Lotus Elan

Lucas Charging System Woes

PostPost by: CG901 » Fri Jul 08, 2016 12:18 am

Having problems getting more than 11 volts to the battery (Elan with Lucas C40 dynamo). Bought a new voltage regulator, same problem. Removed the dynamo, rebuilt completely, bench tested and rose gradually with rpm to 20 volts. I know I have a good dynamo. Put it back and same thing. Removed the new voltage regulator and got the old voltage regulator (Lucas RB106s) on the bench. Removed points on each, cleaned and smoothed contacts, reset contact gaps, and put new one first then old into the car. Same result for both. Now my red ignition light is on all the time, and my turn signal are weak and barely light. My battery is new and fully charged.

I know, I know! You say: "Put the alternator I have sitting in the box and save some more grief"! It has become more than going the 'easy way'. I have to find out why I can't get this charging system to work.

Whilst I go get a cold one, anybody care to tell me what I am doing wrong, before I get the alternator down and give up on originality...........
Current: 1965 S1.5 26/4004, 1966 S3 FHC 36/5192, 1958 Fiat Abarth 750GT Zagato, 1967 Brabham BT21B, 1988 Arrows A10B-04, 1991 Brun C91-001.
Past: 1971 Elan S4/SE DHC, 1972 Europa Special, 1980 Esprit Turbo, 1988 March 881-05, 1990 Leyton House CG90105
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PostPost by: nmauduit » Fri Jul 08, 2016 5:23 am

one thing is bothering me: if the battery is new and fully charged, it should read above 11V at the battery, say 12.6 - then when charging (at a charging rpm, e.g. 3000) it should go a bit above that, says 12.7 or 12.8 (till it gradually charges up some more). You may have an issue somewhere, acting like a short : worth checking the current drawn from the battery engine off, engine on.

if the above is irrelevant, just a thought: have you checked if the charging harness was not oxidized (esp. ground between battery and chassis in the trunk)? Short (...) of checking the actual impedance of the wire, you may also run an other wire in parallel to the battery,
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PostPost by: billwill » Fri Jul 08, 2016 12:07 pm

Here is a google search for details on how to setup the dynamo regulator.

One of these may solve your problem.

https://www.google.co.uk/search?q=tunin ... gAaE5L3IDg
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