battery light on for a while

[mikeversot180]

hi there I have a 3 cylinder 1.0 yaris 2007  when I start it up the Battery light stays on only for perhaps a mile down the road thought it might be the Battery I went to the spares shop and they tested the Battery and said it was unserviceable so I bought a new one but the problem is still there the car starts fine and you can use all the electrical equipment without it failing but park up for a couple of hours and when you start the light is on again I would say for a bit longer each time thanks mike

[fordulike]

Might be one or more diodes in the alternator's rectifier have failed, or a slipping alternator drive belt.

[mikeversot180]

thanks for the reply does that mean I will need a new alternator or is it repairable the belt feels pretty tight and I haven't heard any slipping after a few minutes it goes off and it drives great but I think the amount of time its on is getting longer so probably will stay on in the end and the cold weather is coming so I better get it sorted .

[Mooly]

Those are all classic symptoms of a failing/faulty alternator. A good auto electrician may deem it repairable which should be a substantial saving over a new part.

 

 

 

 

[mikeversot180]

going to book it in on Monday as I have to sort it in case it gets any worse thanks for your help have a good evening .

[mikeversot180]

update went to the garage and had it all tested Battery alternator no faults found he advised me just to drive it so I am going to see how it goes now as its the wives car and she don't take much notice of lights anyway  so fingers crossed .

[fordulike]

When I ran a really old Nissan Micra for a while, I used a plug in volt meter to give me an indication of whether the alternator was charging ok. You can use it to see the voltage of the Battery when the car isn't running, then the charge voltage with the engine running.

12V/24V LED Car Cigarette Socket Voltmeter Voltage Battery Tester Detector

I left mine plugged in all the time, as the lighter socket isn't energized when the key is out of the ignition.

 

 

[Mooly]

If nothing has been done then the basic problem remains. I wouldn't like to comment without knowing what tests they performed, only to say that a check of the charge rate and charge voltage would not automatically reveal a problem that would cause the warning light to illuminate.

[fordulike]

Out of interest, what revs does it sit at idle?

[mikeversot180]

its a three cylinder so it doesn't idle very smoothly but around 800 I suppose and it also has a digital display so quite hard to tell .

[mikeversot180]

car still shows the red light on start up for a while nothing has changed it starts and drives fine so I will keep driving it and see how long it lasts like this and keep you updated if I have any problems that need sorting in the future

[mikeversot180]

update its now January 2019 and the Battery light still remains on for a while and the car haven't failed me once what a fantastic little car I would recommend it to anyone .

[Stevie J]

I would get a multimeter and put it across the terminals of the Battery when the engine is started and its still showing the red Battery light. It should be immediately up to around 14.1V as soon as the engine starts, showing a charging voltage from the alternator. If the voltage is between 11.5V and 12.8V, then this shows there is insufficient charging voltage from the alternator. If the voltage is then measured across the Battery terminals when the light has gone out, and its over about 13.8V, then the alternator is charging properly.

On my own 2006 1.3 Mk2, my red battery light goes out immediately the engine has started, and stays out, and its charging voltage is over 14V - this is how it should be if the alternator is working OK. On a higher mileage engine, over 80,000 miles, then there is a higher chance the alternator carbon brushes may be starting to get worn down, and it becomes erratic in its charging, eventually stopping charging altogether, meaning you'd have to get it replaced or repaired, but a recon unit is usually the best way to go.

[stantheman1]

9 hours ago, mikeversot180 said:

update its now January 2019 and the battery light still remains on for a while and the car haven't failed me once what a fantastic little car I would recommend it to anyone .

Thanks for the update, they're always welcome.

[Catlover]

18 hours ago, mikeversot180 said:

update its now January 2019 and the battery light still remains on for a while and the car haven't failed me once what a fantastic little car I would recommend it to anyone .

I got the wife a mk2 Yaris 1.4 5-gear diesel few years back, loved it so much that I got myself one, same 1.4 diesel but 6-gear. Both really good reliable cars but the 6-gear so much better because of that extra gear. Very happy with them until I "discovered" the pleasure of driving Toyota hybrid cars.