StuRox

StuRox

Well-Known Member
Howdy all,

Have a strange problem with my alternator, as some days it would seem there is no juice coming from it (as internal volt meters drop to arround 10 volts) then all of a sudden it sparks back into life.

Just done a load of tests on it tonight, and I don't think the alternator is at fault, as even with full load (absolutely everything on that we could think of) there was a steady 13.7 volt on the battery terminals. Only when I then put on my veggie heaters did it drop to around 13.4 volt.

I am not sure whether I have the 65amp or 100amp alternator, but I don't have air con if that helps.

I have recently had a bit of a problem with relays in my footwell (being knackered), no doubt a bit of water from one of the many holes :rolleyes: so was wondering where the wiring goes from the alternator, and if this goes to a relay somewhere that might have corroded connections etc...

Have checked the main fuse in the engine bay, and that is fine, although the top of the box says it should be a 100amp fuse, its only a 80amp fuse :confused:

Any comments appreciated, as driving me nuts.......

Cheers
 
alternator can get a bit lazy with old age, sometimes you can replace the regulator pack at the rear.

if you do any off road, give it a damn good jetwashing out with the engine off and then running, to swill the **** out. tbh perhaps try this anyway, mine really loves a good wash out.

we have a defender 300 at work that does not charge until you give the revs a blip. standard lazy alternator me says.

anyway, thats what i think :)
 
yeah, brush packs can wear, springs behind them get weaker...then add a bit of muck in there too, and ya get the symptoms youre gettin.
 
Thanks for that guys, will get the power washer out and give that a try before I shell out for a new one (that I ain't got the pennies for.....:( )
 
i have had lazy alternator out of the blue one day, power washewre curec it and ben fine since.

i have had lazy alternator after a mud bath at off road sites, glugs of water from bottle with engine runningcures that.

i have also had lazy alternator after a long drive and short stop. no amount of water cured that but a single plonk from the hammer sorted it instantly. that one must have been stuck brushes.

i recommend you try a combination of both :)
 
Still trying to sort this, and just checked voltage again today, and alternator is pushing out 13.96 volt and at the battery is 13.26 volt, so I know the voltage at battery is too low, but is it right that it loses volts from the actual alternator, and what voltage does a working alternator kick out from it?
 
Do a volt drop test between the alternator and battery.
Get a digital volt meter connect one end to the pos bat terminal and the other to the battery connection on the rear of th alternator, WITH THE ENGINE RUNNING you should have below 0.5v.
Do the same again between bat neg abd body of alternator, again you should have less than 0.5 v, anymore and you have a poor connection.
As posted before, it sounds like your regulator brushes to me.
 
stchris356 said:
Do a volt drop test between the alternator and battery.
Get a digital volt meter connect one end to the pos bat terminal and the other to the battery connection on the rear of th alternator, WITH THE ENGINE RUNNING you should have below 0.5v.
Do the same again between bat neg abd body of alternator, again you should have less than 0.5 v, anymore and you have a poor connection.
As posted before, it sounds like your regulator brushes to me.
Click to expand...

Ok will try this tonight when I get home.

Just don't want to spend hundred odd quid on an alternator (that I really don't have at the mo) if its something daft like a bad earth etc....

Was going to double check the battery light wire as well to make sure that it is giving it enough to switch it on to charge. Can I just run another 12v ignition switched live to this terminal as a temp measure to see if this cures the problem before I trace all the wires again??

Finally, if I do need to get a new one, is there any one better than others, or a better place to buy, as there are loads on the likes of fleabay.....will be going for a 100amp one is about as much as I know for now....
 
Last edited:
Do not connect a wire direct from battery to terminal on alternator. Just get yo alternator tested on the car. Any Halfrauds or similar can do it. Make sure you get the test printout. Alternator refurb places are only about £50, but chances are yu could possibly do it yoself if you can solder.
If yu want to run a spare wire from batt make sure there is a 5watt bulb in the circuit.
 
As MHM said, don't put a live feed directly to the alternator I'd use a test light with a bulb in it(not LED).
I don't know what part of the world your in but locally to me theres a chap who'll refurb it.
 
Thanks for the recent posts guys - will scrap the idea of putting a new 12v supply to the alternator then, glad I asked now ;)

So is there a better type of alternator to get than others? What sort of price should I be looking at, as they seem to vary quite a bit...
 
StuRox said:
Thanks for the recent posts guys - will scrap the idea of putting a new 12v supply to the alternator then, glad I asked now ;)

So is there a better type of alternator to get than others? What sort of price should I be looking at, as they seem to vary quite a bit...
Click to expand...

To be honest there all pretty much the same, a lot are made by the same people who just put their own branding on.
Just shop around or nip down the scrappy!
 
stchris356 said:
To be honest there all pretty much the same, a lot are made by the same people who just put their own branding on.
Just shop around or nip down the scrappy!
Click to expand...

Cheers, will just go for the one with the 2 year warranty on then, as they are all bout the same price of just over the tonne mark
 
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