battery light....worried..help..

[funinthesun]

right, started the car this morning, hasnt been driven since monday....and the battery light came on, now it started first time, as usual, after about 5 mins of driving it went out...ok just a little flat and now recharged.....stopped to get some fuel, and now its stayed on, again started first time from the petrol station,..


now is this indicating that it really need a new battery, or could it be a loose earth or something else? this is the first thing that has even slightly gone wrong so i might be being a little paranoid but I'd quite like to get home tonight,

thnx


S.

[Incorrigible]

Check that everything's tight on the back of the alternator, and check the battery terminals

If you've got acces to a voltmeter you can test if its charging, should be 13-14volts with the engine running, 12-12.5 volts when not

5 minutes before the light goes out sounds like a dodgy alternator

[GreenV8S]

If the no charge warning light comes on (or stays on after you start), this may be a serious problem and you should check it out immediately (switch off engine, do not collect $200 etc). If the problem is caused by the fan belt breaking/falling off, you will have lost drive to the water pump and if you run the engine with no water circulation you can cause a lot of damage. It would also take out power steering etc if you have this. If the fan belt is there and OK then the problem is 'only' electrical and could be caused by an alternator fault or a wiring/fusible link problem. The only thing likely to go wrong is the battery going flat and leaving you stranded, it's OK to drive if you're happy to take this risk.

[funinthesun]

oh bugger...

[tvrbob]

Isn't there something about an alternator fuse mounted on a cross member that can suffer from corrosion? I’m sure I’ve read these symptoms before.

[jtong]

yes, I have now experienced this twice. The symptoms I have seen are: battery light staying on (but then going out if engine revved hard); indicated very low oil pressure; slow-ish cranking of engine suggesting flat battery.

Both cases have been a faulty 100A alternator fuse which is located in a little black box on the chassis rails near the driver-side front wheel.

[plotloss]

Not sure if this works with Tivs but a test that I have been aware of for sometime (assuming that the fan belt is all present and correct) is to disconnect the battery positive whilst the engine is running.

If the engine stops then chances are the alternators knackered.

[trefor]

plotloss said:

Not sure if this works with Tivs but a test that I have been aware of for sometime (assuming that the fan belt is all present and correct) is to disconnect the battery positive whilst the engine is running. If the engine stops then chances are the alternators knackered.

Hope you don't mind if I stand back while you do that ...

[Leadfoot]

plotloss said:

Not sure if this works with Tivs but a test that I have been aware of for sometime (assuming that the fan belt is all present and correct) is to disconnect the battery positive whilst the engine is running. If the engine stops then chances are the alternators knackered.

ZAP big spark! (& a knackered ecu if the voltage spikes enough to fry it...........)

Check the fusible link in the starter motor to alternator feed first (as been said already & if the belt's ok). Its in a black platic box just underneath the offside engine mount, they can crack/corrode & look ok at first so you might need to take it off or put a meter across it to make sure. They only cost 75p BTW.

[ribol]

plotloss said:

Not sure if this works with Tivs but a test that I have been aware of for sometime (assuming that the fan belt is all present and correct) is to disconnect the battery positive whilst the engine is running. If the engine stops then chances are the alternators knackered.

That old wives tale only worked with Dynamos. You cannot do this with an Alternator, it will kill it dead.

Ivan

[david beer]

The light will not illuminate if the fuse link has blown as the alternator is "giving out". It should be "belt fallen off" or "low voltage output" light. Mine went just last week with no indication appart from the volt meter showing 12v.

[funinthesun]

well, cleaned the car yesterday, might as well look good sitting in the drive, checked all the connections under the bonnet, all seemed fine, started up to see if the light still came on, and it didnt?

let it run for a while still ok, so went out for a spin, still not coming on, but..

while driving seemed a noticable drop in power and on a couple of occations whilst triing to accelerate hard, especially in second and third, felt like it almost stalled vitrually no acceleration at all...

and yes te oil pressure did seem to be a little low, not alarmingly so , but certainly a bit lower than normal.

no overheating though , and the fan belt seemed to be OK (not slipping)..

got home sat in the drive, for a minute, waited until the fans cut in and then the batery light came on, car stalled and havnt been able to start in since.

bugger...

will check the 100A fuse in a minute , but appart from that can think what else to do, and the garage cant book me in until the middle of july..

[funinthesun]

well it all turned out tio be the alternator fuse after all, plus a small coolant leak, that was causing all the problems. Nice people at castlesprot sorted it all out plus the MOt in a little under 4 days from the first call to them...

so I get her back this evening just in time for the weekend

thaks for the advise , and spot on for the fuse call..

always good to know there is a pool of helpful info out there...

now off to check that weather forecast...