Shake rattle n roll. · Oct 8, 2020

Hi all,
Still pretty new to the Landrover scene so please have a heart lol.
I've had my 2a for about 3 months now.
My question is I dont have a charge lamp on my dash it has a standard looking volt meter where the charge light would be. It has 3 terminals on the back of the alternator 2 big - small. The small brown terminal from the alternator goes to a relay by the header tank.
Any ideas why I cant get 14.4v from my charge system and only 13.2v and what is this relay?
I've done the earths over they are clean.
Over a few weeks it runs the battery flat and I have to recharge system over night.

ExMil109 · Oct 8, 2020

Sounds like you have the 11AC alternator that was fitted to some late 2A models. The relay is a field isolator and there should be a 4TR regulator somewhere as well.
Low output voltage could be down to lots of things e.g. bad connections/wiring, worn brushes in the alt or a dodgy regulator, but my money would be on the 4TR regulator. There's a thread on here describing this setup:

https://www.landyzone.co.uk/land-rover/1970-series-iia-88-charging-mystery.356318/

Shake rattle n roll. · Oct 8, 2020

ExMil109 said:
Sounds like you have the 11AC alternator that was fitted to some late 2A models. The relay is a field isolator and there should be a 4TR regulator somewhere as well.
Low output voltage could be down to lots of things e.g. bad connections/wiring, worn brushes in the alt or a dodgy regulator, but my money would be on the 4TR regulator. There's a thread on here describing this setup:

https://www.landyzone.co.uk/land-rover/1970-series-iia-88-charging-mystery.356318/

That would be very helpful. Thanks a lot!

kermit_rr · Oct 8, 2020

I'm not sure why there is no charge light, of it were mine I'd get it plumbed back in. A voltmeter is great but a red light will catch the eye quicker and easier if there is ever a problem

lynall · Oct 8, 2020

Not only that I always thought the charge light bulb was actually needed to tickle the alternators fancy?

kermit_rr · Oct 8, 2020

lynall said:
Not only that I always thought the charge light bulb was actually needed to tickle the alternators fancy?

Yep but any switched 12 v supply will do

Shake rattle n roll. · Oct 8, 2020

Shake rattle n roll. said:
That would be very helpful. Thanks a lot!

Just read most of that. . Not a clue! Lol
I've been all over the wiring and have not found the 4tr, strange. Will look again tomorrow unless anyone knows where to look???
Thanks

ExMil109 · Oct 9, 2020

Strange that you can't find the 4TR.

But one of the challenges with old Landy ownership is that previous owners could have changed stuff and you end up with a mix of old and new bits that take some head scratching to figure out.
From what I recall, there was a batch of late 2A models that used the 11AC alternator instead of a dynamo. Then the Ser 3 came along with the ACR alternator.
The good news is that the 11AC was used in lots of British cars, including the Jag E-Type, so there's lots of info on the web. Here's a link to an E-Type site with some useful info (ignore the bit about the 4AW warning light - Land Rover never used this and gave you a nice voltmeter instead

):
https://www.coolcatcorp.com/faqs/Lucasalternators2.html

Can you take some picture of your setup? It would help identify what you have, then we can figure out how to test (and hopefully fix) it.

lynall · Oct 9, 2020

A127 is a decent upgrade, cheap as well, std fit on many car/boats/tractos/trucks of that era

lynall · Oct 9, 2020

kermit_rr said:
Yep but any switched 12 v supply will do

Did not know that, I alwasys thought had to be a bulb, and bulb of a certain wattage.

kermit_rr · Oct 9, 2020

lynall said:
Did not know that, I alwasys thought had to be a bulb, and bulb of a certain wattage.

You could be right. I was thinking in more general terms, it needs to be excited (ooer missus) to start generating. Perhaps using a bulb (resistor) ensures just enough excitement to get things going without damaging anything by leaving the ignition on for a few minutes, for example

ExMil109 · Oct 9, 2020

lynall said:
Did not know that, I alwasys thought had to be a bulb, and bulb of a certain wattage.

The bulb wattage isn't critical, but it does make a difference. I replaced a dud bulb with one of unknown wattage I found at the bottom of the spares box and found it took a few more revs before it went out, so I splashed out on a new 2.2W bulb and it went off at lower revs.
In theory, you can feed +12V direct to the field on an ACR (this is how the 11AC circuit works) without going via a bulb, but this might cause some heat in the regulator if you leave the ignition on for long periods without the engine running.
What definitely doesn't work is using a LED warning light - as kermit said, that doesn't get the alternator excited...

TheMegaMan · Oct 9, 2020

Once the alternator is up and charging, the alternator provides its own 12V (13.8V) supply to the field coils, which is why the bulb (whose other terminal is connected to 12V) goes out. So connecting the exciter terminal directly to 12V is fine.

If using a bulb, it needs to be sufficiently low resistance to allow the field coil voltage to rise high enough, which is why LEDs don't work - their resistance is so high that the field coil voltage remains too low. You need a fairly high wattage bulb with a lowish resistance to bring the voltage up high enough.

Marmaduke · Oct 9, 2020

Shake rattle n roll. said:
Just read most of that. . Not a clue! Lol
I've been all over the wiring and have not found the 4tr, strange. Will look again tomorrow unless anyone knows where to look???
Thanks

Mine hasn't got a regulator thing either and I made the wiring loom for it. It'd be interesting to see your dash layout.

This is mine and you can see the red charge light in the bottom left. Two thick brown wires come off the back of the alternator to the starter button and the thinner wire goes to the bulb.

Shake rattle n roll. · Oct 9, 2020

My dash.

Shake rattle n roll. · Oct 9, 2020

The exciter wire is the brown terminal on this relay.
I now have no out put at all from alternator I pull off the main at the solenoid and .... well that was that.
So I'm in it for another alternator and hopefully that grey relay.

kermit_rr · Oct 9, 2020

Shake rattle n roll. said:
The exciter wire is the brown terminal on this relay.
I now have no out put at all from alternator I pull off the main at the solenoid and .... well that was that.
So I'm in it for another alternator and hopefully that grey relay.

i think you've found the fault right there

lynall · Oct 9, 2020

ExMil109 said:
The bulb wattage isn't critical, but it does make a difference. I replaced a dud bulb with one of unknown wattage I found at the bottom of the spares box and found it took a few more revs before it went out, so I splashed out on a new 2.2W bulb and it went off at lower revs.
In theory, you can feed +12V direct to the field on an ACR (this is how the 11AC circuit works) without going via a bulb, but this might cause some heat in the regulator if you leave the ignition on for long periods without the engine running.
What definitely doesn't work is using a LED warning light - as kermit said, that doesn't get the alternator excited...

Stranegly whilst hunting for a capless 5w indicator bulbs I came across the 2 watters in a bag, and thought ah ha I remember what they are for.

lynall · Oct 9, 2020

Shake rattle n roll. said:
The exciter wire is the brown terminal on this relay.
I now have no out put at all from alternator I pull off the main at the solenoid and .... well that was that.
So I'm in it for another alternator and hopefully that grey relay.

Thats some quality wiring right there

Shake rattle n roll. · Oct 9, 2020

Dont judge me

I inherited it!

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