dynamo to battery wiring

[jerry atric]

On my new 1936 GTS, I just want to rig up enough electrics to supply a brake light and horn. I have a battery and Marelli dynamo with integral regulator which should work. My question is: Does it matter which terminal supplies the battery +ve and which goes to earth? Any knowledgable advice appreciated please. Thanks in advance and hope.

[Rick Yamane]

To power a brake light and horn you don’t need to hook up the charging system. That’s probably the most complex part of the electrical system. The simplest way would be to just run them total loss, leave the generator out of circuit and charge the battery as needed. 

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From: guzzi-...@googlegroups.com <guzzi-...@googlegroups.com> on behalf of jerry atric <baconsl...@gmail.com>
Sent: Wednesday, October 15, 2025 5:36:30 AM
To: Guzzi Singles <guzzi-...@googlegroups.com>
Subject: [guzzi-singles] dynamo to battery wiring

 

On my new 1936 GTS, I just want to rig up enough electrics to supply a brake light and horn. I have a battery and Marelli dynamo with integral regulator which should work. My question is: Does it matter which terminal supplies the battery +ve and which goes to earth? Any knowledgable advice appreciated please. Thanks in advance and hope.

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[Patrick Hughes]

I have an 11 AH battery on my Falcone, with the headlight on full beam, tail, number plate and stop lights all on, it pulls one Amp. So the battery in theory will power the lights for 11 hours.  I ran it for 6 months like that when the dynamo was being repaired.  All the lights are LED.

 

Regards
Patrick Hughes  

 

From: guzzi-...@googlegroups.com <guzzi-...@googlegroups.com> On Behalf Of jerry atric
Sent: 15 October 2025 13:37
To: Guzzi Singles <guzzi-...@googlegroups.com>
Subject: [guzzi-singles] dynamo to battery wiring

 

On my new 1936 GTS, I just want to rig up enough electrics to supply a brake light and horn. I have a battery and Marelli dynamo with integral regulator which should work. My question is: Does it matter which terminal supplies the battery +ve and which goes to earth? Any knowledgable advice appreciated please. Thanks in advance and hope.

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[jerry atric]

Thanks for the answers, guys. It just seems a waste not to have the dynamo charging the battery; win win! Unfortunately, I'm no good at electrical theory.

[guzz...@aol.com]

maybe try this Jerry ,,,,,,,,,, different bike but same result your looking for

Tim

https://groups.google.com/d/msgid/guzzi-singles/87986755-516b-4354-8091-83612728f4afn%40googlegroups.com

.

[Dave Knaack]

I don’t mean to hyjack the thread but I have a question. I’m refitting the generator to my ‘52 Falcone. The cut-out has been removed and I’m using a DVR2 to control voltage.  Can I use the charge light? And if so how do I wire it into the circuit ? 

Thx, Dave 

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On Oct 15, 2025, at 9:57 AM, 'guzz...@aol.com' via Guzzi Singles <guzzi-...@googlegroups.com> wrote:



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<1948_Airone-rev.jpg>

[RICHARD YAMANE]

I understand, that's a big part of suggesting you forgo the charging system. Electrical work got a lot easier for me when someone told me to imagine it as plumbing. Water flows one way (DC current), pipe size (wire guage) allows more or restricts the flow (amperage/wattage) and voltage is like water pressure, the less there is the larger pipe you need to deliver the same quantity.

It does matter which wire goes where. I would suggest you download the info and diagrams from the internet and print them for reference. One thing I've found is as simple as electrics can be, the Italians have made it an art to complicate them. Who was this Marconi guy anyway?
One other thing is Europeans have been using a nearly universal numering system to ID circuits. I don't have a web address but printed out a couple of pages titled "Bosch Terminal Designations". I think if you search under that you will find it. As far as I can recall the designations apply to the old Guzzi's and they are often stamped on/near the terminals. A lot of the designations are meaningless to our Guzzis but the basic stuff should all apply.
I have a bunch of notes and drawings from when I did my GTV. I'll see if I can dig them out and filter through them. I'm a little busy with some mom care things right now.

 

Rick Yamane

Importer of Vape/Powerdynamo ignition systems and Polisher of bikes at Motion Pro

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[pouma1954]

If the battery is charging   just take the feed from the battery.  + and earth don't matter for the switch or light.

Paul

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[pouma1954]

You could run an electric start with a battery like that.

Paul

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De : Patrick Hughes <patrick...@harmill.co.uk>

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Objet : RE: [guzzi-singles] dynamo to battery wiring

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[jerry atric]

Many thanks for the answers. I didn't realise Marelli used the same numbering as Bosch, I'll have a closer look at the dynamo and see if the terminals are numbered I suppose there's nothing to burn out if I get it wrong (I've got a fuse !)

im, that diagram looks simple enough for me... maybe!

Dave, I have a DVR2 on one of my bikes and the people who make them are really approachable and helpful. Email them and they'll answer your question.

[Dave Knaack]

Thx, Jerry.  I’ll send them an email 

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On Oct 15, 2025, at 1:30 PM, jerry atric <baconsl...@gmail.com> wrote:

Many thanks for the answers. I didn't realise Marelli used the same numbering as Bosch, I'll have a closer look at the dynamo and see if the terminals are numbered I suppose there's nothing to burn out if I get it wrong (I've got a fuse !)

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[Mac Dennis]

What do those numbers mean?

https://en.wikipedia.org/wiki/DIN_72552

Mac

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[John O Regan]

Hi All,

Assuming the dynamo and regulator are working a single wire from 51 to the battery+ will provide charging and regulation

However, I would fit a fuse in the line maybe 5-6 amp? 

I'm sure I have posted what happened to the original dynamo on my GTW when the cutout stuck closed and the Cyclon 6v battery discharged into the dynamo. It burned the innards to a crisp and ruined the battery in spite of having a 10 amp fuse on the battery+

John

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[Dave Knaack]

Yeah, skip Brolund rebuilt the dynamo. The cut-out looked remarkably well but he highly recommended removing it and replacing it with a dvr2n to avoid that sort of thing 

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On Oct 16, 2025, at 3:37 PM, John O Regan <chate...@gmail.com> wrote:



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[jerry atric]

I hadn't seen that post, John. So where does the other wire go? just to earth? In my experience, electronic regulators are great but you never get  second chance with them; anything goes wrong and they are literally toast.

[Dave Knaack]

The two wires from the dynamo go to the dvr, the output from the dvr is one wire to battery positive, and one to ground.  That’s for a negative ground system 

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On Oct 17, 2025, at 1:19 AM, jerry atric <baconsl...@gmail.com> wrote:

I hadn't seen that post, John. So where does the other wire go? just to earth? In my experience, electronic regulators are great but you never get  second chance with them; anything goes wrong and they are literally toast.

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[John O Regan]

Hi Jerry,

The second terminal 61 is used for the charging light.

To use an electronic regulator  the internal regulator needs to be bypassed or removed completely. 

When I converted mine I used one terminal connected to the positive brush that connects to "D" or  + on the DVR 

I used the second terminal to connect to the field coil, "F" on the regulator.

The negative brush and the other field connection are connected to the dynamo body (earthed or grounded).

Remember to buy a negative earth regulator.

I mounted the regulator externally,  I did not check if it would fit inside the end housing

John

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[Dave Knaack]

FYI, the dvr will fit internally if you drill the mounting hole in the correct spot, not a lot of room for error though 

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On Oct 17, 2025, at 5:24 AM, John O Regan <chate...@gmail.com> wrote:



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[jerry atric]

I'm hoping to use the existing mechanical regulator as I'm told it is serviceable. Should find out next week when I finally get everything together. Thanks again for the answers.