Advice from auto electrician

 My mates twin engine sail cat was hit by lightning last year and only just back in the water he is sailing / motoring from Carnarvon to Dampier but has discovered the port engines alternator which is brand new is over voltage ....charging battery bank at 16 Volts rather that the usual 13.8 it simply a faulty alternator or can someone let me know what it might be please? 

Posts: 286

Date Joined: 21/07/14

 I would suspect the voltage

Wed, 2016-06-29 17:27

 I would suspect the voltage regulator is kaput but it maybe integral to the alternator

sunshine's picture

Posts: 2472

Date Joined: 03/03/09

Have been told it doesn't have one

Wed, 2016-06-29 18:15

simply a bridge rectifier but I stand to be corrected 

Posts: 2946

Date Joined: 03/03/10

bridge rectifier

Sun, 2016-07-03 21:24

 actually what a full wave bridge rectifier does is convert ac to dc (the output of the alternator) , a voltage regulator is just that a voltage regulator  over charging would have bugger all to do with with full wave bridge rectifier , the fact its charging means its working the fact its over charging means its a voltage regulator problem 


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Date Joined: 18/01/12

 Bridge rectifier is just a

Wed, 2016-06-29 20:00

 Bridge rectifier is just a set of diodes.

He could just take the belt off the alternator and charge with the other engine if the belt does nothing else or put heaps of load on like flood lites to get voltage down or battery will cook.


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sunshine's picture

Posts: 2472

Date Joined: 03/03/09

Thanks both

Wed, 2016-06-29 20:50

 Diesel mechanic rang me .....seems likely a bad earth and the alternator does have a VR inbuilt but a poor earth will cause it to over-volt so this is being looked at usual fishwrecked a winner !