Help needed - Battery warning light came on whilst driving

[hornet]

Hi as per the title the battery warning light came on today and a message on the dash saying Warning battery / generator. Managed to get home with no problems and on restarting message appeared again.

The manual wasn't much help suggesting it may be a broken drive belt or a fault in the charging system but no loss of power steering or rise in temperature so I'm thinking it's unlikely to be a broken belt but will check this evening.

The battery has been connected to a Ctek trickle charger for the last few weeks with no sign of issues although I believe the battery is at least 7-8 years old. The car is a 2003 Boxster S manual with 50K miles.

I'm guessing it could be the battery or possibly the alternator or I understand there is a voltage regulator. Any idea what order I should get these investigated / changed or if there is anything else I should be looking at.

Thanks

 

[arry]

Have you got a multimeter?

First things first would be to check voltage output of battery with ignition off and then with the car running on idle. Need ~12.4v upwards to show a relatively healthy battery (at least in state of initial charge) and then ~13.6v ish upwards to ~14.2v when the car is started and running, to test the voltage regulator / charging system as a whole.

At 7-8 years old and having just gone through a cold snap there's a fair chance the battery might have started to drop away, but let's do the simple tests first.

Another possible suspect is ignition switch if it's the same as the 996 unit, which I think it is. My 996 ignition switch failed and I was so convinced it was alternator I changed the damn thing only to find it wasn't!

 

[hornet]

Thanks arry - no I don't have a multimeter but strangely have a device to connect my phone to the stereo which plugs into the cigarette lighter and gives me a voltage reading. I'll check as you suggest although no idea if it is accurate or not.

I had a new ignition switch fitted a couple of years ago so probably not that but good shout.

 

[arry]

If you're not a million miles away from Grays I have a multimeter here you can pinch for a few days if it'll help diagnose.

 

[hornet]

If you're not a million miles away from Grays I have a multimeter here you can pinch for a few days if it'll help diagnose.

Thanks I am in Billericay so not too far - really appreciate the offer but am a complete numskull with cars and never used one so wouldn't have a clue what to do with it. I'll check the belts later to be 100% sure it's not that.

Just found a like for like replacement Bosch S4 battery for £90 off eBay which seems incredible value so may just go for that as replacing a battery is just about within my technical competence.

 

[Parsley]

Don't go oldskool and disconnect the battery while it's running. If it dies the alternator is goosed.

 

[hornet]

Go oldskool and disconnect the battery while it's running. If it dies the alternator is goosed

Never heard of that one but will give it a go. I assume if the engine is running I will not get any alarm or other issues

 

[Parsley]

Go oldskool and disconnect the battery while it's running. If it dies the alternator is goosed

Never heard of that one but will give it a go. I assume if the engine is running I will not get any alarm or other issues

Shouldn't do. It's very old school but if you've no voltmeter it's a cheat way of finding out. Obviously if alternator is not working the minute you disconnect the battery it will die. That's only assuming it's just running off the battery. Leave it as a last resort. I would just get a voltmeter as it's a handy thing to have.

 

[hornet]

I've had it on the trickle charger for the last few hours and interestingly only the same 3 leds are lit as when I connected it so looks like the battery is not accepting a charge.

 

[Parsley]

I've had it on the trickle charger for the last few hours and interestingly only the same 3 leds are lit as when I connected it so looks like the battery is not accepting a charge.

How does it start? Does it spin over ok and sound normal speed?

 

[hornet]

How does it start? Does it spin over ok and sound normal speed?[/quote]

Yes started as normal although the battery has been on trickle charge for 4 weeks and only went out for a shortish drive this morning. Sure it is a coincidence but the warning light did come on as I was pressing on quite hard.

 

[Parsley]

How does it start? Does it spin over ok and sound normal speed?

Yes started as normal although the battery has been on trickle charge for 4 weeks and only went out for a shortish drive this morning. Sure it is a coincidence but the warning light did come on as I was pressing on quite hard.[/quote]

Your only choice really is voltmeter or disconnect the battery while running.

 

[arry]

Thanks I am in Billericay so not too far - really appreciate the offer but am a complete numskull with cars and never used one so wouldn't have a clue what to do with it. I'll check the belts later to be 100% sure it's not that.

Just found a like for like replacement Bosch S4 battery for £90 off eBay which seems incredible value so may just go for that as replacing a battery is just about within my technical competence.

Happy to do it for you, if you were to come over. It's 2 mins to do some basic checks.

 

[deMort]

If the car spins over and starts then there is enough charge in the battery and it's not that .

It's more than likely the alternator has packed up .

If you don't have a voltmeter or indeed tools to replace the alternator then book it in with a garage to have it repaired .

Disconnecting a battery with the engine running is Not something i would ever advise .

 

[hornet]

Thanks arry I may take you up on that. I've put the Ctek on recon mode and the battery seems to be charging again so I'll have a look tomorrow morning and see what the score is. Unfortunately I won't get a chance to look properly until Friday so perhaps I can pm you then.

deMort thanks for the advice in my heart I feel you are right re the alternator. I'll see what tomorrow brings.