Thread: 14V-13.8V-13.6V- - - -

the earth cable onto the (below alternator) engine from the fuse box was loose on mine,, I moved it to a threaded hole level with the fuse box. In plain sight now

Originally Posted by Battler

Hey Eevo, while running 12.52 at the battery and 14.34 at the alternator.

Hi Battler and where are you taking the voltage reading from?

As Eevo posted, if the readings are at the battery's terminals, then you have a cabling problem, or a very low or stuffed battery and it's drawing high currents, causing a voltage drop at the terminals, while the motor is idling.

All alternators can safely run at unto 14.7v and not harm a battery, Wet cell or AGM.

New Discovery 4s come with an AGM cranking battery and the alternator will not run at voltages higher than 14.7v, but earlier D4s and all other landies can have voltage outputs up to 15.5v, for short periods of time ( up to 30 minutes ) when you first start driving.

NOTE, if a battery starts gassing at voltages below 14.7v, then there is a problem somewhere, and most likely, it's the battery.

If the ground is OK the alternator output(thick brown wire) goes to the fusebox one side of link FL1 and the battery is connected to the other side(thick red wire)...might be loosened contact or melted FL there as well

Thanks for the help.

The brown wire coming out of the alternator was lose. Tightened and checked voltage; 14.5 at the alternator (on the nut securing the brown wire) and now 11.5 across the terminals of the battery. I tried it on the brown wire where it's clamped at the battery terminal and still got 11.5.

I then took a reading on the terminal in the fuse box where the brown wire from the alternator goes and it was 14.5. Then took at reading the thing called Little Fuse Mega and on one side it was 14.5 and on the other it was 11.5.

So is the fuse stuffed?

The Mega fuse is next to where the brown wire from alternator goes and where the wire to the battery is.

After reading Pedro's post I traced where the earth lead from the battery goes and it goes nowhere! The end is not connected to anything.

So I reckon that might be my problem.

Thanks for all your help guys.

Cheers

I connected the earth lead to a bolt on the engine just near belt tensioner and I'm still getting the same readings.

The battery should be earthed to the chassis.
The motor should be earthed to the chassis.

Originally Posted by Battler

Then took at reading the thing called Little Fuse Mega and on one side it was 14.5 and on the other it was 11.5.

So is the fuse stuffed?

Could be. You should not be getting that big a voltage drop across a fuse. Check the contact points at the fuse for corrosion or dirt.

Originally Posted by Mick_Marsh

The battery should be earthed to the chassis.
The motor should be earthed to the chassis.

Could be. You should not be getting that big a voltage drop across a fuse. Check the contact points at the fuse for corrosion or dirt.

Thanks Mick,

I've earthed the battery to the chassis and I checked the engine earth. The engine earth was connected to the firewall so I moved it to the chassis.

Still getting the same readings of 14.5 and 11.5.