New Alternator and Charge light question . Help !!

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M

mudmuncher

New Member
Posts
122
Hi Everyone

My alternator wasnt charging and the charge light didnt come on at ALL .

I brought a brand new alternator which i believe puts out a few more AMPS that the standard one .

My question is when i start the engine there is NO CHARGE LIGHT as soon as i rev it the charge light comes ON and stays ON !!!

Any one have any idea what the problem could be or should i just forget about it ??
Please help

Many thanks chris
 
Hi

No when i turn the ignition on the light does not come on at all !
As soon as i start the engine it comes on dim and when i rev it it lights up fully .

Like i say its a brand new alternator to i dont understand .

Chris
 
Hi Everyone

I am going to test the output with a multimeter tomorrow so i can see if its over charging or not .

When you test the output do you just check the reading across the battery when she is running, or should you put the lights, heater etc on ?

What range should the output be ??

cheers chris
 
Put the multimeter accross the battery.
With the ignition off you should have about 12 to 13v.
With the engine running you should get 13.5 to 14.5 v.
Any less and the battery will never charge up.
Any more and the battery will cook.
 
Hi Pat

Right i tested the battery with the engine switched off the result was 12.43 volts.

With the engine running at a fast tick over the resilt was 14.35 volts with and without lights fan heater etc

So as far as i know the alternator seams to be working ok.

The charge light seams to be wired up correctly i now comes on when the igntion is on BUT it still doesnt go out i am thinking of just disconecting it and not having a charge light

What do you think ?

Cheers chris
 
i think you need a light to make the alternator start chargeing i once had a light bulb wired to the back of my alternator because the red one on the dash was nt working and it would nt charge also worth cleaning any earths with a wire brush
 
The light is part of the charging circuit so you can't remove it or take out the bulb.
Can you try a different battery?
What is the voltage at 2000 to 4000 rpm?
 
i have heard of peeps changing the bulb fur a different wattage one tho.

just a thought - but it aint an alternator designed fur a deisel, is it? You havent connect the light wire to a rev counter output on the back of the alternator? that would be orf with engine off and, if it is a pulse circuit, would get brighter as the engine revs increased.
 
as MHM sorta suggested you might try a second bulb in series just as a quick check, also check that the dash bulb hasnt been changed for the wrong type

i dont suppose you have got a big load on the alt have you that might make it think it's not outputting enough current, which would then cause the bulb to light ?

my money is on it not being wired up quite right
 
Hi everone

The light comes on when on when i turn the ignition on so this is correct ?

The light is then wired to the back of the alternator on the small spade next to the 2 big spades in one complete plug

When the engine is running between say 1500 and 3500 revs the output is 14.35 volt but the light DOES NOT go out it just stays on !

Any ideas ?? can i just leave it how it is i wont disconnect it just leave it on all the time i know the alternator is charging by leaving it how it is will it cause any harm.

Any ideas anyone

Many thanks for all your replies
Chris
 
Hi, the alternator warning light is a 2.2w bulb this bulb should light up when the ignition is on, once the engine starts and runs the bulb excites the charging circuit and the system is up and running, well that’s the theory.
Disconnect the multi plug into the alternator, (ignition on)there should be no battery warning lamp illuminated. There should be three wires in this disconnected plug, the two large ones are direct battery feed, well via the starter motor solenoid junction ( be warned big sparks will fly if you short out the large wires) find the third small wire, this is the wire from the battery warning lamp, (ignition on) Earth out this wire and the warning lamp should illuminate, if it doesn’t you have another problem.
The circuit is simple, Heavy wires from the Alternator go to the battery for charging.
The ignition feeds battery voltage to and through the battery warning lamp (2.2W bulb, to the small wire into the Alternator, the Alternator earths out the bulb causing the bulb to illuminate until the charge takes over.(engine running)
;)
 
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