Extending earth on battery

An often-overlooked part of the electrical system on the Jimny is that it uses a smart alternator, and it senses the current draw on the battery via a clamp on the negative terminal of the battery. The problem comes in wanting to expand the earth connection, especially with items like winches that require larger negative cables back to the battery directly.

There’s a relatively straightforward way to expand this involving a small bar of copper, and an M8 tap to make it a bit nicer.

The standard strap through the current sensor is a little smaller than 20mm wide.

You need to have a strap ~65mm long to accommodate bolting the factory earth lead and others to it and still have room for the sensor.

No need for a heap of precision here; I just roughly marked out a ~19mm wide selection on some 65mm wide copper bar I obtained. I also marked the centre to make it easier to drill the two holes needed.

The holes you need is an 8.5mm hole at one end for the factory stud, and then a 6.8mm hole at the other end. This 6.8mm hole lets you tap it out to M8 with a standard tap, making it easier to bolt cables to it.

You then undo the 12mm nut to take the terminal apart. The factory earth strap slides out backwards through the current sensor once you’ve released it from the stud on the factory terminal.

The copper bar then goes between the stud on the factory battery terminal and then through the sensor. The M8 hole at the other end is where you attach all of the earth cables like the factory one or one to your winch.

Bolt everything back together and job’s a goodun. You’ll now have the ability to have expanded earth cables or direct connection to the negative on the battery for your winch while maintaining the ECU’s ability to see the current draw to adjust the alternator.