• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Alternator trouble

Share this page

Lin

Lin

Jedi Knight
Gold
Country flag
Offline
I wired the Lucas alternator as depicted in the attached diagram. I am not using the voltage box as a connection point. I eliminated it all together.

I must have something wired incorrectly, because I drain the battery after driving for a while. I pulled the alternator (less than a year old) to test it. I took it to an automotive shop and it tested "OK" at about 14 volts.

I have a NEW Smith's Alternator and Speedometer. They have no ignition warning lights so I added one as shown in the diagram. After testing the alternator I installed the alternator with the added ignition light and I discovered that the light will not go off when the engine is revved. So, I assume I am still not charging the battery.

Do you see any errors in my wiring based on the diagram? Is the fuse panel connection correct? It does go to a switched terminal doesn't it?

Thanks for any help you might offer. I am at my wits end on this thing. It has been a problem for some time.

https://web.mac.com/linwoodrose/iWeb/Healey%20Modifications/Alternator%20Wiring.html

Lin
1960 BT7 in restoration
1959 Bugeye
 
I confess my minimal experience with alternators, but that connection to the unspecified solenoid terminal doesn't look right. Is that the high-current output of the alternator, and what solenoid terminal is that? Do you have a solenoid or a pull switch? In any case, I think the way you have it connected won't get power to the battery.
 
Steve,
Sorry I should have said starter switch rather than solenoid. I corrected the diagram.
Lin
 
Your link now points to something about installing speakers.

But, in any case, you want to connect the alternator output to the battery. If it's connected to the wrong side of the pull switch, then that's definitely the problem. If it is indeed connected to the battery, and the alternator is OK,
it really should be working.

I'm assuming this is the Lucas (or similar) three-terminal alternator, with a built-in regulator, correct?

I'm a little puzzled that the warning light is on. I think that the lamp being off is actually an indication that the alternator is generating power, not so much that the power is getting to the battery. So, the light may not be a reliable indicator if the alternator isn't connected right.
 
I will fix that link! Thanks. I will check on the battery connection tomorrow.

Lin
 
I'm pretty sure all 3 terminals of the alternator should be used. The output lead and the sense lead effectively both go to the battery, but they may not be connected internally, so if the sense terminal is floating it may not be working correctly.

I agree with the others, check on the connection to the solenoid. If it's feeding the starter side of the solenoid instead of the battery side, that's a bad thing.
 
Steve,
Thanks very much for your help. I have corrected my obvious (not to me originally!) error in my diagram and in my car. The Bugeye is now back on the road and running fine. The indicator light illuminates when ignition is turned on and gradually goes off as RPMs are built up. See revised diagram:

https://web.mac.com/linwoodrose/iWeb/Healey%20Modifications/Alternator%20Wiring.html

Lin
1959 Bugeye
1960 BT7 in restoration
 
Sorry, I came in a little late to this discussion. I don't see much wrong with the diagram. Maybe that's why it's working now. Still, the "?" on the ignition switch... Is it marked that way, or is it illegable?

I of course will be doing something similar, later on.

Another thing. Why a Lucas alternator? Aren't the Delco more durable, or a Japanese unit a bit smaller?
 
The question mark is only because I couldn't read the letter in my book. The type was too small. I used a Lucas because I was trying to stay a little closer to original. Others favor more contemporary units. I took a two hour drive yesterday, and everything is now functioning properly.

Lin
 
Back
Top