On 16/05/2026 at 12:54, AGFalco said:

Be warned, on the earth connection the silver nut is painted.

You need to make sure you connect to the cable connector inside the nut.

I learned this the hard way. ☹️

Thanks. AG Falco

I noticed the nuts are painted but the washer isn’t and thats what i fixed the crocodile clip to. Was that ok?

Not a lot of contact area there, try onto the body of the cable ferule, where the insulation meets the socket.

Is the stamped part of the L-shaped metal bracket painted? If not, use that.

Edited 17 May17 May by Warrior193
added information

1 hour ago, scoob said:

I noticed the nuts are painted but the washer isn’t and thats what i fixed the crocodile clip to. Was that ok?

Yeah fine. as long a the crocodile clip had a good firm connection throughout charging. It's not the washer its the end connector of the main earth cable from the battery to the car's body. I've done preventative charges to my wife's car's battery like that for the past 4(?) years.

That is the earth piont as shown in the car's 'Owner's Manual@ (you are reading and refering to the 'Owner's Manual' I hope, if you do then you can know more about the car than many long term owners).

In your photo I'm not sure why that bracket wasn't made into the earth connector for battery charging, when I saw your photo I thought I've never notoiced that bracket(?) before and went and had a look at my wife's car and on her car that bracket(?) is painted but that may not be correct or factory original to be painted(?).

1 hour ago, Warrior193 said:

Not a lot of contact area there, try onto the body of the cable ferule, where the insulation meets the socket.

Is the stamped part of the L-shaped metal bracket painted? If not, use that.

See my previous post. That 'book' earth connection is fine for battery chargibg, your not trying to jump start the car with it, bit fiddly yes, and why on earth a bracket connector post isn't is strange but the German engineers are supposed to know best. 😄

3 hours ago, rum4mo said:

I will drill out the thread on the Audi one and re-tap it, but I need to know the thread size on the existing dome nut first

I was thinking of a plain hole and clamping it with nut and washers if it's only for battery charging. If you want the thread size surely its standard micktrick thread and not one of the other two and a resourcefull chap like yourself has stock of micktrick nuts, bolts (probably in the three threads) and washers (I only have stocks of imperial really). I've just tried a spanner on the domenut and its 13mm spanner so accourding to my homemade table (not wood or metal) that usually means a M8 thread.

Yes I had it "in my head" that it could be M8 - maybe I had checked the "size" of the nut - but, in some cases like this, the nut is made a "useful" size for what its intended purpose is going to be and not conforming with normal sizing.

The "AF" size of the Audi jump post nut, from memory, is way bigger than you might expect just going by its internal thread size, which from memory is M6.

The other reason that I've questioned the thread size is, on the Polo/Fabia etc, this earthing post is a main car body primary earthing point - on cars that have a remote jump post, that junction is can end up just being a node for full time use as a "running supply" loads and very short time use as a jumping point, so that could explain why remote jump post terminal sizes are smaller than main car body primary earthing point terminal sizes.

Yeap nothing is certain. I'm sure you could arrange a set up where you could remove the dome nut and check its thread with a micktrick bolt/setscrew and keep supply continuity but I think it doesn't hurt and possibly helps to disconnect the supply for a while, even perhaps drasin it, to help with past, present and future computer brain-farts on the car.

In my simple mind I'd expect a lug that could be used for jump starting the car to be more substational than one only to be used for charging the battery but I'm certainly not a German engineer (gawd bless their cotton socks) and as I put I'd not be surprised if the Audi part was plastic. 😁 😄 Biased, yes I am. 😁