Alternator is dead??

[ajvx01]

So I got my car running finally!
BUUT.. The battery isn't getting charge?
I had my doubts if it was previously as the gauge sits on 12v not 14v but after letting the car run for an hour tonight to test out the new cooling system (thermos, radiator pump etc) the gauge was sitting on 10V and the starter motor doesn't have the grunt to turn over the motor now and clicks.. So the battery is clearly dead.

The question is why isn't it charging? I've checked and the alternator excite terminal (s) is getting 12V and there's 12v at the batt+ terminal but not 14? Dies this just mean my alternator is buggered?

Alternator is a Bosch Vn type.

Please any help would be fantastic!




Electrical work, Adelaide all areas.
Pm me.

 

[aussie4life]

would be a stuffed regularor. where the 2 pin connector goes into the alternator there should be 2 screws holding the reg in. undo these and the reg should come out. install is the opposite. now it goes without saying that you need to disconnect positive and negative terminals doing this as if you short out the reg removing it, you will be up for a new alternator.

 

[ajvx01]

Thanks mate, I might try to hunt one down today...


Electrical work, Adelaide all areas.
Pm me.

 

[mpower]

Have you also load tested the battery?

I notice you list electrical work as your stock and trade, if you ever need to reco an alternator it's very very simple - takes about 15 mins if that.

You need a lathe, soldering iron and vice (rattle gun doesn't hurt either).

 

[ajvx01]

Yea battery is fine, big bugger just flat from not being charged...
If it comes to that il give u a pm.


Electrical work, Adelaide all areas.
Pm me.

 

[mpower]

Here's a couple of Youtube vids that look like they have the basics covered.

I haven't watched them all the way through but it seems like the guy gives a lot of the electrical theory and multimeter tests as well.

I think he replaces the slip rings doesn't machine them either.

It's pretty much just slip rings, bushes, regulator and bearings. Very easy stuff once you've done it a few times.

If you have the tools it's worth doing the dissasembly to check the state of the slip rings rather than just ripping out the regulator and replacing it - it also depends on the unit, I'm not familiar with the one you have but they do differ a bit not all of them have the regulator attached to the bushes but I would say it's a safe bEt you do. You will know if you pull the regulator out and check.

https://www.youtube.com/watch?v=FXmLjQ5p7y4

https://www.youtube.com/watch?v=SNcKXCB_xVc

 

[ajvx01]

Cheers!

So most likely to be the reg though?


Electrical work, Adelaide all areas.
Pm me.

 

[mpower]

Cheers!

So most likely to be the reg though?


Electrical work, Adelaide all areas.
Pm me.

Generally replacing the regulator (depending on the unit) replaces the bushes (which can often be worn right down) and the regulator as well (most people will obtain a used regulator not a new one). If the regulator is the problem then yes, it will fix it.

The slip rings and bushes both wear but bushes wear faster - slip rings will end up with a big groove in them and just replacing bushes means uneven wear on the bushes from the grooved slip rings.

If your slip rings are worn right down as well your alternator won't perform optimally but it should work - as you can see though from the vid, opening the alternator and giving it a once over is a pretty easy job for someone with the tools.

If your slip rings are worn right down replacing regulator and bushes will do nothing.

Great learning exercise too.

 

[Muke]

Hey ajvx01 - to add to mpower's links, the Gregory's manual for the VN has a few pages on dismantling / testing that alternator. If you go that way and would like, let me know and I'll scan those pages for you, if you like having hardcopy. It lists standard brush length as 9.3mm with a min of 4.0mm if that helps you tell if they're worn too far.

 

[ajvx01]

Quick question, can a reg be installed wrong or does it just screw in?


Electrical work, Adelaide all areas.
Pm me.