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Suspension Killing Battery?

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Wed Dec 06 2023, 10:00pm
Joined: Jan 27 2023
Member No: #5179
Location: Northamptonshire
Hi folks,

bit of a long one. TLDR: flat battery - clicky noises from suspension - HELP!

My C6 came to me having sat 3 years unused so it's had some refurbishment and I'm putting it back into use.

I'd been running it daily for a couple of weeks - mostly short trips but the odd half-hour run to keep the battery charged - then left it parked up for a week.

Monday the car was not interested in starting. No crank, just a click. Came back in the evening, hooked up the boost pack and it started instantly. 14V on the under-bonnet terminals, 14V across the battery, alternator's healthy, good connections across the board. Let it run half an hour, put some charge back in.

This evening it's so flat I can't open the boot even with the boost pack connected BUT whenever it is connected, there's a clicking behind the RH headlamp, where the suspension pump lives.

Main worries:
Has a sensor gone?
Does the car think it's still turned on? (Everything's closed except the bonnet, but it wasn't locked)
Can I avoid this in future by parking in low? Or do I have to pull the fuse every time?
Is the bonnet being open what has woken the car? (so the electrical issue might be nothing to do with the suspension)?

Obviously I can't go changing the battery every week so any ideas would be gratefully received.

The car and I are currently having discussions about the word "ungrateful" and its possible consequences since it blew the instrument panel the day the boot lock was fixed and then a headlight bulb while that was away for repair.
Thu Dec 07 2023, 03:54pm
Joined: Sep 20 2016
Member No: #2793
Location: West Mids
I don't see in your post whether you have replaced the battery or not. If it's an unused for three years job and you haven't replaced it, that's certainly where I'd start.
Assuming a good, properly charged battery, first thing I would do is a current test to see what is going out when the car is theoretically turned off. I think to do this satisfactorily, you will need to run the test cables out of the boot, so you can shut it. Close the bonnet properly, too. If there is a perceptible current drain, the size of it may point to a likely culprit. Were the suspension pump running you would hear it, although I suppose if it's not properly going to sleep whenm off, it might be triggering inetrmittently to maintain the height.

Have you checked all the doors are closing properly ? On mine, if you push them to a little too enthusiastically, they bounce back to the first position, which I think definitely keeps the electrics awake. Have you access to a code reader -- it may throw up a useful clue. I think in general, they don't like standing for prolonged periods. My bitzer car, which I try and keep mobile has a habit of
leaving the windows in odd positions, intermittently.

Fri Dec 15 2023, 12:03am
Joined: Mar 20 2018
Member No: #3475
Location: Tartu
I have been using mine few times in the month in the winters(it gets up to -20C here) and never had any problems with the battery for 15 years.

Suspension does not hog the battery unless something is faulty. The hydraulic pump only fires up when you unlock the car(or open the door if it has been sinking while the car has been unlocked for a long period), it does not self-level while idle. It should not sink but when there is a leak in the system or some other problems, it will sink and it'll sit like that until doors are unlocked/opened

I'd start with battery swap like Mike suggested
Tue Dec 19 2023, 12:40am
Joined: Jan 27 2023
Member No: #5179
Location: Northamptonshire
Thanks for the replies. Since it's not something C6-specific it's been booked into the local garage so they can tell me what's playing up.
Mon Apr 08 2024, 08:30pm
Joined: Jan 27 2023
Member No: #5179
Location: Northamptonshire
A belated update.

The garage confirmed a past-its-best battery and verified that the car was "only" drawing 0.1A when shut off. Apparently this is normal for a modern car.

My maths says that's about 17Ah per week so I'm left wondering how modern cars cope with being parked up.

Anyway, we are now, happily, in the part of the year where a small solar panel can keep up with demand so the car actually started, no ill-effects, after being abandoned for a fortnight while I was away. Should such things be a surprise, or (rhetorical question) am I expecting too much from a modern car?
Tue Apr 09 2024, 08:36am

Joined: Jan 24 2010
Member No: #38
Location: Celbridge
Hello ItsInBits,

A couple of weeks with a good battery will be fine. But over an extended period the battery will go flat from the small draw that the garage identified. If parking up for an extended period either disconnect or maintenance charge. There are posts on the forum about owners solutions and the kit they use.

Best regards,

Phil C.

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