D1 Alternator discussion

[d1driver]

Would a winch isolator help me? I have one, just never installed it.

 

[listerdiesel]

Peter,

the diodes are always marked the same way, have been for many decades now. That said, you are the only person I ever knew of calling cathode a positive electrode and anode - a negative. Chalk it up to semantics.
That said once again, the diode bridge inside the alternator will do the same, and it is by far better suited to that than a 6A-rated little diode.

When used as a rectifier, the cathode of any device is usually the positive output end?

The issue is the chance of getting a reverse pulse into the regulator, which the main alternator diodes will not prevent.

I also suggested a diode rated from 6A - 40A, not just a 6A one, althout P600 diodes are quite effective.

Peter

 

[crown14]

I dont understand how the rectifier bridge in the alternator couldn't handle this.

 

[p m]

When used as a rectifier, the cathode of any device is usually the positive output end?

But you are not suggesting to use it as a rectifier.
I have never heard anyone assign "positive" or "negative" meanings to diode terminals, but the only logic I could see would be this: positive potential to anode and negative potential to cathode = current flows, the other way - it doesn't. Another logic would be that according to prevalence of charge carriers in p- and n-parts of a diode, and this logic would be the same
So if I were to assign these meanings, anode would be positive and cathode - negative. And my guess would be that anyone who were willing to follow your advice would do the same.
I would not even respond to your post if you haven't used all caps for diode terminals assignment.

Now this -

The issue is the chance of getting a reverse pulse into the regulator, which the main alternator diodes will not prevent.

requires some explanation. How the "main alternator diodes" are different from what you are suggesting? I'd be surprised if they allowed for more than 1.2-1.4 V in the reverse direction, which is very unlikely to damage the regulator. Keep in mind that the process of disconnecting current to the starter motor is exactly the same as to the winch motor, with very similar currents involved - yet hundreds of millions of cars on the road seem to handle it just fine.

 

[crown14]

Perhaps he connects his winch to the main power wire on the alternator instead of the battery?

 

[AfiRover]

HA HA :rofl: :rofl:

I had to check to make sure this was discoweb and not pirate im going to get some pop corn and watch this should be funopcorn:

 

[listerdiesel]

The original question was protecting an alternator which failed after using a winch. I have suggested the addition of an inverse diode across the battery to take out any reverse polarity pulse that comes from the winch motor.

It works for plenty of others, no reason why it should not work for Discoweb users.

Peter

 

[p m]

The original question was protecting an alternator which failed after using a winch. I have suggested the addition of an inverse diode across the battery to take out any reverse polarity pulse that comes from the winch motor.

It works for plenty of others, no reason why it should not work for Discoweb users.

Peter

Peter, I guess you don't care to give it a thought - once again, the alternator's own diode bridge will do exactly the same. It does exactly the same, over and over again, every time the starter motor is shut off.

 

[AfiRover]

:bangkb: opcorn: I FEEL CHEATED

I was waiting for the show

 

[AfiRover]

roomer mill has it that there is a rover alternator available with a ford "remote " regulate r
thus allowing it to be mounted out of harms way
just what I here folks

 

[Tugela]

Thread resurrection rather than adding to the clutter with a new one. Been reading a few old threads and I think I know the answer but would appreciate confirmation or correction. 1998 D1.

Symptoms:

• pulsing/flickering lights (dash, brake, and headlights)
• bouncing tach
• scanner data showing voltage range from 13.3 - 14.2 during in-city driving

Working hypothesis is early signs of failing alternator. Once it cools down I'm going to go have a look at the ground. Anything else I should look at or any other culprits I should eliminate before buying a new alternator? I need to drive 700 miles on Saturday so would like to sort this out before then.

 

[discostew]

Ok, I have cooked two alternators now at the Wilds. Last year, using all my lights, which are too many I guess. This year, used my winch for about 10 minutes straight.

Can I use an alternator out of a P38? Should I just plan on a dual battery setup?

What is the cheapest solution?

I think you should look into a dual battery system regardless if you do or don't upgrade your alternator.

 

[p m]

Thread resurrection rather than adding to the clutter with a new one. Been reading a few old threads and I think I know the answer but would appreciate confirmation or correction. 1998 D1.

Symptoms:

• pulsing/flickering lights (dash, brake, and headlights)
• bouncing tach
• scanner data showing voltage range from 13.3 - 14.2 during in-city driving

Working hypothesis is early signs of failing alternator. Once it cools down I'm going to go have a look at the ground. Anything else I should look at or any other culprits I should eliminate before buying a new alternator? I need to drive 700 miles on Saturday so would like to sort this out before then.

Nick,
Do you have a voltmeter or DMM? Test the output directly at the battery terminals, with heater fan and all lights on.
You may have a problem with engine-to-chassis ground connection - besides a potentially dying alternator.

 

[Tugela]

Thanks for the suggestion, Peter. I brought a selection of tools on my road trip but not my multimeter. I'll take a look at the ground.

 

[4Runner]

You might have a jammed or hung brush. You could try tapping on the metal part of the alternator with a small hammer while it’s running and see if your problem changes. Then you can rule out other bad electrical connections. But that might also be a problem as well. I have had really good luck with having alternators rebuilt at a shop that does alternators and starters. They can also mod them for better output if you ask them to.

 

[fishEH]

Damn there's some old user names on this thread.....

 

[Tugela]

I should add that the alternator is a GEMS P38 model. I have some more lines of inquiry to pursue to narrow down the source.

 

[Tugela]

This morning I checked the ground at the frame rail directly beneath the battery. Connection was snug, but I disassembled it, cleaned frame and cable sides, and reinstalled. Then I noticed that the negative battery cable's cluster of copper strands from the core was sticking out from the end of the insulation and connected to the terminal clamp by way of a flat clamp held together by two bolts. So it looks like at least part of the negative cable was assembled from parts (or modified), rather than factory made. I disassembled this clamp, saw the copper strands were a bit grimy, and cleaned them along with the inside of the flat clamp.

After reassembly I went on a 20-minute test drive. Dash lights still flicker but the tach did not bounce. Add to the suspect list: battery cable?

 

[p m]

I should add that the alternator is a GEMS P38 model. I have some more lines of inquiry to pursue to narrow down the source.

I think by now all my alternators are from GEMS P38As.
They still die the same way.
I wonder if you have a blown diode or two in the rectifier- but you have to take the alternator to a store to get it tested.

 

[Harv]

I think you have a bad diode in your alternator causing the flickering lights. It won't necessarily show up on a voltmeter as the pulses are too fast.