Wire gauge for the leads on a Compufire reg\rect?

[posplayr]

Thanks. Each section shows the numbers for each of the 4 legs, with a sum of the voltage drops in red.
Clearly, being 1 foot away you could use 14 ga wire and obtain excellent results.
Since we cannot possible know the loss over the connections, we must assume perfectly clean connections at this time.
At 4 foot, the voltage loss using 10 gauge wire is still greater than the voltage loss at 1 foot using 14 ga wire.
However, at 4 foot using 14 gauge wire is only 0.329V, which is only 1.03% of the total 14.7V.
I normally look for less than 2% loss over the length of the wire, so would you disagree that 1.03% is acceptable? If so, please explain why.
Also, are you using 4 foot because the R/R would be located at the front of the bike, possibly for cooling?
Thanks.

I'm having a hard time deciphering what you are asking; I would have thought most of the below would have been clear from the original post. But I'll give it another go.

"Disagree that it is acceptable...? I'll hazard a guess that you are trying to figure out why your figure of 2% drops is a better answer than 0.1V or more specifically you want me to justify the 0.1V as being preferable to your 2% loss "rule of thumb".

A 2% drop of 14.5V is very nearly 0.3V. That means in a perfect situation (i,e. perfect connectors) and an R/R charging at 14.5V that your battery will never get over 14.2V. With the ga wires I provided the maximum is 14.4V. So in my mind 2% is too much and 0.1V is acceptable in view of what typical connector losses typically are. cThe revised Phase A voltage drops are either 0.2V or 0.25V (I forget) per side. I left them high so that people would not get frustrated trying to make them as small as possible (which I did). If it was 0.25 per side that would be a 0.5V total loss.

My hope is that as they work out cleaning the connections it would finally click click that the higher the drops the lower the charging voltage. At that point perhaps they are motivated to get rid of the voltages drops which are predominately connector losses. So even if teh conenctor losses are only 0.1V less than 1/2 of teh test thresholds and you use your 2% rule, the battery will never charge over 14.0V.

I'm using 4' because there are people that feel compelled to mount R/R's at the front of their bike. I can't possibly understand why people do that, it seem to be in some misguided notion that they will keep the R/R cooler by mounting up near the exhaust. I see microphone says he had no room in back.So the question becomes, how big should the wires be if there are 8 ft of wire drop v.s. 2 foot when only 1 foot away.

I know some of the people that purchased SSPB's for 1150's had to deal with the issue that the fusebox and the R/R are mounted away from each other (opposite sides of the bike) and there is a need for more than 1 ft lengths. That is what originally motivated the spreadsheet as I has already long selected 14 ga for the power leads and the main single point ground, while the tributaries feeding the SPG were 16g.

I think you should go back and reread the original post. It is pretty clear why that the analysis is based on calculating voltage drops so as to ensure proper battery charging. I don't think this has much if anything to do with where your 2% "rule of thumb". I would turn it around and ask you why you think a 2% "rule of thumb" applies but it would be rhetorical as I already know it does not.

[koolaid_kid]

O.K. Jim. As you wish.

[posplayr]

O.K. Jim. As you wish.

Actually wish I had not answered you at all.

I agonized over repeating what was already in the other post, especially since on face value it was very unclear what your question actually was.

Although I had a pretty clear idea about where you were driving; I did not want to jump to any conclusions.

[JEEPRUSTY]

Well good golly got here all connected. Was shocked that a local shop had 10-12 gauge connectors.

Now another problem occurs I get a stumble like the bike is running out of gas or not running on all 4 cylinders. This has gotten worse since it started.

What miraculous fault could account for this? Since it happened right after affixing a healthy clean wiring harness it leads me to believe it must be lectrical in nature. But my battery is charging and when I get the degradation in performance I can blow the horns with aplomb yet I see the fuel gauge rising and falling.

Woe is me a new Ducati for me? Nay I must fix this wretched beast.

Feel free to laugh.

[posplayr]

If you pass the quick test, make sure you have full voltage to the coils.

[JEEPRUSTY]

Yes the coils now where did I put my multimeter?