Just inquisitive really, bought a plug in battery voltage monitor that plugs into the cigarette lighter, and wondered what the voltage should be?

i have got one mine shows 14.1

Should be around 14.4, they are not very accurate though.... Pete
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My faulty battery showed 14v via the 753 hack and the new one shows as 14.5 so have to assume thats about right!

If you are using a lead calcium battery.......and all of us should be.
You most certainly need to be charging in the range of 14.3v otherwise you will get charging issues with calcium batteries.
Mid 14V is what you want to see.

Agreed

kbald wrote:

My faulty battery showed 14v via the 753 hack and the new one shows as 14.5 so have to assume thats about right!

The diagnostics screen voltage is far too inaccurate to be relied upon.

FWIW, to truly check the alternator output, it actually takes a very good multimeter or even an oscilloscope. A normal multimeter is normally adequate though. Visiting from DISCO3.CO.UK
Discovery 3 TDV6 Auto HSE Zambezi Silver

The real time water temp gauge that I fitted also shows voltage, it's reading between 13.9 and 14 volts. As it's not connected directly to the battery, and its' accuracy is unchecked, I'm not overly worried by the readings that I'm getting.

As long as it's more than 13.5 volts and less than 15 volts there shouldn't be any real concerns, this nonsense that it must be 14.4773432739834542 volts =/- 0.000001 volts is a load of tosh. Providing that there is enough power going in to charge the battery and not too much as to over charge, there is nothing to worry about. I think that this is a strong case of temperature gauge syndrome

Too Much Information, what was wrong with the little red light?

I just love the way that manufacturers fill their cars up with unnecessary gauges to make them seam better than the others........... G force? Boost temp? Boost pressure? and there are probably a load more out there. It's go faster boys lures

Voltage is not that important, either it charges or it don't, and a red light is sufficient for this. It's funny how the useful Ammeter ( which shows how much electricity you are using ) has been dropped, as it requires some heavy and long cables to be run and therefore costs more to install.

I know that as ffrr owners we are all conditioned in to worrying about when the ffrr is going to strike next and how financially painful it is going to be, but honestly chaps, it's charging, you turn the key and the engine starts (which is shocking enough) why worry if it's getting 0.5 volts too little. From what you are saying mine is getting 0.7 volts too little, I'm just going to book it in with the stealers and then talk to the Samaritans before impaling myself on a wheel brace  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

Thanks everyone, its showing 13.7 on a short trip (5-6 miles) and not had the chance to test it over a longer journey (not sure if it will rise the more the battery gets charged?). The battery has ran flat a couple of times due to a faulty FSR so unsure if the battery suffered damaged from draining right down, or if the alternator isnt charging as well as it should. Its never not started (touch wood) recently, and I am thinking of fitting a new battery before the winter just to be sure.

I have a good quality voltmeter permanently installed connected to the front fuseboard which generally indicates a running voltage of 14.1V to 14.2V. Charges the battery with no problems.
It's interesting that after a run I often see the battery voltage at 12.8V+ due to surface charge which can take 3-4 days before it decays to 12.6V and stays there.

Thanks Nicedayforit, and you have no problems starting with it sat at 12.6v after a few days? I've not measured the voltage before starting her, but will see later today.

Like I said its only a crude plug in thing from eBay, so not expecting too much accuracy, just working out if i need a new battery for the winter I guess

miggit wrote:

I think that this is a strong case of temperature gauge syndrome

What is exactly?

Quote:

Voltage is not that important, either it charges or it don't...

Fron a charging perspective, yes, sort of. When it really matters though is for ECUs that can be extremely sensitive to voltage, and it becomes the difference between normal functioning and all hell breaking loose... Visiting from DISCO3.CO.UK
Discovery 3 TDV6 Auto HSE Zambezi Silver

@mrblonde.

No problems at all starting with it sat for a few days at 12.6V.
The longest it has been left is 2 weeks and although the voltage had dropped to 12.5V the car started first go.
To be honest I would expect a car to start with 12.0V, particularly at this time of year or warmer.
I think the only time you definitely need 12.6V is during the winter on a particularly cold morning.
I wouldn't expect total accuracy with the voltmeter you are using I had the same initially and it consistently read 0.2V low.
The do give you an indication though.

12.6V is a fully charged battery, so that's what you want to be seeing.  Visiting from DISCO3.CO.UK
Discovery 3 TDV6 Auto HSE Zambezi Silver

Lost for Words, temperature gauge syndrome........ the Range Rover temp gauge is controlled by the ecu and has no direct connection to the engine, so far mine has read "Normal" from 70 deg. C to 98.6 deg. C and not moved a hairs width.

Land Rover did this to stop complaints that the temp gauge was all over the shop. This is however not the best thing in my case as I do push the car to it's limits towing 3+ tons on a regular basis, time is money and knowing when to ease off rather that push on is helpful in not destroying my car, also knowing when it's a good idea to fire up the heater full blast is helpful to the engine / gearbox. Although driving with the heater on full tilt in the middle of the summer is not to be recommended , but it does stop it all going Pete Tong.

And I can confirm that the ECU's are fussy about their voltage, as my car sits at 11.5 volts on the gauge, and every now and then throws up a HDC fault on the screen of Doom, and yes I will probably need a new battery when the cold weather arrives. But it was throwing up the HDC fault all last winter, but carried on starting, and working , and now that I have a voltage gauge I can see the route cause of the HDC fault (very common), but as the car is still starting, I am in no rush to panic buy a battery. I'd rather keep the money in the bank, and get the last squeak of the pig . And with that statement my car will never start again Battery  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!