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Bosch internal regulator alternator wiring diagram.

Bosch internal regulator alternator wiring diagram.

Thought this may be helpful to anyone converting to the later style internal regulator style Bosch alternator.

T, if it is of any use please feel free to add it to the pedia. It is a retail non copyright document. It's also in my shed. Link below


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thanks myeh! that makes things simple to understand!

Great Info

Many Thanks.


My Shed
Holdenpaedia, they're the brakes Mate.


Here ... http://holdenpaedia....


My Shed
Holdenpaedia, they're the brakes Mate.

speaking of alternators, I

speaking of alternators, I took my ute to a mechanic with the evil smell of boiling battery acid coming into the cab and he said the battery was getting 16 volts at idle and making it boil.He thought the regulator had gone in the alternator. I was wondering if replacing the regulator was a diy job or should a auto electrician do the job? thanks AJ

serenity is everywhere

Failed Regulator

The Regulator can be part or all of the Problem.

Disconnect the Battery +ve before changing the Regulator.


My Shed
Holdenpaedia, they're the brakes Mate.

Reg replacement

It is fairly straight forward as long as you're careful. The only tricky part is keeping the brushes retracted fully whilst you manipulate the reg into place. If you don't you can snap off the fragile carbon brushes quite easily. In my 15 years selling these I rejected many hundreds of warranty claims on these regs that were claimed to have been received with factory made broken brushes. Not likely to have happened...

I recently upgraded to a VN

I recently upgraded to a VN V8 alternator in my HG. For anyone that is about to do it the plug is the same as an injector plug from a commodore and finding a 2w BA9s globe was a pain as the major places i went to autobarn, supercheap and repco didn't stock it and could only get me a box. I even tried an auto electrician.
For anyone one on the southside of Brisbane I found Cheapa auto spares at Oxenford have them on the shelf.


Email Me
My Shed

I just replaced the 35 amp

I just replaced the 35 amp unit on my red motor with a brand new 70 amp Bosch unit.
Identical to the old unit it and just bolted straight up.
The 35 amp was on it's limit with the driving lights on and the thermo fan cuttinhg in.

Cheers, Mick.

Alternator Feed

The Alternator Feed Wire *must* be able to handle 70 Amps. Fit a new Wire as required ... http://holdenpaedia....

and here ... http://holdenpaedia....


My Shed
Holdenpaedia, they're the brakes Mate.

There was an article in our

There was an article in our club magazine last month about batteries and alternators.
What the article basically said was that older cars are designed to run at 13.2 volts, whereas modern cars are designed to run 15.2(?)volts.
It went on to say that fitting a modern, 15.2V alternator in a car with an older 13.2V battery will shorten the battery's life as the 13.2V battery will be constantly overcharged.
Similarly, putting a moden calcium type 15.2V battery in a car with and older 13.2V alternator will shorten the calcium battery's life because it will constantly be undercharged.
Do you experts agree with this thinking?
myeh, thanks for the wiring diagram.

Old is good.


They may be quoting me.

Essentially match the Alternator (or Generator) to the Battery. Make the Cables capable of carrying the relevant Currents.


My Shed
Holdenpaedia, they're the brakes Mate.


The Bosch RE60 reg fitted to many many Australian made Bosch alternators will work happily with older technology batteries as well as many of the later types. Calcium-Calcium batteries definitely work at a higher system voltage so should be avoided in our old Holdens. I guess a simple rule of thumb would be "if the Bosch alternator has the old black square regulator built into the back of it your OK". If it's the newer style "European" type reg you should do some further investigation. An example of this Euro style reg is on the new style universal Bosch alternator made specifically for older Holdens BXH1238A. It's 70 amp output and using the later reg and will work happily with older lead and newer silver antimony style batteries.



new Alternator problems

Jusy bought a new alternator for the HZ 253. The old one has a B and B+ terminal the new one has another terminal labeled W anyone know what thats for?

lazzy days

Bosch Alternator

Just got an old Bosch Alternator from the wreckers for my 35Year old Tractor.
It has 2 Terminal connections, D+ and a B+ , what does the D+ mean or what's it's use.
Thank you and cheers for your help, Louis

Internal Regulator

If the Alternator has an Internal Regulator, the D+ isn't used.


My Shed
Holdenpaedia, they're the brakes Mate.

Holden Alternator

Thank you for the quick reply.
Mr. Holdenpaedia, cheers

Bosch alternator wiring

i have fitted the alternator to an old Fordson tractor. The tractor has no warning light as it is fitted with an ammeter. will it still work?

Alternator Excitation

The smaller Bosch Alternators (35, 40, 55 Amp) will self excite when the revs are high enough (1500 or more). That means they don't need the Light Bulb.

I have never found an 85 Amp Alternator to self excite. They need excitation from a 12 Volt source through a Bulb no brighter than 2 Watts. A Bulb larger than 2 Watts will cause the Regulator to fail.


My Shed
Holdenpaedia, they're the brakes Mate.

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