Miwalker Posted January 19, 2011 Share Posted January 19, 2011 I've been having some issues with charging on my 1983 24v landrover 109. I've been reading up on this thanks to Clives Elliott's 'All Charged Up' series of articles, but I thought I'd ask for a bit of help/feedback. Here's the situation. We're dealing with a Generator No 10. Mk3 and a Generator Panel No.9 Mk.4 (90 amp). The system looks to be in fairly original condition with no modificatons. There is no radio equipment, only the 2 vehicle batteries. A couple of weeks ago the charge warning light started to flicker into life and before long, was permanently beaming brightly at me. I can vouch for the fact that what the little light is trying to tell me is indeed true; the batteries are definately not charging. I did some resistance checks over the weekend during which I took the belts and cables off the alternator and unplugged the generator panel and shunt. As is the way with these things, something magically sorted itself for about 10 minutes, before the little light started to flicker again and we were back where we started. Interestingly, the light became brighter whilst the engine was being revved, which fueled my suspicion that the belts might be the issue, but a new set of belts have since proved this to be wrong. So the results of the tests... 1) Voltage at Inspection light sockets: No rise in voltage at inspection light sockets when running the engine. The good news here, however, is that there is no drop in battery charge over a couple of days, so I'm not losing charge unneccesarily. Not really related to the issue in hand, but nice to know. 2) Alternator diode tests (using a digital multimeter): 2a) +ve prod to W & -ve prod to X Resistance = 66,000 Ohms (and rising...?) Diode voltage drop = .8v 2b) +ve prod to X & +ve prod to W Resistance = 70,000 Ohms (and rising...?) Diode voltage drop = No Circuit Theoretically the resistance measurements in 2a should be low. I suspect the high resistance reading is due to the multimeter mode not having enough voltage to get past the diode when it is set to measure resistance, as explained in Clive's 'All charged up - Part 4'. The voltage drop was measured in the mulitmeter's diode test mode and leads me to believe that the diodes are probably working ok. Correct me if I'm wrong! 3) Resistance in field winding: The readings from this are a bit more difficult to interpret as they varied wildly. Readings were anything from about 20 ohms up to about 300 ohms, with a few cases of 'no circuit' in between. I'm not sure if this is due to the use of a digital multimeter, or whether the brushes could be cause of the problem? 4) Alternator test readings taken at generator panel: Readings were similar to those taken in item 2) which suggests that the cable is probably ok. 5) Continuity tests between generator panel plug and inside of shunt. All continuity tests ok. Suggests that cable is ok. Thats as far as I've got. It seems that the brushes might be suspect, but my question is how stable should the field winding resistance be? So, where do I go next? It seems that more reading up is required! Regards, Malcolm Walker Cardiff Quote Link to comment Share on other sites More sharing options...
airportable Posted January 19, 2011 Share Posted January 19, 2011 Hi Malcolm. Again dont know how to link you to much the same prob. I had with my A/P FFR a couple of weeks ago that I started a thread on. Sounds like the same alt. and gen. panel as mine. My prob. started on a very cold day, but has now sorted its self for the time being. When this prob. happened the first time a few years ago (sounds much the same) fitting another gen. panel, sorted it. Happened again following year, advised to try swopping two wires arround in the shunt box. sorted charging in two min. but could not charge radio batteries. Funny how these charging probs. happen in cold, damp weather. Is a pattern developing? Any way have a look at my started thread for intrest. Andy. Quote Link to comment Share on other sites More sharing options...
Miwalker Posted January 19, 2011 Author Share Posted January 19, 2011 Hi Andy, Spotted your post earlier in the week, but have just read it again makes a bit more sense now I'm further into the problem. Depending on the feedback on the alternator, I think i may need to spread my search a little bit. Certainly the earth bonds are a prime target for further investigation, as are the cables. Won't do any harm even if they aren't at fault. Not quite ready for poking about in the panel yet, this is my first time at all this! However, That does lead me to a question. Does anyone know how important it is to seal the panel box? Mines been opened before, I'm missing a couple of nuts and the seal is falling apart. Being a canvas top, it's pretty moist in there at the best of times! Malcolm. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted January 19, 2011 Share Posted January 19, 2011 Malcolm, sorry to hear of the problems. But it is unusual to find such precise & comprehensive symptoms laid out together with the steps you have taken to diagnose it. So often I see posts of the type "My Landy's not charging, what do you think is wrong" with no information as to whether it is 12v or 24v, 40A or 90A nor the basis of the "not charging". Anyway no such problems with you post. Intermittents are a pain! Digital meters are a pain! Your Test 2 As you have a Mk 3 Generator you are stuck with having to test two diodes in series. As you realise measuring a diode with a multimeter will not have enough voltage to drive the diode to conduct & here you have two in series. Although it sounds promising that on the diode test position it is forward biasing both diodes into conduction. But of course measuring between X & W you are measuring 3 pairs of diodes in parallel. One could conceive all sorts of scenarios where just one diode in each pair is defective either open or short circuited yet would pass the diode test on the meter. Indeed even more depressingly the two other pairs may have similar problems. So a digit diode function may reveal less than an analogue resistance reading. A way round this, to test less diodes would be to follow the "Testing the diodes without a meter" paragraph. Your Test 3 A little bit of 'no circuit' is ok. I have had readings 15-30 ohms but above that does point to brushes. Before dismantling the alternator, I would try to measure its outputs. Take the lid off the Gen Panel. See if you can pick up a healthy 28v or so when revving on test point T4. See if it is still as good on T1 (ie is the relay switching it) If it is not see if it has a similar voltage on T3 (that supplies the relay winding) If not try T2. Let me know what happens. Quote Link to comment Share on other sites More sharing options...
Miwalker Posted January 19, 2011 Author Share Posted January 19, 2011 Excellent! Thankyou Clive! Plenty there to keep me busy. I'm away for a week or so but I'll come back to you soon after. On the bright side of all this, there's no better way to get to know the insides of the landrover! Regards, Malcolm. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted January 19, 2011 Share Posted January 19, 2011 Malcolm yes doing is learning, reading is helpful but it doesn't have the same impact. Quote Link to comment Share on other sites More sharing options...
Miwalker Posted February 2, 2011 Author Share Posted February 2, 2011 Hi Clive, and anyone else following this! Back home again, so have managed a couple more tests with the voltmeter tonight. Haven't managed a diode test on the generator yet. Here are the results for the generator panel: T4: 4v at tickover, rising to about 15v at mid revs and up to about 27-28v only at unhealthily high revs! T1: 1.5v - 2v T2: 2.5v T3: 0.8v Your interpretation would be very much appreciated. I'm into unfamiliar territory now! Regards, Malcolm. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted February 2, 2011 Share Posted February 2, 2011 Malcolm, T 1, 2 & 3 readings are at tickover? What are they at med-high revs? Quote Link to comment Share on other sites More sharing options...
Miwalker Posted February 2, 2011 Author Share Posted February 2, 2011 Hi Clive, No change whilst revving, certainly not like there was on T4. Regards, Malcolm. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted February 2, 2011 Share Posted February 2, 2011 Malcolm can you make absolutely certain that there is no short circuiting of the HIGH/LOW switch if there is it will charge at the low rate. Even so at 2,000 rpm you would still be getting 26v or so without having to do high revs. I hate these solid state regulators, there is so much less to test & do something about! Earlier Mks you can power up 'in reverse' & take readings around the voltage regulator & get some pointers without the generator being connected. Your field winding isn't getting enough voltage to give proper output. That could be because of your regulator module or there isn't enough output from the low power diodes in the alternator. A rather chicken/egg situation. Check that the black rubber bullet connector is sound. A grotty there will cause the field winding voltage to go right down. Unplug both ends of it & make sure the contacts still look silver plated on the plugs themselves & inside the coupler. There obviously isn't enough voltage to charge the batteries as there is way too little voltage on the winding of the battery relay. It looks as it the winding for the relay is ok as there is a voltage drop over 100 ohm resistor from T2 to T3. It would be nice if the was someone nearby with a 90A system with whom you could plug in your generator panel & see if it worked. Failing that you need to go measuring the diodes, with ideally an analogue meter if you can. Then you get rid of the flickering of readings & the "and rising" readings you mentioned. As you know the benefit of digital meters & before that, valve voltmeters was that it made little appreciable impact on most electronic circuits one was measuring. Indeed with moving coil multimeters the goodness factor of its lack of impact on a circuit was measured in thousands of ohms per volt. But in these charging circuits we are not hunting for piffling little voltages that might wither away when tested. No in my own testings I just can't put up any more with digital meters flickering & dithering even when they are measuring nothing. Although I have a couple of Avo 8s they have high ohms per volt & ranges that are not needed for automotive electrics. I have just bought an Avo 12. A classic reliable meter intended for automotive diagnostics, no nonsense here it is 200 ohms per volt. This will determine if there is a proper voltage there or not! With ranges DC ranges of 36, 18, 9 & 3.6 volts it is ideal. Two resistance ranges that will drive any tested diode into conduction & DC current ranges of 3.6 & 36 amps. With an external shunt it can read 360 amps. No nonsense classic quality British instrument sadly no longer made. These do crop up. One sold on ebay a couple of days ago for about £72 it did have the 360 amp shunt. Mine doesn't have that but it only cost me £12.50 on ebay the week before! Quote Link to comment Share on other sites More sharing options...
mike65 Posted February 3, 2011 Share Posted February 3, 2011 Hi Clive, and anyone else following this! I am atleast. Makes interesting reading as a 109 "4V 90amp owner just in case I have a problem. Better not offer any advise as I would only be wrong, not very good with electrics when it comes to volts and amps. Better to leave you in the capable hands of Clive. Mike Quote Link to comment Share on other sites More sharing options...
andym Posted February 3, 2011 Share Posted February 3, 2011 I don't know anything about Land Rover electrics, but noting your comments about the problem temporarily fixing itself after you'd dismantled it I'd suggest a good look at the cables and connectors might be useful. If you can dismantle the connectors and look inside, so much the better. Andy Quote Link to comment Share on other sites More sharing options...
Miwalker Posted February 3, 2011 Author Share Posted February 3, 2011 Hi All, Clive, some things there for me to do this weekend. I'll keep an eye out for an Avo 12, I think I might be getting some use out of it! Andy, I was just considering the same thing when you posted. I'll check all the connectors carefully as it did appear to fix itself for a while the last time I played around. I'm sure this wouldn't occur if it were a electrical component fault, would it? Mike, that's what forums are for! Thanks Everybody, Malcolm. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted February 3, 2011 Share Posted February 3, 2011 (edited) I don't know anything about Land Rover electrics, but noting your comments about the problem temporarily fixing itself after you'd dismantled it I'd suggest a good look at the cables and connectors might be useful. If you can dismantle the connectors and look inside, so much the better. Andy Andy absolutely with you there. It is always tempting to pick on the major components as suspects without fully scrutinising what connects them together. Connectors & cables are much more vulnerable to tugging, being crushed, knocked around, corrosion etc. This is not a scientific appraisal but a based on experience assessment with systems like this, the faults seem to be: 5% Generator 25% Generator Panel 70% Cables, plugs, leads within plugs & earth problems Andy, I was just considering the same thing when you posted. I'll check all the connectors carefully as it did appear to fix itself for a while the last time I played around. I'm sure this wouldn't occur if it were a electrical component fault, would it? .....Malcolm. Apart from tugging & nudging cables & connectors, the use of a hard rubber or plastic hammer can be useful to stimulate panels, plugs etc to bring about a change so often only experienced when you have an intermittent fault when driving along. Be wary of accepting continuity tests on cables, inspect the insides & gently tug at the wires. Like these dry joints below, that passed on low current continuity tests, but in effect were just intermittently wedged in place. There was a third grotty one as well! These wires are particularly prone to damage by getting tugged on whenever the main cable is pulled or bent. They supply the field winding & output from the low power diodes. If that all seems ok try the flow sequence of tests in ACU 3 to get the culprit ie generator, panel or cables. If that is inconclusive if you can't substitute a panel of any Mk (although charge light won't work with wrong one) then start at the generator with test & work back to the panel. BTW I have a spare Gen Panel, I think Mk 3 though, that you could try & buy if it cures it. I am near Salisbury. Edited February 3, 2011 by fv1609 Quote Link to comment Share on other sites More sharing options...
fv1609 Posted February 3, 2011 Share Posted February 3, 2011 I'll keep an eye out for an Avo 12, I think I might be getting some use out of it! An Avo 8 was an industry standard & can do many things that an Avo 12 can & indeed far more things than are needed for automotive work. Although it is limited to 10 amps DC, whereas the Avo 12 goes up to 36 amps DC. Given the rarity of the Avo 12 it might be tempting to go for an Avo 8. In fact I have just purchased a nice Avo 8 as well. A word of warning if anyone is tempted to an Avo 8 currently on ebay, I can recognise, from certain micro characteristics, a meter that looks like one I returned with some defects being offered for sale again. PM me in confidence before bidding! Quote Link to comment Share on other sites More sharing options...
Miwalker Posted February 5, 2011 Author Share Posted February 5, 2011 Breaking news! I may have identified the problem. I am in the process of checking the cable between the alternator and the generator panel. Whilst poking around the back of the alternator, I noticed that the metal shielding on the cable is heavily frayed where it passes through a clamp mounted on the engine. I suspect that this clamp, which has been eating it's way through the cable, has just reached copper! My plan is to temporarily remove the clamp to see that fixes / bodges the problem sufficiently for us to get back on the road. I'll let you know how that goes. I will, however, definitely need a new cable. Any assistance in sourcing one will be gratefully received! Regards, Malcolm. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted February 5, 2011 Share Posted February 5, 2011 Sounds promising Malcolm Quote Link to comment Share on other sites More sharing options...
andym Posted February 5, 2011 Share Posted February 5, 2011 In my experience as an electrical engineer, most "electrical" faults are mechanical in nature! Andy Quote Link to comment Share on other sites More sharing options...
Miwalker Posted February 5, 2011 Author Share Posted February 5, 2011 Hi All, Removing the clamp seems to have cured it! I would post a photo but the clamp is far too inaccessible to get the camera in. I guess the learning point for this is to make sure you carry out a really thorough physical check of the system before you jump deep into the electrical side of things. Clive's rule of thumb that 70% of the time the problem lies on the cabling has proved true in my case. Still, it took a bit a hunting to find it and without this forum I wouldn't have known where to start. Thankyou very much to everyone who has contributed and particular thanks to Clive who has guiding me through this problem. I recommend anyone with similar issues to read and digest his articles on the subject. Now to source a replacement cable... I believe the part no is 54950615. Can anyone confirm this. Regards, Malcolm. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted February 5, 2011 Share Posted February 5, 2011 Malcolm in a few days I will be rummaging where there may be such a thing. The problem is that it will be rather heavy to consider posting. So it would be a collect only thing, from Salisbury. Where are you? From time to time you do seem these cables as take-offs, I've never seen a new one. But if I had a vehicle that used one I would have bought one. Not just as a replacement but to use for diagnostic purposes. If you get fixed up with a replacement then it is worth repairing or rewiring the old one to some degree to use for diagnostic purposes for some future problem that may occur. Another truism of automotive diagnostics I would say that 90% of "carburettor" problems are electrical;) Quote Link to comment Share on other sites More sharing options...
airportable Posted February 5, 2011 Share Posted February 5, 2011 (edited) Thank you malcolm for posting your thread on the problem. Followed with intrest and real pleased you have sorted it. (My prob. sorted it's self, allways a little worrying) Harness, My first port of call this part of the world would be, John Richards, 01952 550391 (bought my spare harness off Him few years back), or LMS (Lichfield) Ltd.01543 480600 (had parts for 24v L. at Stoneleigh) Andy. Edited February 5, 2011 by airportable Gramma Quote Link to comment Share on other sites More sharing options...
fv1609 Posted February 5, 2011 Share Posted February 5, 2011 I believe the part no is 54950615. Can anyone confirm this. Yes certainly for a Rover 10 or 11 Quote Link to comment Share on other sites More sharing options...
Miwalker Posted February 5, 2011 Author Share Posted February 5, 2011 Clive, I'm in Cardiff so if you do come across a suitable replacement I would quite happily drive down to pick it up. If you don't find one, not to worry, I'll go with Andy's suggestions. Incidentally I bought some alternator belts from John Richards for a good price a couple of weeks ago. Thanks Guys, Malcolm. Quote Link to comment Share on other sites More sharing options...
fv1609 Posted February 5, 2011 Share Posted February 5, 2011 Malcolm what I will come across will be a take-off. I think you will do best trying to source something newer, otherwise you may be buying into gremlins that may be lurking in an old item, which we have all agreed is so prone to some sort of deterioration. Yes John Richards seems a good source of things. (Humber/Ferret owners, I see he still has brake switches) Quote Link to comment Share on other sites More sharing options...
Miwalker Posted February 6, 2011 Author Share Posted February 6, 2011 Clive, No problem, I'll get on the case and start looking for a new one. Thanks once again and I hope to bump into you sometime so that I can buy you a pint or something. Regards, Malcolm. Quote Link to comment Share on other sites More sharing options...
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