Battery Indicator flashes during stop/start traffic

[misterpoh]

Hello,

Just yesterday while I was driving, I saw the battery light come on and off. It flickers very quickly. Headunit shuts down by itself and starts again.

How it happens :

Only during stop/start traffic

After that, I stopped the car and waited till the traffic was more freeflowing.
Drove the car then, no problems. Drove the car over small bumps etc, no problems. Problem only occurs during stop/start traffic.

Battery is brand new fitted to a volt stablizer.
Checked all battery wiring, no problems.
Checked Headunit wiring, no problems.
Checked Volt stablizer, no problems.
ECU flash, no problems.

What else can I be looking at?

Many thanks,

Alan

[thebob]

I had this problem, my ulternater was dying. If you head unit has a voltage meter setting on it put it to that and see if your volts are dropping.

[misterpoh]

I had this problem, my ulternater was dying. If you head unit has a voltage meter setting on it put it to that and see if your volts are dropping.


Thanks for your prompt reply. I figured it maybe along those lines. Just hoping to get more opinions to reconfirm :D

Many thanks.

[egSi]

i also vote for alternator, i had a similar problem recently. got mine rebuilt, great now. your manual i think mentions it as being a battery charge problem.

maybe try that :thumbsup:

[misterpoh]

i also vote for alternator, i had a similar problem recently. got mine rebuilt, great now. your manual i think mentions it as being a battery charge problem.

maybe try that :thumbsup:


Awesome, thanks for the prompt reply guys.. geez.. almost seems like you are logged on 24/7 haha. Anymore ideas?

[misterpoh]

Oh.. nearly forgot.. If the problem really is the alternator, I dont understand how it affects my headunit. The headunit shuts down and turns on again. Any ideas?

[egSi]

im not sure y that is^ the alternator charges the battery so when its not charging it will slowly run out and die. maybe the battery level is so low that when the battery is not being charged, there is not enough residual battery power to run the HU?

im not an auto electrician but just trying to help from my own experience. im sure u can test the alternator before you go the effort to remove/replace/rebuild.

how many ks on the motor/alternator Alan? FYI: My motor had done 130000ks when my alternator died, (it was rebuilt with new bushes btw)

do you have a huge stereo which needs more power?

[destrukshn]

your head unit may turn off becuase there is not enough volts to run the head unit, so it will turn off then back on when there is enough volts when you drive.
or sometimes when there isn't enough volts, it will just turn off and on as well.
most probably your voltage regulator in your alternator is dead.
there really ain't much else that could go wrong.
you can also check the belt just in case, if it's loose and slipping.

but in my opinion, it's your voltage regulator or at least something in the alternator. lol

[destrukshn]

check what volts your car is at when the light comes on as well.

[misterpoh]

im not sure y that is^ the alternator charges the battery so when its not charging it will slowly run out and die. maybe the battery level is so low that when the battery is not being charged, there is not enough residual battery power to run the HU?

im not an auto electrician but just trying to help from my own experience. im sure u can test the alternator before you go the effort to remove/replace/rebuild.

how many ks on the motor/alternator Alan? FYI: My motor had done 130000ks when my alternator died, (it was rebuilt with new bushes btw)

do you have a huge stereo which needs more power?

Thanks for your reply bud.
My battery is 2 months old.
My car has travelled approximately 85,000kms.
I am running a small 4 channel amp. 6x9 and 6" splits on the amp and another set in the front off the headunit.
The wiring for system was DIY and all were soldered on properly and heat warpped.

[misterpoh]

check what volts your car is at when the light comes on as well.

The battery light only comes on when the vehicle is in motion. When I had my battery replaced 2 months back, the battery man from RACV did a voltage check and said all was good. Could he have put in a wrong battery resulting in voltage spike? My previous battery had a higher cranking capacity vs this battery I have now.

[misterpoh]

your head unit may turn off becuase there is not enough volts to run the head unit, so it will turn off then back on when there is enough volts when you drive.
or sometimes when there isn't enough volts, it will just turn off and on as well.
most probably your voltage regulator in your alternator is dead.
there really ain't much else that could go wrong.
you can also check the belt just in case, if it's loose and slipping.

but in my opinion, it's your voltage regulator or at least something in the alternator. lol

The belts are tight. No problems there. As for the voltage regulator, wouldnt there be an ECU code if its faulty?

sorry, noob question lol. -1 rep point for asking.

[dsp26]

- check the voltage w/ engine off = ~12.3v
- check the voltage w/ engine on = ~14.4v
- check voltage at various revs = ~14.4v. big fluctuations past +-0.4 mean ur alternator is dying. If it even goes beyond +-1v either way then consider it dead. it will kill your new battery quickly as the regulator exponentially dies... check it specifically around say 5000rpm. the regulator is inside the alternator. the faster the alternator pulley spins, the more power is created, however the regulator is there to obviously regulate it at 14.4v which it should achieve around 2,500rpm.

If the light blips on/off during motion, have you checked your battery connections? A place change my gfs one a while ago and we couldn't figure out why it was doing that on her celica.. and on fast turns the car would stall... turns out the replacement batetry was smaller than stock and couldn't be screwed down properly.. kept moving around and the positive connector kept grounding to body.

[misterpoh]

- check the voltage w/ engine off = ~12.3v
- check the voltage w/ engine on = ~14.4v
- check voltage at various revs = ~14.4v. big fluctuations pas +-.4 mean ur alternator is dying

If the light blips on/off during motion, have you checked your battery connections? A place change my gfs one a while ago and we couldn't figure out why it was doing that on her celica.. and on fast turns the car would stall... turns out the replacement batetry was smaller than stock and couldn't be screwed down properly.. kept moving around and the positive connector kept grounding to body.

That sounds logical. However in slow motion ie between 20-40kph car will show signs of battery failure and headunit on and off. Over those speeds, car is perfectly fine. No issues with Headunit and battery indicators.

Many thanks for your figures on voltage. I will definately do a voltage check after work.

[egSi]

the voltage regulator is apart of the alternator isnt it?

Alan have u called an auto electrician and asked their opinion?

[misterpoh]

the voltage regulator is apart of the alternator isnt it?

Alan have u called an auto electrician and asked their opinion?

Not yet buddy.. Wanting to get some info here first. May go down that path if I cannot figure out the problem.

[dsp26]

yeah it is inside the alternator. no auto elec will 'fix' it as they won't make money... the cheapest if you do have to get one is to do the core swap.

misterpoh: i'll give you another example though....
- cars with CANNON mufflers rattle the car and drone at lower revs because the vibrations are slower
- but when revving it... the tone gets a bit higher because the vibrations are faster.

what i'm getting it is that it won't likely show its symptoms at thos higher speeds... BUT... at the end of the day its a free check you can do yourself first.

[misterpoh]

yeah it is inside the alternator. no auto elec will 'fix' it as they won't make money... the cheapest if you do have to get one is to do the core swap.

misterpoh: i'll give you another example though....
- cars with CANNON mufflers rattle the car and drone at lower revs because the vibrations are slower
- but when revving it... the tone gets a bit higher because the vibrations are faster.

what i'm getting it is that it won't likely show its symptoms at thos higher speeds... BUT... at the end of the day its a free check you can do yourself first.


I dont really follow what you are refering.

In reference to the alternator core > Does the ECU pick that up? ie Throw out an error code.

If I was to take out the alternator and dismantle the core out, what is it exactly I should look out for to know that it is a faulty core?

EDIT : Anyone got any ideas about the voltage regulator?

[riruiz_88]

the reason why ur altenator isnt chargin ur battery is cause the brushes on the shaft are most likely worn out. these brushes are not makin a good connection with ur shaft which is why ur gettin all these voltage spikes. u might wanna have a look at these first.

[misterpoh]

the reason why ur altenator isnt chargin ur battery is cause the brushes on the shaft are most likely worn out. these brushes are not makin a good connection with ur shaft which is why ur gettin all these voltage spikes. u might wanna have a look at these first.

Thanks for your feedback. However, the issue isnt with the battery not charging but more onto voltage spiking. The battery is brand new (2months old) and I am not running heavy power consuming gears in my car.

Question :

1. The previous battery had a higher cranking output. Current battery has a lower output. May this be a contributing factor?

2. Problem happens only during slow stop/start style driving. Even tho the alternator isnt generating enough electricity due to a slow drive, the current battery is new so I cant see how the battery is low on power already. Can the problem possibily be the battery itself?

[bennjamin]

as above - check alternator.

Also - disconnect the battery (atleast the negative) and check the alternator power wire (its a 10 or 12mm nut holding it on)- sometimes it can loosen up and give issues like the above.

[destrukshn]

batteries will not throw up a light on the dash.
notice if your battery went flat, or shit it self, the light doesn't come up.
lol

[misterpoh]

No, the problem is the dodgy alternator is not recharging the battery so when you go slow your running off battery voltage which is down due to the bad alternator. your getting voltage spikes because SOMETIMES the alternator puts out some power then drops out again.


Awesome Claymore. Thanks for that. I shall get a new alternator and see how things progress from there.

Anyone got one for sale?

[misterpoh]

as above - check alternator.

Also - disconnect the battery (atleast the negative) and check the alternator power wire (its a 10 or 12mm nut holding it on)- sometimes it can loosen up and give issues like the above.

Thanks Ben, Will give that a check also prior to getting a new alternator.

[bennjamin]

Thanks Ben, Will give that a check also prior to getting a new alternator.

just DISCONNECT the battery first ! You might get a SHOCK :thumbdwn:

[misterpoh]

just DISCONNECT the battery first ! You might get a SHOCK :thumbdwn:


Awesome, will take that advise ! Many thanks again. +1 rep point for all those that gave an "informative" technical contribution in this thread.