v8bertha Posted March 17, 2008 Share Posted March 17, 2008 Hi chaps Me and lecktricks don't mix... if you can't fix it with spanners and a big hammer, it just ain't normal! Hence my needing the worldly combined knowledge of you lot 300tdi Camel 110... Some months ago the battery warning light on the dash on the Camel stopped working. It doesn't come on when you start the engine and it don't come on if you run the engine without the belt on or if you stall the engine. I have checked the bulb... it works fine. The following may well be related, but I ain't sure. Since the light stopped working my split charge system has become very intermittent. Its a VSR type that clicks in at 13.7 volts and starts to charge the other battery. The battery monitor that I have shows about 13.2 volts being delivered to the battery in normal running conditions. Every now and then it'll jump up to 13.7 and activate the relay which then starts charging the other battery, but this happens very rarely these days, whereas it it used to be the norm. I'm also pretty sure I have something draining the battery as overnight the battery's power will drop right down "into the red" whereas it used to stay towards the top half of the yellow. I have chucked on a spare altenator that I have and the same problem occurs. Edit to add: If I put a meltimeter on the alternator while the engine is running, it shows about 13.8/9 volts. I'm aware that if the diode pack dies then the battery warning light becomes illuminated even when the ignition is off and that can flatten a battery. But this is the opposite of whats happening at the mo, i.e the light doesn't light up. Sooooo..... how do you go about testing and finding the reason for all this wierdness? Cheers Dan Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted March 17, 2008 Share Posted March 17, 2008 Does the WL have a decent connection on the back of the alternator? to test the WL wire, if you remove it from the alternator and earth it, the dash light should come on. the WL circuit is used to energise the alternator on starting, so if the WL wire isn't connected, or is connected badly, it would explain some of the alternator's poor performance. Quote Link to comment Share on other sites More sharing options...
v8bertha Posted March 17, 2008 Author Share Posted March 17, 2008 Does the WL have a decent connection on the back of the alternator?to test the WL wire, if you remove it from the alternator and earth it, the dash light should come on. the WL circuit is used to energise the alternator on starting, so if the WL wire isn't connected, or is connected badly, it would explain some of the alternator's poor performance. Yup, the wire if eathed makes the light come on... thats a darn sight easier than taking the bulb out, init!! With the ignition off, should there be 12 volts at that pole? Cos there is Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted March 17, 2008 Share Posted March 17, 2008 nope, that explains why the WL isn't lighting. I'd say diode fault in the alternator. Quote Link to comment Share on other sites More sharing options...
steve_a Posted March 18, 2008 Share Posted March 18, 2008 Take the brush pack off the back of the alt as a start. I had similar issues and it turned out that salisbury plain chalk is great for binding the bushes up. The pack has 2 sets of brushes, one of which is connected to warning light as the engergising current, if this is stuck and not connecting then you don't get light and depending on luck you don't get the alternator excited and hence no charge. If there is no sign of that then it will probably be the diodes, which AFAIK means taking the alt apart to fix it (the diodes will be under the rear cover). Send a pm to SimonB if this is the case, he does a home hobby of replacement alts and will do a swap for your yours at a sensible price and is over in Fareham. He will also provide much better electrikery help... S Quote Link to comment Share on other sites More sharing options...
v8bertha Posted March 18, 2008 Author Share Posted March 18, 2008 Luke, cheers... So I definately know I have two alternators with the same fault! Steve_a... cheers for the contact, I'll drop him a PM see what he has knockin about Quote Link to comment Share on other sites More sharing options...
v8bertha Posted March 20, 2008 Author Share Posted March 20, 2008 Good news I have solved part of the problem. I tested one of my alternators on a mates motor... same problem with the ignition warning light, so I went out and bought a shiny new alternator and fitted that. Bingo, Ignition warning light now comes on (And goes off again when the engine is ruinning ) BUT..... ( and you though it was all over so soon!!) I still have concerns. What would be a normal amount of voltage drop between the alternator and the battery. My new alternator is chucking out 13.9 volts, but only 13.4 is getting to the battery. This isn't enough to trigger the voltage sensitive relay (split charge thingy) which opens and allows the second battery to charge once 13.7 volts has been reached. I know its only half a volt, but it makes a big difference. Am I right in thinking that I can run a new wire directly from the alternator to the battery to test? Does the normal wire run through a relay or anything like that? Once the wire is in, if it increases the charging voltage at the battery, will it do any harm if I leave it there? Cheers again chappies Dan Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted March 20, 2008 Share Posted March 20, 2008 No harm in running a new wire from the alternator to the batteries. The original wiring is from the alternator, to the post on the starter motor, and then to the battery. You're right to be concerned about the voltage, the battery needs 13.9 - 14.4 volts across it. Quote Link to comment Share on other sites More sharing options...
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