Low Alternator output?

[veebs]

Hi all,

Have had a bit of a read on AULRO, but can't find much info on my problem.

Was driving along, and suddenly noticed my cheap cigarette lighter voltmeter was reading 12.2 volts - unheard of.

I drove home, and with the car still idling in the driveway plugged the IID tool on, which confirmed the voltage. I took a couple of live values:

169123

Battery is fairly new, and seems good. Alternator was changed about 60,000km ago. Just came back from the local indy after getting two new intake manifolds.

Please tell me these cars have some kind of 'battery test' mode, where they deliberately run it down to check SOC or something? I've dropped almost $9k on it already this year, and really don't feel like spending another ~$1200...! [bawl]

[veebs]

...neglected to add, no faults are reported on the IID either

[drivesafe]

Hi Veebs, there is a battery test routine that the D4 can go though.

This will deliberately drop the alternator voltage down to 12.2v and then the D4s own power requirements are used to discharge the battery down to 12.2v.

Once the battery voltage is down to 12.v, the alternator voltage should then rise to 14.7v and the D4s BMS then monitors how long the battery takes to fully charge, and how much energy it take to get the battery to a fully charged state.

It is a very clever process but there have been plenty of occasions where the BMS gets stuck at 12.2v and does not raise the voltage.

This is NOT an indication of a faulty alternator, it just requires a software “patch” to be installed by a dealer and it should be done for FREE.

You can usually get a dealership to check to see if your D4 has had the patch or not.

[veebs]

Cripes, that’s a load off! Fingers crossed for a software procedure fix!

I assume this patch isn’t something I can check for myself with the GAP tool?

[drivesafe]

I can’t help you there veebs.

The patch upgrade should have been carried out during one of the services.

But, if this is the problem, any Land Rover dealership should be able to tell you, over the phone, if this has been done or not.

[Discodicky]

What an extraordinary co incidence.

My MY13 3.0 diesel has done exactly same thing today; down to 12.2/12.4V on the Scanguage.
Last week it went to 15.1 then down to 14.9 for a coupla days.

Is usually low 14's from memory.

I just put a volt meter onto the battery terminals whilst it was idling (no one around to rev the engine for me), and the voltmeter went BACKWARDS, ie, off the scale towards negative voltage.

Not sure if i am imagining it but felt I could detect an odd smell under the bonnet.

Vehicle done 149,000 so I presume an alternator failure?
Battery was replaced in 2017 and is Bosch.

[drivesafe]

Hi DiscoDicky, URGENT

Please go and first take the negative ( - ) terminal off your cranking battery and then take the positive ( + ) terminal off.

It sounds like your alternator is stuffed and it will stuff your battery.

Go disconnect your battery and hopefully I am wrong.

D3s do not have the battery condition checking that a D4 has!

[DiscoJeffster]

Hi DiscoDicky, URGENT

Please go and first take the negative ( - ) terminal off your cranking battery and then take the positive ( + ) terminal off.

It sounds like your alternator is stuffed and it will stuff your battery.

Go disconnect your battery and hopefully I am wrong.

D3s do not have the battery condition checking that a D4 has!

He said D4 MY13 3.0L [emoji2369]

[drivesafe]

Sorry DiscoDicky, yes it is a D4 ( going by the year ), I read the 3.0L as a D3.

Still urgently need to disconnect the battery.

Thanks DiscoJeffster.

[Discodicky]

Hi DiscoDicky, URGENT

Please go and first take the negative ( - ) terminal off your cranking battery and then take the positive ( + ) terminal off.

It sounds like your alternator is stuffed and it will stuff your battery.

Go disconnect your battery and hopefully I am wrong.

D3s do not have the battery condition checking that a D4 has!

Thankyou.
Mine is a D4.

[drivesafe]

Not sure if i am imagining it but felt I could detect an odd smell under the bonnet.

Vehicle done 149,000 so I presume an alternator failure?
The fact you have that smell, particularly if it is an electrical burning smell, you need to disconnect your cranking battery till you sort out what's going on.

When the alternator goes in these Land Rovers, it can literally suck the hell out of your cranking battery and damage it as well.

[Discodicky]

The fact you have that smell, particularly if it is an electrical burning smell, you need to disconnect your cranking battery till you sort out what's going on.

When the alternator goes in these Land Rovers, it can literally suck the hell out of your cranking battery and damage it as well.

Thankyou for your prompt advice it is much appreciated.

My next door neighbour owns a business in Hobart which specialises in European cars (Audi/Saab etc) and vehicle elec work and in particular is a highly regarded Bosch service agent.
He did all the elec work on the D4 for trailer towing, Anderson plug, etc. so I left it with him at 8 am this morning.
His business is only 4 klms up the road from me near the airport.

This coming weekend is a Long weekend in Tas and I need the car so necessary to get it sorted asap.

Car started fine this morning; I hadn't disconnected the battery as per your advice, simply 'cos I went off line last night before seeing it.
On the drive over the Scanguage fluctuated between 13.8 and 12.2/12.4 but mostly at 12.2V

Intended replacing alternator as preventative m/ance anyway prior to next mainland trip (COVID depending! [bigwhistle]) so I don't feel too bad about the failure except at "only" 150,000 klms, although apparently that's normal?
At least I now know I wouldn't have unnecessarily replaced it..............[tonguewink]

[veebs]

My original alternator went at 132k, though thankfully by way of a charging system fault, coupled with a very confusing system error that had even the expert indie scratching his head for a few days.

Back to today, and I charged the battery up, then ran a replacement battery cycle in the car, because frankly after the other repairs so far this year I really didn’t want to add this.

Started up fine, and happily charging around 14.7v, ramping up from low 12 after starting, just as it should. Phew!

I think you were on the money drivesafe!! And I need to spend less time worrying :-)

[Discodicky]

On same subject and following on from my stealing of this thread, on Monday last week I dropped it off at my auto electrician who had it all week and couldn't fault the bloody thing!
Around 14.4 V all the time!

Purchased a $19.95 volt meter from Jaycar (which plugs in cig lighter) in order to keep my Scanguage honest, just in case that was the problem, however I feel it was more likely as described by more learned person/s in earlier responses.

Over the recent Long Weekend in Tas I did around 250 klms and it has behaved itself perfectly.

Also had a bit of a think about my comment re the volt meter going backwards, and have come to the conclusion I should probably offer a "mea culpa", in as much as the lovely 1950's voltmeter I have which was my late father's has confusing markings where the red/black leads fit.

I reckon in my haste I put them arse about which culminated in basically putting the wrong lead on each battery terminal!
Duh!!
[bighmmm][bigwhistle]

Once again thanks to all for your input!