Preconditioning issues - Low battery warning

[mrlossyman]

I've been having issues with using preconditioning via the app. When I start preconditioning on the app it says it is running, but when I get to the car I have a message on the dash saying preconditioning failed battery low.

Now I've just done a 300 mile round trip so there's no way the battery is low and I think I've had this issue since the sensus upgrade back in October. I just haven't used the precon much but each time it's failed.

I am getting really p$ssed with this car, the time you need the functions they never work! Has anyone with precon suffering from the same issues and is there a known fix? Otherwise it's back to the dealer again....

Thanks..

[Lexman8]

I had this happen once at the end of last winter but it never repeated. It was probably a genuine error in my case because the car had made several short journeys and had also been parked up for 2 or 3 days. I had a Sensus update in Oct there and pre-con has been working fine. I've used it a few times recently now that it's colder.

Sorry, can't suggest a solution because, as you say, after a 300-mile trip the battery should be sufficiently charged.

[Philip Fisher]

Mine used to give this warning all the time. Never worked out if it meant 12v or 400v battery. Had a software upgrade many months ago and it never repeated. Been working flawlessly this season.

[mrlossyman]

Thanks for the replies. Used it all the time last winter and never had an issue. Very odd it doesn't work this year..

[Deman77]

Had no issues (happened 3 times in total) over last two winters and last week car gone into stand by after just 3 days idle and when woke up refusing to do preconditioning.

It’s going for failing stop start investigation which works for dealer test after fully charging the batteries but fails for me after spending a couple of days on the drive. I suspect they are related and battery drain is the problem. My stop start has not worked (well a couple of times after 1hr plus journey) since new look software update in summer.

[nu11eaf]

Originally Posted by Deman77

Had no issues (happened 3 times in total) over last two winters and last week car gone into stand by after just 3 days idle and when woke up refusing to do preconditioning.

It’s going for failing stop start investigation which works for dealer test after fully charging the batteries but fails for me after spending a couple of days on the drive. I suspect they are related and battery drain is the problem. My stop start has not worked (well a couple of times after 1hr plus journey) since new look software update in summer.

I have same problem with my D5 stop/start, works for about a week or so after fully charging battery then stops working, until charged again, dealer has had car in for this but I think they just charged the battery up again. Did not last long after getting it back, that was in summer. I think the small support battery is not big enough or does not hold charge long enough. Cold mornings with seat and steering wheel heaters/screens etc on does not give it a chance to work either.

[Lexman8]

I almost hesitate to say this but stop/start and pre-con work fine for me. (if only everything else did!)

Mid-week the car can be unused for a couple of days and/or make very short journeys with most or all of the electric heaters on but I never get low-battery issues of any kind. After maybe 3 days of non-use stop/start doesn't work for a while but a decent length journey and all is well again.

After 18 months I've not yet had to connect my Ctek charger once.

[KNVXC90]

Originally Posted by nu11eaf

I have same problem with my D5 stop/start, works for about a week or so after fully charging battery then stops working, until charged again, dealer has had car in for this but I think they just charged the battery up again. Did not last long after getting it back, that was in summer. I think the small support battery is not big enough or does not hold charge long enough. Cold mornings with seat and steering wheel heaters/screens etc on does not give it a chance to work either.

Looks like a dodgy battery that needs replacing by the dealer, instead of just chaging to fix it temporarily. My Stop/start works fine even after a 3 or 4 day non-use period, in this cold weather.

I once left the car at home for 4 weeks, and when I came back, the Stop/Start started working within an hour of driving.

[Lexman8]

Originally Posted by nu11eaf

I think the small support battery is not big enough or does not hold charge long enough. Cold mornings with seat and steering wheel heaters/screens etc on does not give it a chance to work either.

I might be wrong about this but I think the so-called stop/start battery (the small support one) is only used to maintain a constant voltage feed to some key electronic systems while the main battery feeds everything else including the starting motor. The starter motor draws several hundred amps which would cause a voltage drop across anything else connected to the main battery and thus the need for a support battery.

So it may not be the support battery that's the problem but rather the main battery. Wasn't there a batch of dodgy batteries way back?

[nu11eaf]

Originally Posted by Lexman8

I might be wrong about this but I think the so-called stop/start battery (the small support one) is only used to maintain a constant voltage feed to some key electronic systems while the main battery feeds everything else including the starting motor. The starter motor draws several hundred amps which would cause a voltage drop across anything else connected to the main battery and thus the need for a support battery.

So it may not be the support battery that's the problem but rather the main battery. Wasn't there a batch of dodgy batteries way back?

My starter battery starts car instantly no problem even after a period of none use and in very cold weather, the stop/start wont work if support battery is not above a certain level of charge. Now you have mentioned this I think my service manager said they had lowered that figure as it was set too high. But it still did not last long, I do a lot of short trips (mostly short trips) so doubt that support battery gets enough charge or not holding it, but short around town trips are when you need stop start the most not on long trips.
Its never lasted long from new. I have just got used to it not being available, I will mention it again at next service in June.