Charging

Firstly, Hello all.  My name is Guy and I'm a new member. ... Well, me and GCG144, a '47 Saloon. GCG has been slowly and progressively dragged out the doldrums by myself an my 90 year old dad over the last three years.  I got her from a chap in the west country, where she'd been off the road since....well he can't remember but we think since about '78. She now seems to represent reliable transport on sunny weekends and has taken us to and from numerous pubs and coastal fish and chip shops over this summer. BUT....last week I suddenly got paranoid about her over charging. After start up the charge needle swings to +15 to +20 once the revs are up, ( sits at '0' at tick over )  then progressively falls back to about +10. That seems quite high? The needle has quite a bit of swing and flicks about every 5 seconds, swinging down to '0' and up to about +15 then centres on +8/10.  Surely it shouldn't be putting that much current out once the battery is back up to charge? Where is that 120cwatts going ? We've cleaned the point sin the RF91 regulator as best we can and points make and break freely. We took the battery out and put in another one ( true , neither of them are young and sprightly ) and it made no difference. The second battery seems OK when put on a drain tester. We cleaned the main earths and this seemed to help a LITTLE. Should the needle swing about so much and should it not just sit JUST above '0' under normal circumstances? Could the regulator be goosed? We slackened the lock nut on the points adjuster on the top of the regulator and turned the adjuster anticlockwise about an eighth of a turn but it didn't seem to change anything.  Your thoughts gentlemen? Posted by trampintransit 30/08/2013 13:43:30

to help with this, you need to measure the DC volts across the battery terminals in the following conditions:  1 engine off 2 engine running at idle 3 engine running at moderate road speed (say 1500 to 2000 rpm) 4 - as 2 with headlights on and wipers on  5 - as 3 with headlights on and wipers on  there are many web sites for diagnosing charging faults - it is usually dirty connections within the dynamo or a poor earth somewhere in the charging circuit (eg at the regulator box).  good luck Posted by DaveT 02/09/2013 11:42:08

Cheers Dave.....I just found this;-  <!-- m --><a class="postlink" href="http://www.gomog.com/allmorgan/LucasFault.pdf">http://www.gomog.com/allmorgan/LucasFault.pdf</a><!-- m -->  I'll wade through it ..  I guess my question was....what is 'normal' behaviour for the charge meter?......what does yours do? Posted by trampintransit 02/09/2013 22:02:10

Interesting document - a keeper for sure!  The needle in my TA14 isn't that different from yours in terms of overall behaviour. Once the battery has been replenished after starting the car, it drops back to a lower point. I don't particularly trust the ammeter as a measurement device, though - more of a general indication of health. The 'flick' every few seconds is undoubtedly the petrol pump doing its job.  Like you, I've been concerned about overcharging, as there is sometimes a drop or two of overflow from the battery. However, it's so long since I owned a car with a dynamo that I may have forgotten what 'normal' behaviour is. I don't think the previous owner of my car was particularly knowledgeable about the electrics, so it wouldn't surprise me to find that the Control Box needs adjustment.  If all else fails and your pockets are deep enough, Holden sell an alternator which looks just like a dynamo, together with a dummy control box. Not for the purists, perhaps, but a solution to a problem.  Tony Posted by tonyl 03/09/2013 10:43:31

Cheers for that Tony.  So a needle hovering ( flicking around but centering on ) about 8 amps is normal. I guess I just thought....where the hell is 100watts going?   I'm going to do as suggested and take some readings next time I'm out for a spin. I think I was concerned because I had a ' 56 Sunbeam that seemed to always charge its battery but the ammeter hovered ( without flicking ??) just over '0' ?   Presumably if there was a partial short to earth somewhere then it's drop the loom voltage and the regulator would try to up the charge rate to compensate? Or does it not work like that.....would a short show as a drop below zero? Guy Posted by trampintransit 03/09/2013 20:58:39

Guy,  Greetings from Richard in Melbourne and welcome.  I am not happy with the 8 amps. Either something is chewing up current or else you appear to be overcharging. Is the battery electrolyte being boiled off? If so you are overcharging. Your regulator is an earlier version of the RF95 as used in the TA21. Both used the same LRT 9 regulator and both settings are the same from my research. Go to the web and type in &quot;Lucas Generator and Control Box Instructions and you should be able to get a PDF that explains how to test the regulator. With the A terminals disconnected from the regulator and joined you should be get a reading of 15.8-16.4 volts at 20 degrees C when the voltmeter is placed across the D and E terminals with the engine speed above tickover ie the generator is charging. I recommend that use an analogue meter as the digital won't like the quality of the generators DC. I would also recommend that use a set of leads with clips on the end, that way you can adjust the regulator with the meter operating.   With all the above you may find that the contacts are terribly worn/burned. If they are you will need to replace them. If they look OK then they should be cleaned with a very fine wet/dry paper and the gaps reset. The PDF will give the correct gaps.  I hope this helps.   Regards  Richard Posted by RichardWallach 05/09/2013 07:34:57

Guy,  I didn't say (or didn't mean to say) mine was normal! It sounds as though it might be dodgy, too, maybe not as dodgy as yours. As I said, I do lose the odd few drops of battery electrolyte.  Tony Posted by tonyl 05/09/2013 08:42:57

All of you are lucky in that the needle at least goes the needle goes the right way.  On my '48 car, it moves to minus when it is charging, and plus when it is discharging.  Something I have learned to live with.  On another matter, but related to the fluctuating charge of a dynamo, I am about to fit LED bulbs (not yet in stock) in the headlamps, thanks to advice from this forum. Graham Posted by langford 24/01/2015 12:54:04

Graham - you just need to swap the two big terminals on the back of your ammeter (disconnect the battery first) to solve your issue of having a reversed ammeter reading. Posted by drdowhitt 25/01/2015 11:15:20

The ammeter is working back to front either because someone has switched the leads by mistake or they have changed the polarity of the car from  +ve earth to -ve and not switched the ammeter leads. If the polarity has been changed the heater blower will probably be running backwards,the clock will have fried and there may be issues with the dip solenoid switch however you will be able to charge your sat nav and fit a modern radio.Also check that the &quot;new&quot; live terminal on the battery is well away from anything it could short on. Posted by Peter Martin 26/01/2015 10:15:31