Possible Alternator issue? Low voltage

[pbgt]

Looking for some advice on alternator voltage.
80 main battery loosing charge rapidly and having to switch to leisure battery to start.

Measuring voltage at alternator to earth and all I'm getting is 11.4v

Switch all electrical equipment and getting 10.5v.

Am I missing something or is my alternator toast? I've checked earths and all seem fine. Can o check anything else before removing the motor?

Thanks

 

[Towpack]

Yes that's too low and out of spec, it should be between 13.5 - 15v. If all connections are good you need to test the alternator & IC regulator.

 

[stumog]

As above, would also add to check the belt adjustment. After that new alternator

 

[pbgt]

Thanks for the advice lads. Never thought of the regulator.

 

[Michael80]

Is your red light on above the voltage indicator?
Are all of your warning lights on on the dash?

 

[pbgt]

Not that I've noticed mate, will check shortly

 

[pbgt]

Is your red light on above the voltage indicator?
Are all of your warning lights on on the dash?

Red light comes on momentarily on start up but disappears when running.
Analogue voltage continually reads half on gauge

 

[Michael80]

It sounds like you have an internal fault with the alternator.
Sometimes all of the warning lights stay on when the diode pack fails.

 

[pbgt]

Thanks Michael, looks like I'm pulling it off

 

[Michael80]

I’m unsure which make if alternator you have but you can buy a brush box, regulator and diode pack for around £50.
They are easy to replace as long as the slip rings are ok.

 

[essexpete]

Does your engine have the pre heat in the air intake? I had a problem nearly 20 years ago with the heater not cutting out and dragging down the batteries. On short journeys the alternator could not cope with the draw and the batteries would fairly quickly drop below starting ability. On a longer journey the really would suddenly activate and switch of the pre heat. It took me ages to establish what the problem was.

 

[pbgt]

I believe all Uk 24v had them Pete. Thanks for pointing that out. How do I disconnect safely? Remove a relay or cable?
I've only been doing short journeys recently so that could be the issue alright!

 

[Towpack]

The heater problem has been mentioned on here numerous times. I believe there was a Toyota recall for the problem back in the day. The relay sits underneath the driver's side (RHD) battery tray and connects to the battery via a fusible link. I had this problem when the faulty relay was drawing down the batteries (around 400ma) parked up. I ended up replacing the relay with a motorcycle starter relay and moving it from below the battery tray but the engine will start OK without it if you want to remove it completely. If you measure current draw from the batteries when parked up and alarm set it should be around 40-50ma.

Heater relay problem

 

[essexpete]

I just removed the relay (IIRR), as said above, the engines are good starters.

 

[Michael80]

you could disconnect the heater supply and test the alternator charge voltage again.