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:

IMG_1866.jpeg

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...!

[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

[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.