17 replies to this topic

[MrElliott]

Same as title. I have had three this year and cant narrow the fault down. It cant be right for them to keep dying. I have fitted electronic ignition recently. Could demanding higher current than its rated for damage an alternator? Not sure what amp the electronic ignition runs at.

Cheers for any help
elliott

[HarrysMini]

How do they break? Is the belt the correct tightness? If its too tight, it'll cause the bearings to fail prematurely.

[gazza82]

Unlikely to be the ignition ... you have to look at the total amps needed ...

What make and size amp (as in amperage) are you fitting each time? What pulley size (too small could be running it too fast)?

[ACDodd]

If you take the old unit too a rebuilders and ask them to tell you what has failed inside the alt. This will give you a good clue as to the likely cause. One of the biggest causes of alt failure is a loose plug. This generates arcing and hence large electrical spikes. These cause diode failure. If you still have the other alts they could very well be in otherwise excellent condition. As an alternator rebuilder myself, i am Happy to take a look for you if you can get them to me.

 

AC

Edited by ACDodd, 28 November 2014 - 07:35 PM.

[geoff-d]

Check the main live wire that runs under the car as they short out on the floor & the alternator will not like that .

[MrElliott]

Just went outside to see if it was any loose wiring and nothing obvious so i undone the alternator plug and put it back in and it all works again :/ im starting to think that there is just a break in the wiring to the alternator

[KernowCooper]

If you removed the plug and it started charging correctly again, then you need to remove the plug again (engine Off) and inspect the condition of the lucar connectors for weak clamping or burnt/dirty surface on the lucar. If in doubt replace if they look suspect, if you have trouble getting the right one mini spares keep them as a repair kit.

 

If you ignore it as AC has pointed out the issue of the contact being loose and the alternator spiking and taking out the diode pack.

[MrElliott]

thanks for the responses! ill get on to mini spares to grt that kit as the plug didnt exactly look mint :/

[MrElliott]

http://www.minispare...px|Back to shop

 

Is this the one you were sugesting? looks about right

[Spiffingly Good]

I had the same problem on a previous mini. Turned out to be a poor engine earth making the alternator work extra hard.

Check the output both at the battery terminals without load and underload, and also check the output taking the earth from a clean spot on the engine to a positive.

If there is a notable difference between the voltages most likely a earth.

[MrElliott]

So now instead of being either on or off my red dash light has started flickering and refuses to go out :/ i guess its new alternator time? I think im going to change the earth lead and plug too

[MrElliott]

I have found that its the tension of the pulley which is to blame :) i have brought a new earth lead and plug anyway so i can be sure to extend the life of my alternator. Thanks for your suggestions

Edited by MrElliott, 03 December 2014 - 05:33 PM.

[KernowCooper]

Your belt tension must have been really bad to not put the light out

[MrElliott]

Yer it was pretty loose as the nut on the adjuster bracket wasnt done up tight afted i swapped a fan belt :/

[Dusky]

For future reference for some people : 

 

my alternator had the same, sometimes it worked, sometimes it didn't, red light flickering on and off,...

 

The problem was that the startermotor nut was comming loose so there asn't enough contact area between the terminals of the alternator wires and the big posetive battery cable.