the-lase-rate Posted February 28, 2014 Share Posted February 28, 2014 Hi all, After 15 minutes driving today, my battery light started to flicker on and then stayed on, and will only go off at high revs. I checked battery voltage and it was 12.7 off, 12.5 at idle... The light comes on with just ignition on. Probably unrelated, but also today whilst driving the power cable to the fuel pump popped off (the roads are bumpy round here!) so it ground to a halt while idling but easily solved. Its a 1986 110 with 300tdi conversion. Any ideas what this problem might be would be most appreciated.. is it the alternator?? Cheers. Quote Link to comment Share on other sites More sharing options...
SORNagain Posted February 28, 2014 Share Posted February 28, 2014 It's definately not charging then... Alternator does sound suspect - I'm just wondering if the brushes fail open then would this leave the charge light on or off? Not sure - off probably. Which means the flickering is difficult to explain; I normally expect rectifiers & regulators to go with a pop! I guess all you can do is check the connections and then throw a new one on it. I'd check the voltages on the back of the alternator to see if it's a wiring problem. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted February 28, 2014 Share Posted February 28, 2014 Sounds like a brush has fallen to bits in the alt to me. Quote Link to comment Share on other sites More sharing options...
AMB Posted February 28, 2014 Share Posted February 28, 2014 May be the regulator or the field winding connection on the alternator Quote Link to comment Share on other sites More sharing options...
the-lase-rate Posted February 28, 2014 Author Share Posted February 28, 2014 Hmm doesnt sound good. I'll try to take the alternator off tomorrow and see whats happening inside.. Thanks for the advice guys! Quote Link to comment Share on other sites More sharing options...
the-lase-rate Posted March 2, 2014 Author Share Posted March 2, 2014 All the wiring looks fine, I suspect its the diodes or something... So, I am planning to order a new alternator and probably a 100amp one as in the future I am planning to split charge to two batteries. I've read elsewhere that I would need to double up the brown wire to the starter motor is that correct? Are there any other changes that I should do at the same time? Cheers, Luke Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted March 2, 2014 Share Posted March 2, 2014 You dont need a 100amp alt to charge 2 batteries. 65amp is ample. Quote Link to comment Share on other sites More sharing options...
the-lase-rate Posted March 2, 2014 Author Share Posted March 2, 2014 You dont need a 100amp alt to charge 2 batteries. 65amp is ample. Ahh. My bad. Quote Link to comment Share on other sites More sharing options...
AMB Posted March 2, 2014 Share Posted March 2, 2014 New regulator (incl brushes) for an A127 less than £10 incl postage. Complete repair kit (regulator, brushes, rectifier, slip rings and bearings) <£25 on Ebay, compete with instructional video. Suggest that you check the earths and tidy up as necessary and, if your alternator is fitted with a sense wire make sure trhat it connects to the battery via a low current path Quote Link to comment Share on other sites More sharing options...
the-lase-rate Posted March 2, 2014 Author Share Posted March 2, 2014 Great. Thanks. I prefer fixing things rather than just getting rid of it. Cheaper too Quote Link to comment Share on other sites More sharing options...
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