Battery completely flat, no life at all. Had the odd warning regarding battery levels previously. Have been trickle charging overnight just to be on safe side since. During the week normally only short runs of some 10miles each way. This is intermixed at odd intervals with longer runs of up to 150 miles round trip.
Took car into main dealers who found battery ok, but that charging rate was only 12.5 volts.
They connected to diagnostic system and found no faults stored
They found a Land Rover Bulletin regarding this issue and carried out an update to the Body Control Unit and retested.
Charge rate now 14.6 volts.
Let's hope that cures the problem. One Discovery, gone
Now on third Freelander 2
2013 HSE Auto Orkney Grey

Almost certainly will solve the problem as 12.5v alternator output will not charge a battery.
14.6v will though
Bit on the high side, possibly due to your battery being so low. Another member of the failed FL2 clutch/DMF club, twice.

Hi Pegleg, if 14.5V is on the high side and 12.5V is low, how much would you say precisely is the optimum charging voltage?

WGG1848, so how is the fix coming? Battery issues gone?

About 14.2 should be the optimum charging voltage.

12.5 is waaay too low.

My usual approach to take battery voltage across the terminals at 4 separate occasions.

1) After standing, should be about 13.2V or greater.
2) During engine cranking, should be > 10V
3) When charging, should be 14.2V up to about 14.5 at higher revs
4) After engine cut off, should be about 13.8 and not visibly dropping.

If anything in the car is running during 1 or 4, including computers, the readings will be a bit lower.

If charging voltage is less than 14V it will never recharge properly so there is an alternator/wiring fault.

If cranking volrage is < 10V the battery is , go and buy a new one.

If it drops rapidly after the engine switches off below about 13.5, the battery is , go and buy a new one.

If it reads below 13V after a short standing time, the battery is or something is draining it.

Andy

emetoolite wrote:

if 14.5V is on the high side and 12.5V is low, how much would you say precisely is the optimum charging voltage?

The optimum is temperature dependent... So, it can't be said precisely...
If you ask me at 5 deg. Celsius, for a wet cell battery, I will say 15.0V.
And if you ask me at 38 deg. Celsius, for a wet cell battery, I will say 13.8V.
See below...
The good thing is that the FL2's charging system is taking temperature into consideration.

Click image to enlarge

Thank you very much andycwb for not just proving the info, but also a sort of procedure on how to check the voltage, when to check, and the reading implications. What type of voltmeter would you recommend - Analog or Digital? Also, i guess if charging voltage is less than adequate (<14V) i should first sort out the alternator or wiring issue before doing away with the battery. And one more question, will all measurements be made across the battery terminals?

alex_pescaru, thank u also for ur input and ofcourse the very informative table. I have to make sure to keep track of the ambient temp while taking those andy measurements. By the way, engine room temp is going to change pretty signficantly after start-up (that is if it cranks) to take idling measurements. I'll see how i manage with this.

FWIW, my figures are at around 20 degrees C so might be lower if it's chilly....

I use a digital meter (I have several, go figure) which is pretty accurate but not calibrated. So if it shows 9.9V on cranking, I don't worry, but if it's 7V I'm straight down to the local purveyors of fine batteries to the gentry.

Hi Guys
No problems at all since the software update.
You mentioned the charge rate could be on the high side because the battery condition was low, could there be a problem if it continued to charge at this 'slightly high' rate? One Discovery, gone
Now on third Freelander 2
2013 HSE Auto Orkney Grey

No, it won't cause a problem.
The weakest link is tungsten filaments; too much voltage shortens their life. But with the volt drop of the electrical system at an alternator output of 14.5v, there is nothing to worry about  Another member of the failed FL2 clutch/DMF club, twice.

I was once told that Osram lamps were optimised to run at 13.8v, automotive use thus gave a reasonable life span. I was designing a new dental light and we were struggling to get the lumens from the lamp at 12v along with the right colour temperature, a bulb run at less voltage produces a lower colour temperature, dentists need the correct colours for shade matching filling materials etc.

ISO3559 specifies the max and min working voltage for lights fitted to Automobiles  Another member of the failed FL2 clutch/DMF club, twice.

Meaning 12.1 to 14.5 roughly...

ISO3559 was my Bible  Another member of the failed FL2 clutch/DMF club, twice.

Just brought mine back from dealers with same problem. Before : charging voltage 12.7v, kept getting the battery low 3 minute warning, after: charging voltage 14.5.

Battery still showing 12.5v when standing, better than 12.1 of course, but would 8 months of low charging have damaged the battery at all? Do I need to wait until after a long journey to see an improvement in the battery level?

Took me a while to round to taking it in, as it didn't really prove an issue over the summer, but now with heated seats, screen etc, and lights on all the time... Have I killed the battery? Fuji White MY13 SD4 Dynamic
gone: Rimini Red MY10 td4_e XS

Depends how long the battery has been standing without a charge. However, assuming the battery hasn't been fully charged, 12.5 volts is ok ish.
Perhaps a decent run or a trickle charge will bring the battery voltage up
Low charging will not damage your battery

Methinks you've nothing to worry about Another member of the failed FL2 clutch/DMF club, twice.