Ford focus 09 alternator question

[Shannianni]

Hi all

Many thanks for letting me join your fantastic site.
I have a Ford focus 1.4 09 plate.
My battery was going flat so green flag said the alternator wasn't putting enough power into the battery at 13.1 and needed to be replaced.
I replaced the battery in March but the battery wouldn't start the car last week due to kids sitting in the car which wasn't running and having everything on blower. Radio etc
I took it to a garage and a friend of mine put a new alternator on it. When he checked the output from the alternator it said 13.1. He said it must be a dud alternator and ordered another.
The next day he put this one on and once again 13.1. He then put my alternator back on and said it can't be the alternator.
He has also checked the earths but said they was all ok.
We are both baffled why 3 alternators 2 being new are putting out 13.1.

Can anyone please help?

Regards

Shannianni.

[Coilspring]

Shannianni said:

Hi all

Many thanks for letting me join your fantastic site.
I have a Ford focus 1.4 09 plate.
My battery was going flat so green flag said the alternator wasn't putting enough power into the battery at 13.1 and needed to be replaced.
I replaced the battery in March but the battery wouldn't start the car last week due to kids sitting in the car which wasn't running and having everything on blower. Radio etc
I took it to a garage and a friend of mine put a new alternator on it. When he checked the output from the alternator it said 13.1. He said it must be a dud alternator and ordered another.
The next day he put this one on and once again 13.1. He then put my alternator back on and said it can't be the alternator.
He has also checked the earths but said they was all ok.
We are both baffled why 3 alternators 2 being new are putting out 13.1.

Can anyone please help?

Regards

Shannianni.

Wrong alternator type I guess.

This has the smart charge system fitted ?

[littleredrooster]

Coilspring said:

This has the smart charge system fitted ?

Could be this - the ECU only 'tells' the alternator to charge under certain conditions - e.g. when throttle is closed, when a large load is placed on the battery etc. It is difficult to actually measure the output unless you have it on the bench with the correct test equipment. 13.1 could well be correct under 'no load' conditions.

Only other way would be to wire a voltmeter into the car and watch it on a long downhill slope, for example.

[northwestrecovery]

Could be a faulty smart charge module on the battery cable , was the car reprogrammed when the battery was fitted ? you can't just replace a battery these days .