Click, Click, Click

May 03, 2022

I have a new puzzler. I was reminded of this while I was in my office, talking to myself and reading through technical service bulletins. I had nothing better to do.

I was reminded of a car we had come in, many years ago. I don't remember what year the car was. This was during my brother's tenure as Senior Floor Sweeper and Chief Mechanic.
We had a customer that came in with a Dodge van. And the problem was that the battery was going dead. He'd had a new battery put in because that's what you do. 
Then a few weeks later, the battery was dead again. He went out to start it one morning and turned the key. Click, click, click, click, click. Nothing would happen.

So, he took it to his neighborhood mechanic. The neighborhood mechanic said, "You need a new alternator." Of course, this was the same mechanic who replaced the battery, so he had to say something different. If it were a new mechanic, he would have said to replace the battery again. But it was the same guy so, a new alternator. He puts a new alternator in and everything is alright for a few weeks. 

And then, lo and behold, a few weeks later the same thing happens again. Right to the click, click, click when he tries to start the car. New battery. New alternator. Click, click, click. He goes back and gets another alternator and another battery, all under warranty, of course.

Each time they're putting in the best quality parts. Everything works. They put in a new voltage regulator and made sure the belt is tensioned correctly. There are no drains in the system. You know, the dome light isn't on, glove compartment lights...

So, there he is with this problem. He has an electrical system. All of the parts are perfectly okay. All of the components in the charging system are fine. All of the wirings is fine. The battery is fine and there are no drains on the system. And yet every two or three weeks, the battery goes dead. When it's jumped, it starts to run. And if you charge up the battery fully, even without doing any other repairs to it, it may run again for two or three weeks. Until finally one morning, it's dead again. Click, click, click. 

The puzzler question is, what's going on here? I mean, other than the fact that he's spending a lot of money!

Beyond that fact, what's going on technically to cause this?



So Dodge van, the battery keeps going dead. The mechanic checks everything out. Everything seems fine. The alternate he put in is terrific, and he even put in a voltage regulator. Nothing can possibly go wrong. He tested the thing to make sure there was no current drain that might kill the battery overnight.  And we will stipulate that there is no drain and yet the battery keeps going dead after two weeks of running. 

Well, the truth is there was probably nothing wrong with the original battery. What was wrong was that the alternator was in fact faulty. The first alternator the mechanic replaced was indeed the right alternator, but it had the wrong size pulley. The pulley was too large in diameter and wasn't turning fast enough.

Big pulleys turn slowly and little pulleys turn fastly, as they say.

What possible difference could that make? Well, it makes all the difference in the world.
Everyone knows that the amount of electricity that you make is a function of how fast the moving conductor is moving.
This becomes especially important if you're driving around in stop-and-go traffic. If you were driving 60 miles an hour, this would not have happened.


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