A note on charging issues posted a lot

[RJRENTON]

What they are getting at is the block for instance is better to ground to than running a wire to the battery. You’ve got a battery cable to the block, then the block itself, then maybe six inches of wire, which is better than say a 14 wire running for five feet.

For the conspiracy minded, you can find this idea in wiring up an amp. They want a ground within 18 inches of the amp. I went looking for such things when I figured out what they were angling at.

It all depends on the ampacity of the conductor.....AWG size x length....open air or in conduit, ambient temp....SHOW YOUR CALCULATIONS to support your premise.....otherwise, what you say makes no sense, abstract or otherwise......not just what some uneducated "buddy" thinks or or says......
BOB RENTON

 

[Don Frelier]

I'll take the #14 wire running 5 feet.

with #14AWG wire at 0.0025 ohms/Ft x 5 = .0125 ohms
Since I = V/R the voltage drop for every ampere would be .0125 volts (pretty close to nothing)
The connections would likely have more resistance than the wire.

 

[RJRENTON]

I'll take the #14 wire running 5 feet.

with #14AWG wire at 0.0025 ohms/Ft x 5 = .0125 ohms
Since I = V/R the voltage drop for every ampere would be .0125 volts (pretty close to nothing)
The connections would likely have more resistance than the wire.

I'm totally aware of how to calculate ohm's law (having a degree in Electrical Engineering)..... I just wanted to know if you did....at this point, discussion is moot.....
BOB RENTON

 

[RemCharger]

What a strange request from a grown man on an open forum.

 

[Don Frelier]

What a strange request from a grown man on an open forum.

I actually agreed with him, supported his argument, showed my calculations (at his request) and still got criticized to some extent.

 

[451Mopar]

I'll take the #14 wire running 5 feet.

with #14AWG wire at 0.0025 ohms/Ft x 5 = .0125 ohms
Since I = V/R the voltage drop for every ampere would be .0125 volts (pretty close to nothing)
The connections would likely have more resistance than the wire.

Derated to about 70c under hood temps, the resistance slightly increases to just under 0.003 / foot, with 10 Amps through the 5 feet of 14 AWG wire voltage drop of about 0.150 Volts, still pretty small unless higher currents try to pass through the wire. As mentioned, the connector resistance will add the the voltage drop.
What I was trying to say is if the alternator output is way higher than Battery voltage, then there is bad wiring between the two that should be fixed.

 

[Black_Sheep]

Please don't sand the paint off under grounded items like a voltage regulator. It may cause trouble sooner or later. The auto manufacturers don't sand paint off the body with grounded items, and they made 10's of millions of cars that made it out of warranty and beyond with no problems

The ground occurs between the bolt threads and the body, then the head of the bolt to the voltage regulator. Make sure the sheet metal,screws are getting harder tie turn while tightening them and the bolts and regulator are clean and rust free. The paint on the body doesn't mean a thing.

If you want to ensure a good ground use star washers under the bolt heads and run a ground wire from the engine block to the regulator.

I put a KEP nut on the back side of the firewall on the bottom screw for the regulator to ensure an adequate ground. The bolt wouldn’t tighten well because a previous owner probably over torqued it at some point.

 

[ynst]

Just HOW DO YOU THINK circuit is completed?? Firewall ground is the same as the connection as the battery ground thru the engine block and auxiliary ground wire thru the engine block to the firewall.....someone is blowing smoke up your ***......multiple grounds don't accomplish anything but can be confusing to the uneducated or naive.......
BOB RENTON

Right on the button, Bob.

The ONLY difference between grounding the regulator directly to the battery as opposed to, say, the firewall is that the firewall ground path all the way back to the battery may involve two or more connections, each of which adds additional resistance to the path.

The only reasons I could think of for not grounding the regulator directly to the battery are (1) the connection at the battery could be subject to corrosion at the battery post or (2) the ground wire will be unnecessarily long and ugly-looking.

FWIW, older cars ran a dedicated wire from the generator case to the voltage regulator base. Many current replacement generator regulators still have the hole in them for the self-tapping ground screw.

 

[ynst]

Speaking of grounds and ground paths, I have a 2008 Dodge Magnum that, repeatedly, won't turn over when the key is turned. The solenoid clicks the gear into the ring gear and nothing happens. The problem is more prevalent on cold mornings and, once the car is warmed up, it starts just fine. (after everything swells up due to the heat generated)

It's been back to the dealer twice because it's a warranty issue related to the re-manufactured transmission that Chrysler installed years ago.

What's the transmission got to do with it, you say? Well, the rear mounted battery isn't grounded directly to the drive train. It's grounded to the body approximately a foot-and-a-half from the battery. Somewhere under the body there's another cable that runs over to the aluminium transmission case. THAT'S where the problem exists. The servicing dealership never cleaned the old cable nor did they put any of the required protective coating on the connection to the transmission. On the return trips months later, all they do is tighten the bolt.

If I place a truck jumper cable on the battery and run it all the way up to the engine block, the engine starts. Take it off and it won't start. The voltage between the "battery" stud on the body control module and the engine block reads around 10 volts when the starter is trying to engage.

BAD GROUND!

I don't have access to a lift anymore so, as a work-around, I put a bypass circuit on the starter relay and there's a convenient push-button starter switch lying in the cup holder.

One of these days, I'll connect a 4 gauge wire from the stud on the frame where the battery ground cable is fastened in the spare tire well all the way up to the bellhousing where I can get at it easier.

Steel isn't the greatest electrical conductor. Copper is much better.