Is it the battery, alternator or the starter motor going?
Discussion
My car has just stopped starting despite running fine for a week since I bought it. On the day in question, the headlights and the radio was working just fine with the dashboard lights on as normal using just the battery power. I then went to start the ignition and had a rapid clicking noise which I hadn’t experienced before. Another 4 times and the rapid clicking noise persisted which then led to the increased dimming of the dashboard lights. After then giving up, I’ve gone to lock the car and by pressing the lock button on my key, the car alarm kept getting set off (requiring me to press the lock button a 2nd time to turn off the alarm and keep the car locked). I did this a few times to test this out to see if it was reoccurring as i never had this issue prior to the non-starting issue. So thoughts people is it the battery, alternator or starter motor?
Your battery needs charging.
The question is why does it need charging.
It could be because the car has been left unused for a long period, could be you have something draining it or it could be because the alternator is not working.
If the alternator was not working you should have seen a warning on the dashboard last time you drove it.
Whatever the cause, if the battery is now that discharged it may be beyond full recovery and you may need a new battery.
Don’t fit a new battery until you found out why the old one discharged otherwise the same will happen to the new one.
The question is why does it need charging.
It could be because the car has been left unused for a long period, could be you have something draining it or it could be because the alternator is not working.
If the alternator was not working you should have seen a warning on the dashboard last time you drove it.
Whatever the cause, if the battery is now that discharged it may be beyond full recovery and you may need a new battery.
Don’t fit a new battery until you found out why the old one discharged otherwise the same will happen to the new one.
Scrump said:
Your battery needs charging.
The question is why does it need charging.
It could be because the car has been left unused for a long period, could be you have something draining it or it could be because the alternator is not working.
If the alternator was not working you should have seen a warning on the dashboard last time you drove it.
Whatever the cause, if the battery is now that discharged it may be beyond full recovery and you may need a new battery.
Don’t fit a new battery until you found out why the old one discharged otherwise the same will happen to the new one.
I assuming that by warning light appearing on the dashboard last I drove it would be either the battery light or the engine light? If that’s the case I didn’t see one last time it was actually drivable The question is why does it need charging.
It could be because the car has been left unused for a long period, could be you have something draining it or it could be because the alternator is not working.
If the alternator was not working you should have seen a warning on the dashboard last time you drove it.
Whatever the cause, if the battery is now that discharged it may be beyond full recovery and you may need a new battery.
Don’t fit a new battery until you found out why the old one discharged otherwise the same will happen to the new one.
Scrump said:
It would have been the battery light.
Do you have a voltmeter, or some other way of measuring voltage? If so you can measure the voltage across the battery terminal with car off and then again with it running, this will let you know if the alternator is working.
Cheers for the suggestion mate. Should be able to get one, however by car running I’m assuming you mean with everything running bar actually starting the ignition as I wouldn’t be able to start it to measure the voltage with the car’s engine runningDo you have a voltmeter, or some other way of measuring voltage? If so you can measure the voltage across the battery terminal with car off and then again with it running, this will let you know if the alternator is working.
Don't rely on the alternator/battery warning light to show alternator failure
Alternator/battery warning light will very likely be wired to the alternator field circuit
Warning light will not illuminate If alternator brushes lose contact with slip ring, rotor winding goes open circuit or regulator fails
As above
Measure battery voltages
Alternator/battery warning light will very likely be wired to the alternator field circuit
Warning light will not illuminate If alternator brushes lose contact with slip ring, rotor winding goes open circuit or regulator fails
As above
Measure battery voltages
Your symptoms suggest a flat battery.
Use the voltmeter to see what reading you get from the battery in its current state with the car not running.
Fully charge the battery with a battery charger & see what happens.
How old is the battery - or how old is the car?
Have you been using it for a lot of short runs using lights, heaters etc since buying it? This will drain the battery & won't put much back into it.
https://www.optimabatteries.com/experience/blog/fa...
Ignore the redtop bluetop etc advertising in the last paragaph
Use the voltmeter to see what reading you get from the battery in its current state with the car not running.
Fully charge the battery with a battery charger & see what happens.
How old is the battery - or how old is the car?
Have you been using it for a lot of short runs using lights, heaters etc since buying it? This will drain the battery & won't put much back into it.
https://www.optimabatteries.com/experience/blog/fa...
Ignore the redtop bluetop etc advertising in the last paragaph
Could be that the battery has got to its bin-by date and needs replacing. Sometimes they just die without any warning 
As said, get the engine running and check the voltage at the battery terminals. It should be 13+ volts to overcome battery push-back. If it is then the alternator is doing its job.
As said, get the engine running and check the voltage at the battery terminals. It should be 13+ volts to overcome battery push-back. If it is then the alternator is doing its job.
What car is it? Relevant because older cars are generally simpler to diagnose.
Certainly sounds like low battery. The rapid clicking you heard will be the solenoid cycling, which is typical. It closes then releases when the starter comes into circuit and drops the circuit voltage below the solenoids threshold.
Testing battery (unloaded) voltage with a voltmeter doesn't really tell you anything useful, beyond the fact that the meter works. Testing voltage with the engine running tells you more - it should tell you right away if the alternator is faulty.
So you need to start the engine.
Either charge the battery first to get it going or jump start from another vehicle.
If charging from flat a smart charger is the best bet. They are not even expensive. Mine was less than 30 quid and has brought several batteries back "from the dead ".
If jump starting let the engine run for a minute or so before removing the cables, to let the cars own alternator get into its stride and start doing something.
Either way, once your engine is idling for itself you can check voltage at the battery poles with a voltmeter. The alternator voltage should be higher than the nominal 12v. A healthy alternator should shove out around 14v even at idle, but check that everything possible is switched off to minimise voltage drop.
If that's okay, then something else has been draining the battery. Lights in the boot are a common culprit - it happened on my MG so I simply disconnected it. Didn't need it and don't miss it.
Another common one, though slightly weird, is the radio. Modern radios usually have Bluetooth so you can play your choons from your phone and if it's left enabled in the settings they can switch themselves on trying to make friends with random passers-by phones. Happened to a girl I know who couldn't work out why her BMW radio was playing in the mornings (she usually parks near a bus stop).
Go to settings and disable Bluetooth.
One that used to be very common with older cars (like my MG, ahem...) is the starter motor itself leaking current. Mine was showing a constant 2 Amp drain which was enough to flatten the battery in 24 hours. Not so common now but can still happen and since the starter has a permanent live connection it happens even when everything you can switch off is switched off.
Good luck; it's unlikely to be a complicated problem.
Certainly sounds like low battery. The rapid clicking you heard will be the solenoid cycling, which is typical. It closes then releases when the starter comes into circuit and drops the circuit voltage below the solenoids threshold.
Testing battery (unloaded) voltage with a voltmeter doesn't really tell you anything useful, beyond the fact that the meter works. Testing voltage with the engine running tells you more - it should tell you right away if the alternator is faulty.
So you need to start the engine.
Either charge the battery first to get it going or jump start from another vehicle.
If charging from flat a smart charger is the best bet. They are not even expensive. Mine was less than 30 quid and has brought several batteries back "from the dead ".
If jump starting let the engine run for a minute or so before removing the cables, to let the cars own alternator get into its stride and start doing something.
Either way, once your engine is idling for itself you can check voltage at the battery poles with a voltmeter. The alternator voltage should be higher than the nominal 12v. A healthy alternator should shove out around 14v even at idle, but check that everything possible is switched off to minimise voltage drop.
If that's okay, then something else has been draining the battery. Lights in the boot are a common culprit - it happened on my MG so I simply disconnected it. Didn't need it and don't miss it.
Another common one, though slightly weird, is the radio. Modern radios usually have Bluetooth so you can play your choons from your phone and if it's left enabled in the settings they can switch themselves on trying to make friends with random passers-by phones. Happened to a girl I know who couldn't work out why her BMW radio was playing in the mornings (she usually parks near a bus stop).
Go to settings and disable Bluetooth.
One that used to be very common with older cars (like my MG, ahem...) is the starter motor itself leaking current. Mine was showing a constant 2 Amp drain which was enough to flatten the battery in 24 hours. Not so common now but can still happen and since the starter has a permanent live connection it happens even when everything you can switch off is switched off.
Good luck; it's unlikely to be a complicated problem.
Error_404_Username_not_found said:
Testing battery (unloaded) voltage with a voltmeter doesn't really tell you anything useful, beyond the fact that the meter works.
Seriously?Simple stuff first.
Expect a reading of 12.6 volts or above for a fully charged battery.
If the reading you get is down towards 12v - or less - it will tell you that the battery is discharged & you need to do something to rectify that before you start on the starter motor or alternator.
Don't bother trying to charge the battery by jump starting the car & then running it for a bit.
Best you will do is put a bit of a surface charge into it but little else & you will be wasting your time.
Either replace with a known good fully charged battery or fully charge your own with a battery charger.
When you've done that & with a fully charged battery fitted to the vehicle check the voltage across the terminals with engine off.
Start the engine & recheck - you may need to raise the rpm.
The reading should increase.
If the reading stays the same then there is an issue in the charging circuit which may be the alternator.
As an example with my Range Rover Classic I would expect a reading of battery voltage not running and around 14.4volts across the battery terminals (the regulated voltage) at 2000 rpm with all electrics off.
Some cars will be lower & if it's an ECU controlled alternator I haven't a clue
Edited by paintman on Monday 3rd May 18:35
New Battery
Keep an eye on its voltage for first few days if the previous one does not look like its time for it to be changed. If it looks like it needs changing (3+ years old, then just fit another battery and dont bother checking.) Its normal dead battery behaviour
Keep an eye on its voltage for first few days if the previous one does not look like its time for it to be changed. If it looks like it needs changing (3+ years old, then just fit another battery and dont bother checking.) Its normal dead battery behaviour
Edited by sliks on Tuesday 4th May 03:36
paintman said:
Error_404_Username_not_found said:
Testing battery (unloaded) voltage with a voltmeter doesn't really tell you anything useful, beyond the fact that the meter works.
Seriously?Edited by paintman on Monday 3rd May 18:35
Recently had the same on my daughters Kia and myself on a Passat.
No notification of failing battery and then they suddenly die. Both just over 5 years old; just like it was designed in failure. Hmmmm.
Oldred_V8S said:
paintman said:
Error_404_Username_not_found said:
Testing battery (unloaded) voltage with a voltmeter doesn't really tell you anything useful, beyond the fact that the meter works.
Seriously?Edited by paintman on Monday 3rd May 18:35
Recently had the same on my daughters Kia and myself on a Passat.
No notification of failing battery and then they suddenly die. Both just over 5 years old; just like it was designed in failure. Hmmmm.
Below 10.5 volts & the starter turning slowly or just clicking then suspicion falls on the battery being discharged. Fully charge & try again.
As you say, funny how batteries seem to die just after the warranty period ends!
TheWed said:
Yeah it was the battery. It was running at 7 volts normally. As soon as a new one was fitted it was running at 12v normally and 14.4v with engine on, thus meaning the alternator is working as it should. Could of been worse. Thanks once again everyone
Nice simple fix thenGood of you to post back, many don't
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