Disco 4 - Wiring extras to the battery terminals.

[bobnsue]

I have a disco 4, which has a rear Anderson Plug, Rear mounted Thumper Back-up Battery System, Extra cigarette ports in the cab, twelve pin trailer plug, rear caravan camera. all these are powered through the cranking battery, positive to positive and negative to negative terminals. My car has been slow to turn over and an analysis shows the cranking battery only operating at 78% efficiency. The dealer mechanic advises that this is because all those extras are connected to the negative on the battery. He says they should all be connected to the positive terminal, but that the negative side should be earthed to the body not connected to the negative battery terminal. I am struggling to understand this, can anyone help?[bigsad]

[Tombie]

Your vehicle is equipped with an Intelligent Charging system. The negative lead has a sensor circuit to detect system loads and the charging system reacts appropriately.

By connecting to the negative terminal you are bypassing this sensor and the system can not understand the loads imposed upon it correctly.

[Tombie]

Same as the days of just jump starting or
Even just disconnecting the battery are gone!
You need to RT(F)M [emoji41] - don't just assume anymore.

[DiscoJeffster]

Tombie is spot on. There are numerous earth points on the body you can make use of.

[duderduderini]

Your vehicle is equipped with an Intelligent Charging system. The negative lead has a sensor circuit to detect system loads and the charging system reacts appropriately.

By connecting to the negative terminal you are bypassing this sensor and the system can not understand the loads imposed upon it correctly.
Hey
so if you earth to the body instead, the negative terminal sensor figures the load?
I am not challenging this Tomie, I just dont get it.
I am thinking of adding some power take offs in vehicle and was considering taking it off the positive of the battery but want to clarify if this is in fact kosher
Thanks
Nick

[Tombie]

Take power from Positive.
Connect Negative to the earth points around the vehicle.

Just the same as a Multimeter can not test current - you need a shunt - the vehicle essentially uses a Smart Shunt to measure current draw..

[AndrewM]

Take power from Positive.
Connect Negative to the earth points around the vehicle.

Just the same as a Multimeter can not test current - you need a shunt - the vehicle essentially uses a Smart Shunt to measure current draw..

Hi Tombie,

What about earthing heavy loads like a winch? Can the various earth points handle several hundred amps?

Andrew

[Tombie]

Yes they can.
My winch earths to the post in front of the battery box as per LR install manual.

[BMKal]

If you need additional and larger earth posts, Tim (Traxide) offers a stainless steel earth plate / posts which bolt to the OEM earth points on the left inner guard.[wink11]

[bobnsue]

Thanks Tombie. I understand now. Obviously a few workshops around here need to have a lesson as well.
Further question though. If I want to put a trickle charger on the battery while it is sitting in the drive for several months, do I connect it to both the battery terminals.

[drivesafe]

If I want to put a trickle charger on the battery while it is sitting in the drive for several months, do I connect it to both the battery terminals.
No.


Battery Charger Positive ( + ) to the cranking battery’s positive ( + ) terminal.


Battery Charger Negative ( - ) to a ground point, such as the two Earth Studs Tombie posted about.


https://www.aulro.com/afvb/images/imported/2017/05/26.jpg