what is the maximum allowed alternator voltage?

Thread Starter

pothineniuk

Joined Dec 20, 2009
2
Hi,

Today I took my Ford focus car to garrage for servicing and MOT. The guy told me that the alternator needs to be replaced as it is producing 14.9 volts power. Do we have any upper limit for the voltage?
Could anyone suggest me if it really needs to be changed? as it costs more than £150?

Thanks for the help.

Babu
 

SgtWookie

Joined Jul 17, 2007
22,230
14.9v is quite high. I would check the battery voltage after the car has been sitting with the engine off for at least 4 hours. It should measure about 12.7v to 12.9v when fully charged.

£150 sounds about the going rate for an alternator replaced by a mechanic.

However, if you are handy with tools, it is not very difficult to replace the regulator module in the alternator. It is much less expensive if you do it yourself; I'd guess you could fix it for about £10 if you already have the tools. However, I have no idea how mechanically inclined you might be.
 

THE_RB

Joined Feb 11, 2008
5,438
A lot of the newer alternators especially on smaller cheaper cars have the regulator integral to the alternator. It's not always replaceable. Sometimes riveted in, some are even molded into the endcap of the alternator.
 

Thread Starter

pothineniuk

Joined Dec 20, 2009
2
Thanks for the useful advise.

14.9v is quite high. I would check the battery voltage after the car has been sitting with the engine off for at least 4 hours. It should measure about 12.7v to 12.9v when fully charged.

£150 sounds about the going rate for an alternator replaced by a mechanic.

However, if you are handy with tools, it is not very difficult to replace the regulator module in the alternator. It is much less expensive if you do it yourself; I'd guess you could fix it for about £10 if you already have the tools. However, I have no idea how mechanically inclined you might be.
 
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