Pulling out of work today noticed the battery light on the dash

Got home and tested with Multimeter.was around 10

Just came out and ran engine for a bit and battery light still on,when i switched on fan and radio and lights the radio cut out.

Eventually car started spluttering a bit so turned off

Now as im standing here the voltage in battery is slowly rising.was 9.7 now its up to 10.1

Sound like Battery stuffed or altenator?

Is there any way i can test the altenator?

The belt seems ok and tight and cable is ok.No melting on top of battery or anything.

Car is Mk 1 vrs. Battery about 2 years old

Was just going to do the xmas shopping too,grrrrr

Its up to 10.7 now

How is the charge building with car just sitting here?

Its up to 10.7 now

How is the charge building with car just sitting here?

Because the battery is recovering.

Sounds like your alternator is goosed or if there's fuses attached to the battery cover check for bad/melted connection here.

With the engine running, if you have 14volts(or thereabouts) at the battery terminals then the alternator is working assuming the wiring between alternator and battery is good.

If you can measure the voltage right at the alternator output terminal, with the negative meter probe on the (scratched clean) body of the alternator, while the engine is running, you can go a step closer to implicating or ruling out the alternator.  Just be careful that you don't short the positive meter probe to anything metal other than the output post of the alt while measuring.

This measurement will remove the effects of any bad connections between alt and battery.

 

I suspect you'll find the voltage still very low right at the alternator though, which may suggest the brushes have worn out.

Here's a guide I found in Practical classic cars https://www.clubpolo.co.uk/forums/topic/335902-testing-your-alternator/ for testing your alternator

Thanks fellas. Ive been watching videos on testing but seems i need fully charged battery for the test to work so will probly have to charge the battery over nite and then try with the multimeter again in morning. Anyone know if the altenator on my vrs would be same as one on a 1.6 or 1.9?

Thinking of breakers yard

Took battery out.have it charging. Was up to 11volts already sonim thinking battery probably ok and altenator is stuffed.

Still trying to find out if other models or mk4 golf ones would fit mine and also is it much of a job removing and replacing.Looks like with the throttle body out the way might have enough room

Here's a guide I found in Practical classic cars https://www.clubpolo.co.uk/forums/topic/335902-testing-your-alternator/ for testing your alternator

thanks for that. Will try with multimeter again in morning with fully charged battery

Got the alternator refurbished. Probably cheaper going to breakers but least i onow it has new bearings and reg and brushed etc

Thanks for help and suggestions

Straight forward job by the way removing and replacing

Had the exact same thing happen to me a few days ago, also mk1 octy. It was the alternator.

Had the exact same thing happen to me a few days ago, also mk1 octy. It was the alternator.

My battery doesnt seem to be holding charge it should. Read it should be bout 13.8-14.2

After I put the alternator back in today was only holding about 12volts. could the battery be damaged by the dodgy alternator

Will check it again after a drive

Did you notice anything like this?

The battery should only show voltages in that range when the engine is running.

The battery should only show voltages in that range when the engine is running.

sorry should of said

it was running idle

My battery doesnt seem to be holding charge it should. Read it should be bout 13.8-14.2

After I put the alternator back in today was only holding about 12volts. could the battery be damaged by the dodgy alternator

Will check it again after a drive

Did you notice anything like this?

I think the voltage should be around 13.8 - 14.2 when the car is running. You can try measuring the alternator output by putting the multimeter directly to it

instead of measuring it from the battery. Maybe a cable is broken somewhere?

With my octy I replaced the alternator (bought one from a Scrapyard). After putting it in I measured the output and it was reading 14.10 ish. Unfortunately the old alternator

had ruined the battery, so it couldn't hold the charge, had to get a new one.