M-Unit Blue on the 1982 GS750

[posplayr]

The point of the SPG is to keep the wire from SPG to R/R(-) a short a possible (less than 25 cm) with the fewest conducting surfaces. Conducting surfaces are either Faying (means things that provide conductance by being face to face) or crimped (airtight crimps that are only temporarily airtight) or clamp surfaces like the battery ends that attach to the battery posts.

If you construct the T correctly, you only need a single 15 amp fuse. If you do it wrong, you need bigger fuses and therefore have less protection.

That 40 amp sure sticks out like a sore thumb as it is clearly violating the assertion I just made.

[LarsKroghStea]

The point of the SPG is to keep the wire from SPG to R/R(-) a short a possible (less than 25 cm) with the fewest conducting surfaces. Conducting surfaces are either Faying (means things that provide conductance by being face to face) or crimped (airtight crimps that are only temporarily airtight) or clamp surfaces like the battery ends that attach to the battery posts.

If you construct the T correctly, you only need a single 15 amp fuse. If you do it wrong, you need bigger fuses and therefore have less protection.

That 40 amp sure sticks out like a sore thumb as it is clearly violating the assertion I just made.

I read your threads about charging and get the point you made about the short R/R(-) now

I agree with the 40 amp fuse, the reason it's there is because the documentation for the m-unit states that it should be protected by its own 40 amp fuse. That's because the "start" output is rated to 30 amp and can drive some starters directly. I've read that the starters on our machines need more than that and one should use the m-unit to trigger the original starter relay. So I guess I could move the T behind the 15 amp fuse and remove the 40 amp fuse as the m-unit shouldn't reach 15 amps of load anyway.

[LarsKroghStea]

So, I've organized the ground wires better by where they're going on the bike and moved the T after the 15 amp fuse. You think 15 amps is enough for everything? I might change it after I se how much current the attached equipment draws. Most of the lights are LED so it shouldn't be much.

I think I'm getting a better understanding of this now I still may change my mind about where the wires are connected to eachother when I lay them out on the bike, but I won't know before I get there. The bike is 1,5 hours drive away at my fathers, and I don't have time to go there as often as I'd like.

Noisemaker_koblingsskjema by Lars Krogh-Stea, on Flickr

[posplayr]

You still have a mental block! When charging, All current returns to R/R(-) not to the negative side of the battery.

the SPG should be as close to the R/R as practical (less than 1 foot with 14 AWG wire)

[LarsKroghStea]

You still have a mental block! When charging, All current returns to R/R(-) not to the negative side of the battery.

the SPG should be as close to the R/R as practical (less than 1 foot with 14 AWG wire)

I don't think you read my text, but only look at the drawings.. the wire lengths are not to scale. The R/R is mounted next to the SPG. Does the wire from the SPG to the negative on the battery also need to bee longer for the return current to route where you want? Also, I don't quite see how the R/R will see much of the the return current as it is connected in parallel to the circuit with the other loads and offer more resistance than the return wire between the SPG and the battery (-) . The only way I see see the R/R seeing more current is if I remove this cable but then the voltage it reads will be all over of course I think the final drawing is a good picture of what goes where. I'll keep wires short and use the right dimensions, and I think this will work fine for a long time As I have the M-unit blue I will also get a warning on my Bluetooth headset if battery voltage gets to high.

[posplayr]

I don't think you read my text, but only look at the drawings.. the wire lengths are not to scale. The R/R is mounted next to the SPG. Does the wire from the SPG to the negative on the battery also need to bee longer for the return current to route where you want? Also, I don't quite see how the R/R will see much of the the return current as it is connected in parallel to the circuit with the other loads and offer more resistance than the return wire between the SPG and the battery (-) . The only way I see see the R/R seeing more current is if I remove this cable but then the voltage it reads will be all over of course I think the final drawing is a good picture of what goes where. I'll keep wires short and use the right dimensions, and I think this will work fine for a long time As I have the M-unit blue I will also get a warning on my Bluetooth headset if battery voltage gets to high.

I'm clairvoyant.