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View Full Version : Multi meter reading @ 18 volts!



Barney Rubble
2nd April 2012, 10:33 AM
Hi there guys, i have posted this in another thread but realised now you have a dedicated place for electrical.
My guage when i am driving reads at 18 volts, so i bought a multi meter and tested it thinking that perhaps it was a faulty reading. but NO.. it is actually reading at 17.63 volts. What could be causing this and how should i go about fixing this?

Cheers Barney Rubble.

Bigrig
2nd April 2012, 10:37 AM
Over charging isn't good boss ... can cause the battery to blow in some instances.

More than likely a stuffed alternator, but others with more auto sparky knowledge will be able to assist no doubt ....

Something to be ironed out quick smart though mate.

AB
2nd April 2012, 10:56 AM
Hi mate, I would be getting that battery out of the vehicle and away from anything of value until someone on here can give better advice.

As discussed, It may be your regulator on your alternator overcharging your battery as it happened to me but it nearly exploded at only 15 volts. 17.63 is huge mate and I would very very careful. I didn't even know it could get up that high without blowing some cells at least.

BearGUST
2nd April 2012, 11:00 AM
Voltage regulator, get the alternator looked at straight away.
This would be likely causing a heap of other issues in the car. Blown globes at least.

Barney Rubble
2nd April 2012, 11:18 AM
heading down to find an auto elec now... will update with findings.

AB
2nd April 2012, 11:30 AM
heading down to find an auto elec now... will update with findings.

Unplug your alternator to the battery mate and turn everything possibly on in your car if you are driving it down there...

Music, air vent, all your lights, chargers, etc....Try and drain that battery!!!!

bazzad
2nd April 2012, 12:42 PM
Yeah, sounds the voltage regulator in the alternator. Have a look in the cells of the battery and top them right up with demineralised water before you head off anywhere to stop them boiling dry. Leave the alternator connected if you are driving but put on the a/c and crank your stereo and lights on. The battery will handle this for a short time but it does need looking at.
Cheers, bazzad

Protius
2nd April 2012, 01:05 PM
You may also start blowing bulbs and electronics in the car if you're not careful. Had to replace every bulb on an n14 pulsar that was doing this once.

Yendor
2nd April 2012, 01:38 PM
Check the voltage regulator sense wire at the alternator. It is the small white wire in the two pin plug that connects to the alternator.

It should read the same as the main power connection at the alternator (large wire wire).

On the GQ, the small wire connects to the large wire about 6inchs away from the alternator and it's not uncommon for this connection to fail.

Does your alternator/battery warning light in the dash work correctly. The light comes on when the ignition is turned on and then goes off when the engine is started.

If the above are ok then the fault will be with the alternator.

Barney Rubble
3rd April 2012, 10:21 AM
Thanks guys... the GQ is in at the mechanics now. Auto elecs had moved.

Barney Rubble
10th April 2012, 07:35 PM
all sorted, get a new alternator, apparently there was an earthing problem which caused a spike which in turn burnt out the alternator.