Series 2a Alternator Upgrade

[moofletch]

I have a standard alternator in my wagon, Series 2a 1966 petrol. I have an alternator from a Zaphira 120 amp output. Will there be any adverse effects to the wagon if I replace the old one with this new super powered one? I have several electrical extras added to the wagon which will draw quite a lot of current. I hope someone can help me.

 

[gramor]

Get an auto electrician to check what the regulator fitted on the current alternator is allowing through, you might be surprised.
Series 2 vehicles were fitted with dynamo's when originally built, so someone has already altered yours and it would be a good idea to have the wiring checked before loading up the system.

 

[moofletch]

thank you for the advice, I'll talk to my local auto electrician.

 

[clivees]

Yep your amp meter will not be able to cope as a altenator will put out much more than a dynamo.

 

[The Mad Hat Man]

Shirley an alternator will only output enough current to supply any items needing it, so unless there have been loads of bolt on electrical goodies, the ammeter will be ok - maybe just a different shunt required?

 

[clivees]

Yep and if you want to have lots of bolt on goodies it will quite happily melt your wires.
ps not too sure if the batt charging cct go's through the amp meter but if it does then that could prove interesting on a cold morning after a difficult start.

 

[The Mad Hat Man]

an ammeter is only a voltmeter with a shunt across it. and the starting circuit dont go through it, just everything else.

 

[gramor]

Yep and if you want to have lots of bolt on goodies it will quite happily melt your wires.
quote]

I'm with Clivees on this one, Series II electrical systems were designed for powering ignition system, lights and the horn. Bolt on goodies may draw much more power from the battery than the alternator can replace. Many car alternators are restricted through the regulator to 50% to ensure a longer service life, but your battery won't like repeated heavy discharge cycles. Second issue for consideration is the possibility that previous owners have hacked into the electrical system taking feeds off anywhere they can.(from bitter experience) resulting in more power consumed= more heat = Fire.

 

[moofletch]

Thank you all for your advice.

I ask the question as I have an electric heater matrix out of a pug I think and it draws 80 amps when on fully hot.

I fabricated a heater box and fan around said heater so when the engine is running and new alternator spinning, there will be instant heat in the mornings.

I have re-wired the feed to the heater so it goes through a heavy duty fuse and high power relay for switching. All new cables running from a new bus bar direct from a new battery.

If I understand correctly, an alternator will only give out its full ampage potential if it is called upon from a circuit. It isn't kicking out all of the 120Amps all of the time. (please correct me if I'm wrong).

 

[moofletch]

Oh and there is no ammeter at all in the circuit, only a battery volt meter.

 

[The Mad Hat Man]

same thing - just works diffrent.

 

[gramor]

If I understand correctly, an alternator will only give out its full ampage potential if it is called upon from a circuit. It isn't kicking out all of the 120Amps all of the time. (please correct me if I'm wrong).

Some pictures would be good, and yes alternator output is regulated by demand, but only gives full output when it is up to running speed, i.e. avoid idling with the heater on for long periods as it may still draw more power from the battery than the alternator can replace.

 

[moofletch]

ok brilliant. Thank you for that. It could still give me a comfortable ride for the first few until the engine gets up to temp while driving normally. I needed to clarify things before I tinkered with fitting the new alternator and wiring. All design first so I got things right.