DC-DC 12V Converter

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The DC-DC 12V converter is a solid state switching power DC step-down converter designed to produce low voltage DC power from the pack voltage.

The converters mentioned here are used on Gen2 and Gen3 models.
DC-DC Converters
Years Platform Manufacturer Model Replacement Options
2013-2014 S and X Sevcon Sevcon DC-DC 300W converter OEM or via Thunderstruck Motors
  • NOTE: Select the 300W model! connector hardware is an extra
2015+ Sevcon DC-DC 500W converter OEM or via Thunderstruck Motors
  • NOTE: Select the 500W model! connector hardware is an extra
Appearance
It's about the size of a long box of soap with a black surface, but for 2013-2014 models will be covered entirely with Nashua aluminum ducting tape, so will appear silver.
File:DC-DC Sevcon 500W Converter - 1.png
500W Sevcon DC-DC converter - top
File:DC-DC Sevcon 500W Converter - 2.png
500W Sevcon DC-DC converter - connector
File:DC-DC Sevcon 500W Converter - 3.png
500W Sevcon DC-DC converter - connector side
File:DC-DC Sevcon 500W Converter - 4.png
500W Sevcon DC-DC converter - side
File:DC-DC Sevcon 500W Converter - 5.png
500W Sevcon DC-DC converter - backplate (upside down)
File:DC-DC Sevcon 500W Converter - 6.png
500W Sevcon DC-DC converter - backplate (as installed)
S-Platform Location
Below the front of the seat under cable runs, between the MBB (separated by a bracket) and the back of the battery frame area.
Quick and dirty illustrative video of how to find and access the converter
X-Platform Location
Below the removable battery compartment. See our FX teardown layout guide.
Protections
  • Ingress: IP67
  • Short circuit overload
  • Reverse polarity
  • Fully isolated
  • Can parallel with diode safeguard
Mounting
The Sevcon 500W DC-DC converter is mounted to its own baseplate via 4 Torx T10 cap head screws and there are 3 additional Torx T15 cap head screws in the middle.
The Sevcon baseplate is then bolted to Zero's board mounting plate with 4 10mm hex head bolts which have 6mm outer diameter, 16mm length, and 1mm pitch.
Removal
  1. Remove the board mounting plate.
  2. Remove the converter from the board using a 10mm hex socket wrench.
  3. Disconnect the connector if appropriate.
Installation
  1. Attach the converter to the board mounting plate with a 10mm hex socket wrench.
  2. Install the board mounting plate with the converter back into the bike.
Connections
There is a 5-pin connector controlling the converter, facing the left as installed on the bike, connected as follows:
Pin Function Measurement Component Years Wire MBB Pin Illustration
1 Enable signal Battery voltage when key is on MBB 2013 Orange (Red) 18AWG 21 400px
2015 20
2 Input (Positive) 116V Battery 2013 Orange (Blue) 16AWG 7
3 Input (Negative) 2013 Orange (Black) 20AWG 5
4 Output (Positive) 13.5V Fuse Block 2013 Blue (16AWG, 14AWG) wires
5 Output (Negative/Ground) 12V return conduits 2013 Black 10AWG
Output
It is configured to output 13.5V DC; usually produces ~13.8V DC.
There is very little ripple that is typical of a gas-power motorcycle's alternator-driven DC supply.
Capacity is 300W (20-25A) for pre-2015 bikes and 500W (35-40A) for 2015+ models, with most of that excess needed to run ABS pumps, etc.
Operation
The input side is always-on DC from the battery, upstream of the contactor.
This is the best place to tap for an always-on power supply.
The converter is enabled by a 12V signal from the MBB.
Environmental Vulnerability
  • The Sevcon DC-DC converter is rated to IP67 for intrusion protection and seems very robust as such.
  • However, the connector is not sealed, faces the left side of the inside of the frame arms with not much splash protection from beneath; on 2015+ models, it is also vulnerable to debris and splash impact from the rear near the motor and belt.
  • No sealed connector option is currently available for Sevcon's DC-DC converter models that Zero uses.
  • Connector looseness could age and wear the converter prematurely due to sporadic voltage input or output changes.
  • Leakage across pins could cause the enable signal to activate inadvertently.
Connector Inspection
Try to inspect the pins' tabs to ensure they are in the right shape to clamp that enable pin securely.
The connector is not well-sealed, and the pins are too easy to bend into not-connecting if there's any tension/tugging on the wires.
If the connector seems grimy, remove and clean it while de-energized; then apply grease once dry before re-seating it.
Test the connector before fully re-assembling the bike.
Failure to De-energize Condition
The converter can fail in a way where it shorts its enable line and will not turn off even if the bike is keyed off.
  • If this condition happens in rain:
    1. Let the bike dry out until it clears.
    2. Attempt a dielectric grease application to the inputs while de-energized.
If the DC system output disappears:
  • Check DC voltage upstream of the fuse block in case the fuse block is faulty.
  • Check the continuity and snugness of the connectors and pins.
  • Check for the enable signal from the MBB
    Continuity: < 1Ω between pins.
    Not shorted to B+?: > 151kΩ from pin 20 to pin 7.
    Not shorted to ground?: > 1MΩ from pin 20 to 18.
Protection Recommendations
  • Splash protection around the left-side's connector from all sides is worth considering.
References
Re: My DC-DC converter has died again, local dealer has gone bust
Re: A puddle, some rain and some problems