Night Time + Headlights = No Bingo

[DamageInc]

i have a problem...

my car drives fine during the day , but soon as i have to drive with my headlights on the battery goes flat. another thing is the wipers go really slow all the time and so do the windows.

ive replace the battery twice in the last 2 months , same with the alternator and starter motor , just to be sure..

but the problem keeps persisting. i dont see it being the alternator as its the same problem happening time and time again , and its not the battery because ive bought two new ones..

how the hell can i find out whats happening?

[blind_elk]

Use a multimeter to test the voltage at the battery under the various conditions - lights on, lights off, stereo on, stereo off, engine at idle, engine at 2000, any others you can think of.

Q - have you checked the tension on the alternator belt?

[DamageInc]

Use a multimeter to test the voltage at the battery under the various conditions - lights on, lights off, stereo on, stereo off, engine at idle, engine at 2000, any others you can think of.

Q - have you checked the tension on the alternator belt?

i haven't checked the tension but it seems to pretty tight like there isnt any play in it i dont think

by testing all them things what will that achieve?

[DamageInc]

did some testing with my multimeter and this is what i got :

Front Of Car, Car Off : 12.4

Boot Of Car, Car Off : 12.4

Boot Of Car , Car Off, Headlights on : 11.9

Front Of Car, Car Off, Headlights On : 11.9

Front Of Car , Running : 12.0

Boot Of Car , Running : 12.0

Boot Of Car, Car Running, With Lights : 11.7

Front Of Car, Car Running , With Lights : 11.7

Front Of Car , Car Running, With Lights , Stereo : 11.7

Boot Of Car , Car Running , With Lights , Stereo : 11.7

Boot Of Car , Car Running , With Lights , Stereo , Power Windows Going Down : 11.6

Front Of Car , Car Running , With Lights , Stereo , Power Windows Going Down : 11.6

[blk94r33]

did some testing with my multimeter and this is what i got :

Front Of Car, Car Off : 12.4

Boot Of Car, Car Off : 12.4

Boot Of Car , Car Off, Headlights on : 11.9

Front Of Car, Car Off, Headlights On : 11.9

Front Of Car , Running : 12.0

Boot Of Car , Running : 12.0

Boot Of Car, Car Running, With Lights : 11.7

Front Of Car, Car Running , With Lights : 11.7

Front Of Car , Car Running, With Lights , Stereo : 11.7

Boot Of Car , Car Running , With Lights , Stereo : 11.7

Boot Of Car , Car Running , With Lights , Stereo , Power Windows Going Down : 11.6

Front Of Car , Car Running , With Lights , Stereo , Power Windows Going Down : 11.6

That's way too low. Car idling your battery should be getting at least 13 volts. Did you change your alternator with cheap second hand ones both times? Could be duds?

[DamageInc]

That's way too low. Car idling your battery should be getting at least 13 volts. Did you change your alternator with cheap second hand ones both times? Could be duds?

cars been on charge all yesterday so...

both are 2nd hand

[jiffo]

As mentioned above, alternator is stuffed.

Anyone having continual battery trouble should do a simple multi meter voltage check by gradually applying loads (headlights, wipers etc) to ensure the alternator is capable of keeping up.

If at around 2500rpm it drops below 13.8-14V with full electrical load, either the drive belt is slipping or the alternator is sad.

Useless replacing batteries if they're not getting full re-charge while driving.

[blind_elk]

Generally, the alternator is a dud. With engine running, battery should be in the range 13.8 - 14.4V, even with engine only idling.

[The Bogan]

A general rule of thumb for the correct tightness is being able to twist a belt with a thumb and finger a 1/2 turn and feel resistance. If you can turn it more than a 1/2 turn, you do not have enough tension on the belt. If you cannot turn it a 1/2 turn, you have too much tension on the belt. Loose belts will result in premature belt wear caused by the belt slipping along the pulleys. This can also cause an alternator to be unable to replace a charge to the battery fully. There may also be a pronounced squeal from the belt during operation from the belt slipping. Over-tightened belts can cause internal damage to the bearings inside the pulleys. It can also cause overheating of the belts and premature wear.

Read more: How to Adjust a Belt Tensioner | eHow.com http://www.ehow.com/how_5091204_adjust-bel...l#ixzz16SuNZ3dL

[blk94r33]

cars been on charge all yesterday so...

both are 2nd hand

Your options are:

1. Dud alternator, check the output from the alternator output terminal (the big one on the back of the alternator to earth) with the car running to see if you have more than 13.5v

2. Slipping belt (as per mlr's post)

3. If step one is deemed successful, a loss in connection between your alternator, battery and earth.

Your battery is a storage device, designed to start the vehicle and run accessories with the car off, your alternator then replenishes this once the car is running and supports all electrical needs.

[Jax]

Yes, do what blk94r33 says. If the alternator is working, you now have the task of finding the reason it's not charging the battery. Either someone you know who has a few clues about car electrics - or an Auto Electrician.

In hindsight ( and for future reference ) a trip to an Auto/Lec in the beginning, and have it fixed first go, may have been cheaper than 2 Batteries and 2 S/H Altenators, never mind all the inconvenience you've been through.

[DamageInc]

Yes, do what blk94r33 says. If the alternator is working, you now have the task of finding the reason it's not charging the battery. Either someone you know who has a few clues about car electrics - or an Auto Electrician.

In hindsight ( and for future reference ) a trip to an Auto/Lec in the beginning, and have it fixed first go, may have been cheaper than 2 Batteries and 2 S/H Altenators, never mind all the inconvenience you've been through.

wasnt that expensive , got the alternators free from a mate and i got the batteries on trade

got another alternator last night so gonna see if that works , if not ill try find the problem somewhere in the wiring on the car before i get paid then if i have enough ill take it to an auto elec, just not keen on leaving my car there overnight/weekend

[DamageInc]

swapped alternator over and hello 12v yet a-fking-gain

[blk94r33]

swapped alternator over and hello 12v yet a-fking-gain

Are you checking this from the back of the alternator or the battery? You could have three good alternators but a broken connection between the alt and the battery/earth....

[DamageInc]

Are you checking this from the back of the alternator or the battery? You could have three good alternators but a broken connection between the alt and the battery/earth....

straight off the power on the alternator and also off the battery terminals in the engine bay

same power output no matter what i do

[blk94r33]

Ok, so you've had 4 different alternators on the car, belt tensioned, running, and still only getting 12 volts??? Your other option is giving the alt a *LIGHT* tap on the housing near the regulator as this can sometimes get them temporarily running again. Is the battery light on the dash staying on with the car running? Something VERY suss going on as I doubt you could get 4 dud alternators.....

Edited November 28, 2010 by blk94r33

[DamageInc]

Ok, so you've had 4 different alternators on the car, belt tensioned, running, and still only getting 12 volts??? Your other option is giving the alt a *LIGHT* tap on the housing near the regulator as this can sometimes get them temporarily running again. Is the battery light on the dash staying on with the car running? Something VERY suss going on as I doubt you could get 4 dud alternators.....

have had 3 alternators on it and thats including the one that came with the car that the motor was originally from

belt tension is perfect, have given it a couple of taps on the housing

battery light isnt illuminated at all , the only light that comes on for memory is just the handbrake one but thats obviously because the handbrake is up.

im starting to think theres a leak somewhere in the car ? just dont know where or what from...

[mad082]

i'd check the following 2 things:

1: the major wires running to and from tha alternator

2: the earth wire for the battery

sounds like 1 of them may be the issue and the reason why you aren't getting charge. i had a falcon that wouldn't charge the battery. turns out the earth wire from the alternator was completely shot. had a mates falcon do the same thing. the fact that you have put multiple alternators on and it hasn't changed makes me think it is a wiring issue.

[t_revz]

got ignition power at the plug in the back of the alternator?

[DamageInc]

Bare with me as I'm posting off my phone now

Me and my mate started testing everything again , long story short the plug That goes in the side of the alternator was only getting power on one side of it. Basically it wasn't getting excite or something.

Tested it with a test light and multimeter and nothing. Found an ignition power source , wired it to the plug and we have 14v on idle now. Headlights are brighter and everything works mint!