Battery light started flashing intermittently this morning. Just plugged in the IID and it's showing 11.4 volts and doesn't increase with revs. I'm guessing the alternator has gone.

There is a smell coming into the car which I can only describe as like incense. Not electrical burning smell (i know that one!). It's quite prominent outside the car as well. Quite pleasant actually!

How much are replacements?

the smell is the diesel , the alternator should ideally push out around 14.2 volts.. ... - .- -.




Y. O. L. O.
.

This isn't a diesel smell Stan. Nothing like

Sounds like the smoke has escaped from the alternator. Take it to a place where they can put the smoke back in.

Normally burning diodes, smells quite ozone-ey, sweet almost, rather than the acrid electrical burning smell of wire coils self incinerating.

Either way, 11.4 volts indicates it's NFG.

Disconnect the battery as a damaged diode back can short the battery and kill it pretty quickly

stan wrote:

the smell is the diesel , the alternator should ideally push out around 14.2 volts..

^ You don't need to change the alternator and battery together.
13.6V is not an adequate charging voltage, to me it's no more than a maintenance charge.
As an example it's what my Ctek charger gives out when the battery is fully charged if the charger is left connected.
In my opinion you firstly need a new alternator unfortunately, I would be inclined to leave the battery until you see what a new alternator does, the battery may well just need charging properly which is not being achieved at the moment.
Not saying you don't need a battery but you may not.

Thanks. New alternator having read a few posts on it - ouch! Thanks for the advice though

Boodog,
I would hate to see you spend out £xxx on a replacement alternator without the need for it.

All I can tell is from my own knowledge and experience and from the information you have provided so far. I do not know the usage of your vehicle, whether there are other faults with it (such as excessive parasitic current drains) or even what model year you have and battery type fitted.

A lot of the confusion comes as the L322, over it's lifetime, has had two battery types fitted (Standard flooded wet-cell Lead Acid and AGM) which require different charging regimes. People often quote what they think is an acceptable alternator voltage output based on their own vehicle without checking what battery and system you have on yours.

The voltage an alternator outputs is dependent on lots of factors such as battery type, battery charge, engine rpm, load and if the controlling ECU is clever enough the ambient temperature too. I would definitely NOT change an alternator if it was putting out 13.6V which is sufficient voltage to charge any 12V wet cell or 'sealed' type battery. Anything supplying over 12.6V at the battery with sufficient current, (2.1V/cell, standard flooded cell Lead Acid) will put some charge into it.
The absolute maximum voltage the alternator will put out on a non-AGM equipped and ECU programmed L322 is 14.5V (from the workshop manual). Personally, I would start checking the alternator if the voltage output dropped to around 13V, again though that would be dependent on the operating conditions.
Later vehicles with AGM batteries will differ and output a higher voltage (14.7V and possibly higher) until the battery is full and then drop the voltage to around 13.6V-13.8V as float charging a full AGM battery at higher than 2.4V/cell can permanently damage it. It's why you need to update the ECU if you fit an AGM battery as the conventional maximum ceiling of 14.5V is too high for float charging an AGM battery.

You can't compare an alternator output to the float charge on a mains battery charger as the requirements between float and bulk charging when the battery is low are different. Float charge voltage is when the battery is FULL, it can take higher voltages without damage (as mentioned up to 14.5V float for standard type, 13.8V for AGM). For bulk charging you gradually increase the voltage from 12.7V up to 14.4V (14.7V AGM) to prevent damage BUT with a high current (as described in the CTEK charger manuals and on the front of charger itself in graph form, top graph is voltage, bottom current).

The only thing wrong with yours I can see from the info provided is the battery needs charging. A brand new, fully charged flooded cell Lead Acid starter battery should sit at 12.6V or higher.
It's possible you might need a new battery but you won't know that until you fully charge the old battery and check it's voltage once it's sat for awhile afterwards (to remove the surface charge). If it sits at 12.6V or higher the battery is fine, if it drops lower then it shows signs of battery aging and you might consider changing it.
Why the battery got low depends on the useage or possible faults/issues. Lots of cold starts with high loads especially this time of year and no time for the alternator to recharge it means the battery will eventually get low. Parasitic drains can also be another cause.
The alternator may also not be charging correctly, that can be down to a number of factors though, a slipping belt, poor connections, faulty internal electronics giving a ripple on DC etc. Everything needs to be ruled out BEFORE considering changing a major part or it will just as likely happen again.

You do not need to change the battery when you change an alternator unless the battery has also been damaged.

If you think you have issues please go and get it checked out by a recommended proper Auto Electrician who knows LR systems. You've done the right thing by going to two separate garages but by the looks of it one was trying to rip you off and the other, National Tyres, were correct.

Thanks for such a comprehensive reply Weejock. I went for a 3rd opinion today with our local tyre/exhaust/battery dealer and they said same as National Tyres and yourself so I definitely won't be going down the new alternator route until I've checked everything else including charging the battery and the testing. The car is a 2003 4.4 V8 petrol. My wife uses it but only for local runs averaging around 8 miles from start to stop (home to shops) and given the quantity of electrics and electronics on the RR I suspect the battery isn't getting sufficient charge between start/stops.

Again, thanks a million for such great advice

Have just replaced our battery in the Black Friday sales and have ventured into the cold harshness of the north- all seems to be much better now......