Glyn Harper Posted May 21, 2018 Report Share Posted May 21, 2018 I recently fitted a recon alternator I got from the USA which is a straight swap for a standard one. Sure enough it went on fine. The main pulley was slightly larger so I had to go up one belt size (only a couple of cm longer) When driving though, the red battery light is staying on, although not as bright as normal. ive just driven about 20 miles, checked the battery, and it has 13.43v in it so I’m not sure exactly what’s going on to be honest. I’ve checked the smaller wire is connected to the small terminal and it is. Any ideas? If it wasn’t charging, would it have gone flat in the 20 miles or so I drove the car? I’m wondering if it’s the ecu giving an incorrect reading or something like that, as It’s possible my battery warning wire comes from the emerald m3d ecu I have. I can’t remember exactly as I fitted it about 18 years ago Any checks I can do? Quote Link to comment Share on other sites More sharing options...
Glyn Harper Posted May 21, 2018 Author Report Share Posted May 21, 2018 Just checked the bent tension which seems ok. But it’s definitely not charging. Ran the engine with amultimeter on the battery and watched it slowly going down. Quote Link to comment Share on other sites More sharing options...
Gold FFM Sparky Posted May 21, 2018 Gold FFM Report Share Posted May 21, 2018 Stick the multimeter on the alternator output whilst idling. What does it read? Quote British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland. And Shitfaced Silly Sod to Sweden. Link to comment Share on other sites More sharing options...
Glyn Harper Posted May 21, 2018 Author Report Share Posted May 21, 2018 (edited) Is that on the smaller connector or the main one? The smaller connection gives me 1.95v at idle. Edited May 21, 2018 by Glyn Harper Quote Link to comment Share on other sites More sharing options...
Gold FFM Sparky Posted May 22, 2018 Gold FFM Report Share Posted May 22, 2018 The big one. Quote British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland. And Shitfaced Silly Sod to Sweden. Link to comment Share on other sites More sharing options...
Glyn Harper Posted May 22, 2018 Author Report Share Posted May 22, 2018 Ok, do I disconnect the wire from it first? Otherwise I guess I’m just reading the battery voltage. Quote Link to comment Share on other sites More sharing options...
Gold FFM Sparky Posted May 22, 2018 Gold FFM Report Share Posted May 22, 2018 No, just probe the output. Try and read it at idle and at approx. 3000RPM. Quote British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland. And Shitfaced Silly Sod to Sweden. Link to comment Share on other sites More sharing options...
Glyn Harper Posted May 22, 2018 Author Report Share Posted May 22, 2018 (edited) Ok, it’s just that the big wire goes to the starter and then the battery so am I not just going to read that? or do you mean to check if I’m getting a loss along the cables? I was only seeing the battery level drop when I tested at the battery end, so yeah, I’ll check what I get directly at the alternator when I pull it out today. I need to the use it to go on a course today, typical! My daily driver is in having the bumper painted. Edited May 22, 2018 by Glyn Harper Quote Link to comment Share on other sites More sharing options...
Jacques Posted May 22, 2018 Report Share Posted May 22, 2018 While it's just a suggestion, and knowing that your alternator is brans new, I would still take the Liberty taking a peek at the pick up points and see if they were touching coorrectly, as well as internal wires from those pick ups to the voltage regulator. Just a suggestion. Dead earth wire or point? Kind regards, jacques Quote Nobody does it better - than Lotus Link to comment Share on other sites More sharing options...
Glyn Harper Posted May 22, 2018 Author Report Share Posted May 22, 2018 I did check the connections last night which did seem to be ok. But I’ll do some continuity checks this morning to make sure. Thanks everyone. Quote Link to comment Share on other sites More sharing options...
Glyn Harper Posted May 22, 2018 Author Report Share Posted May 22, 2018 It showed about 13.4v before starting the car, then 12.5 when I had, and then gradually goes down rather than up. New alternator I guess. Quote Link to comment Share on other sites More sharing options...
Gold FFM Sparky Posted May 22, 2018 Gold FFM Report Share Posted May 22, 2018 You need to check the alternator output. 13.43v if engine not running is suspiciously high. Your alternator may be overcharging, and this can cause the light to flicker. You can check this by reading the alternator output directly at the output pole. You say you got it from the States? Maybe it's a left-hand drive alternator. 1 1 Quote British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland. And Shitfaced Silly Sod to Sweden. Link to comment Share on other sites More sharing options...
Glyn Harper Posted May 22, 2018 Author Report Share Posted May 22, 2018 It is an alternator meant for the Esprit. its only 13.3v when I’ve just taken it off the battery charger. It drops back to about 12.5 pretty quick after the charger comes off. i tested it with the engine running at the alternator output and it was just going down from 12.5 which I’m pretty ire was just reading charge from the battery. going to order another from SJ today. Pretty sure it’s faulty. I’ll see if I can get a refund. Quote Link to comment Share on other sites More sharing options...
Gold FFM Barrykearley Posted May 22, 2018 Gold FFM Report Share Posted May 22, 2018 Alternators work or don’t Quote Only here once Link to comment Share on other sites More sharing options...
Glyn Harper Posted May 22, 2018 Author Report Share Posted May 22, 2018 Well, how about this for odd. I had to use the car today to go on a course, and all the way there it had the battery light on as it has been for the last few journeys. I parked it up all day, but when I drove it home after being in the course for about 6 hours.. no battery light. I checked when I got home with a meter (engine still running) and it was showing 13.6v! I shut the engine off, and the battery was still at about 13.4v, so fully charged. So somehow, it's mysteriously come back to life while it was say for 6 hours.. either that or it's just going to be intermittent from now on. I'll leave the other one on order with SJ Sportscars anyway as I'm always going to be worried about it otherwise. But any idea what would cause it to do this? Most strange. As you say, they either work or they don't, normally. Quote Link to comment Share on other sites More sharing options...
Gold FFM Barrykearley Posted May 22, 2018 Gold FFM Report Share Posted May 22, 2018 Check the earth to that alternator. Are you sure the mounting is tight Quote Only here once Link to comment Share on other sites More sharing options...
Glyn Harper Posted May 22, 2018 Author Report Share Posted May 22, 2018 I checked and tightened it all last night, and it was fitted with new bolts when I installed it in August, so it should be ok. I'll check though for sure. It's weird how it wasn't charging this morning, then after being left alone all day worked perfectly on the way home. Quote Link to comment Share on other sites More sharing options...
Gold FFM Barrykearley Posted May 22, 2018 Gold FFM Report Share Posted May 22, 2018 It earths through that mounting bolt - it’s critical it’s tight Quote Only here once Link to comment Share on other sites More sharing options...
Glyn Harper Posted May 22, 2018 Author Report Share Posted May 22, 2018 It is pretty tight now, yeah. I fair swung on it last night. Hard to get to, but I did make it quite tight. Quote Link to comment Share on other sites More sharing options...
Glyn Harper Posted May 22, 2018 Author Report Share Posted May 22, 2018 This is odd. Tried the car again tonight and it wasn’t charging again. Ran a temporary Earth lead to check if it was a bad earth but that made no difference. I decided to see if it really go flat so I put all the fans, lights and stuff on to draw as much load as possible. Then a few minutes later it started charging again fine! as it’s not a genuine Lotus alternator, is it possible it’s some sort of intelligent system that only starts charging when the voltage drops below a certain amount? Quote Link to comment Share on other sites More sharing options...
Chillidoggy Posted May 23, 2018 Report Share Posted May 23, 2018 The alternator voltage regulator does just that - it senses voltage within pre-set limits and regulates accordingly. Around about 14 - 14.2 volts, I think, depending on the regulator. If the previous alternator was working OK, then it suggests the new one is faulty in some way. Quote Margate Exotics. Link to comment Share on other sites More sharing options...
Glyn Harper Posted May 23, 2018 Author Report Share Posted May 23, 2018 (edited) I spoke to the company in the US I got the alternator from and they tell me they never have issues with the actual alternators, so they also suspect the regulator. I think it's somehow set too low, so it's only kicking in below 12.3v or something. Which is actually fine in a way, but I'd rather it right. So yeah, sounds like you're correct there Ian. They're sending me another one to swap it. I've also ordered a new plenum chamber gasket as I've worked out it's going to be easier to remove the plenum box to get to the regulator than remove and refit the alternator again to do it! Edited May 23, 2018 by Glyn Harper Quote Link to comment Share on other sites More sharing options...
CarBuff Posted May 23, 2018 Report Share Posted May 23, 2018 16 hours ago, Glyn Harper said: as it’s not a genuine Lotus alternator, is it possible it’s some sort of intelligent system that only starts charging when the voltage drops below a certain amount? LOL "Intelligent Charging System"????? 🤣 Maybe. If you leave your headlamps on, they go out all by themselves, eventually. 1 Quote Atwell Haines '88 Esprit Succasunna, NJ USA Link to comment Share on other sites More sharing options...
Glyn Harper Posted May 23, 2018 Author Report Share Posted May 23, 2018 Ha ha!! I'm so used to the IBS intelligent battery system on my BMW. I think on a Lotus it's more a case of when all the bad earths occasionally manage to make some contact! 😂 Quote Link to comment Share on other sites More sharing options...
Jacques Posted June 7, 2018 Report Share Posted June 7, 2018 Glyn, A new alternator with a new voltage regulator an dpick ups, will have to have the pick ups bed in to make them take the shape of the rolls inside the alternator. Can you show a Picture of the alternator you bought and a closeup of the voltage regulator? When my original voltage regulator melted it plastic on the rearside (towards the alternator itself), it dripped into the pickup points and the rolls the touch, preventing them from sending any voltage, or only a very low voltage, to the regulator, and then onwards. Take a look here: https://www.thelotusforums.com/forums/topic/67095-the-story-of-little-red-riding-hood/?page=15 Kind regards, Jacques Quote Nobody does it better - than Lotus Link to comment Share on other sites More sharing options...
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