C5 battery gauge

tim · Unread post by **tim** » 07 Aug 2011, 17:39

Hi got a 51 plate 2.0 hdi sx estate. When i turn on ignition in the morning or after being stood for a few hours the battery gauge only just regesters on the gauge... never more than a 1/4 way. When started the gauge rises slowly to about 3/4.. (no Traffic master voice) If you turn the ignition off and back on, the gauge goes staight to max and the trafficmaster voice speaks...Tested battery, its something like 11volts when ignition is turned on drops to 10v when turning over and when running its 14.4v. Is this the norm or is there a problem with the battery? Local garage says the battery is fine. What does every ones elses gauge do??
Which leads me to wonder if this has anything to do with the dreaded Anti pollution fault, when it comes on, normally as the battery gauge reaches half way...theres no engine warning lights, sometimes it goes into limp mode sometimes it dosent..If it does, i stop, turn off ignition for about 10 seconds trafficmaster speaks and it runs fine, no limp mode
Makes me think the battery is at fault, but the garage says not

Sorry for the long question, just wondered if anyone has had similar problems? Got no code reader or know anyone local that does

Cheers Tim

Citroenmad · Unread post by **Citroenmad** » 07 Aug 2011, 18:21

I can't say I pay that much attention to what the gauage is doing when im starting it up, however I don't ever remember seeing the gauge on full. When running it shoudl ideally be at around 3/4s. It does rise slowly to this point as the car starts to charge once its been started.

tim · Unread post by **tim** » 07 Aug 2011, 22:01

Yes, when running its at 3/4...It goes to max after its been running and i switch off and back on again

Unread post by **myglaren** » 07 Aug 2011, 22:13

Mine is usually at about ¼ while cranking and just after ignition then fairly rapidly climbs to ½ or just over and stays there, never seen it any higher but then I don't take a great deal of interest in it.

I did fairly recently buy a new battery to cure a problem but it turned out the battery was fine, new battery exhibits the same characteristics.

It may be worth connecting a DVM to your battery terminals and see what the dash guage positions actually correspond to - overcharging will dramatical reduce the life of your battery.

cachaciero · Unread post by **cachaciero** » 07 Aug 2011, 22:50

The only thing I can add to this is a bit of background.
The instrument does not read volts directly. Voltage is read by the BSI encoded and sent on the data bus to the instrument panel. So the instrument is effectively displaying what the BSI tells it to display, the BSI is involved with many things on the car including electrical power managment, both your problems could be due to BSI problems.

Are you saying that you ONLY get the Anti Pollution message on starting?

cachaciero

tim · Unread post by **tim** » 08 Aug 2011, 07:17

Yes, only get Antipolution when first start up (not always though) and it dosent usualy go into limp mode then...If it dosent come on when first start up, it may come on about 1/2 - 1 mile down the road and then it will go into limp mode. So just pull over turn off for 10 secs or so and when i turn the ignition back on an start up its out of limp mode

Also when i turn the ignition back on i sometimes get a voice saying "volume check 7 6 5 4 3 2 1 2 3 4 " Im not used to driving "modern cars" i drive classic cars normally finding this all very strange LOL

SaabC5 · Unread post by **SaabC5** » 08 Aug 2011, 09:55

Change your battery, it should be running 12V at least. My battery meter goes to just over half and stays there, only time it goes lower is if i put EVERY single electrical device on at once. See the post below i found on t'internet.

Best way is to buy a battery tester which includes a heating coil and meter. Machine Mart sell one for about £35. Plus you need a hydrometer. As you will know from electronics a fully charged lead acid cell is 2.2v e.m.f which, practically speaking, is about 2.11v in a typical car battery application when surface charge on the plates has been removed (either by an eletrical load or the passage of time). So a fully charged car battery of nominal 12v is actually approx 12.67v when fully charged (depending on temperature) and each cell should have a specific gravity (relative density) of 1.25. A cell is fully discharged at about SG 1.15 and the open circuit voltage reading on a digital meter would be about 11.7v when the battery is effectivly discharged. These voltages vary with temperature so, coupled with the small range between charge and discharge, this means that open circuit voltage is not a very accurate guide to a battery's state of charge and ability to provide cold cranking amps.

I'd recommend this firm for batteries, had nothing but problems with customers coming in with Halfords batteries that have died after 8 months.
http://www.carbatteriesonline.co.uk/

tim · Unread post by **tim** » 08 Aug 2011, 17:20

SaabC5 wrote:Change your battery, it should be running 12V at least.

That was my intention when i went to local garage, but they said the battery was fine