The advice on always grounding a connection

[jkwpajero]

Thanks all.

Forgot to add: what about rust between the connector & body? Since the site is not stainless. So if you scuff the paint back wont rust inevitable develop between the connection?

I dab of dielectic grease will look after that. I actually use battery post spray grease on all my connections to the body and it works a treat. Easy to reapply anytime.


James

[Bru9]

I found these articles useful

http://www.w8ji.com/negative_lead_to_battery.htm

http://www.w8ji.com/battery_wiring.htm

It explains why you should use ground connections instead of the negative post.
Also one can find description and photos of proper ground connections.
Here is an extract from the article:

Sharing the negative battery lead to engine bolt with anything else or connecting directly to the battery negative post with anything except the block and chassis grounds is a terrible idea. (Connecting electrical devices or hardware directly to a battery negative post is a bad idea (no matter who tells you to do it) unless the negative connection is 100% ground isolated at the electrical device.) When an electrical device is directly connected to the negative post, if the negative post to block or chassis connection opens up or develops excessive resistance, the battery negative post will divert alternator or starter current through whatever is attached to the negative post. This can be hundreds of amperes! Very few devices and wiring will suffer a fault like this without permanent damage. It is also a fire risk.

After reading this I'm unsure if my setup is safe? As that page talks about a very thick separate cable run from starter neg terminal direct to chassis for alternator.

My starter's negative wire copper size looks to be no bigger than 6 AWG max & it runs to small steel plate that is bolted/grounded to body.
Then that wire continues to run off into a thick collection of other tapped up wire I presume to engine chassis.

[sandgroper 123]

Why is this always suggested over just going to the batteries negative terminal? say with spotlights & cable runs for fridges.

All parts of the vehicle exposed body have paint & are not bare metal, so there must be some significant resistance from the layer of paint. My bonnet pressure switch did not work while touching the metal frame, only in a pre existing hole where some of the paint was not present i think.


In my bonnet the main ground site looks to be attached to a worn area with no paint. or maybe an area that is rustless steel?

maybe I'm wrong about the paint? please correct me if so.

thanks

Its a lot to do with smart alternates and shunt devices , going to terminal bypasses this system .

[Bru9]

I just decided to go with a basic 100amp rated busbar installed under bonnet and run all my negatives back to it. This busbar is for all loads ran when engine is started. The busbar itself is connected with 2ga wire to the earth bolt site between stock battery and fuse box, easy to get to. However the busbar may see up to 50+amps with all lights on along with hids. Or even using compressor alone is 40amps.

So wondering if that current can go through the bolt and thread of body easy?

Also original bolt was worn and would not screw in with 3 large lugs under it, so i just used a generic high tensile bolt. Not sure if i should tighten it up too tight?


I also went busbar as trying to find places to earth individual cables is just awful.