Difference between revisions of "12V Power Always On"

Latest revision as of 05:52, 19 February 2020

When the entire 12V circuit stays, despite keying the bike off and disconnecting charging sources.

This may be continuous or intermittent.

Related Confirming Symptoms

With the ignition is keyed off, the key removed, and the bike unplugged from charging sources:

• Headlamp and running/brake light are both on.
• Dash/instrument cluster backlight is on but the bike does not operate.

Potential Causes

• Ignition Switch is faulty.
• DC-DC 12V Converter is faulty.
• MBB is faulty, sending an enable signal to the DC-DC converter.

Risks

This will slowly drain the battery.

A continuous use of the headlamp might drain the battery in a week's time or less.

Time to discharge (hours) = SoC (%) / 100 × capacity (kWh) × 1000 / 55W.

If the condition is a result of a short circuit around the DC-DC 12V Converter, it may over-discharge the MBB, causing failure of that critical component.

So try to diagnose and solve this problem as soon as possible!

Troubleshooting

1. With the bike keyed off, check the voltage across the Ignition Switch, or check if the MBB is on and whether it reports in the console that the ignition switch is shut.
2. With the bike keyed off and unplugged, access the DC-DC 12V Converter connector with a voltmeter that has needle probes.

   On the SDS Platform, you'll need to remove the board mounting plate.

3. Verify the battery State of Charge via input/bus voltage:

   Check voltage present between (+) pin 2 and (-) pin 3.

   This should be between 95V and 116.2V, and roughly indicates State of Charge.

4. Test whether the MBB is sending the enable signal:

   Check voltage between (+) pin 1 and (-) pin 3.

   If this is zero, then the DC-DC 12V Converter is faulty independent of the MBB.

   If this is not zero, then the MBB is enabling the DC-DC 12V Converter, and is faulty.

5. Confirm output from the DC-DC 12V Converter:

   Check 12-14V present between (+) pin 4 and (-) pin 5.

6. Test whether the DC-DC 12V Converter responds to the enable signal:

   Connect pin 1 directly to pin 2 using a piece of cable.

   Connect power to (+) pin 2 and (-) pin 3.

   This should transmit high voltage to the enable input at pin 1, and should make the DC-DC 12V Converter work if it is functional.

If the DC-DC 12V Converter is faulty with the MBB okay, then the bike should run normally, but with a Loss of 12V Power.