Landy7 Posted March 14, 2017 Share Posted March 14, 2017 For my 200tdi (disco engine) I ordered a new Britpart DA1196 alternator, it's a 100A one, I also installed new belt. Connected battery to the B+ terminal but battery is not charging. I connected a 'volt meter' to the B+ terminal when the engine was running but .. 0V .. Did I miss something? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 14, 2017 Share Posted March 14, 2017 Have you connected the other thin wire up? Even if not, it should still get going itself when you raise the revs to say 2000rpm. If still nothing then you have a duff item, hardly surprising really, given the name of the supplier. Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted March 14, 2017 Share Posted March 14, 2017 You need the thin wire to excite the alternator, it may not even kick in, even at high revs. Cheers Peter Quote Link to comment Share on other sites More sharing options...
Landy7 Posted March 14, 2017 Author Share Posted March 14, 2017 No I did not connect the thin wire, can't remember I ever did that? I thought that was for the warning light or something? Quote Link to comment Share on other sites More sharing options...
western Posted March 14, 2017 Share Posted March 14, 2017 it is for the charge light but also 'excites' the alternator to get it charging, connect the thin brown/ yellow trace wire to the WL or IND terminal Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted March 14, 2017 Share Posted March 14, 2017 The charge light actually creates a small amount of current that starts the alternator charging, which then self excites and when that point is reached, the charging light goes out, so you know it is working! Simples! It's normally a spade connector. Cheers Peter 1 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 14, 2017 Share Posted March 14, 2017 Indeed, connect all the wires Quote Link to comment Share on other sites More sharing options...
Landy7 Posted March 15, 2017 Author Share Posted March 15, 2017 Thanks guy's, makes sense! Will try that in the weekend, need to extend that thin cable.. Quote Link to comment Share on other sites More sharing options...
David Sparkes Posted March 16, 2017 Share Posted March 16, 2017 It's about now I start to wonder if the previously unused thin wire is still connected to an ignition switched 12 volt supply behind the dashboard. Regards Quote Link to comment Share on other sites More sharing options...
Snagger Posted March 17, 2017 Share Posted March 17, 2017 Sort of. It runs from an ignition switches feed in the fuse box via the charge warning light on the instrument panel to the alternator diode pack. When you switch the ignition on, battery power runs through the lamp, illuminating it, and energises the field coils in the alternator. Once the engine is running, the alternator becomes self-exciting and sends power back along the thin wire to the bulb. Now that the bulb is getting decent voltage from both sides, there is no current and the bulb extinguishes. Stop the engine with the ignition still on and the alternator will no longer self-excite and will draw battery power again through the bulb. However, if you don't have that batter power to excite the alternator coils, it won't produce power until it gets to very high rpm. Think of it as a magnetic primer. Quote Link to comment Share on other sites More sharing options...
neil110 Posted March 17, 2017 Share Posted March 17, 2017 (edited) On mine the exciter wire at the alternator is the standard brown/yellow. However, somewhere in the recesses of the dashboard there is somethng which looks for all the world like an inline fuse holder. After which the wire, to the warning light, is white. Within the confines of the fuse holder is something which is the same sort of size and shape as a glass cartridge fuse, but it isn't a fuse, at least I don't think it is. It has the same end caps as a glass fuse but the bit between the end caps is covered in a the same sort of stainless mesh as Aeroquip brake hoses. I have a spare one in my electrics box, just in case, if anybody is curious I will take a picture of it. Question is, what is it's function? Edited March 17, 2017 by neil110 Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted March 17, 2017 Share Posted March 17, 2017 Diode possibly? Cheers Peter Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 17, 2017 Share Posted March 17, 2017 LR did fit diodes to prevent the charge back-feeding the ignition system, on diesels you only need enough power to keep the stop solenoid energised to "leak" back up the wire and it'll never shut off. Quote Link to comment Share on other sites More sharing options...
GW8IZR Posted March 17, 2017 Share Posted March 17, 2017 2 hours ago, neil110 said: On mine the exciter wire at the alternator is the standard brown/yellow. However, somewhere in the recesses of the dashboard there is somethng which looks for all the world like an inline fuse holder. After which the wire, to the warning light, is white. Within the confines of the fuse holder is something which is the same sort of size and shape as a glass cartridge fuse, but it isn't a fuse, at least I don't think it is. It has the same end caps as a glass fuse but the bit between the end caps is covered in a the same sort of stainless mesh as Aeroquip brake hoses. I have a spare one in my electrics box, just in case, if anybody is curious I will take a picture of it. Question is, what is it's function? Its a resistor, it's in parallel with the warning light so that the failure of the charge warning light on the dash doesn't stop the alternator getting excited. on TDI's only a tiny amount of current is needed to hold the fuel solenoid open once its been activated. On TDI conversions using the old NA Di or 4cyl petrol wiring the combination of the resistor and charge indicator current is often enough to hold it open when you turn the key to position zero. This can be resolved by fitting a diode capable of handling a few amps and with a PIV of more than about 50V in series with the excite wire, a 1N5401 will do the job. A disadvantage / unintended consequence of fitting the diode is that there is a bit of volts drop and sometimes a blip of accelerator is needed to get the alternator going. HTH Quote Link to comment Share on other sites More sharing options...
neil110 Posted March 17, 2017 Share Posted March 17, 2017 Thank you for clarifying that for me gentlemen. The engine is a V8. The wiring harness is a military item which came from autosparks at a silly cheap price. Lots of fun removing items intended to stop things from working and trying to decipher the non standard wiring colours. Grey/brown for indicators and similar pleasant surprises Quote Link to comment Share on other sites More sharing options...
Landy7 Posted March 26, 2017 Author Share Posted March 26, 2017 allright, I extended the thin brown/yellow wire to the alternator (D+), when I turn the ignition key, the battery light is lit, but even when the engine is running, it stays lit I connected a voltage meter to the B+ terminal but nothing, 0V .. even at high rpm's, battery light in dash stays lit.. When I put the voltage meter on the D+ terminal, I get 2.5V, is that enough? What else can I try? It looks like it's a dead on arrival part.. Quote Link to comment Share on other sites More sharing options...
western Posted March 26, 2017 Share Posted March 26, 2017 charge light [red battery] light on dash should be connected to terminal marked WL or IND or D+ as the alternator is not giving a outputvoltage reading I reckon it's duff, you should be getting at least 14 volts & often seen the charge light on which indicates no charge with engine running & damaged or dead diodes on the rectifier pack inside the alternator case. Quote Link to comment Share on other sites More sharing options...
Landy7 Posted March 26, 2017 Author Share Posted March 26, 2017 Bummer, it's a brand new one, I already contacted the supplier (lrdirect) but I need to ship the part, after they received it they will test the part and when it's indeed faulty, ship a new one, prox. 4 weeks.. I can't keep it in the garage for 4 weeks :/ Quote Link to comment Share on other sites More sharing options...
western Posted March 26, 2017 Share Posted March 26, 2017 they should be doing a direct swap, not keep you waiting for a replacement in 4 weeks time Quote Link to comment Share on other sites More sharing options...
Ex Member Posted March 26, 2017 Share Posted March 26, 2017 If there is zero volts at the B+ connection, then the other end of the wire can't be properly connected to the battery. It should, in the least, show battery voltage. Quote Link to comment Share on other sites More sharing options...
Landy7 Posted March 27, 2017 Author Share Posted March 27, 2017 The B+ terminal is connected to a 'battery splitter' because I have 2 batteries installed, so maybe that's why it's showing 0V .. I might have an old alternator that could still be working, I will try that today. Quote Link to comment Share on other sites More sharing options...
Mediamab Posted February 27, 2022 Share Posted February 27, 2022 On 3/14/2017 at 8:37 PM, Puffernutter said: The charge light actually creates a small amount of current that starts the alternator charging, which then self excites and when that point is reached, the charging light goes out, so you know it is working! Simples! It's normally a spade connector. Cheers Peter Hi! Jumping in as I’ve managed to cause this issue with my TD5, no battery light and now charge when engine running. I’m a bit confused where to find this wire and connector though? I was changing the bulbs so assume I’ve knocked it out but struggling to know what to look for? Quote Link to comment Share on other sites More sharing options...
western Posted February 27, 2022 Share Posted February 27, 2022 Td5 uses a battery sensed alternator so is slightly different to Tdi vehicles. Quote Link to comment Share on other sites More sharing options...
Mediamab Posted February 27, 2022 Share Posted February 27, 2022 10 minutes ago, western said: Td5 uses a battery sensed alternator so is slightly different to Tdi vehicles. Ah so this may not be my issue? The battery stopped charging (when engines running) since I reconnected everything and the battery light also no longer shows when I turn on ignition. Any thoughts? Quote Link to comment Share on other sites More sharing options...
Escape Posted February 27, 2022 Share Posted February 27, 2022 59 minutes ago, western said: Td5 uses a battery sensed alternator so is slightly different to Tdi vehicles. I don't think they do. The wiring diagram shows the NY wire going through a header and then to the warning light, if the light has failed or has a bad connection, the alternator will not get the current to excite it. If the dash was out recently and the light never comes on, that's were you need to start your search. Quote Link to comment Share on other sites More sharing options...
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