DC-DC 12V Converter

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.

500W Sevcon DC-DC converter - top

500W Sevcon DC-DC converter - connector 500W Sevcon DC-DC converter - connector side

500W Sevcon DC-DC converter - side 500W Sevcon DC-DC converter - backplate (upside down) 500W Sevcon DC-DC converter - backplate (as installed)

SDS 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

XMX Platform Location

Below the removable battery compartment. See our FX teardown layout guide.

FST Platform Location

Inside the tank, on the right of the bin, on the board mounting plate.

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
				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