Why wire the R/R to the battery directly?

[Guest]

I've heard a number of people say to wire the R/R tot he battery directly with a fused line but I've not really heard an explanation why.

It seems simpler, but why wouldn't Suzuki have just done that to start with?

[tkent02]

Suzuki wasn't worried about the effects of thirty years of corrosion on the electrical connections.

[MAJikMARCer]

Suzuki wasn't worried about the effects of thirty years of corrosion on the electrical connections.

So is it primarily to reduce the number of connection/corrosion points?

[Big T]

So is it primarily to reduce the number of connection/corrosion points?

Probably

It's just one of those things that some member tried once, it worked and word got around

I've seen charging systems go from mediocre to fully functional with just that one wire

[Steve]

That's basically it. Although the bikes are designed to last seemingly forever, time does take its toll on the electrical bits.

Routing the R/R output to the battery avoids one of the common areas that goes 'bad'.

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[Dogma]

So is it primarily to reduce the number of connection/corrosion points?

Partially. On the example Steve showed me while doing this mod, there is a soldered joint in the wiring harness that goes bad. The other reason I don't remember fully, but it has to do with current flows before and after starting, and what's fused and what's not.

It probably won't be long before he turns up to correct or complete my description. Edit: See, he turned up while I was typing.

[MAJikMARCer]

When I get all my bits I'll do a 'dry fit' and make sure I have the setup right (seems simple enough) that way I don't get my hands slapped by the gurus.

[Steve]

Partially. On the example Steve showed me while doing this mod, there is a soldered joint in the wiring harness that goes bad. The other reason I don't remember fully, but it has to do with current flows before and after starting, and what's fused and what's not.

It probably won't be long before he turns up to correct or complete my description. Edit: See, he turned up while I was typing.

And now I'm back here to correct you.

Actually, that connection that goes bad is not soldered, it is merely crimped. Yes, it is then covered and wrapped in the main harness, but is still susceptible to corrosion, which is where the problems arise.

The difference in current flow is because that junction is between the main fuse and the ignition switch. Before starting the bike, all current comes from the battery, through the MAIN fuse, past the R/R junction and then to the ignition switch and the rest of the bike. After the engine is running and the R/R is doing its thing, the bike will take whatever current it needs, any excess will go back through the MAIN fuse in the other direction to charge the battery.

When you move the R/R lead to the battery, ALL current to run the bike will go through the MAIN fuse ALL the time. Whatever the bike does not need will still charge the battery, the only difference is the MAIN fuse. Because it now has to handle ALL the current to run the bike, it needs to be increased a bit from the stock 15 amp rating.

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[MAJikMARCer]

When you move the R/R lead to the battery, ALL current to run the bike will go through the MAIN fuse ALL the time. Whatever the bike does not need will still charge the battery, the only difference is the MAIN fuse. Because it now has to handle ALL the current to run the bike, it needs to be increased a bit from the stock 15 amp rating.

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Just to be clear, this has nothing to do with the line-fuse between the R/R and the battery correct? All I'll need to do is get a larger amp cartridge correct? I don't necessarily have to change the fuse block? What is the recommended size? My 650E doesn't have any extras, it's a stock setup. 20, 25, or 30 A?

[tom203]

Stock fuses are 15 main,10 amp others. If you wire R/R direct to battery, use a 20 or 25 amp fuse inline in a seperate fuseholder. Make sure your R/R negative wire has a direct (or almost direct) connection to battery negative- do not rely on any battery box grounding.

[Steve]

Just to be clear, this has nothing to do with the line-fuse between the R/R and the battery correct? All I'll need to do is get a larger amp cartridge correct? I don't necessarily have to change the fuse block? What is the recommended size? My 650E doesn't have any extras, it's a stock setup. 20, 25, or 30 A?

That is correct. You will still need a fuse between the R/R and the battery, because there is always the possibility that the R/R might fail in a "shorted" position. The fuse will protect the bike from the resulting massive current draw.

Add up all the loads the bike is likely to see. Headlight, 5 amps. Coils, 3-4 amps each, 6-8 amps total. Tail light and instrument lights, about 1 amp. Brake light, 2.5 amps. Turn signals, 2.5 amps each, total of 5 amps per side. So, worst-possible case, if you are stopped, with the brake light and turn signals on would be about 21 amps. Blow the horn(s), you will add another 3-5 amps. Probably be good to put a 30 amp fuse in there.

The reason the stock fuse gets by with being smaller is that the R/R usually feeds the bike more directly. It sends power through the ignition switch to the three individual fuses, which are 10 amps each. Only the excess beyond what the bike requires is sent back through the MAIN fuse to charge the battery.

On the other hand, you would almost expect that if you turned the key ON (but did not start the bike), turned on the brake light and the turn signals, then hit the horn, you should blow the stock fuse, as you will be exceeding its 20 amp capacity. Fortunately, most fuses have a bit of "reserve" built in. It might actually take a few more amps to blow the fuse, or it might have to maintain that excess current for a certain amount of time before it blows. Besides the amp rating, fuses are also rated by how quickly they blow when subjected to over-current.

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[MAJikMARCer]

Stock fuses are 15 main,10 amp others. If you wire R/R direct to battery, use a 20 or 25 amp fuse inline in a seperate fuseholder. Make sure your R/R negative wire has a direct (or almost direct) connection to battery negative- do not rely on any battery box grounding.

This is what I ordered for my in-line (R/R to battery) fuse:

Metri-Pack 280 30A Single Fuseholder

[Steve]

This is what I ordered for my in-line (R/R to battery) fuse:

Metri-Pack 280 30A Single Fuseholder

.................................

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[Dogma]

And now I'm back here to correct you.

Actually, that connection that goes bad is not soldered, it is merely crimped. Yes, it is then covered and wrapped in the main harness, but is still susceptible to corrosion, which is where the problems arise.
...

And now I'm back to correct you! This is fun!

When I got into the harness on my 1000GT, I found this (and every other) connection was soldered and taped. The solder on this joint was showing corrosion, all the others were clean. Do you suppose there is variation from one model to the next? I didn't see any evidence that I wasn't the first person into that harness.

[gwshoemaker]

this is the ground from the r/r direct to the battery you all are talking about? i just did that cuz it was loose and i couldnt think of any better place to put it....serendipity