# Battery Voltage Measurement

**URL:** <https://community.ecumaster.com/t/battery-voltage-measurement/4303>\
**Category:** EMU BLACK / CLASSIC\
**Created:** [August 25, 2025, 12:29am UTC](https://community.ecumaster.com/t/battery-voltage-measurement/4303 "2025-08-25T00:29:10Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![AbZeX](https://avatars.discourse-cdn.com/v4/letter/a/ecb155/32.png) [@AbZeX](https://community.ecumaster.com/u/AbZeX)\
**Post date:** [August 25, 2025, 12:29am UTC](https://community.ecumaster.com/t/battery-voltage-measurement/4303/1 "2025-08-25T00:29:11Z")

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Hello!

Could you please to answer where (which input pin) the EMU Black measures the Battery Voltage?

It looks like from B13, but this is not noticed anywhere.

P.S. Trying to create a new engine harness, and it seems there should be a wire with Constant Battery Voltage, where the B13 should be connected, then after, from this point should be a relay switched by Ingition Switch Key, and from this relay should be supplied coils and injectors.

Stock Toyota JZ harnesses have another type of scheme, separate BATT line, and Separate Coils and Injectors line “across the seven seas” (by Ign Switch) power supply. There is a difference between these lines in voltage.

Thank you.

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**Author:** ![Greg](https://avatars.discourse-cdn.com/v4/letter/g/71c47a/32.png) [@Greg](https://community.ecumaster.com/u/Greg)\
**Post date:** [August 25, 2025, 6:34am UTC](https://community.ecumaster.com/t/battery-voltage-measurement/4303/2 "2025-08-25T06:34:40Z")

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Ignition 12v that the voltage you see as battery voltage