for charging my cell phone or small tablet that travels with me, especially on trips where wilderness camping is an occurrence.
A GPS is an essential piece of my gear, as I travel extensively - sometimes to remote locations - places where a mobile phone just doesn’t “cut it”.
Adding these items requires a proper distribution system for power that an auxiliary fuse block provides, while protecting the motorcycle and it's wiring from common faults and potential fire hazards.
In this post, I will explain how to properly install a fuse block of this type, and how to safely choose wiring and fuses for each application.
The first item that needs to be installed is a proper fuse block. There are a number of these out on the market, but I have found that the model FZ1 from fuzeblocks.com is among the best. The FZ1 has the advantage of having a built in relay and six available channels, any combination of which can be configured for constant or switched use. It was designed exclusively for installation on motorcycles, and as such is built more robustly than most. It has a total capacity of 30 amps, which is more than enough for most motorcycling applications.
Before you start the installation, you need to work out the location for this block. It should be accessible (in case fuses need to be replaced), but also protected from the elements. Most times there is an adequate location somewhere under the seat for this - in this tutorial I will be showing how it was installed on my 2015 Ducati Scrambler.
After deciding on a suitable location, you need to start wiring up all of your accessories. As mentioned, the FZ1 has six available channels, each with it’s own ground and output bus for connections...

Wire sizing for your accessories is an important consideration, as is the choice of fuses, Wire size should be chosen according to the individual current draw of the unit being fused. Wire length is usually also a consideration, but in a application such as this it is less likely to matter as the wire runs will almost always be short (mostly less than 8 feet or so). Most of my intended accessories draw 5 amps or less when in use, so 16 AWG wire is more than suitable.
The one exception is the “DIN” plug connection that is intended to power my heated clothing. In this case, careful consideration must be made to size everything accordingly. In the most extreme case, I will be using a pair of heated gloves (27 watts - 2.2 amps), along with a heated jacket liner (30 watts - 2.5 amps) & a pair of insoles (15 watts - 1.2 amps). The total draw for all these items is 72 watts - and almost 6 amps, so 14 AWG wire, at minimum, should be chosen for this circuit.
Run your wires to the appropriate bus on the block, making sure to tin each exposed end before insertion.
Fusing is another matter, the fuse size should exceed the total draw of the accessory, but not by too much. For the volt meter, I use a 1 amp fuse, a 3 amp fuse is correct for both the USB and GPS, and for the “DIN” socket a 10 amp fuse is appropriate.
The FZ1 has the capability of making any of the circuits “constant” (always on, regardless of the state of the bikes ignition switch) or “switched” only on when the key is actuated. This is accomplished by the position of the fuse for each circuit. Looking at the photo of the unit above, you will notice that each circuit has three “legs” for insertion of an ATM type fuse. The middle “leg” is always utilized, but depending on your choice the fuse will either be installed using the middle and left “legs” (constant) or the middle and right “leg” (switched).
After you have completed the accessory wiring, it’s time to wire the fuse block itself. The FZ1 has a total potential capacity of 30 amps, but my intention is to not exceed 20. As such 12 AWG wiring is sufficient for power connection to the battery. Run a length of wire from the negative battery terminal to the blocks input bus (labeled “GND” in the photo above). Positive connection should also be 12 AWG wire, but MUST include an additional fuse in-line (located as close to the battery terminal as possible) - the fuse size for this should not exceed 20 amps.
All that is left is to run a trigger wire for the relays switched operation. 24 AWG wire is suitable. Simply tap into an existing wire on the bike that is energized when the ignition is turned on - most will choose the wire positive side of the wire going to the tail light, but I chose the wire going to the Scramblers USB connection under the seat. You can make this connection easier by using a “posi-tap” type connector, like shown below...

That’s it, you’re all done. Now go out and ride, knowing that you will so so safely. Here are some additional photos, show the details of my latest installation on the Scrambler:
Fuse Block

Battery Gauge

Waterproof USB

“DIN” Socket

Originally posted on my personal blog, HERE.