Anyone know stuff n things about alternators??

[Mr-Paulio]

Hi team,
Looking for a little help with some alternator issues I've been having. My 3VZ has gone through x2 in 1 week. I believe the cause is the dodgy looking main cable, which looks as though it has been arcing to ground in probably 2 places.

Wiring

At the alternator where the insulation has become brittle and cracked.

Batt Wire

And at the fuse that has become the same.

Fuse

I have replaced this cable with a new circuit breaker. And checked the sense, ingition and lamp wiring, also hacked up. But seem to be working as they should and wired correctly.

Upon testing the alternator still does not charge.
I suspect the damage is already done.
SO, my actually question is... Should I get another alternator? Are the issues with the alternators the same? And consistent with shorting out?
Here are some pictures... (I'm not sure what I am looking at here really)
Alternator #1

Alternator 1.1

Clearly the rectifier has got hot (arcing) and broke at the battery wire terminal. And I can't see a way to reuse it. Inside looks okay?

Alternator 1.2

Alternator #2
We didn't have the same problem with the battery wire terminal. But the inside perhaps looks melted? Unsure how to test this anyway?

Alternator 2.1

Alternator 2.2

And just for fun. Alternator #3 (was on the engine when I bought it) Shows signs of wear on the rectifier.

Alternator 3 wear

So I have 3 alternators with bad rectifiers, I guess my option of making one good alternator is buggered.

So my main question is really, should I now be safe to instead just buy another alternator and not have an issue now the battery wire is replaced?? I'd hate to fry another one!!

Any help, thoughts, opinions will be appreciated. Thanks guys!!

[Mr-Paulio]

I guess this helps clear things up a bit. FYI
https://itstillruns.com/causes-alternat ... 73337.html

But I am still interested in people's thoughts before buying another alternator.

[MIKEP]

Hi Paul

Need to have really good battery cables.One of the biggest killers is low voltage that stresses the rectifier and cable that is crap.if the insulation on the cable allows it to arc the shorting current can fry the diodes.

If your battery is in the front dependant on the distance and cross sectional area of the cable you will get voltage drop and
So it will be like a flat battery so rectifier will be hard on all the time.If the cable is crap with a high internal resistance
This will cause issues

General rule of thumb for DC is every 1.0 mm2 is 10 amps so you need cable of at least 16mm2. There is a voltage drop off
About .7v over 3 metres using this size.

Use decent copper cable not the Chinese imported stuff often aluminium copper blend

[Mr-Paulio]

Thanks Mike.
I ran a new main battery sized cable from the alternator to the circuit breaker. And CB right on to the battery.
Battery is in the boot so not too far. Probably 2 meets of cable. Also used plenty of heat shrink on the lugs and connections. And conduit the entire way. So no shorts now! Hopefully that's resolved.
Will check tomorrow if the best option is a new rectifier for one of my existing alternators. Or just getting another complete, second hand one.

[MIKEP]

New diode pack should be ok as long as the stator is ok.Might be a cheaper way.Anyone like Ashdowns or PAn pacific should have A rectifier pack .just check if you need to put it. On with heat sink grease or not

[Mr-Paulio]

Sweet Mike, Thanks. I'll check them out. Got heat sink grease also from work.
Cheers

[Mr-Paulio]

Fingers Crossed!!