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Td5 Alternator

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Hi all,

Recently I seem to have problems starting my landie. I seem to end up with a flat battery after parking for 2 days. Yes, something somewhere is draining the battery. I'll have to find it an nail it soon or just have to start the landie every 12hrs.

My question is, what's the output voltage of the Td5 alternator. When i start it up, it's say 14.2v and as I drive i get 13.8v after about 40min of driving. When I put on the main lights and stuff, I get as low as 13.6v.

Is this normal or is it supposed to chuck out 14.1v all the time?

The battery is a 2mth old optima yellow top. 55Ah rating.



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try disconnecting the earth lead off the battery when parked up.

if its ok when you do that then it is probably the diodes in the alternator have packed in allowing the current from the battery to energise the alternator thus flatten the battery when parked up.

if it still dose it with the earth lead off the battery disconnected when parked up then its you battery that is duff

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I'd expect around 14-14.1v when running at say 2500rpm.

At idle the alternator isnt spinning fast enough to deliver its maximum output, hence the voltage will drop when you turn lots of electrical load on, it should recover if you bring the revs up, if it doesnt, then theres something wrong with alternator or the wiring somewhere.

What you need to do is connect an ammeter between the positive terminal and the positive lead, with the ignition off, and see if theres any noticable draw. If there is you can start pulling fuses until it drops to try and identify the circuit causing the drain.

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