Battery drain, alternator and relay problems. Help!

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lahi
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Model: Elite, Elise, Europa, Europa

Battery drain, alternator and relay problems. Help!

Post by lahi »

Hi,

I have a few questions about the charging system in my 1975 Elite. Seems to be a Chrysler squareback alternator with external voltage regulator and the Lucas warning light control relay.

See description in this picture. I have added some comments to clarify.

Image

- The battery drains very quickly.
- The relay (or whatever it is...) gets warm.
- Total current draw is 0.7A with ignition off.
- If I disconnect the ground wire from the Lucas warning light control relay the current draw drops to 0.2A which seems a bit odd? Reason for that might be mentioned further down so please keep reading ;)
- If I disconnect the wire between warning light control relay and alternator it drops to 0A draw.
- If I split the wire between warning light control relay and alternator, and measure the wire connected to the relay, it is grounded. There's connection to ground. Seems odd as I thought that wire should see 12V while charging?
- With the above connection still split I measure +12V coming from the alternator through the wire that goes to the Lucas relay. Should there be 12V? Thought that was only when the engine is running... Ignition is still off.
- Help please?

How do I fix this? New relay? New standard alternator? One wire alternator? And if I go that route, how do I take care of the charge light? If I have one? Remove it and rely on the volt meter perhaps...

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lahi
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Joined: Wed Sep 28, 2022 13:33
Model: Elite, Elise, Europa, Europa

Re: Battery drain, alternator and relay problems. Help!

Post by lahi »

I read somewhere that Mopar alternators might have a diode preventing voltage going the other way in the exciter wire. Could that be it? And that the alternator is grounded through the relay via this wire as a result of a broken diode? And that the relay is seeing 12V from this wire (and it shouldn't) and hence grounding the alternator through the relay and destroying the relay? The feed wire between relay and alternator sees ground as I described above.

Pete Boole
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Colour: Monaco White
Year: 1974
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Re: Battery drain, alternator and relay problems. Help!

Post by Pete Boole »

The alternator is definitely full of diodes - I've got one in bits that came as a spare with my car. Only cars with a/c got the Chrysler alternator.

Pete

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lahi
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Model: Elite, Elise, Europa, Europa

Re: Battery drain, alternator and relay problems. Help!

Post by lahi »

Pete Boole wrote:
Fri Feb 03, 2023 19:04
The alternator is definitely full of diodes - I've got one in bits that came as a spare with my car. Only cars with a/c got the Chrysler alternator.

Pete
I spoke to a alternator company here today and we came to the conclusion that it's my rectifier that's broken. Replacement is ordered to the amount of 180 SEK and that's about 15 USD :D Will have it next week.
My alternator is a Chrysler item. I have a 503 so with a/c and power steering.

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lahi
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Re: Battery drain, alternator and relay problems. Help!

Post by lahi »

But I do have a problem and feel a bit stupid :roll:
How do I get the alternator off? The bolts are off course removed but there's some kind of sleeve inside so I can't remove the alternator. How do I remove this sleeve? Haven't even had a whisky yet...

EDIT: It's off!!! It needed some persuasion...

Image

Pete Boole
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Posts: 3711
Joined: Tue Apr 04, 2006 21:28
Model: Elite
Colour: Monaco White
Year: 1974
Location: Nottingham

Re: Battery drain, alternator and relay problems. Help!

Post by Pete Boole »

Well done! I looked everywhere for the rearmost bush but couldn't find it (won't be used).

Pete

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