Faulty Voltage Gauge

[Ian H]

Hi Peeps
Had a good blast down to Devon and back with the family this weekend for a mates 40th.
Relentless rain all the way there and back so I can confirm windscreen wipers and traction control are working well.
One thing I have noticed is my Voltage meter sits quite happily at 11-12v charging voltage - This is clearly wrong.
I have a non standard Banner Power Bull battery which came with the car.
From checking with a multi meter across the battery terminals the battery indicates 16v when not under load and 15.5v with the ignition on and engine off.
With the engine idling the voltage increases to 19v so I think the alternator is fine (although this sounds a bit high ?) and there is zero evidence of battery drain on the long trip.
The gauge seems to wander (over hourly periods) from 11 -12v with no direct correlation as to what loads (lights, heaters, etc.) are applied.
As an aside, when you turn the heater from full to off with the engine idling you do get a momentary jump of ~100 RPM?
Is this just a dodgy gauge or should I be a bit more worried/ be checking other stuff?
How big a job is getting to the gauge to replace it - is is a whole dash apart job?
I am just sizing up the handsfree options so if the side post covers have to come off to mount the mike maybe doing this at the same time may make sense.
Or maybe I just leave it as a design feature ....
Many thanks
Ian

 

[Contigo]

There are big differences between mine on the 3200 too. I measured across the battery with a DMM and found 14.5V with ignition off and 17.8V with ignition on. Gauge in car shows about 13v most of the time. Don't worry about it.

 

[RossWA]

Mine too, sometimes when cruising it will sit on 10V and then kick up to 13V when the alternator starts charging. I also think the readings on the dashboard voltmeter are not particularly accurate.

 

[davy83]

Yup, sounds normal. I am not sure why the meter is so bad. It has a lot of averaging so it responds very slowly. However it also reads completely the wrong voltage. I think it was connected to a very noisy part of the power system creating a lot of random readings, and instead of fixing it they just put a huge amount of averaging on it, and hoped for the best. So as a result it some times roughly reflects whats going on, some time after its happened and some times it doesn't. Get a regular voltmeter and check across the battery terminals once in a while and ignore the dash meter, that's what i do. 15v stationary and 19 running sounds high, i would check your meter is ok before getting too excited though.