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Lotus Europa Forums => Technical Articles and DIY tools and tips => Topic started by: Fotog on Wednesday,October 26, 2022, 02:22:13 PM

Title: Twin Cam Battery / Ammeter / Alternator circuit diagram
Post by: Fotog on Wednesday,October 26, 2022, 02:22:13 PM
Over the past couple of days we've had a lot of back-and-forth with our casman about how to connect his new alternator.  I hope it will have been helpful.

But along the way I looked at the TC wiring diagram in the vicinity of the alternator, battery, and ammeter enough to realize that although it's accurate as a wiring diagram, it is laid-out such that it isn't very good with respect to understanding the operation.

All the various wires surrounding the ammeter have confused me, and finally it dawned on me that what's really going on is...
The ammeter is in the middle.  On one side is the battery.  On the other side of the ammeter is the alternator and all the regular loads from circuits in the car.  So the ammeter shows if the net current is flowing to the battery or from the battery toward the car's loads.

I got carried away and made a simplified schematic to show this, below.

There are a couple of exceptions.
1.  For reliability, the hazard lights operate directly from the battery supply, minimizing components in the circuit.
2.  The starter is connected on the battery side of the ammeter also.  It draws a great deal of current and would likely peg and maybe damage the ammeter if it were on the 'car side' of the ammeter.  And extra connections would contribute resistance and sap some of the energy otherwise available to start the car.  It's not part of 'regular operation' of the car either.
3.  'signal' wires like the alternator Remote Sense and Charge Indicator wires aren't shown.  Only power wires.

Keep in mind: this doesn't show physically how or where the wires are connected.  But it does show the electrical connections accurately.

-Vince Harris
Title: Re: Twin Cam Battery / Ammeter / Alternator circuit diagram
Post by: Fotog on Wednesday,October 26, 2022, 02:26:58 PM
Sorry, I meant to re-size the diagram to fit.  Try this:

[any way to edit attachments?  Replace one with another?  I didn't see it.]
Title: Re: Twin Cam Battery / Ammeter / Alternator circuit diagram
Post by: BDA on Wednesday,October 26, 2022, 03:10:27 PM
Use the "Modify" button in the upper right of the post. You will be able to add or delete attachments along with changes in text.
Title: Re: Twin Cam Battery / Ammeter / Alternator circuit diagram
Post by: dakazman on Thursday,January 05, 2023, 03:32:58 PM
   Don't you just love running thru wiring diagrams. :FUNNY:
  Very astute observation, making changes to it are all trade offs. I would love to add this to the TC
Both the UK And the special .
Dakazman