Bad alternator?

Alc · Apr 30, 2013

Ive put a multimeter on the battery reading 12.22.... When i start the engine it reads 13.08.

Shouldn't it be higher than this?

If i leave it parked up for 2-3 days my battery is dead but used daily its fine, occasionally gives a tiny struggle to start but usually its ok.

The Mad Hat Man · Apr 30, 2013

get it tested at halfrauds - tiz free.

it will be the alt

neiltce · Apr 30, 2013

Just a thought, check the alternator drive belt tension, I've had belts slip in the past, and cause the same symptoms

ebbadger · Apr 30, 2013

should be over 14 as soon as the revs pick up 14.4 - 14.8 does sound as though its worn

cheers steve

vec150 · Apr 30, 2013

Find an electrical company local to refurb it especially if a genuine alternator. Cost me £20 for a refurb and its like new and better than a cheap after market job.

Khranok · Apr 30, 2013

Mine went last month, good opportunity to upgrade my 200tdi from 60amp alternator to a 100amp however! The drain could be a bad battery or connection though, my battery was also draining, it turned out to be the earth from my battery that wasn't connected!

Alc · Apr 30, 2013

I shall nip it to garage and have them check it over,... Im useless with electrics

mikescuba · May 1, 2013

Mine was giving a similar reading when I was having battery problems. I put a new alternator on and the reading went up to 14 something. I also had to change the battery as it wasn't holding its charge. The battery was just under two years old. The starter motor was also buggered pulling out 350 amps on start up which killed the battery. I changed the starter motor and now everything if fine.

mundungus · May 1, 2013

I think I'd more likely be checking for a drain somewhere. If it wasn't charging, you'd be having problems even on the days you use it back to back.

Alternator is an expensive fix for it to turn out to be something else.

Datatek · May 1, 2013

mundungus said:
I think I'd more likely be checking for a drain somewhere. If it wasn't charging, you'd be having problems even on the days you use it back to back.

Alternator is an expensive fix for it to turn out to be something else.

13 volts will not charge a modern battery, it needs 14.2 or more. Worth checking the voltage at the alternator output as it could be bad connections dropping the volts. If it's low at the alternator then it needs an overhaul, new diode pack, regulator and brushes or complete replacement.

Oldseadog · May 1, 2013

Start at the beginning and check all your earths first!

Your multimeter should show a dead short between your battery earth and every other bit of metal on your vehicle!

Bad alternator?

Alc

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The Mad Hat Man

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neiltce

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ebbadger

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vec150

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Khranok

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Alc

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mikescuba

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mundungus

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Datatek

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Oldseadog

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