Flat ??? Battery

[Telegram Sam]

Any ideas what might be causing an intermittent sudden random flat battery syndrome? One day the engine starts up as normal, another day when I switch on it looks as if the battery is totally (= totally) flat. Significant in such cases is a clicking sound from the front offside which someone once said could be a "relay". The battery is not new but not a write-off judged by when I take voltmeter readings. It might just be a loose connection or bad earth somewhere which I will need to get an auto electrician to trace.

[Robsey]

If you are sure the battery is okay,

And all leads / cables to the battery, starter motor, gearbox earth point and the inner wing earth point are all clean and securely fitted,

My first port of call would be a worn out ignition switch.

The switch when it gets past it's best can often become hit and miss.
In extreme cases the switch can give off a puff of smoke when trying to crank.

There is said to be a starter relay "K5", but
-
from experience the weak spot is a loose cable (mentioned above) or a faulty ignition switch.

[Telegram Sam]

Tks, noted. Would a dodgy ignition switch be compatible with the other symptoms - no lights on the dashboard when I turn the key + just the clicking sound from the front (relay??). If the ignition switch was dodgy but not kaputt that would explain why on other occasions it is normal service.

[Robsey]

Very likely indeed.

[Envoy CDX]

If you have charge in the battery, likely to be the ignition switch as suggested.

[Telegram Sam]

Update for readers: The car was returned to my home in my absence this afternoon from having some work done by the local garage. They had had no starting problems. The engine was still warm. Battery reading 11.8 / 11.9 V. Turning the ignition key > lights in the dashboard illuminated in the usual way. But engine refused to turn, not even slowly. Instead a new more rapid more audible clicking sound which seemed to come from somewhere central in the engine compartment (not offset to the nearside as before). Accompanied by the dashboard lights flashing more or less in sync with the clicking sound. It would not take a lot to persuade me that it is the ignition switch that's responsible but any further suggestions welcome.

[Cavalier342]

If you have any spare electrical contact cleaner spray kicking around, it may be worth spraying a load of it through a straw directly into the switch (remove the lower steering column plastic cowling), give it a while to dry out then try flicking the ignition on/off a few times, start her up and see what happens. If all appears normal then the ignition switch is indeed your problem, and will need to be replaced at some point.

[Telegram Sam]

I'm reluctant to do anything more than strctly necessary with the interior trim for fear of breaking the brackets. It might be worth it just to replace the ignition switch anyway without faffing about. Would you go along with any (or all) of these?:
https://www.autopartspro.co.uk/vauxhall ... ion-switch

[Cavalier342]

I don't know which switch will fit your car, as there are different types, but you won't be breaking anything by removing the steering column cowling, it's just screwed in place. It's the only way to get to the switch.

[Envoy CDX]

11.8 sounds a bit low.

[Robsey]

11.8 sounds a bit low.

I would agree.
Fully charge the battery to be sure.

[Telegram Sam]

What would you regard as "normal" for the battery to hold once it's been charged but is not in daily use? I usually disconnect it for such periods in case there is a slight drain. I'd come to think that it would drop to somewhere between 11 and 12 V in the normal course of events and that this would be sufficient for starting purposes.

[Envoy CDX]

Taken from Haynes:
A good healthy car battery should register no less than 12.6 Volts. Due to the way batteries discharge it's important that you test the battery after it's been sitting for a period of time to get what's called the 'resting voltage'.

Leave the car overnight (preferably longer) and test before you start the car in the morning to get an accurate gauge of the health of your battery.

If you've recently been for a drive, the battery is likely to give a higher reading than the resting voltage, and so could be misleading.

https://haynes.com/en-gb/tips-tutorials ... ar-battery

It's possible you have a drain on the system somewhere, or the battery is just getting old.
It could also be that the alternator hasn't been charging the battery correctly too.

[iangsi]

Can you get someone to help you to measure the voltage while trying to start the car if it drops to lower than 5 or 6 volts I’d say it’s your battery.

[Envoy CDX]

Can you get someone to help you to measure the voltage while trying to start the car if it drops to lower than 5 or 6 volts I’d say it’s your battery.

[Telegram Sam]

Not easy to turn the ignition switch whilst faffing around with the voltmeter on the battery terminals, one handed .. The battery's showing a green light so the condition would appear to be OK. Having left it disconnected for 24 hours it reads 11.7 V. Would this normally be enough to start it if things were OK? Because it isn't!

[Telegram Sam]

I had a brainwave and put on a pair of connected jump leads to provide the boost if indeed 11.7 V was not sufficient to start the engine. >> Same result, dashboard lights illuminated and clicking sound from front nearside but otherwise zilch. All points in the direction of the ignition switch (+ barrel?) which I am trying to source from eBay if I can identify the correct part numbers.

[ilovedmymantas]

You're battery does sound goosed!
Taken from the link that envoy cdx posted

"...the resting voltage should be ideally no lower than 12.6V....when a battery goes down to 12.2V it's only 50% charged, and below 12V it's classed as discharged."

I'd start there.
I would;
get a new battery
Fully charge it, leave it a day , check the resting voltage.
Fit it, check the resting voltage again after another day, If it's dropped below 12.6V (or a fair bit) you'll know it's a drain somewhere.
I'd like to add to the possible causes previously posted.
The symptoms you describe sound like my first mk3 (1990).
In my case it was the starter motor/solenoid. (nearside clicking). New brushes fitted and all was good again.

A good bit of info here
https://www.qxcomponents.co.uk/articles ... r-failure/

small excerpt-
" Defective Ignition Switch
Starter motor failure and ignition switch failure present quite similar symptoms. One key check, that can tell you the difference between the two, is to see if the oil, brake and charge light function is present at position two. If the lights fail to turn on this could be a sign of electrical issues in the ignition switch."

I don't know if that key check applies to our cavaliers but the page is worth a read

[Telegram Sam]

Tks for the useful info which does of course open up the scope for other factors being responsible. May be there is more than one. ..
* My thought about using the jump leads was to test whether a "new" battery would solve the problem. The fact that the car still failed to start makes me think that a new battery alone would not be sufficient (I'm guessing that getting a battery via eBay is probably not economic on account of the carriage charges compared with Halfords etc). What faith do I put in the wee green light on top if the present battery is knackered?

* I have long suspected that there is a drain somewhere but have never been able to identify where. Which is why I disconnect the terminals when the car is not in use for some time.

* "your" clicking sound now makes me suspect the starter motor. Re the key check: the warning lights do come on when the key is turned. Hopefully starter motors are reasonably widely available even for antiques such as ours.

[Robsey]

You may find Euro Car Parts can supply and deliver a battery much cheaper than just driving to Halfords and getting a battery from them to fit yourself.

[Telegram Sam]

Thanks I will follow that tip if it turns out that the battery is at fault.

Point of info: My "brainwave" as above using the jump leads connected to the other car, but which failed to start the Cav. Does this "prove" that replacing the battery would NOT solve the problem???

[Cavalier342]

If you don't want to waste good money on a new battery, you can always get a used one from a scrapyard, they test them for you and it saves you a bundle of cash. I've never bought new batteries for my old cars as I didn't see the point in spending £60+ when a £20 battery of the same spec and size worked fine.

[Robsey]

A new battery would not necessarily fix your issue, if any of the following are loose, dirty or corroded.
1 - Any connection to the battery,
2 - Any connection to the starter motor.
3 - The heavy earth cable or braid between the bell-housing and the inner wing or battery negative post.
3 - The big barrel-shaped connector next to the battery (X5).

[Bob Dodds]

I had similar problems with my 1.7 TD. Turned out to be the braided earth cable snapped between gearbox and nearside inner wing. This would be the main engine earth. A new braided cable solved it.

[ilovedmymantas]

Point of info: My "brainwave" as above using the jump leads connected to the other car, but which failed to start the Cav. Does this "prove" that replacing the battery would NOT solve the problem???

Apologies for not explaining myself very well, I sometimes forget we're all wired a bit differently
I expect the drain on the battery will be solved by the advice of the more experienced members replies here.

What I was trying to say is replacing the battery is a necessary starting point.
Unless your home charger (I assume you use one?) is showing a full charge (more than 12.6V) and holding it for 24hrs - it's a duff battery and needs replaced.
If you're relying on the alternator only for charging and the battery is at 11.7 V that might be my starting point after all the other suggested checks.

…. Having left it disconnected for 24 hours it reads 11.7 V. Would this normally be enough to start it if things were OK? Because it isn't!

No.
11.7 V is discharged. I doubt you'll be able to narrow down the fault until you're using a fully charged healthy battery as a starting point. Some electrics/electronics don't cope well when starved of juice!
As mentioned, a used one would be the wiser option, at least until you solve the puzzle.