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Lotus Europa Forums => Garage => Topic started by: 4129R on Wednesday,October 27, 2021, 03:09:21 AM

Title: Alternator Wiring Problem
Post by: 4129R on Wednesday,October 27, 2021, 03:09:21 AM
When connecting my battery, I noticed a mild spark when I connected the earth, even though the ignition was off.

Then I noticed the alternator was hot. It is a 17ACR.

The brown and purple wiring on the alternator is connected to the main thick + wire at the starter solenoid connected to the battery, so that brown and purple wire is permanently live.

Can someone please explain why you need a permanently live wire to the alternator connected direct to the battery, and unfused, which is making the alternator hot, and flattening the battery.
Title: Re: Alternator Wiring Problem
Post by: jbcollier on Wednesday,October 27, 2021, 05:13:16 AM
The "mild spark" is not unusual depending on what you have.  There can be electronics that charge capacitors, etc when first hooked to power.  I use an ammeter to check the actual draw.  When I hook it up, it's normal for it to jump to 1 or 2 amps, slowly fall and then stabilize.  It's fine as long as it stabilizes at 80 milliamps or less.

The alt getting hot indicates a diode has failed inside the alt.  Unfortunately, this not unusual for Lucas alternators.  They have under-spec'd diodes that do not like to be run at full capacity and will pop if you do for anything but a brief period.  That's why they come with a warning to fully charge the battery before running a replacement alt.

Whole alts and parts are readily and cheaply available but I would recommend replacing it with something more robust.

Alternators use diodes to rectify their AC output.  They do not need to be disconnected when off and run most efficiently when hooked directly to the battery.  Repair or replace your alt and it will be fine.
Title: Re: Alternator Wiring Problem
Post by: 4129R on Wednesday,October 27, 2021, 06:14:47 AM
The alternator was brand new, and the engine has not even run yet.
Title: Re: Alternator Wiring Problem
Post by: RafM on Wednesday,October 27, 2021, 06:34:29 AM
I would double check all of the connections are correct plus make sure there is not a short circuit somewhere, back of the ammeter perhaps?
Title: Re: Alternator Wiring Problem
Post by: jbcollier on Wednesday,October 27, 2021, 08:10:45 AM
If the alternator is getting hot, then it is wired incorrectly, or the alternator has a problem.  Can you post a picture of how your alt is wired?  The small terminal is for the charging warning light.  If that was hooked to 12v, it might be causing the issues you are experiencing.

https://redpowerphotos.s3.us-east-2.amazonaws.com/monthly_2020_08/1000951245_LucasAlternatorwiring.png.c3e1b61309901ec18d0686c672fe657f.png

https://redpowerphotos.s3.us-east-2.amazonaws.com/monthly_2020_08/lucas-17acr-alternator-wiring-diagram-7.gif.ed668b27d0f34af08f67a026b50ebd0d.gif
Title: Re: Alternator Wiring Problem
Post by: 4129R on Wednesday,October 27, 2021, 08:13:58 AM
I would double check all of the connections are correct plus make sure there is not a short circuit somewhere, back of the ammeter perhaps?

There are only two wire connections, the thick brown wire to the ammeter, and the brown and purple wire from the starter solenoid. There is no connection for the ignition warning light. I have even run a dedicated earth wire from the alternator to the chassis.

Why would a brand new alternator get hot, when the engine has not even run?
Title: Re: Alternator Wiring Problem
Post by: jbcollier on Wednesday,October 27, 2021, 08:19:27 AM
Can you post a picture of your connections?
Title: Re: Alternator Wiring Problem
Post by: jbcollier on Wednesday,October 27, 2021, 08:23:26 AM
There are three connections:

NP - to main battery connection at the starter solenoid
NW - to ammeter
NY - to charge light

NP and NW connect to the large connectors (3/8"?)
NY to the small connector (1/4")
Title: Re: Alternator Wiring Problem
Post by: 4129R on Wednesday,October 27, 2021, 08:53:47 AM
There is no connection on the back of the alternator for a second small connection.

The two large male connections are joined together.
Title: Re: Alternator Wiring Problem
Post by: jbcollier on Wednesday,October 27, 2021, 11:46:35 AM
You can see it right there.  The silver connector takes the NY wire.  It also provides the initial "excitement" for the field on start up.  The NP and the NW go to the two large terminals.  Yes, they are joined, that's the way it's supposed to be.
Title: Re: Alternator Wiring Problem
Post by: 4129R on Wednesday,October 27, 2021, 12:33:56 PM
You can see it right there.  The silver connector takes the NY wire.  It also provides the initial "excitement" for the field on start up.  The NP and the NW go to the two large terminals.  Yes, they are joined, that's the way it's supposed to be.

Thanks for that. Banks seems to have told me incorrect information when I specifically asked him about this.
Title: Re: Alternator Wiring Problem
Post by: jbcollier on Wednesday,October 27, 2021, 01:26:22 PM
Don't know Richard that well but most mechanics are simply awful on wiring. Not as bad as bodymen though, never ever let a body hook up wires!
Title: Re: Alternator Wiring Problem
Post by: 4129R on Thursday,October 28, 2021, 04:20:59 AM
Like this?

At least now the ignition warning light comes on.
Title: Re: Alternator Wiring Problem
Post by: jbcollier on Thursday,October 28, 2021, 07:05:17 AM
Yes.

You can get a connector kit:

https://www.autoelectricsupplies.co.uk/product/47

Make sure any connectors are properly attached.  Insulated crimp connectors like the middle yellow one are notorious for developing poor contact over time.
Title: Re: Alternator Wiring Problem
Post by: 4129R on Thursday,October 28, 2021, 07:27:46 AM
Thanks for that, the connection is right up against the luggage box so a close right angle connector is needed.
Title: Re: Alternator Wiring Problem
Post by: BDA on Thursday,October 28, 2021, 07:36:57 AM
Or a slight modification to the luggage box!  :)
Title: Re: Alternator Wiring Problem
Post by: jbcollier on Thursday,October 28, 2021, 12:10:53 PM
All the usual British suppliers carry the connectors.
Title: Re: Alternator Wiring Problem
Post by: dakazman on Thursday,October 28, 2021, 01:33:29 PM
     JB,  Do they have the power window connector?  I know you don't have power windows in a S1.
 Dave
Title: Re: Alternator Wiring Problem
Post by: jbcollier on Thursday,October 28, 2021, 03:19:22 PM
Do you have a photo of the power window connector?
Title: Re: Alternator Wiring Problem
Post by: SilverBeast on Thursday,October 28, 2021, 04:34:20 PM
If you mean on the motor it's just two standard insulated spade female connectors on my TC.
Title: Re: Alternator Wiring Problem
Post by: dakazman on Thursday,October 28, 2021, 07:30:30 PM
  No pics JB , I just had two separate spade terminals on the harness.
 Silver, correct but a connector would be better than standing on your head.
 
Dakazman
Title: Re: Alternator Wiring Problem
Post by: jbcollier on Thursday,October 28, 2021, 07:39:51 PM
I have some S2 doors lying around.  I'll have a look.
Title: Re: Alternator Wiring Problem
Post by: GavinT on Thursday,October 28, 2021, 09:07:37 PM
This look right, D'man?

The window motors are of GM origin.
From a quick search, here's the first hit but there may be better options/prices/locations.

https://jcaparts.com/products/1955-1976-gm-power-window-motor-wiring-harness-connector-pigtail
Title: Re: Alternator Wiring Problem
Post by: EuropaTC on Thursday,October 28, 2021, 09:45:36 PM
Thanks for that, the connection is right up against the luggage box so a close right angle connector is needed.

When I fitted a 17ACR unit I had to use one of those connectors as well. The 17ACR does fit but it was probably somewhere around 1/8" clearance on my car.  The 16ACR unit is fractionally smaller but I ended up with a modern (ish) A127 unit which gives more power and bags of clearance.

There's some notes on initially fitting the 17ACR & subsequent A127 on another thread;  http://www.lotuseuropa.org/LotusForum/index.php?topic=4553.msg49433#msg49433 (http://www.lotuseuropa.org/LotusForum/index.php?topic=4553.msg49433#msg49433)

Brian
Title: Re: Alternator Wiring Problem
Post by: 4129R on Friday,October 29, 2021, 06:44:28 AM
Yes.

You can get a connector kit:

https://www.autoelectricsupplies.co.uk/product/47

Make sure any connectors are properly attached.  Insulated crimp connectors like the middle yellow one are notorious for developing poor contact over time.

Ordered yesterday, delivered today. That is what I call good customer service. It is a very good tight fit against the alternator, so should clear the rear luggage box.