Battery Earth location

[Catmint10]

Hi all

I've had a search through the forum, and can't find an answer for this one!
I'm having starting issues at the moment, and thought it may be due to having the incorrect alternator on my van (bought a replacement one)...but now I've been told it could be an earthing issue.

I've had a look at where the earth lead goes from my battery, and it is mounted to the big metal thing (technical term!) that holds the alertnator in place. Not sure, but I don't think is the best place for it to earth to. Shouldn't it be attached to some bodywork?

Any advice anyone?

Cheers

Jon

[Oldiebut goodie]

https://club8090.co.uk/wiki/Al ... ing_Earths

[Catmint10]

Thanks, good information point!

Given my expertise in this area, it looks like an auto-electrician job.
The van is actually up for grabs if anyone can be arsed with it cos it's a bit of an electrical wreck!

[California Dreamin]

And I will say this again....you can add earths, you can double up on earths, you don't necessarily have to remove an old corroded earth lead as this will often result in a stripped or snapped bolt.
What you will find is the bad earth is still working in most cases but is offering a resistance because of corrosion. A new earth along side the existing cable (not necessarily in the same place) will be better for leaving the old cable in place,
Always choose flexible multistranded braided cables for the engine/gearbox and fix them at a point where they move the least..

Martin

[ghost123uk]

And you can check if it is a bad earth problem by temporarily connecting a (decent quality !) jump lead from the negative terminal of the battery to a solid bit of metal (on the engine is best, like the alternator bracket, but take care the wire and crock clip are clear of the fan belt ) An improvement in cranking speed would then indicate a poor earth from the battery.

[Catmint10]

Thanks all ...I will try the doubling-up of the earth I think, and see if that makes a difference!

Hey ho...wish me luck (I am such a novice!)

[billy739]

just stick a jump lead from the battery to the engine for a temorary measure

some times with a voltmeter across the battery and engine running connecting / disconnecting the extra lead will show a change in voltage if you have a really bad earth or supply line, as remember it could be a poor feed as much as poor earth!

[California Dreamin]

All good ^^^^^^
To emphasize.....
A headlamp bulb is usually about 60 watts which is approximately 5 amps the wire feeding such a circuit is going to be around 2mm2 fairly heavy for an automotive wire....

On the other hand: A starter motor on a diesel engine cranking from cold: normally draws between 165 and 196 amps...nearly 40 times the current of the bulb

The wire...as expected, is very thick indeed but more importantly, the connections and termination of the wires (how they are crimped and held in place) has to be 100% electrically sound..no loose wires, untightened battery clamps, poorly crimped terminal ends or oxidized braided earth leads/wire termination ends.

Even when a connection looks good, this amount of current needs perfect contact for current to flow without resistance.

Martin

[PaulG]

What Martin says! I have spent all Summer finding a duff connection (that I didn't know I was looking for!) which resulted in a 2 or 2.5mm squared wire measuring 2.5 million ohms resistance instead of 0 ohms resistance! I found out the hard way that current does not flow well though high resistances!

PaulG

[Oldiebut goodie]

So many people seem to look at the connection and see no external corrosion and say that it is OK. Time and time again advice is given to remove ALL connections and clean them up but they only do half the job and wonder why they still have the problem!

[Catmint10]

Thanks everyone....been on holiday but have now fixed it! I took the advice and cleaned up all the battery connections, positive and negative, and wire-brushed and greased the earth points...it now starts straight away! Didn't realise such a small thing as oily crud would prevent it from starting.
Thanks all, I can drive it again!!