Stupid Electrical Design

[Ulu]

I discovered that I had made a serious mistake on the electric boat, and while it never actually came back to haunt me, it could have been a very unhappy day on the water because of my stupidity.

And this is not a matter of ignorance, because I knew about this problem and have experienced it before.

This is the matter where I did things in a rush so that I could get out on the water. This is one of the last things that I did and I wasn’t thinking real clearly based on the evidence.

To explain the situation it’s very simple: I placed a non-conductor in my electrical connection. I put a bolt through a board and put a flat washer on it and two battery cables and a nut and tightened it down. This works fine as long as the wood never ever compresses and allows your connection to become slightly loose.

But of course wood on a boat swells and shrinks with time. After four years, this was enough to cause the connection to become slightly loose. You could tell how hot it got because there was char on the board.

Anyhow, it was a simple enough fix to re-order the connections so that there Was nothing but metal between the two nuts.

So why am I kicking myself in the ass so hard about this? Because I have owned three General Motors cars where the ground connection from the heater blower was a rivet from the brush wire to the steel case. In each case, a fiber insulator (which is the base of the brush holder assembly) was placed between the steel motor housing and the brass ring terminal. A rivet holds it all together, for a while.


After about 60,000 miles (more or less depending on how rough the roads are where you live) the fiber insulator will compress and degrade and your ground connection will come slightly loose. Now that damn piece of fiber has absolutely no reason to be in the connection, except it was convenient at the manufacturing and assembly. It is a total design error.

One day your blower motor is OK, and the next day it is growling because of low voltage. You’ll hit a bump and then it will work fine again and you’ll think what the heck? Eventually it will burn the motor up or it will just quit from lack of electricity.

Anyhow I have seen this happen on my Cadillac, my Bel Air, and a Silverado as well. I do not know what other vehicles & devices this mistake could affect, but it’s something to keep an eye on if you work on such things.

[Plymouthy Adams]

this is one of the major reason Lucas has a bad name....the problem is not actually Lucas as much as the folks using their components and switches etc where the grounds are daisy chained across a wooden dashboard of these little cars....secret is when mounting your harness and grounds is to nut the component in place then use a couple washers to sandwich the grounds between the first nut and a second nut....run an dedicated ground to the chassis also...

 

grounds still are the very first cause to new cars with so many sensors and such with the EFI and other systems....

[Frank Elder]

4 hours ago, Ulu said:

Anyhow I have seen this happen on my Cadillac, my Bel Air, and a Silverado as well. I do not know what other vehicles & devices this mistake could affect, but it’s something to keep an eye on if you work on such things.

So quit buying GM......lol.

[Tooljunkie]

Way back when i was installing and repairing remote starters, my first wire was the ground. Ring terminal,wire soldered and a new drill tap into solid body metal under dash. So many times i have seen an installer use an existing screw that holds plastic trim to dash frame. Bad idea. 
in my install courses it was implied the ground also contributes to a better range for recieving signal. 
i cant see how, but i never did a comparison. 
Good solid connections are priority to me. 

[Sniper]

That's one of the issues when using the plumbing analogy to teach electrical theory, no one talks much about the return side of things.  Electricity needs a good path for both supply and return.

[chrysler1941]

One can never have enough ground

[Frank Elder]

Bare metal and STAR washers for BITE, then paint.

[Ulu]

On 4/9/2021 at 6:37 PM, Frank Elder said:

So quit buying GM......lol.

I have not a bought a General Motors car in over 20 years. That was not the point at all. Some people here are General Motors owners, so this was just a tip for them.

 

We all think about electricity wrong because Benjamin Franklin guessed wrong when he assigned the positive and negative terminals to a cell.

 

But the ground is where all the electrons come from. It’s not how they go back.

 

I still wasn’t happy with my wiring and I went back into the panel and cleaned it up some more. Anyhow I’ve been fiddling with woodwork on the boat and tomorrow I’m going to take it out and see how everything works.
 

Edited April 12, 2021 by Ulu

[Frank Elder]

It may have not been your point but it certainly was mine.

[Ulu]

This little wood bin covers & protects up all the wiring on my rear seat platform. It also replaces that ugly lime green plastic thing you also see in the picture. 

These are the main 36 V battery cables plus some 12 V wires that operate the phone charger & fishfinder. 

I made some standoffs from off cuts of PVC coated PVC foam window framing.

 

 

 

[Ulu]

100% success!

Boat runs great and fish were caught.

 

I also finally renamed her.

She’s been on 36 volts for years now.

 

Out fishing with my granddaughters.

 

[Sniper]

On 4/12/2021 at 9:53 AM, Ulu said:

We all think about electricity wrong because Benjamin Franklin guessed wrong when he assigned the positive and negative terminals to a cell.

 

But the ground is where all the electrons come from. It’s not how they go back.

 

For all intents and purposes how electrons flow is irrelevant at our level.

 

It is irrelevant at the level I was trained at, Navy Electronics Tech, it was irrelevant when I worked in semiconductor R&D.

 

What was relevant in all cases was that you need both a good supply and a good return, regardless of your ground's polarity.

[Frank Elder]

Did you go through B double E or is that just a brown shoe school ? That ought to confuse all you civilians.......lol!

[Sniper]

I was never a brown shoe and I went thru all of BEE and ET A school.  Took a year and a half with no summer vacation, spring break, Holiday vacation, etc, 8 hours a day, 5 days a week plus extra study.