My series 3 alternator is overcharging the battery at 18.5 volts. The battery is warm and the battery is hissing with vapour, so not using it. I have ordered a new voltage regulator. The alternator was overhauled and reconditioned about 1000 miles ago. Are there any other things that can cause this.
Thanks
Mike
Alternator overcharging at 18.5 volts
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#1 Alternator overcharging at 18.5 volts
1973 Jaguar E Type Series 3 OTS Signal Red
1968 Proteus Jaguar C Type Ecurie Ecosse Flag Blue
1963 Triumph TR4 Signal Red
2020 Mustang Bullitt Highland Green
1968 Proteus Jaguar C Type Ecurie Ecosse Flag Blue
1963 Triumph TR4 Signal Red
2020 Mustang Bullitt Highland Green
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#2 Re: Alternator overcharging at 18.5 volts
If you look at one of my previous posts, the operation of the regulator is explained.
Basically, the field coil current is too high on average. Instead of switching on and off continuously, it is staying on continuously. Either it is sensing that the battery voltage is too low or the the big transistor is continuously conducting.
Trace through why either of those two conditions is true and you have your answer as to why it is overcharging.
kind regards
Marek
Basically, the field coil current is too high on average. Instead of switching on and off continuously, it is staying on continuously. Either it is sensing that the battery voltage is too low or the the big transistor is continuously conducting.
Trace through why either of those two conditions is true and you have your answer as to why it is overcharging.
kind regards
Marek
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#3 Re: Alternator overcharging at 18.5 volts
Thanks Marek,
To the electrical novice, will the replacement of the voltage regulator cure the problem or could something else be going on?
Mike
To the electrical novice, will the replacement of the voltage regulator cure the problem or could something else be going on?
Mike
1973 Jaguar E Type Series 3 OTS Signal Red
1968 Proteus Jaguar C Type Ecurie Ecosse Flag Blue
1963 Triumph TR4 Signal Red
2020 Mustang Bullitt Highland Green
1968 Proteus Jaguar C Type Ecurie Ecosse Flag Blue
1963 Triumph TR4 Signal Red
2020 Mustang Bullitt Highland Green
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#4 Re: Alternator overcharging at 18.5 volts
Dear Mike,
You should at least attempt to isolate where the problem is before spending money first.
The last time someone came on to this forum with the same problem, it turned out that the electrical connector was corroded and broken, so it under reported the battery voltage back to the regulator, so buying a new regulator would not have solved the problem.
Use the wiring diagram and a long spare wire and an ohm meter to determine via loopback tests whether the harness and its connectors are sound first. Without the right input, a correctly working regulator doesn't give the right output. You may simply find that the 12v battery connection to the regulator is poor.
kind regards
Marek
You should at least attempt to isolate where the problem is before spending money first.
The last time someone came on to this forum with the same problem, it turned out that the electrical connector was corroded and broken, so it under reported the battery voltage back to the regulator, so buying a new regulator would not have solved the problem.
Use the wiring diagram and a long spare wire and an ohm meter to determine via loopback tests whether the harness and its connectors are sound first. Without the right input, a correctly working regulator doesn't give the right output. You may simply find that the 12v battery connection to the regulator is poor.
kind regards
Marek
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#5 Re: Alternator overcharging at 18.5 volts
Thanks Marek,
Appreciate your advice, as always.
Kind regards
Mike
Appreciate your advice, as always.
Kind regards
Mike
1973 Jaguar E Type Series 3 OTS Signal Red
1968 Proteus Jaguar C Type Ecurie Ecosse Flag Blue
1963 Triumph TR4 Signal Red
2020 Mustang Bullitt Highland Green
1968 Proteus Jaguar C Type Ecurie Ecosse Flag Blue
1963 Triumph TR4 Signal Red
2020 Mustang Bullitt Highland Green
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