Hello,

I am wondering if someone can inform me. My alternator is currently not charging at all. I have a dedicated ground off the housing of my alternator to the battery and I also recently powder coated my accessory brackets.
Does the alternator need to be grounded to the engine block for the voltage regulator to work properly or is the dedicated battery ground sufficient for the alternator to function properly.
I've tried a new alternator and the same issue, not charging. My plan is to add more grounds from the alternator housing to the block and then the block to the firewall.
I'm guessing it needs to be grounded to the block as well. but just wanted to confirm if that's my issue.
Thanks for the advice.

 

Yes.

Think of your car's electrical system including the wiring as being like a series of pipes and fittings. Compare to, say, the water coming into your house. Where are the pipes the largest? They're where the flow is greatest, no? The single biggest pipe is where the water comes into the house, and then as it gets distributed to faucets and whatnot, the pipes get smaller, no? Well, electricity works EXACTLY the same way. All of the wiring, or other forms of connections, which are essentially the "pipes" and "fittings" for the electricity, MUST BE the largest wherever the current is the largest. So let's think some more:

Hmmmm... what are the various currents that can flow here and there in the system, and how large are they? Let's list them, more or less in order of magnitude.
.

• Starter motor: 300-500 amps
• Alt output: In reality this includes NOT ONLY charging the batt BUTT ALSO providing power to run the car (lights, ignition, accessories, etc.) - so let's say 100-150 amps; basically, whatever the alt can put out
• Headlights: 15 - 20 amps
• Radio:
• Tail lights:
• etc. on down from there

OK: WHERE DO THE CONNECTIONS NEED TO BE THE LARGEST? That's the key to sizing the wires and making the connections.

#1: Battery cables. These are the largest wires in the car, as we all know, because the starter draws the single largest amount of current in the whole car, BY FAR. They should go STRAIGHT from the battery to the starter. Subject to, the starter is a big chunk of metal that's FAR more conductive than any little skinny cable, even a "battery" one, and the block is even more so. Kind of like, connecting a 1" pipe by using an adapter up to 4" and then connecting THAT. Therefore, those big chunks of metal are ENTIRELY suitable as the conductors for this MASSIVE current. Therefore the positive batt cable should go from the batt to the starter, and the negative one should go from the batt to the block. NOT to the chassis, since that's a detour off of the path between batt and starter. Usually, to make it as short as possible while getting to those even better conductors with as little resistance as possible, it's actually very short, and goes to an accessory bracket, which ALSO is generally a MUCH better conductor than any little skinny wire. If so, the brackets involved need to make VERY GOOD electrical contact with the block, and the cable end to the bracket it goes to, and any junctions between brackets as they stack up in their installation. GET RID OF anything that can interrupt PERFECT electrical connections among ALL of those pieces of metal. That means paint, rust, dirt, corrosion or ... powder coating. GONE. Clean bare shiny metal EVERYWHERE that they touch.

#2: Charging circuit. The alt, much like the starter, is grounded to its bracket(s) which are grounded to the block, and that connection is VASTLY superior to some skinny little cable. Again subject to, ALL connections wherein the alt case touches brackets, and those brackets touch each other or the block, MUST BE free of anything that gets between the pieces of metal ANYWHERE. That means paint, rust, dirt, corrosion or ... powder coating. GONE. Clean bare shiny metal EVERYWHERE that they touch.

#3: The WHOLE REST of the car. All of this draws less power than either #1 or #2. Therefore its connection, while certainly important, isn't necessarily as large as the 1st 2. The positive side is covered by the Big Red Wires that connect to the batt terminal on the starter via their fusible links. The negative (ground) side is provided by the chassis, which then must connect to the neg terminal of the batt somehow. Usually the chassis connects to the engine somehow somewhere, and then from that point, the current that has gone through stuff within the car can flow through the block and all that, to get to the neg batt cable, and onwards to the batt; all of which path is MASSIVELY more conductive than any wire of equal length could be. The factory makes this connection with a piece of braid between the engine and the firewall. However it can be accomplished equally well by a suitably sized piece of wire between the engine and some other place on the chassis, for example a short piece of batt cable type wire between a motor mount bolt going into the block, to a nearby point on the "frame". The factory did it the particular way they did because in addition to being adequate and proper, it was convenient TO THEM. It's not the absolute only way butt if you don't understand why and how they did it and what it's doing, best to just retain it as-is.

Don't bother with "adding grounds". Wrong answer. Take out and get rid of whatever of that sort of GARBAGE you've added and add no more. Instead of further hacking, fix what you effffed up with the powder coating. Make sure that you clean off ANYTHING that gets between those electrically critical pieces of metal (block, brackets, alt, starter, batt cable ends, etc.). That means paint, rust, dirt, corrosion, or ... powder coating. GONE. Get rid of whatever "grounds" you think you "added". Just do it right and it'll work right. Wouldn't hurt to put a thin schmear of dielectric grease on all your freshly cleaned scraped sanded bare shiny metal spots, to keep them from corroding as time goes on.