wiggs wrote:

Not that I noticed Tim ....

Thanks anyway.

D4mation wrote:

I'm a bit late into this topic but I thought it would be the best place to add my tuppence worth.

Got my D4 HSE in November 2011 and had a few problems soon after with FBH not working sometimes and giving me the "battery/fuel low" message but I wasn't using the car much so suspected the battery was low, so I did nothing about it. The car had it's first service in November 2012 and the dealer applied software patch Q210 to fix a potential problem with the Navscreen going blank after an incomplete FBH cycle, even though I'd never experienced this problem myself.
Anyway, in January 2013 the flipping Navscreen went blank after an incomplete FBH cycle so I took it into the dealer who did some more software stuff. I posted about this Here

Since then the FBH has never worked - it doesn't give me any warning messages, just simply does not start neither with the remote nor the manual setting on the Navscreen. I haven't been back to the dealer yet because I've discovered that the battery voltage is only 12.2v before I start the engine, probably because of my driving pattern which is mostly shortish journeys. Once the engine has started the voltage goes up to 15.0v which I hope means the alternator is OK.
12.2v means the battery is at best at 60% charge. So, having waded through this saga of a topic I have decided to start charging the battery overnight with my trusty CTEK 3600 to see if this will bring the battery back up to near full charge, and then retrying the FBH.
I will report back how I get on.

D4mation wrote:

UPDATE 16-Feb-2013

Battery is
EXIDE 90Ah 850A
AGM/VRLA/MF
BH42-10655-BA

Previously the park heating wasn't working neither on the remote nor by using Timed Climate screen and the battery was showing 12.2v. Put the battery on charge and didn't start the car for the next 48 hours.

After 24 hrs charging on 3.6A CTEK battery went up from 12.2v to 12.5v but charger indicated not yet fully charged.
Battery drops to 12.35v with ignition on
Park heater came on by using remote plipper and battery voltage remains at 12.35v
Timed Climate did NOT work, neither 7 day event nor single event.

After 48 hrs charging battery settled at 12.55v but again charger indicated not yet fully charged, so maybe not man enough for the job.
Again battery drops to 12.35v with ignition on
Tried Timed Climate first this time and again neither 7 day event nor single event would work.
However the park heater worked with the remote plipper and again voltage remains at 12.35v

Obviously got a problem with Timed Climate but by charging up the battery at least I've got the FBH working on remote. I've taken the battery off charge now and will monitor for the next few days. I'm also going to make up a charge lead for the tow socket because it's much easier than lifting the bonnet and removing the plastic battery cover.

D4mation wrote:

Nipped out in the car last night which was the first time it's been driven for 3 days, after a 48hr charge on a 3.6Amp CTEK and messing about with Park Heating.
I've fitted a cheap and cheerful LED voltmeter This one to monitor battery voltage, and it's quite accurate. I noticed it was showing 12.3v which is down a bit from 12.5v when I had finished charging earlier in the day.

Anyway, after starting the engine the voltmeter remained steady at 12.3v on tickover, and even when bombing along at 40mph it didn't change. 3 days ago, before I started the battery charging, I checked that the alternator was putting out 15.0v, but it wasn't doing it last night.
Tested it again this morning, using my multimeter, and even turned on all seat and screen heaters to see if the alternator could be coaxed into putting some juice back into the battery, without luck.

Is this normal or is my alternator goosed ?

Edit: I think I'll start a new topic with this one rather than hijack Landylad's thread.

You're all right - it's about the same topic so no need. Better in one place if you ask me.

From experience, with this new AGM battery, I've found there's fluctuations in the voltage when driving. Before, with the flooded battery, it was almost always 14.7v, but now, especially after a charge, this one shows 12.2v when driving, which is weird to say the least.

To be honest, I wouldn't put much onus on the ciggy lighter meter. The important thing is, what's the multimeter saying when the car is at rest. If it's anywhere between 12.5-12.8v with everything booted down, then I think the battery is ok. Your FBH should most definitely kick into life and give at very least, two or three 20 min cycles before the battery start to protest (in my experience at least).

Again, to try and draw some form of conclusion from my umpteen trips into the garage about this, together with countless stories on here, I think the problem lies in the design. It's just not up to working within a window of 1.0 - 1.5 of draw voltage from the battery when the FBH is on and the car not running. The alternator isn't up to back charging it and a proper charge is required.