Author Topic: alternator amperage (Read 4909 times)

jbturgeon · « **on:** April 20, 2009, 02:36:20 pm »

how many amp should my alternator have on my 95 golf 1,9td no a/c? I just bought a new 70 amp one and my car wont start anymore. My alt and oil light were on last night when my car died. My starter wont even start. The voltage at the batt. terminal is 12 v.

thx

Vincent Waldon · « **Reply #1 on:** April 20, 2009, 02:57:29 pm »

The amp rating of the alternator is the maximum current it can deliver, all accessories on, dead battery, etc, and won't be related to your ALT light or starting problems. In particular, on an AAZ with no A/C 70A should be fine... unless you enter rap competitions with your car stereo!

With the engine running you should see a minimum of 13.5V at the back of the alternator and, by extension, at the battery posts themselves.

With the engine off a fully charged battery will show a minimum of around 12.6V (I say "around" because temperature plays into it a bit... fully charged can vary a couple 10ths of a volt or so).

If you're seeing less than 13.5V with the engine running *and* the alternator light is on someone probably gave you a bad alternator!

jbturgeon · « **Reply #2 on:** April 20, 2009, 05:11:01 pm »

Is my starter bad? What is the clicking noise i was earing when i attemped to start my golf this morning? Should i change my starter? Can i test it?

thx very much

catlin_cava · « **Reply #3 on:** April 20, 2009, 05:17:46 pm »

Have You tried to boost the car to see if it will start? if its standard jump start it. let it idle a bit to see if it may charge up the battery. When My starter went it didn't make any noise at all.

jbturgeon · « **Reply #4 on:** April 20, 2009, 06:23:16 pm »

When i tried to start it, it did that clicking sound from the relay opening and closing under the dash and the anti thief started loud.. Every time i tried, the same pattern happened. Alarm will start sounding after the clicking from the relay... I have been driving the car for 3 days since i changed the alternator. The oil and alt. light were out at idle only and after a couple kms, no more light in the dash..the morning after, it never started!

Nice electric problem.. Big puzzle..

I might try to start it with an other starter i will take from the junkyard and see what happen.

Any ground i haven't seen?

burn_your_money · « **Reply #5 on:** April 20, 2009, 06:48:37 pm »

Check all the connections between the battery and the starter.

Also, when you are trying to start the car, take a voltage reading of the battery under full load.

Vincent Waldon · « **Reply #6 on:** April 20, 2009, 06:58:36 pm »

The clicking noise from the starter and the alarm sounding are both signs that the battery is discharged.... the starter clicks because there's only enough power to run the solenoid, and the alarm sounds to warn you that the car is unprotected because the battery is too weak to run the alarm for long.

Your best bet is to get the car started again by boosting it (or hook a charger to the battery overnight) and then measure the alternator output... my spider sense says the car will start with a boost (meaning the starter is fine) and you're going to measure less than 13.5V, meaning your new alternator is gone south. 3 days is about how long I'd expect a diesel to run just on the battery.

jbturgeon · « **Reply #7 on:** April 20, 2009, 06:59:46 pm »

the reading between the cable and the battery is 12 v. Can a bad starter lead to a bad connection? As the starter and alternator are on the same cable, can a bad starter suck some electricity.

My tach is not one from a diesel, can it be at the base of the whole problem? I have been driving with this tach for a year and never had any prob.

I don't know where else to look!!

thx again very much

jbturgeon · « **Reply #8 on:** April 20, 2009, 07:04:25 pm »

Thanks vince, that was my bet. You just confirm what i thought could be the problem. The only electric part i have been recently working on is my alternator. I am pretty positive i bought a bad alternator.. I ll change it tomorrow.

Let you know later..

Thx

Vincent Waldon · « **Reply #9 on:** April 20, 2009, 07:04:49 pm »

To be clear: you have the car running and you're reading 12V at the battery?

jbturgeon · « **Reply #10 on:** April 20, 2009, 07:16:57 pm »

My car is not running yet. The 12v is only what i mesure when i plug the positive cable of the battery and take a reading from the positive to the alternator cable end. I think it means that the connections are ok. I am not an electrician..tell me if i am wrong. I am used to have more than that anyway with my older alternator with the car not running.

I am going to put my starter back in tomorrow morning and boost it with my brother's car. I should have done it before i took my starter out and almost dropped my engine!!