Winch earth strap

[jimc]

Was thinking about this at lunch time today. If the D3 has large earth studs on each side of the car, why not connect a winch earth strap to the more accessable one in dual battery compartment?.

Surely earth is earth. Is there a difference?

Sorry if this seems like an ignorant electrical question?

[Geedublya]

Closest to the battery is best for high current draws.

[winaje]

I bought one of these plates

https://www.aulro.com/afvb/images/imported/2015/08/184.jpg

http://www.aulro.com/afvb/d3-d4-rrs/209715-wire-winch.html#post2264506

from Drivesafe for $10 and added a second M8 earth bolt and nut to it, will be earthing the winch to it.

[Lotz-A-Landies]

Personally I would be taking the winch negative cable directly to the battery terminal.

There are resistance losses and potential failure points every time you add an electrical terminal and a winch has a high current draw.

[winaje]

Personally I would be taking the winch negative cable directly to the battery terminal.

There are resistance losses and potential failure points every time you add an electrical terminal and a winch has a high current draw.
From what I have read, and a lot of others have said, connecting an earth, especially a high current one from a winch, to the negative terminal directly, will cause the battery management system of the vehicles to sense voltage incorrectly. Unsure of the finer details, but the consensus is don't connect anything directly to negative on main battery.

[disco4now]

If you have something like this on your negative battery terminal this is the battery monitoring system.



https://www.aulro.com/afvb/images/imported/2014/12/580.jpg


This shows wiring for both Diesel V6 2.7L and 3.0L. You can see that the DV6 3.0L circuit has the BMS in series with the -ve battery terminal.
If you connect earth for other stuff directly to battery negative you are bypassing the BMS which wont now to see all the current flowing.
The wiring diagrams (for 2010 anyway) seem to indicate BMS on the D4 diesel 3.0L but not on the diesel 2.7L


https://www.aulro.com/afvb/images/imported/2014/12/581.jpg

Regards
Gerry

[drivesafe]

Hi Garry and spot on the money. The D4 2.7L has similar wiring to the D3 setup.

I have only just recently heard of damage being caused when someone connected to the negative terminal of a D4, needing a jump start.

In the first place, you should never connect to the negative terminal of the disabled vehicle, and not just Land Rovers, but any disabled vehicle.

But it would appear that this can cause damage to the BMS in Land Rovers.