1.8 GTI wont drive at night ?

my car ACTUALLY wont drive at night …


well … few days back my car died at a petrol station since then i've hooked up a multimeter from the battery into where i sit

so i can see whats going on with the charge etc … well .. at night with the lights on etc … the battery drops .1 every 7 seconds

battery starts off at 12.87

i was out for … about a hour tonight … and i had to bomb it home because it started dropped really fast


O btw … in the day … it holds it charge but it stays in the 12.40-12.90 range


is the my alternator ?  :dontknow:

CARS SCARED OF THE DARK LOLOL - mum just said that

Take it to a fast fit centre and ask them to test the battery with the proper tool. It will probably reveal, there's a dead cell.

What's the voltages of the battery just before starting, just after (with the alternator light still on), and then just after you've revved it up and the alternator light goes off; and then say 5-10 mins after the car's been running?

The battery light on the dash … actually .. doesnt work …

but before turning the key its 12.89

then when the ignitions on buzzing its 12.59

then when the engines running it stays up in the .70 range

doesnt really decrease in the day time ?

chris_VW_1987 said

The battery light on the dash … actually .. doesnt work …

It should do. I'd put a voltmeter on the blue wire off the alternator, to see if it works directly.

theres nothing on that blue wire ? no volts

chris_VW_1987 said

theres nothing on that blue wire ? no volts

WHen is there 0V? Try it with ignition on but not started; just started, not revved up; and started and revved up to, say, 2000rpm.

hmm i got a flash of voltage but its not constant ?

wtf ?

chris_VW_1987 said

hmm i got a flash of voltage but its not constant ?

WTH ?

This is no use - you're not providing enough information. Whats "a flash of voltage" and when do you get it?

at the 2k rpm ... it would flash some current every few seconds ?

With the engine running you should be getting a voltage reading of around 14v at the battery. If you're only getting readings of around 12v, then I suspect your alternator is probably at fault.

Mike.

Hmm yeah, this Friday im going to get it sorted out if the garage is all " omg were fully booked " etc should i charge up some battery's and take my car there like a radio controlled toy ? lol

because I've gotta get to Essex , who's rewiring my car electrics entirely
like , i noticed
for the first 40 mins the battery starts above 10v but after the 40 mins

it drops rather quickly … also

the battery today was showing 12.51v …. then i tried to start the engine and it dropped to 6v , the engine didn't start it sort of went " Clump" lol … so i tried to start it again and it worked and the voltage shot up to 10v but kept falling quickly


should i swap the alternator for another spare i have ? just to get to essex or should i just charge up loads of battery's ?

I had the same problem got a cabriolet the battery would work my dvd player and my electric hood, but wouldn't even turn the engine over.  a couple of days before my lights died in the dark.  shat myself so bypassed the battery with some jump leads and limped it home.  didn't happen again for ages untill uit wouldn't start.  got a new battery and hey presto.  functions perfectly every time.

stick a new battery in - if the problem replicates stick in a new alternator- you'll soon know.

stop p*ssing about

it sound like the alt to me.

the alt has a set of diodes in it that control the amount of charge it makes.  under more load( lights, radio, heater, etc) it will use more diodes to allow more current to be made. if the diode on the high side is burnt out then it sill make power just not enough to compensate for the higher load needed at night.
i worked for an auto electrican rebuilding starters and altenators.
pretty boring didnt last long.
go to halfords they can do a free test on the charging system.