battery light? [Archive]

RAGOONEY

31-12-2008, 13:50

Got a strange fault....
My battery light has just started to flicker on sometimes, but only at high revs, and not all the time. Could this be the alt belt slipping? alt fault? Just fitted a new water pump and the belt is tight enough......any suggestions?:)

Tiny Tim

31-12-2008, 13:51

Bad earth
Alt on its way out
battery on its way out

Get a tester on that battery.

RAGOONEY

31-12-2008, 13:56

Don't have a tester....can you buy them from good old halfords?:)

Tiny Tim

31-12-2008, 13:57

Or pretty much any motor factors. Maplins are quite cheap too.

RAGOONEY

31-12-2008, 13:59

Now the tricky part........
When I buy it......where do I test? and how will I determine if it is the battery or alt?
Soz for all the questions!:)

Bigfoot

31-12-2008, 14:03

If you got a local halfords not that far away, they do a free battery test, if its the battery, use the excuse of that you will go get your wallet, then go buy at a motor factors which are normally a lot cheaper.

Tiny Tim

31-12-2008, 14:05

Use the DC setting, ignition off, anything mid 12's or higher is good. Anything below 11 would suggest the battery is dying a horrid death.

As for the Alternator:

http://www.carbasics.co.uk/How_to_test_your_alternator.htm

RAGOONEY

31-12-2008, 14:06

Would do but the car is not on the road legally yet!:crap:

RAGOONEY

31-12-2008, 14:13

Thanks alot mate, will get testing, cheers:cool:

UNICRONICUS

31-12-2008, 15:47

Just to add, with the engine running you should be seeing higher than 12v on the battery, otherwise there is a fault with your alternator or somewhere in the wiring from the alternator.

bones660

01-01-2009, 16:04

you want a min charge rate of 13.5 volts and max of 14.2 volts:agree:

OUTLAW

01-01-2009, 20:16

i think you can run the engine....and with it idling..remove the earth strap of the battery,(or is it the pos?) the alternator should keep the engine ticking over....if the engine fails...then a new alternator is required......(i think...anyone varify this).....:)

newbstar*

01-01-2009, 21:27

amp clamp time.

RAGOONEY

10-01-2009, 13:02

bones660

10-01-2009, 13:14

tested battery and alt and all is fine.
Still get the flickering battery light at high revs and my speedo jumps about now!
Is there an earth I can check behind the dash?
The earth at the water pump and battery are ok.
check the earths in the footwel's mate . maybe one of them are lose . or could be the speedo head it's self developed a fault . not uncommon for them to fail . :agree:

also mate check alt belt is tight . check the charge rate with the lights and heater blower on . let us know what the voltage is when you have done these test's:agree:

clee

10-01-2009, 13:24

The alt on my GTA has a separate feed to the warning light ie it's not the 12v feed to the battery .My warning light has been on for ages but I know it's charging and also have another charge monitor in the car that says all ok .
Do you have a two pin plug at the regulator ?

michael tierney

10-01-2009, 13:41

dont disconnect bat with engine running...not good practice,if u remove the regulator after checking ur connections you might find one of the brushes is very worn..u can buy a reg seperately

RAGOONEY

10-01-2009, 18:45

just been to see my mechanic friend and explained it to him! the alt is making noise....he reckons the alt has about had it! Where abouts is the earth in the footwell just to double check?

bones660

10-01-2009, 19:03

just been to see my mechanic friend and explained it to him! the alt is making noise....he reckons the alt has about had it! Where abouts is the earth in the footwell just to double check?
you have to remove the kick panels to find the wiring . :agree:

i had an alternator go weak once . and had similar problems to you . mine wouldn't boost properly though . because the amperage was down . so the engine wasn't getting the required power it needed to boost properly . :agree:

tiff_lee

11-01-2009, 14:53

you have to remove the kick panels to find the wiring . :agree:

i had an alternator go weak once . and had similar problems to you . mine wouldn't boost properly though . because the amperage was down . so the engine wasn't getting the required power it needed to boost properly . :agree:
I'm sorry, your alternator went weak so your car wouldnt boost properly?

bones660

11-01-2009, 15:47

I'm sorry, your alternator went weak so your car wouldnt boost properly?
yep . that is correct . the alt wasn't puting the right power in. hence battery was discharging slowly . therefore not putting out enough for a strong enough spark . hence car wouldn't boost properly . the car in question was c- reg phase 1 .
fitted new alt , no battery light coming on at higher revs . boosting fine .

you will find that the gt turbo has a higher amperage rating than a non turbo 5 . due to extra power drain that the gt turbo produces . :agree:

i had the alt checked at lsuk in yeovil . they told me that it was the amperage output that was weak . but it was still charging . but wouldn't be enough to supply what the car required . :agree:

Markey Mark (BD)

11-01-2009, 15:47

RICHIE

11-01-2009, 15:51

i would be inclined just to check the wires in the engine bay maybe when your reving higher the engine tilt could be interfering with the wiring in some way

RICHIE

11-01-2009, 15:55

yep . that is correct . the alt wasn't puting the right power in. hence battery was discharging slowly . therefore not putting out enough for a strong enough spark . hence car wouldn't boost properly . the car in question was c- reg phase 1 .
fitted new alt , no battery light coming on at higher revs . boosting fine .

you will find that the gt turbo has a higher amperage rating than a non turbo 5 . due to extra power drain that the gt turbo produces . :agree:

i had the alt checked at lsuk in yeovil . they told me that it was the amperage output that was weak . but it was still charging . but wouldn't be enough to supply what the car required . :agree:

i would have thought the spark power was the same on and off boost

Markey Mark (BD)

11-01-2009, 16:13

i would have thought the spark power was the same on and off boost

It is :agree:

bones660

11-01-2009, 18:04

i would have thought the spark power was the same on and off boost
if you haven't got the right amount of power needed to create the spark it will be weak . little test for you . drain your battery down . disconnect your alt [ only way i know to create a false alt fault ] just so your battery is not charging . take your car for a spin .you will find it won't boost properly . because the battery can't supply the amount of power needed to create a strong enough spark to cope at high boost levels .plus you have to take into consideration the other things needed to keep the car running .
ie electric fuel pump , speedo, brake lights , infact all the lights , rev counter , the renix unit . ect . all need power . so if your alt is running weak amperage . allt these things won't work to there full potential . :coffee:

RICHIE

11-01-2009, 18:12

if you haven't got the right amount of power needed to create the spark it will be weak . little test for you . drain your battery down . disconnect your alt [ only way i know to create a false alt fault ] just so your battery is not charging . take your car for a spin .you will find it won't boost properly . because the battery can't supply the amount of power needed to create a strong enough spark to cope at high boost levels .plus you have to take into consideration the other things needed to keep the car running .
ie electric fuel pump , speedo, brake lights , infact all the lights , rev counter , the renix unit . ect . all need power . so if your alt is running weak amperage . allt these things won't work to there full potential . :coffee:

but the spark doesnt require more power on or off boost so if there wasnt enough power getting to the aei it would run full stop.

tiff_lee

11-01-2009, 18:23

[quote=bones660;34443]if you haven't got the right amount of power needed to create the spark it will be weak . little test for you . drain your battery down . disconnect your alt [ only way i know to create a false alt fault ] just so your battery is not charging . take your car for a spin .you will find it won't boost properly . because the battery can't supply the amount of power needed to create a strong enough spark to cope at high boost levels /quote]
So basically you're saying the ignition system is breaking down under load?

Markey Mark (BD)

11-01-2009, 18:28

if you haven't got the right amount of power needed to create the spark it will be weak . little test for you . drain your battery down . disconnect your alt [ only way i know to create a false alt fault ] just so your battery is not charging . take your car for a spin .you will find it won't boost properly . because the battery can't supply the amount of power needed to create a strong enough spark to cope at high boost levels .plus you have to take into consideration the other things needed to keep the car running .
ie electric fuel pump , speedo, brake lights , infact all the lights , rev counter , the renix unit . ect . all need power . so if your alt is running weak amperage . allt these things won't work to there full potential . :coffee:

You just answered your theory in the first sentence, 'drain your battery down'. The reason for a possible weak spark is because the battery is flat.
The battery will go flat because it is no being charged by the alternator but if the alternator packs up or just momentarrily cuts out and the bat is fully charged you will hardly feel any differnce is power as the electrical system is still getting its 12v it needs.

Mart

11-01-2009, 18:29

little test for you . drain your battery down . disconnect your alt [ only way i know to create a false alt fault ] just so your battery is not charging . take your car for a spin .you will find it won't boost properly

And then you'll breakdown with a flat battery, won't be able to restart, and thus will be stranded at the side of the road. Who in their right mind would be thick enough to carry out that 'test'? :sad2:

Ragooney, check the yellow wire going to the top of the alternator is making good contact/isn't held in place by a strand of wire or 2. Likewise, check the main feeds going to the + & - terminals of the alternator.

RICHIE

11-01-2009, 18:33

And then you'll breakdown with a flat battery, won't be able to restart, and thus will be stranded at the side of the road. Who in their right mind would be thick enough to carry out that 'test'? :sad2:

Ragooney, check the yellow wire going to the top of the alternator is making good contact/isn't held in place by a strand of wire or 2. Likewise, check the main feeds going to the + & - terminals of the alternator.

obviously im thick enough to carry out the test:cry:

bones660

11-01-2009, 18:35

but the spark doesnt require more power on or off boost so if there wasnt enough power getting to the aei it would run full stop.
the faster the engine turns the stronger the spark will be . ie if you run your car at 500 rpm say it needs to spark 500 times . if you increase the rpm to 1000 you will need double the amount of sparks . to ignite the fuel being used. so if the amperage is down. your battery is not receiving the right amout of power or charge to cope with the the drain the car and engine need . hence the term a weak spark .

i know what i mean . just not very good at explaining things . :agree:

Mart

11-01-2009, 18:35

obviously im thick enough to carry out the test:cry:

You mean you'd purposely disconnect the alternator, take your car for a spin, knowing full well that when the battery eventually fully discharges you'd be fecked?

The IQ level on here drops another notch... :(

RICHIE

11-01-2009, 18:40

:eek:
You mean you'd purposely disconnect the alternator, take your car for a spin, knowing full well that when the battery eventually fully discharges you'd be fecked?

The IQ level on here drops another notch... :(

mart you do know im not being serious :eek:

Mart

11-01-2009, 18:42

It's hard to tell sometimes on here these days... :D ;)

bones660

11-01-2009, 18:44

You just answered your theory in the first sentence, 'drain your battery down'. The reason for a possible weak spark is because the battery is flat.
The battery will go flat because it is no being charged by the alternator but if the alternator packs up or just momentarrily cuts out and the bat is fully charged you will hardly feel any differnce is power as the electrical system is still getting its 12v it needs.
that is what i am trying to say .the amperage was down on my alt . so as not to put enough charge to the battery to cope with the power drain on the battery to power everything to it's full . hence something had to suffer . in my case it was the engine cutting out when the turbo come on boost . although this happend the alt still showed 13.5 v charge rate .

RICHIE

11-01-2009, 18:48

that is what i am trying to say .the amperage was down on my alt . so as not to put enough charge to the battery to cope with the power drain on the battery to power everything to it's full . hence something had to suffer . in my case it was the engine cutting out when the turbo come on boost . although this happend the alt still showed 13.5 v charge rate .

now im even more confused:(