Krismc
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| posted on 28/3/11 at 06:31 PM |
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Alternator Questions?
Had a alternator it lasted few years while building car it went to MNR and the Alternator Failed they replaced it and recently it failed again, i
suspected it was a wiring fault so ive added a diode to charge warning light wire, Alternator was refubished today and i fitted it straight away but
it doesnt work. WHY??
Turn too ignition and no battery light, start car and no charge and still no battery light.
There are 2 wires, One large (red) charge wire, One Small (brown) charge light wire, on the alternator ive got 3 terminals, 2 big terminals (positve)
and linked together internally and 1 small terminal (for charge light) and it earths through chassis.
I connected the diode inline on the charge light wire Cathode (white stripe) away from the starter.
Just like this which i slightly edited/stole from google
Do alternators only charge spinning in one direction?? or could he have wired it wrong??
Here is my engine and the alternator - is it running right direction?
Let me get this right.... the Engine runs clockwise, water pump anti clockwise and there for alternator clockwise.
(Crank - rusty, waterpump-orange and alt - silver)
Ideas, opinions and jokes all welcome 
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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daviep
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| posted on 28/3/11 at 06:42 PM |
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You're diode looks wired in the wrong way if it's in the way it's drawn!!!
Alternators will charge spinning both ways but the fan only works one way.
Davie
“A truly great library contains something in it to offend everyone.”
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Krismc
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| posted on 28/3/11 at 07:04 PM |
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quote:
Originally posted by daviep
You're diode looks wired in the wrong way if it's in the way it's drawn!!!
Alternators will charge spinning both ways but the fan only works one way.
Davie
Diode, cathode- white stripe towards car, anode- black end towards alt.
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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daviep
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| posted on 28/3/11 at 07:07 PM |
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Sorry didn't read the text properly sounds like you have wired it in the correctly but drawn it backwards 
Why have you fitted a diode? What was your original wiring fault? Have you tried the new alternator without the diode?
Cheers
Davie
[Edited on 28/3/11 by daviep]
“A truly great library contains something in it to offend everyone.”
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Krismc
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| posted on 28/3/11 at 07:27 PM |
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My 3rd alternator in 4 years(50miles) plus lots of rolling roads. Last one fitted a few months back before iva and then it burnt out first time
legally on road, I suspect cause I had 12v on the warning wire, just on ignition and even when not connected so its backfeeding from bright6.
Surly I don't need charge warning wire even connected to get alt power
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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ReMan
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| posted on 28/3/11 at 07:37 PM |
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I dont know which thread to respond to now !
Have you got a diagram for the Bright 6 thing you can post?
Need to understand that too I think
www.plusnine.co.uk
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Krismc
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| posted on 28/3/11 at 07:41 PM |
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quote:
Originally posted by ReMan
I dont know which thread to respond to now !
Have you got a diagram for the Bright 6 thing you can post?
Need to understand that too I think
Sorry yea, that makes both of us. Bright6 drawings all over net and there website, in tintop at moment so can't grab one. But will later.
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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daviep
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| posted on 28/3/11 at 07:42 PM |
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As per your drawing the charge light is fed a permanent live from the ignition at all times, it is required to "excite" the alternator to
get it charging. The current flows from battery through the charge light, through the field windings and to earth. Once the alternator begins charging
the small terminal on the alternator comes up to 12v and then there is no difference across the bulb and it goes out.
A quick google shows that bright 6 warning lamps are LED's, there is a well known problem using LED's to excite the alternator in that the
low resistance of the LED doesn't draw enough current to get charging started, it's been discussed on here loads but not for a while.
Davie
“A truly great library contains something in it to offend everyone.”
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Krismc
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| posted on 28/3/11 at 07:45 PM |
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So what you are saying is I don't need a diode, then why would I keep killing alternators?? I've got a good earth, decent battery leads,
could my battery be too small or vice versa? I don't want too connect it back up until I'm sure of fault, cheers for that post its
enlightened me.
[Edited on 28/3/11 by Krismc]
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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ReMan
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| posted on 28/3/11 at 07:51 PM |
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quote:
Originally posted by daviep
As per your drawing the charge light is fed a permanent live from the ignition at all times, it is required to "excite" the alternator to
get it charging. The current flows from battery through the charge light, through the field windings and to earth. Once the alternator begins charging
the small terminal on the alternator comes up to 12v and then there is no difference across the bulb and it goes out.
A quick google shows that bright 6 warning lamps are LED's, there is a well known problem using LED's to excite the alternator in that the
low resistance of the LED doesn't draw enough current to get charging started, it's been discussed on here loads but not for a while.
Davie
This is whate I was wondering now i've seen the diagram.
Some alts may get upset at not having the detect wire connected to 12v too and try to overcharge
www.plusnine.co.uk
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Krismc
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| posted on 28/3/11 at 07:59 PM |
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Hmm, so I've had it wired right, I don't need diode, alternator should be ok, 12v on that wire is fine.
If I remove diode it will work, but what keeps causing fault are you saying The bright6 cannot be used with this type off alternator, should I change
the battery warning too a different type?
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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daviep
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| posted on 28/3/11 at 09:17 PM |
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You definately shouldn't need a diode in the circuit, although I believe some people add them to prevent running on without any problems.
Internet seems to suggest that Bright6 module should excite the alternator.
What keeps popping your altenator.
Yeah I don't know sorry 
Where have you been buying your replacements?
Davie
“A truly great library contains something in it to offend everyone.”
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Krismc
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| posted on 29/3/11 at 08:19 AM |
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Surely if the alternator is used too seeing 12v to excite it, then pops up to 14v when charging, that extra voltage normally keeps the bulb off - so
do i need a resistor saying as ive only got a LED (bright6)
and whats the conversion again??
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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daviep
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| posted on 29/3/11 at 08:32 AM |
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You could try running a 3w bulb as a temporary charge warning light and see how you get on.
Is the alternator situated somewhere really hot like under the exhaust manifold?
Here is a nice basic drawing of a charging circuit
[Edited on 29/3/11 by daviep]
“A truly great library contains something in it to offend everyone.”
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Krismc
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| posted on 29/3/11 at 08:50 AM |
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Under neath exhaust and water pipe yes, 2 inches from pipe, 10inches from manifold? I've got heat retention problem under bonnet, see other
thread which I'm fixing also
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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Krismc
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| posted on 29/3/11 at 10:37 AM |
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I've ducted the alt with some tubing, just in case, removed diode and hey presto the car starts and charges, but runs on after switching off.
Edit... Spoke too bright6 technical, some alternators (not many 2 i think he said)with a certain field resistance and in this case mine, have a issue.
Im going too try a bulb in parallel with the charge warning led 2moro and see if that helps,
Am i getting this right a 28 Ohm bulb is around 5W??, bloomen halfords dont have them marked up properly it says 12v 28Ohm
[Edited on 29/3/11 by Krismc]
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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daviep
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| posted on 30/3/11 at 12:44 PM |
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Can you post a wiring diagram of your car?
Davie
“A truly great library contains something in it to offend everyone.”
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Krismc
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| posted on 31/3/11 at 02:09 PM |
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quote:
Originally posted by daviep
Can you post a wiring diagram of your car?
Davie
I could but i never got one, i just got a connection list. unless another MNR owner has one??
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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