Rectifier/Charging Qurestions

[Rocketman]

I would really love nothing more than to measure the voltage drop between the rr(+) and the battery (+), but again, the results are confusing. I am connecting the black digital multimeter lead to the battery (+) and the red digital multimeter lead to the red output wire of the rr. At idle, I get 0 as a reading. As I ramp up to, and eventually get to 5,000 rpm, the reading fluctuates every 3 to 5 seconds from 4.1v to 14.9 volts and back to 4.1 volts, and on and on. I think I'm supposed to be getting a fixed/steadymultimeter reading of less than 0.25v. I don't yet understand why my readings are fluctutating, and again after reading the instructions and asking here, I don't know why the hot lead of the rr to the battery would read between .25 and .75v if there's juice running in that wire, at 12 volts or more. How do you measure a voltage drop in a hot wire anyway? And believe me, I know a lot about my bikes, but I'm nowhere near as knowledgable about electrics as you all are, but I must be missing something obvious here. Sorry if I'm aggravating you, but its giving me a headache too.

[posplayr]

I would really love nothing more than to measure the voltage drop between the rr(+) and the battery (+), but again, the results are confusing. I am connecting the black digital multimeter lead to the battery (+) and the red digital multimeter lead to the red output wire of the rr. At idle, I get 0 as a reading. As I ramp up to, and eventually get to 5,000 rpm, the reading fluctuates every 3 to 5 seconds from 4.1v to 14.9 volts and back to 4.1 volts, and on and on. I think I'm supposed to be getting a fixed/steadymultimeter reading of less than 0.25v. I don't yet understand why my readings are fluctutating, and again after reading the instructions and asking here, I don't know why the hot lead of the rr to the battery would read between .25 and .75v if there's juice running in that wire, at 12 volts or more. How do you measure a voltage drop in a hot wire anyway? And believe me, I know a lot about my bikes, but I'm nowhere near as knowledgable about electrics as you all are, but I must be missing something obvious here. Sorry if I'm aggravating you, but its giving me a headache too.

I don't understand what is going on with your meter. Have you tried another? It is possible that the R/R is acting funny, but I have done this same test and it is the same recommended in the original stator pages. The only change I have made is to do the test a full current load when the bad connections will show up.

We are talking about really small resistances causeing relatively big voltage drops. Many meters will only measure to 0.1 ohms and at 10Amps that would equate to a full volt of drop. So just a little corrosion could casue that.

See the wire running between the R/R to the Battery is not just a low resistance current path; there are small resistances typically at the crimp connections. Any resistance will generate a voltage drop and since the R/R regulates voltage at it's output not from the battery voltage that drop directly corresponds to charging errors(at teh battery).

Lets say you have 14.5V at 5K RPM at the output of your R/R; there is also 10 amps flowing out. 0.1 ohms of resistance would have you with only 13.5 volts at the battery. The 1.0V drop would be observable by measuring the drop from the R/R(+) to the battery(+).

When you measure the overall battery voltage, you don't know if it is low because of the stator , the R/R setpoint or the voltage drops.

[koolaid_kid]

I don't see how that large of a variance could be caused by the system, unless the R/R is toast.

[aviliora]

confused issu

Hi,
This is odd,voltage across the battary in any rpm did not pass the 13v its mean no charge but at looking at the main light the brightens of the light chang so what is going?
Thaks
Avi