Electrical 101

Electrical Knowledge 101 

Additional Resources

What is a DC electrical system?

  • Direct current (DC) is the unidirectional flow of electric charge.
  • Most common electrical system found on motorcycles.
  • Think of a DC electrical circuit as a loop that the electrical current flows around like water in a “lazy river” beginning and ending at the battery.

Voltage, Amperage, and Resistance

  • For this discussion. Think of voltage and amperage as water. Voltage is the speed of flow.
  • Amperage is the volume of flow.
  • Resistance is how we measure if there is something preventing flow.

Circuit components and what they do:

  • Wire – Transports electrical current. The greater the current, larger the wire needs to be.
  • Connectors – Allows connecting of wires to devices, components, or other wires.
  • Fuses – The sacrificial “weak link” in an electrical circuit
  • Switches – The “faucet” of an electrical circuit.  Stops and starts and stops the flow of electrical current.
  • Relays – A switch for one electrical circuit that is controlled by another.
  • Diodes – A device that only lets electric current flow one way.
  • LED (Light Emitting Diode) Electric will only flow one way through it and when it does, light is produced.
  • Resistors – a device that decreases voltage by creating resistance.


  • Every electrical device we sell has at least a couple of these components in them and sometimes we need to explain what they do or troubleshoot a problem.

Examples of simple electrical circuits we sell

  • “Canbus” adapter
    • Wire, connectors, and a diode
  • Power hub
    • Wire, connectors, fuses, and a relay
  • Soundbomb horns/wiring kits
    • Wire, connectors, a fuse, and a relay
  • Denali single intensity light kits
    • Wire, connectors, a fuse, a switch, a relay, some LEDs
  • Some Coocase and some GIVI Baseplates
    • Wire, connectors, a fuse, a resistor, and a couple diodes. 

Think of electricity as water flowing in pipes. It makes it easier.

What's a relay?

A relay is a high current switch. Applying a low current to the "trigger" (pin 86) of a relay opens the "valve" providing a high amount of current out of the output (pin 87). Approximately <0.5 milliamp at >5 volt will trigger a typical 12 volt relay.

What's a diode?

A diode is a one way valve allowing electrical current to flow in one direction, but not in the reverse direction. Diodes are tiny (usually less than 3mm dia. x 5mm long).The line on a diode is on the allowed "exit" side of the diode.

What's an LED?

LED stands for "Light Emitting Diode". Like a normal diode, it's a one way valve allowing electrical current to flow in one direction, but not in the reverse direction. When the current flows in the allowed direction, the LED emits light.

What's a capacitor?

A capacitor is a device that accumulates and holds a charge of electricity, then lets it out at a steady or smoother rate. Adding a capacitor to an input wire with current fluctuations (like pulse width modulation) smooths out the voltage and current on the output side of the capacitor. We are working on a universal capacitor/diode kit. Capacitors are tiny and fragile (usually less than a few mm long)

CAPACITORS ARE LIKE A FAUCET AND A HOLEYBUCKET If your input wire is pulse width modulated (like a faucet turning on and off), a capacitor makes your output constant voltage and current (like the water flow out of the hole in the bucket). The bucket (capacitor) does this by storing up water (electrons) and releasing it at a constant rate. Capacitors provide even flow, just like a battery or Eddie Vedder.

What's Pulse Width Modulation?

Click here to see a video explaining Pulse Width Modulation (watch the first minute, then skip to 2:25 and watch the rest)Basically, PWM switches a wire on/off from on (+12 volt) to off (no voltage) for a certain fraction of a second in a high speed cycle (600+ switches per second). For example, the 10% diagram above shows that the power is turned 100% on 10% of the time. Basically, PWM is a fancy efficient dimmer that doesn’t waste electricity.

CANBUS Background

What is CANBUS?

Simply put, a way to run multiple functions on and/or monitor a circuit. No, it's not marijuana.

How does CANBUS run multiple functions?

They can vary voltage or use Pulse Width Modulation (PWM).  PWM is where the computer switches the circuit on and off at a rapid rate; like 600 times a second.  Switching 12 volts on and off at that rate will give you the equivalent of 6 volts if you were to use a voltmeter.  Why do it this way?  Restricting 12 volts to a lower voltage is usually done using resistor, and that wastes electrical power by creating heat.  Using PWM does not.  The faster they switch the power on and off, the ‘higher’ the effective voltage would be.  Keep in mind they are switching voltage on and off so it really is still 12 volts at the end of day.  You need an oscilloscope to determine at what rate the power is being switched on and off.  A relay is fast to react and can be heard clicking as the power is switched.

An incandescent bulb as an example.

An incandescent bulb is slow to react as the filament needs to heat up and create the glow.  Keep in mind that the switching of power on and off isn’t visible to the human eye.  Therefore, using a 600 cycle (per second) switching on a tail light bulb will cause it to glow at a running light intensity.  Increasing the switching time will make it brighter, and decreasing it will make it dimmer.  Again, all done without creating heat.

How does CANBUS monitor a circuit?

The computer knows that a tail light bulb should only use a certain amount of power.  If the circuit sees that too much power (or not enough as it the bulb is bad), it will in most cases create an indicator in the dash panel telling the rider the bulb is out.  If it is too much load, the Canbus circuit will give a fault indicator, shut that circuit down,  put the bike into ‘limp mode’ where travel speeds can be reduced, or even prevent the bike from starting.  This is where adding additional loads becomes an issue.

What causes a CANBUS error?

  • More current load on a circuit than the bike is expecting
    • This can be prevented by only adding relay trigger wires to the original BMW wiring harness.
  • Current backflow through an unintended ground
    • This can be prevented by placing a diode in every wire you connect to the original BMW wiring harness.

Relays in the trigger circuits of our products (Denali, Powerhub, etc.) have built-in diodes to prevent backflow.

How do you resolve too much load?

Adding a relay is usually the easiest way.  The amount of power the relay needs to trigger and turn on isn’t going to cause any issues in the Canbus system.

What is the minimum I need to know to help customers install our products?

What's a safe "keyed on" trigger wire in CANBUS and non-CANBUS bikes for Denali or Powerhub installations?

"Keyed on" sources are used for Powerhub and Denali low beam or single intensity (triggered by bike on) applications.

  • Low beam power wire (not good on most bikes: may have CANBUS signals, may also turn off when high beam is turned on
  • Front running lights (they often turn off when turn signals are activated)
  • Running light power wire (good on non-CANBUS bikes, usually causes a fault if used on CANBUS bikes to trigger a relay. CANBUS effective voltage is often about 6 volt (PWM 50% of 12 volt, which may not trigger a relay)
  • OEM GPS wire (good on all bikes, may stay on 30 seconds after bike is turned off)
  • OEM power socket wire (good on all bikes, may stay on 30 seconds after bike is turned off)
  • 194 bulb adapter (very limited applications - see app chart)

Denali and Powerhub trigger wires have a diode built into the relay to prevent CANBUS errors due to current back-flow. No additional diode is necessary.

For BMW customers that do not want to tap the OEM GPS wires, plug-and-play GPS dongles are available from BMW for about $20 - $25:

  • Two BMW part numbers seem to be in use for the OEM GPS dongle; check with a dealer to see which item fits which bike:
    • 83300413585
    • 83300413586
  • Applications of these two parts are being researched now
  • Dongles have three output cables:
    • Brown = ground
    • Blue/Green = speed pulse (do not use this wire)
    • Red/White = switched 12-volt

Tips for installing Admore light bar and luggage lighting products

The red "power" wire on the Admore controller is the only one that draws significant current. The other wires are simply "trigger" wires and do not normally cause a CANBUS fault.

  • On all BMW bikes EXCEPT the BMW R1200GS Adventure LC and newer 1250's:
    • Connect the red "power" wire of the Admore controller direct to battery, OEM GPS wire, OEM power socket wire, a 194 bulb CANBUS adapter, or a switched power distribution block. DO NOT connect the red "power" wire of the Admore controller to the running light, as this would typically cause a CANBUS error.
    • Connect the blue "running light" trigger of the Admore controller to a switched 12-volt source (this can be all of the above wires EXCEPT direct to battery)
    • Connect turn signal and brake trigger wires normally.
  • On the BMW R1200GS Adventure LC:
    • LED headlights and turn signals have replaced the normal halogen system
    • Admore kits cannot be installed as tapping the LED signal wires causes a CANBUS fault, regardless of where the red power wire is connected.

Tips for installing Gerbing brand and other heated clothing products

  • Install sockets and hookups as constant on, direct to battery or a power distribution block. No special CANBUS treatment is needed.
  • If connecting your Gerbing clothing to an OEM "Euro" socket, remember that pretty much only gloves can be attached to the 5-amp OEM socket without exceeding the CANBUS socket limitation and causing a fault. If you're going to connect a jacket, or jacket and gloves, or vest and gloves, or most other multi-garment combinations with the OEM power socket, you'll need to bypass the original CANBUS wiring and wire the socket direct to battery or a power distribution block.

Tips for installing heated grips

  • Connect the power wires to a switched power distribution block or the OEM "Euro" socket power wires. No 194 adapter or relay required

What's that funny 194 bulb CANBUS adapter?

  • It's a pass-through for power being sent to the small 194 marker bulb on some BMW bikes
  • It provides a switched, dioded output to trigger a relay, usually on running lights or a power distribution block
  • It only fits bikes with a 194 marker bulb. No 194 bulb? Can't use this part.
  • Some bikes with a 194 marker bulb have a narrow tube that runs into the headlight to connect to the bulb. This tube form factor prevents the 194 adapter from being used, even if a 194 marker bulb is present.
  • Even if you can't use the 194 bulb adapter, there are plenty of other ways to provide a switched source as noted above.
  • There is not a single BMW bike you NEED to buy this for, but the device can sometimes make installation easier than finding and directly tapping a switched source elsewhere.
  • See example photos of 194 applications and parts.
  • Max load maybe 2 amp, but it's vehicle dependent.
  • If no output from trigger wire, flip adapter 180 degrees.

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