Help with alternator/Battery (FIXED NOW :))

[NCpaj]

Hey fellas, after some time in the shed i could start my car. i managed to get it started after jumping it off my mums car. however after running it for a while it dosent seem to be holding its charge?

when i first measured it was on 9.6v
i ran it for 15mins and it got to 10v

i then took it out of my car then charged it off my mums car for 20mins it now starts my car.

it then measured 11.86v
i then started my car and ran it for 10mins
then the battery measured 11.69v
i then ran it for another 10mins
and then it measure 11.69v


i think my alternator isnt propley topping up the battery.(i got the battery in feb last year).

-how much do new alternators cost, can i fix my old one (clean it out somehow).


hope this makes sense ,

Thanks

[plowy]

sounds like your not getting any charge from the alternator
give it to a auto shop and let them fix it

[RAY185]

Test the voltage at the battery with the engine running. Over 13.8(ish)V means the alternator is ok and the battery is cactus. If its not getting that then the alternator may be faulty and require reconditioning. Test the voltage at the alternator itself (neg probe on battery neg and positive probe on power terminal on the back of the alternator) if you get 13.8V or over then the problem is in the wiring from the alternator to the battery. If not sure on any of this go see an auto elec.

Ray

[NCpaj]

Test the voltage at the battery with the engine running. Over 13.8(ish)V means the alternator is ok and the battery is cactus. If its not getting that then the alternator may be faulty and require reconditioning. Test the voltage at the alternator itself (neg probe on battery neg and positive probe on power terminal on the back of the alternator) if you get 13.8V or over then the problem is in the wiring from the alternator to the battery. If not sure on any of this go see an auto elec.

ive just tested the battery, its kept the same voltage from since this afternoon. ive also measured the votage from the alternator when the car was running, it was 10v.

so i guess the prob is with the alternator.

thanks heaps fellas.

on the 4wdm forum the reackon, you can just changew the bushes. how do you do that.

[Reddo]

ignition light usually comes on if the alternator voltage falls below battery voltage. Changing the brushes is relatively easy - if it is that - do a search. I would first try another battery, it sounds like that to me.......but if the voltage stays low, most likely the alt - brushes or regulator. Try tapping the lternator with a hammer - gently, so see if the voltage rises as the remainder of the brushes grab a hold on the armature - a sure sign it's the brushes...

[bazooked]

first question is how long has it been sitting 4 and wats the date stamp say on the battery?, if the battery had low volts ie 1-8 volts and u jumpstarted it u will not get a true reading of out put from ur alternator it will read alot lower, so in short if its been sitting for sumtime charge the battery up on a charger and go from there, also check ur fluids in ur battery, if 1 cell is low or dry compared to the others get a new battery.

[NCpaj]

first question is how long has it been sitting 4 and wats the date stamp say on the battery?

it was sitting for about 3weeks and at random times if used the radio/uhf and the date on the battery is feb 05 when i got it.

[-Scott-]

Your battery sounds like it's able to hold a reasonable charge, so I don't think that's your problem. Even if your battery is getting old, your alternator should be showing a higher voltage than you've measured - fix your charging, then worry about the battery.

It may not be your brushes - it could be the regulator, or possibly (unlikely) a blown charge indicator light not allowing the dynamo field to energise.

I think you need an auto-sparky.

Good luck,

Scott

[Pinball]

If you wanna get a clean read on your alternator output coz u suspect the battery is pulling it down (collapsed cell) then once car is running lift terminals off battery and measure across them for alternator output.

But i gotta admit, alternator sounds dud, if it's your brushes you will see arc 'n spark from the comm as brush holders short the windings.

Spock

[NCpaj]

well i had a mate come round last night and we charged the battery properly last night and after a few little tests kinda came to the conclusion that it must be the alt.

after last nights charging , its holding the charge well and the alt still measures 10v when the car is running.

once again thanks for all your help

[bazzle]

You need to 1st charge the battery for about 24 hours on a 240v battery charger, not just an hour or so jumped on another car.

Then read the batt voltage on the charger. Charger on and charger off.
12 volts plus
Then put in vehicle , start and run at high idle for 10mins, then measure running voltage. 12volts plus.
proper voltages dont matter at this time.

Report again
DO NOT disconnect batt with engine running.

Bazzle

[ST391GQ]

DO NOT disconnect batt with engine running.

Bazzle

Wot he said


Cheers Keith

[NCpaj]

dont worry

DO NOT disconnect batt with engine running

i had a mate over last night , and we charged it over night, the battery kept its charge so its not the battery. i just rebuitl the alt with new bushes, its not that so im going to put a new regulator in it to.

[chops]

Never disconnect a battery with the engine running. This used to be ok when cars had generators. When an alternator has no battery connected to it, it runs uncontrolled (ie flatout). This usually blows the diodes and then sends out an uncontrolled AC Voltage which can blow the shitter out of pretty much everything electronic in the car (ECUs, Stereos etc.)

[NCpaj]

thanks fellas, ive replaced the bushes and it didnt work so i replaced the regulator and all is working nicely. i went down to burleigh auto electrics on christine ave.

they helped out alot they gave me good prices on the brushes i got yesterday and wat i got today and installed the new regulator for free between jobs--

[Pinball]

Never disconnect a battery with the engine running. This used to be ok when cars had generators. When an alternator has no battery connected to it, it runs uncontrolled (ie flatout). This usually blows the diodes and then sends out an uncontrolled AC Voltage which can blow the shitter out of pretty much everything electronic in the car (ECUs, Stereos etc.)

That answers the first question that popped into my head... (i was figuring ppl were worried about sparks in a h2 rich environment...)

so what causes the run away... should still have a load... thats what it apparently blows, related to the voltage sensing hookup?

Spock