Hi

I have a Rover 214Si '98

In April my battery went flat (after standing for only 9 hours) and wouldnt start the car (usual clicking noise from starter motor). I replaced the battery as it was the original. I suspected a current drain and had it checked out but the garage found nothing wrong so i put it down to it being an old battery. No trouble for months then...

... tried start the car on sunday and nothing happened (clicking noise again) :shake: . The battery is only 6 months old and is a decent one (calcium). Unfortunately i cant get home until the weekend (cos im at Uni)but i suspect it is a faulty alternator. Before anyone asks about the boot light - it has been disconnected since the last problem.

Am i right in thinking it's probably the alternator - it is the original, so its 7 1/2 years old. Would it sometimes fail or all the time 'cos its been 6 months since the last problem? Also the car only gets used for fairly short journeys.

I am going to get a multimeter to check but would be grateful for any advice/help.

Cheers

I once had an alternator on a 414sli which leaked several amps but still charged the battery when the car was running...

If you pull all the fuses and it still leaks current then its probably the alternator!

-- Andrewh

 

thats what i was thinking - seems to be a common problem on 200's when they get to a certain age.

I think that it must be charging it ok because its been fine for 6 months and i have quite a bit of audio - so the battery wouldnt have lasted that long if it wasnt getting any charge (i dont play it when the engines off before anyone asks).

The car had been stood for a week so the alternator leeking current could have easily run the battery down. Would this be a constant problem - ie everytime the engine was off, or could it just be occasional because as mentioned above its been fine for 6 months.

 

Sounds the same as me! Alternator is brilliant at charging the battery, but pulls nearly 4 amps when the engine isn't running. My alternator used to buzz too when the engine wasn't running.

I successfully bid for an alternator for £6.50 from ebay, but haven't had a reply yet My plan was to swap the alternators and keep the car on the road and get my existing alternator fixed (and kept as a spare).

I now disconnect the -ve lead from the battery every time I leave the car. However my alternator has now stopped buzzing, and I no longer get a big spark when I reconnect the battery. Has it healed itself??????

PS. For ref:

Engine running voltage: 14.27v
Current draw (engine off, alt connected): 3.92 amps
Current draw (engine off, alt disconnected): 0.48 amps

I might recheck the alt this weekend...

 

those figures you gave show that with the alternator connected it is drawing quite a bit of power out of the battery - over time this would make it flat. Disconnecting the alternator brought it down considerably but 0.48 amps still seems way too high to me - should be between 0.02 and 0.12 if i remember correctly.

 

I had the doors open a the time - not sure if this makes a difference....

I might have to have another look. I have noticed my ECU clicks as I disconnect the battery. Is this normal?

 

Having the doors open would make a difference as the interior light would be on, therefore using power.

I know the ECU clicks after about 20-30 seconds after you switch off the engine due to it shutting down. I personally havent heard this noise when disconnecting the battery. Someone else might be able to shed some light. Hope this helps

 

Not sure how long it takes me to switch off tthe engine, pop the bonnet and disconnect. Could be 30s...

Thin I need to have anothe look. I hate electrical problems as there is so much guesswork. All I have is a multimeter

 

I'm fixing one tonight - battery goes flat overnight, the alternator is pulling 2.5A out of the battery.

 

When checking the amount of amps being drawn when car is 'parked' you need to make sure all doors are shut and locked etc, as it would be when you leave it as some things can remain active. Also, if it shows an amp drain over around 0.2 then it would be sufficient enough to drain the battery - but this would take around 48 hours. If it is draining in 9 hours then it must be draining some serious amps, so, if it does turn out to be the alternator replace it asap as they arent expensive.

 

It was my old battery that drained in 9 hours - it was 7 years old so i think it was a combination of alternator and old battery.

The new one was left for a week. This would be plenty of time for the alternator to drain the battery. Problem is that i am 150 miles away at uni and cannot get parking here so the car only gets a run out once a week.

How can i check if it is the alternator that is the problem? I know that i can put a multimeter in series with the battery but that will only tell me that i have a drain - how can i tell if its the alternator specifically?

 

Could anyone tell me how i could test specifically if it is the alternator that is the problem?

 

See your fusebox, near the battery? There are five or six large screwed in fuses underneath a plastic cover or two.


Disconnect the fuse nearest the front of the car - does the current draw disappear? If so, then it's the alternator. You could also disconnect the alternator - but that gets dangerous, what with live terminals around. Be careful!

 

Thanks for the advice Major - now i know what to do at the weekend when i get home.

I take it is is safe to take the fuse out and that its only dangerous if i actually disconnect the alternator?

 

Dont disconnect the alternator with the engine running. Also, If you have charged up the battery and there is a current drain, do not disconnect it as there is a risk of a battery explosion. Not nice I was stupid enough to cause one but lived to tell the tale.

A current drain of 3-4A makes me suspicious of a regulator fault in the alternator. You can check for this by placing somehting magnetic on the end of the alternator shaft by the pulley (engine not running) If the rotor winding is on, then you should feel a magnetic pull. If not then the alternator rectifier pack has a dodgy diode, but that usually results in a huge current drain and a cooked alternator.

Failing that, buy a bettey isolator switch that disconnets the battery when you are not using the car. Also makes a good immobiliser!

 

I should have made it clearer - only disconnect the alternator to diagnose where the current draw is - don't attempt to start the engine! There is no need to.

 

dont worry i wouldnt try to start the engine with the alternator disconnected. im not that silly. - it wasnt me who said about starting the engine

I meant would it be ok and safe to take the alternator fuse out when the battery is connected?

About the isolator switch - i have a clifford alarm and so cant isolate the battery as there will be no alarm on.