Member Since: 20 Jan 2018
Location: Warwickshire
Posts: 141
Hey - no offence taken DSL. Annoyed and embarrassed at myself, no-one else.
Just been looking at details of what a good output from an alternator should be. That lines up with your assessment. I expected the voltage to drop further than that tbh.
Still confused though on how the FBH won't run on a charged (even if partially) battery, even after an overnight charge.
Will see what happens tomorrow.Current : Discovery 4 HSE (2012 spec)
Current : BMW Z4 20i MSport
Current : BWM Z4 3.0SI Sport Auto
Previous : Freelander 2 HSE
3rd Mar 2018 7:16 pm
Redline
Member Since: 20 Jan 2018
Location: Warwickshire
Posts: 141
12.59V after overnight charge. Maybe a tiny bit lower than you’d expect but close. 15 miles this morning (which I know isn’t enough to expect it back to full charge) and it was 12.43V after everything had switched off.
Looks like no fault in the FBH and probably not the battery after all. Expecting to have to change the alternator as suggested.
Any one know how long it takes to replace?
It looks pretty inaccessible.
Got to do 200 miles on Wed and 300 next weekend. If I can’t get it changed am wondering if I can trust the alternator over that distance. I suppose as long as it is providing some charge it will be ok.
Wednesday I can take another car but next weekend I the D4.Current : Discovery 4 HSE (2012 spec)
Current : BMW Z4 20i MSport
Current : BWM Z4 3.0SI Sport Auto
Previous : Freelander 2 HSE
4th Mar 2018 2:10 pm
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 72787
Battery is still suspect in my non techie eyes, after overnight charge it should be way higher, esp with its surface charge. Dying alternator might have asked for company.
4th Mar 2018 2:16 pm
Redline
Member Since: 20 Jan 2018
Location: Warwickshire
Posts: 141
There goes my new VANOS solenoids and DISA valves for the Z4 for another month
Like you said DSL - it’s only money.Current : Discovery 4 HSE (2012 spec)
Current : BMW Z4 20i MSport
Current : BWM Z4 3.0SI Sport Auto
Previous : Freelander 2 HSE
4th Mar 2018 2:39 pm
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 72787
Agreed, you'd only spend it on things you'd enjoy.
4th Mar 2018 2:46 pm
Sloss
Member Since: 18 Aug 2013
Location: Aberdeenish
Posts: 1691
A simple voltage does not give the full status of the batteries capacity.
You need to get an auto electrician to properly diagnose your problem. I would not just stick on an alternator based on comments on here no matter how well meaning we are 👍Stew,
2010 D4 gone but I really loved it
Went back to Merc - C350 AMG
4th Mar 2018 3:02 pm
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 72787
I did make sure I bunged in the "non techie" words every now and again.
4th Mar 2018 3:04 pm
Sloss
Member Since: 18 Aug 2013
Location: Aberdeenish
Posts: 1691
I would not just stick on an alternator based on comments on here no matter how well meaning Des is👍
Sorted!Stew,
2010 D4 gone but I really loved it
Went back to Merc - C350 AMG
4th Mar 2018 3:28 pm
Redline
Member Since: 20 Jan 2018
Location: Warwickshire
Posts: 141
As I said earlier Sloss, the battery is being replaced on Tuesday anyway. If that proves to not be the problem it’s likely I’ll run out of time.
I just need the car for next weekend. None of the other cars I own are suitable - all too small. If I can’t trust the D4 I’ll have to hire a car anyway. Will see how it is after Tuesday.
Got a good relationship with my Indy. He won’t allow me to shell out for anything that he is sure isn’t needed. I still owe him for an ac gas recharge he did a few weeks ago because he suspects a small leak.
Got a similar guy who does the Z4 for me. They’re hard to come by.Current : Discovery 4 HSE (2012 spec)
Current : BMW Z4 20i MSport
Current : BWM Z4 3.0SI Sport Auto
Previous : Freelander 2 HSE
4th Mar 2018 3:48 pm
Redline
Member Since: 20 Jan 2018
Location: Warwickshire
Posts: 141
Am I chasing rainbows here. I presume I should be able to expect the aux heater to run several times of day. A reasonable couple of runs would be useful.
New battery fitted today but the old one passed load test etc. Same with the alternator - consistently supplying 14.7V under load at idle. So, I'm back to square one on the aux heater failing to run for a full cycle when it was most needed.
It's looking less likely to be the battery directly causing the problem. Don't see quiescent drain causing it because the heater ran for only 6 minutes after I took it off charge. It switched off before chucking out any real heat and it was -4 or lower then
So, a couple more questions.
Is it the heater or the car that commands a shutdown on low voltage and what voltage level is chosen and what measures it and where.
Could the heater be demanding far more current than the normal start-up and run demand? There are rather a lot of Watts available from a 95Ah battery. Most things should be able to take a few hours from the cells keeping it cool. L
12.6V. At the battery tonight but that was dropping slowly. 12.2V after a while. Got 5 hours motorway driving tomorrow. That should see enough charge put in the new battery.
Hoping that it won't be needed now until the back end of the year, but, if anyone locally has the webasto diagnostics capability an hour of your time would be gratefully received.
Hopefully there has to be a problem hidden away somewhere otherwise having the aux heater is only useful with the engine running. A bit like having a dog and barking yourself.Current : Discovery 4 HSE (2012 spec)
Current : BMW Z4 20i MSport
Current : BWM Z4 3.0SI Sport Auto
Previous : Freelander 2 HSE
6th Mar 2018 11:54 pm
Redline
Member Since: 20 Jan 2018
Location: Warwickshire
Posts: 141
Maybe a clue as to what's happening on the battery voltage that is affecting the aux heater.
Did over 200 miles and monitored the voltage (as well as the cabin temp) over the journey.
Always up at 14.6/14.7V for the whole journey.
After switching of after 100 miles the battery voltage slowly decayed was readying 12.8V. Six hours later it was down at 12.5V. Wasn't expecting such a drop but maybe that is typical.
Again, it maintained 14.6/14.7V for the whole journey back.
Get home then after twenty minutes had to move the car.
On starting up the heated screens came on and the voltage never went above 11.7V until I switched them off - even revving to 1,500rpm. Put them back on and after a brief drop it went back up to 14.7V.
Back to a suspect alternator? Any thoughts?Current : Discovery 4 HSE (2012 spec)
Current : BMW Z4 20i MSport
Current : BWM Z4 3.0SI Sport Auto
Previous : Freelander 2 HSE
7th Mar 2018 11:21 pm
ontheair79
Member Since: 03 Mar 2018
Location: Dublin
Posts: 39
Quick question if low coolant level will affect star of FBH. I have Discovery 3 since 3 weeks and had lots of cold mornings but FBH never started. Fit bread new battery. Clear all errors, check fuses, reset FBH. No luck. Waiting for spring.
9th Mar 2018 9:43 am
Sloss
Member Since: 18 Aug 2013
Location: Aberdeenish
Posts: 1691
Ontheir79,
Search on this Forun for FBH, There is loads of info and how to's.
They can be very frustrating things Stew,
2010 D4 gone but I really loved it
Went back to Merc - C350 AMG
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