Has my alternator packed up?!

[marcusa]

Tried to start the car at the weekend.....crank,crank,crraaankk and then finally. Battery has gone flat (new bosch battery as of 05/2016) so my thinking is alternator? any ideas guys?

[10:45PM]

Is the car making any squealing noise?... it's common if it's left for the alternator to seize up (it's easy enough to sort out without replacing the alternator)

They don't always squeal , but belt will be riding the pulley , so it won't be long for the belt to break

[marcusa]

When I switch off the ignition there is a squealing noise yes

[marcusa]

I have been driving the car everyday though so it hasn't been left sitting.

[10:45PM]

Then it doesn't usually seize overnight , it takes a week or so of non-use.

You will now need to get a multimeter to confirm battery terminal voltage , when the engine is stopped , and also when it's running.

Come back with those two readings, one will be around 12.5V (if the battery is healthy) , the other around 14volts (if the alternator is charging)

[marcusa]

Sure, I will look at these tonight, thanks for your reply and advice.

[Thrumbleux]

Check the belt. Were it slack it could squeal. And slip - denying the battery its due charging. It also drives the water pump - enough said....

[marcusa]

I will check the belt, haven't seen engine temp rise quickly or anything...

[marcusa]

OK battery voltage off = 12.5V Voltage across battery while car running = 14.4V. I drove the car into work this morning and there is a constant belt? squeal...more noticeable on idle. Checked the belt last night and feels tight enough..

[Thrumbleux]

Can you make the squeal louder by loading the electrics ie, with engine running, switching on as many high load items (headlamps, rear screen demister, etc)?

[10:45PM]

That ^^

Is it 'just a squeal' or a screaming banshee sort of squeal ?

On the face of it , your alternator appears to be outputting ok, your battery appears to be ok (although a drop test would be next check to fully confirm its charge state)

Do you still get the poor startup? , is it cranking slow (still) ? , or just taking a while to actually fire ?

[marcusa]

It starts fine now no cranking issues. Perfect on startup; the squeal is just a squeal but continues the entire time

[marcusa]

Tried to make the squeal worse, started the car just now and no squeal at all! but battery did go flat. Come to think of it when cleaning at the weekend i did retract the roof and wind it up without power on,,could that really have caused battery to go flat?

[10:45PM]

No to the roof thing.

When you say "started the car just now and no squeal at all! but battery did go flat."

What do you precisely mean ?

How long did it take to go "flat" , and how did that manifest itself ?

[marcusa]

Sorry, that doesn't read very well....

Started the car just now and the squeal is gone.
Battery seems fine and car starts with no issues
So symptoms have gone.

But I am worried that there is an underlying problem that caused the battery to go flat at the weekend.

[Thrumbleux]

But I am worried that there is an underlying problem that caused the battery to go flat at the weekend.

Test # 1. When next parking up turn engine off then immediately restart. If it restarts then alternator can be assumed to be charging and battery isn't being drained during running/use of car. If battery is flat when next called upon to start - then faulty battery or something draining it while it sits idle.

Test # 2. With everything electrical switched off disconnect a battery lead and brush lead against battery post. Sparks indicate current draw. If so, either repeat with each fuse removed one by one until sparking is no longer present. The circuit that fuse belongs to is where the fault is. (Alternatively get a low current ammeter that has fuse blade terminals and insert in each fuse holder and look for drain currents that shouldn't be present).