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Hi all, here goes my mate had a shot of my disco for the weekend so I was using his td5 defender and I parked it up on Monday and left it for half an hour and when I went back to it it wouldn't start it turned slowly then went dead so I put some jump leads on it and away it went so went back to my house (10 min drive) turned it off and tried it again still nothing so I put the charger on it low over night and in the morning it started about 3 times then it went dead again so I checked the voltage while running was at 12.5v slowly dropping, so check the earth to the battery that seamed fine, checked the plug on the back of the alternator gave it a wee clean, then tried a known good battery of my motor but it did exactly the same thing and the starter seams the be turning free enough, so would I be right on saying it needs an alternator?

Cheers

its something to do with alternator yea.you could test what voltage is coming out of the alternator, may give you some clues

Is the fan belt sticking, alternator isn't charging the battery? Check the alternator.

I'd agree with the above. Alternator or (at a push) the connections from it. Sounds like the alternator though. It should be up in the 14 volts whilst running.

Scott90 said:

...I checked the voltage while running was at 12.5v slowly dropping...

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Your alternator is knackered. It should be kicking out about 14.4V, anything less than about 13.5V will not charge the battery as there isn't enough voltage to overcome the batteries internal resistance. A good battery well charged up can sit at well over 12V, even 13V. So the Alternator MUST output more voltage or else the battery will not take a charge. As the batteries voltage falls (the more depleted it becomes) then in theory a lower voltage charger would work, BUT, it would only take it up to a point. If the alternator can not hold a good voltage against the battery that is because it cannot generate enough currant, so the voltage drops off. Failed regulator would cause this. These are easily replaced and cheap enough.

Ok checked all that and nothing different happened, so I put an alternator on it.......still no charging?????? Pos faulty altarnator?

The Battery hasn't been completely discharged has it when you've popped it on the battery charger...? If the fuse in the battery charger blows this would normally result in the battery being discharged!

Check the terminals, its possible that there may be a little corrosion or a bad connection. It still sounds very much like a faulty Alternator (re-check the wiring). Keep us posted!

If you have access to a replacement battery try it with that...! Possibly a faulty battery.

Sounds like the batterys had it to me