Motec M150 ecu hold power strategy

Does anyone know how the ecu hold power works on M1 platform? If the batery ( +) inputs to ecu are driven through a ecu hold power controlled relay, how does the ecu recive power?

How is the baterry backup pin connected? Is it actually used on M1? Should this be a switched battery (+) through another relay or ignition switch?

The info is quite vague in help file

Thank you

Its pretty straight forward and if done incorrectly will yield in loss of inputted data at every key cycle and all kinds of other weird shit.

ecu receives permanent power from the battery. ecu sees key switch as a input as well. ecu triggers your wired main relay which is independently powered by the battery. the main relay powers the ecu and this is what is actually drawing the power from and relying on for all operations.

Its actually how just about every automotive ecu works.

I don't think the response is applicable to the M1 series ECUs. From my research the M1 Battery Backup pin is not yet used in most firmware and the ECU does not use volatile memory.

Wanted to share my research in case others are looking for information specific to the M1 ECUs.

Additional consideration for those potentially running a John Reed Racing firmware package... he has a video using one of the CAN keypads that recommends wiring the battery backup in order to have the ECU retain the button's last value (button has a flash backed configuration).

I am fairly new to building harness for an M150

can someone share a schematic or a link to this info?

I have 12 volt from batt supplied via electronic master disconnect with momentary on and off inputs.

I also have the original ECU Ign switched power supply

Recomendations please?

Race car or street car application? In wiring for a race car, typically the ECU will be on with the master switch (controlled through a PDM or straight to your electronic master switch. You would only use a power-hold relay if the ECU is powered only when the ignition is on, and you need to keep it powered after the ignition is switched off (say to run fans or water pumps).

For a race car, I wire the ECU power to the coils, and use ignition power as an input so I can use it as a driver switch for the "Engine Run/Stop" function.

If you are building a harness for the M150, I suggest you first configure the package in M1 Tune, then use the Help->Firmware wiring window as your starting point for wiring documentation.

The power is the least trickiest thing about wiring a Motec M1. The most tricky is to use the proper 0V pins for the Analog Temperature inputs (see the help), and use matching 5V/0V supplies for other sensors. It's helps to have matching colors (like Orange + Brown for 5VA + 0VA and Orange/White + Brown/White for 5VB + 0VB, etc).