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/2 12v fuse off (+) batt terminal advice

Datchew
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Joined: Sun Dec 21, 2008 10:38 pm

/2 12v fuse off (+) batt terminal advice

Post by Datchew »

1964 R50/2 upgraded to 12V.
Got a new battery recently from benchmark and it's BIG. Had to creatively fit the beast into the frame.
Vech recommended a fuse off my (+) side and I was hoping to get tips or pics from others that have done similar.

Thanks,
M

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jwonder
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Re: /2 12v fuse off (+) batt terminal advice

Post by jwonder »

Inline fuse like the one pictured. This one has two leads off the battery, one to the motorcycle and one for a battery tender but you only need one if not running a tender.
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Datchew
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Re: /2 12v fuse off (+) batt terminal advice

Post by Datchew »

thanks much.
I'll get one similar and put it inline on the (+) side wire

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Re: /2 12v fuse off (+) batt terminal advice

Post by schrader7032 »

Just curious since I don't understand this elektrickery. Why couldn't the fuse be on the negative side? How does the current flow in a circuit? My thought was that the electrons "leave" the post terminal and find their way back to the negative post. So, if that's it in a simplistic fashion, then maybe it makes sense for the fuse to be just after it leaves the positive terminal if something downstream shorts and there's a big demand??? :?:
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
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Re: /2 12v fuse off (+) batt terminal advice

Post by jwonder »

Full disclosure, I copied this off a web page and modified it for our use:

The negative terminal is ground and if you put the fuse there (on the return path) then when the fuse is blown the whole circuit will be sitting at high potential. The fuse goes on the positive terminal so when it is blown the circuit is disconnected and grounded.

Always place the fuse as close to the source of power as possible to minimize excess wire between the power source and fuse.

Getting either of these rules wrong can start fires or cause injuries because part or all of the device will be left without fuse protection.
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Re: /2 12v fuse off (+) batt terminal advice

Post by schrader7032 »

Makes sense!
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
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Re: /2 12v fuse off (+) batt terminal advice

Post by Micha »

jwonder wrote:
Tue Jul 20, 2021 2:53 pm
Inline fuse like the one pictured. This one has two leads off the battery, one to the motorcycle and one for a battery tender but you only need one if not running a tender.
Sorry, I could not figure out what was being done here.
I also have a conversion to 12 volts and I was also advised to put a fuse on the plus side.
But what you have done here, is to connect the 2 ends of the fuse to one single connection.
So where will the other side go, if its in use here?
After all, the fuse should sit in a line inside the circle?
If so, I understand I performed the fuse implant incorrectly. Please enlighten my eyes on the subject.
Thanks in advance.
Michael Steinmann
R51/3 1952
Engine Nr. 529466

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jwonder
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Re: /2 12v fuse off (+) batt terminal advice

Post by jwonder »

Michael,

The fuse is between the battery and the main harness the other lead goes to the battery tender plug. I don’t run the battery tender through the fuse but direct to the battery. Hence the spade for the battery with two lines off it.

I am replacing the original picture with a better one as well.
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Re: /2 12v fuse off (+) batt terminal advice

Post by wa1nca »

I am also confused
Looks like fuse is inline on the small wire not in line with the large wire which should be the main wire going the generator and then to the headlight
Tommy Byrnes
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Re: /2 12v fuse off (+) batt terminal advice

Post by jwonder »

The /2 harnesses have 12 gauge wire for the main. The only plugs I have for the battery tender are 10 gauge (because I use them for my heated gear, and other electrics on my R1200GS). That’s why it looks that way, because it is.

You do not need a 10 gauge wire for a battery tender by the way. If I have plugs with 18 gauge wire for the tender I would use it in a heartbeat but I have a whole box of 10 gauge plugs. :D
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