classic battery warning light

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Well just done mine fitted ok though bit fidly, but...........exactly the same battery warning light glows and gets brighter with any load ie lights and when engine revvs

Could it be anything else other than the alternator? before i spend money i dont have
 
the plot thickens just been on to Paddocks and they recon its the wrong alternator on it, its an rtc5680e 65A , as its a brooklands with air con they recon it should be an 80A , as its only done 90,000 , thought it was a factory fitted item

while i think would this problem account for the engine running slightly rough?
 
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Well just done mine fitted ok though bit fidly, but...........exactly the same battery warning light glows and gets brighter with any load ie lights and when engine revvs

Could it be anything else other than the alternator? before i spend money i dont have

Connect a jump lead between the battery negative and the exhaust manifold and see if it turns over faster when trying to start it.
I suspect you have a bad earth and no matter how many alternators you fit they will all light the light and possibly be broken.
I have seen this so many time before on various vehicles.
The alternator being the wrong size would just affect the charging of the battery as assuming its wired correctly the light should go out once the engine starts
 
the fault you describe is a dodgy diode in the rectifier pack..its soldered in place..

the alternator is a 3 phase AC generator, the diode pack is there to convert the ac to dc that the car wants to see..

if light is glowing replace the alternator..it aint worth repairing as a new/recon one is so cheap..UNLESS you get gen OE diode pack cheap..thats gen lucas or whatever make alt is, dont need to buy from LR..AND THEN you must be able to solder proper like..
while replcing diode pack change reg/brushes and bearings..silly not to..

cost of above= to buying a new one with warrenty..

and as to worth doing soon..yes.unless you wanna breakdown in the cold at night..
 
Connect a jump lead between the battery negative and the exhaust manifold and see if it turns over faster when trying to start it.
I suspect you have a bad earth and no matter how many alternators you fit they will all light the light and possibly be broken.
I have seen this so many time before on various vehicles.
The alternator being the wrong size would just affect the charging of the battery as assuming its wired correctly the light should go out once the engine starts
No earth to the alternator and the charge light should not illuminate as it's circuit is from 12 volts at the dash then via the regulator and armature coil to earth. It is extinguished when the alternator starts to charge by the voltage developed in the field coils feeding via the regulator to the armature, thus the lamp has 12 volts on each side.
Size of the alternator has little effect on battery charging as the charge rate drops to a few amps within a very short time, it does however affect the power available for all the lights, ECU's and other gizmo's.
 
Sorry im getting confused, is it worth trying the earth from battery negative terminal to the manifold to see if the charging light goes off therefor indicating a bad earth somewhere in the circuit , or are we saying that after fitting a new regulator pack and its still wrong then a newe alternator is the only answer : )
 
Sorry im getting confused, is it worth trying the earth from battery negative terminal to the manifold to see if the charging light goes off therefor indicating a bad earth somewhere in the circuit , or are we saying that after fitting a new regulator pack and its still wrong then a newe alternator is the only answer : )
No earth and the charge light will not illuminate, poor earth and it will illuminate but should also go out.
No harm in trying a jump lead from the alternator case to battery negative.
If the regulator or brushes are badly fitted or you have the wrong or faulty regulator it would cause the problem.
 
What Zen is saying is that it looks like the diode pack is gone.

an alternator is simply a shaft with magnets and a wound wire. like an electric motor, when it spins, the effect of the magnets and the wound coil creates a charge (an electric motor works in a simlar fashion, but putting elctricity through the wound wires causes the motor to spin the shaft.. an alternator works the same way but opposite, the spinning shaft creates an electric field)

if the diode packs are failing (a diode allows electricity to flow one way but not the other IE out of the alternator) then that would create a fault. the regulator regulates the amount of electricity (if the shaft is spinning fast or slow as with engine revs, its driven by the engine remember) then the output would change with engine RPM so the regulator regulates the output.

In short what Zen is saying is that if the regulator is good, then it's probably the diode pack and if you are going to replace one, might as well replace both so you have in effect refurbished the electrical components of the alternator.

what winchman is saying is check the earthing.. a poor earth can cause faults so check that too.

I'm going to go ahead and get a diode pack and replace it.. ive done the reg so may as well do the diode pack. Electrics can last for decades or for weeks, days, seconds.
7 quid for a regulator and 11 for a diode pack is cheaper than a new alternator (a shaft with magnets, wound wire, regulator and diode pack in a housing) i will of course check the earths anyway and the bearing on the shaft has no play.
 
What Zen is saying is that it looks like the diode pack is gone.

an alternator is simply a shaft with magnets and a wound wire. like an electric motor, when it spins, the effect of the magnets and the wound coil creates a charge (an electric motor works in a simlar fashion, but putting elctricity through the wound wires causes the motor to spin the shaft.. an alternator works the same way but opposite, the spinning shaft creates an electric field)

if the diode packs are failing (a diode allows electricity to flow one way but not the other IE out of the alternator) then that would create a fault. the regulator regulates the amount of electricity (if the shaft is spinning fast or slow as with engine revs, its driven by the engine remember) then the output would change with engine RPM so the regulator regulates the output.

In short what Zen is saying is that if the regulator is good, then it's probably the diode pack and if you are going to replace one, might as well replace both so you have in effect refurbished the electrical components of the alternator.

what winchman is saying is check the earthing.. a poor earth can cause faults so check that too.

I'm going to go ahead and get a diode pack and replace it.. ive done the reg so may as well do the diode pack. Electrics can last for decades or for weeks, days, seconds.
7 quid for a regulator and 11 for a diode pack is cheaper than a new alternator (a shaft with magnets, wound wire, regulator and diode pack in a housing) i will of course check the earths anyway and the bearing on the shaft has no play.
There are no permanent magnets in an alternator, that's why the current flow from the charge light is needed to kick of the generating process.
 
ok thanks got it :) will go for the diode pack, thats obviously a alternator off the car job, am i right in understanding there will be some soldering involved
 
just been out and done the earth test with jump lead and no difference so thats it i guess diode pack or new alternator
 
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