Merlin Alternator Controller

[seadog42uk]

I have one of these controllers fitted, it seems to have gone wrong as after a few minutes running it drops the charge rate down to about 5 amps. Yesterday I removed the two fuses from the unit and obtained a full charge rate. Does anyone know anything about these units?

 

Stuart

[WotEver]

... after a few minutes running it drops the charge rate down to about 5 amps.

What was the battery voltage at that time?

 

What alternator do you have? If a modern one, and if your wiring is good, then the controller will do nothing worthwhile.

 

Tony

[seadog42uk]

What was the battery voltage at that time?

 

What alternator do you have? If a modern one, and if your wiring is good, then the controller will do nothing worthwhile.

 

Tony

 

 

The voltage was about 12.3, I don't know the alternator type but it was fitted new four years ago. We were running the engine for hot water for the washing machine, when inverter cut out the voltage was 11.6 with only 5amps from the alternator. After I removed the fuse from the unit the charge went up to 48amps.

I cannot see how to remove tne controller as the wires go into the loom, do you think it will be OK to just leave the fuses out?

[WotEver]

... do you think it will be OK to just leave the fuses out?

Definitely, for now.

 

Someone will be along soon who will know this controller well and who may be able to make suggestions as to what's wrong with it.

 

Tony

[Gibbo]

I am banging my head here trying to work out how a faulty alternator controller can stop an alternator charging if the alternator still has its own internal regulator connected (which this one must have). As far as I can see it's impossible.

 

I suspect there's something more going on here but I can't work out what.

[WotEver]

I am banging my head here...

Don't do that, you'll get a headache and then get all grumpy.

 

Tony

[Gibbo]

Don't do that, you'll get a headache and then get all grumpy.

 

I don't need to bang my head to be grumpy.

Edited August 17, 2011 by Gibbo

[WotEver]

I don't need to bang my head to be grumpy.

Well, yeah, I knew that, but I was being polite

[Keeping Up]

I am banging my head here trying to work out how a faulty alternator controller can stop an alternator charging if the alternator still has its own internal regulator connected (which this one must have). As far as I can see it's impossible.

 

I suspect there's something more going on here but I can't work out what.

 

There IS one way, if the alternator has been changed (or the wrong type of controller has been fitted).

 

We used to have a Motorola alternator, which needed the external controller to be in the positive supply. When I had the alternator rebuilt once, (one of many times!) the mechanic didn't believe me and rebuilt it with an internal regulator in the negative supply; I got some charge until the Adverc kicked in and then the charge almost stopped.

 

The mechanic also tried to prove to me that I must have got my connections wrong by bridging the Adverc with a screwdriver. The internal regulator made a most satisfyingly loud bang!

 

Not saying that is what has happened here, just making a suggestion that might stop you from banging your head against the wall.

[Gibbo]

There IS one way, if the alternator has been changed (or the wrong type of controller has been fitted).

 

We used to have a Motorola alternator, which needed the external controller to be in the positive supply. When I had the alternator rebuilt once, (one of many times!) the mechanic didn't believe me and rebuilt it with an internal regulator in the negative supply; I got some charge until the Adverc kicked in and then the charge almost stopped.

 

The mechanic also tried to prove to me that I must have got my connections wrong by bridging the Adverc with a screwdriver. The internal regulator made a most satisfyingly loud bang!

 

Not saying that is what has happened here, just making a suggestion that might stop you from banging your head against the wall.

 

Yeah I'll go for that as a distinct possibility.

 

I did write...

 

I suspect there's something more going on here but I can't work out what.

 

Perhaps that should have been

 

Someone hasn't told us the full story

 

 

It possible!

 

Well, yeah, I knew that, but I was being polite

 

Are you trying to say I'm grumpy?

 

I'm actually particularly cheerful at the moment because I'm on holiday. Unfortunately I'm back at work on monday so the usual (grumpy) service will resume at that time