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Old 03-24-2012, 10:54 AM   #59
JoelWisman OP
Beastly Adventurer
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Joined: Apr 2009
Location: STL, MO, USA
Oddometer: 1,392

I thought I might be loosing my mind, but looks like NCD's bike has a BMW test regulator in it or for whatever other reason is an outlier.

Either way, it is ALWAYS a good idea to check idle and mid RPM voltage on your individual motorcycles before making decisions.

Mike C. I think your old, cheap, and shitty Digitech meter might be more accurate then your Amprobe LOL, though the Amprobe sure is cute and accurate enough for most things. 13.84 volts is normally what I see at 3,000 RPM and it has seemed consistent across all the F8's I have measured.

Lower voltage at higher RPM when the alternator isn't fully loaded isn't odd, its wrong. Without getting overly technical, the R/R BMW selected for these bikes is quick to sense and slow to adjust. It should be ignoring the peaks and shooting for an average RMS voltage of, well 14.4 volts in my book, but 14.1 if BMW was thinking the bike was going to be released with a gel battery. What happens with this R/R is it senses the peaks (harmless, actually beneficial) and drives down the RMS average to keep the peaks around 14.1 volts. It's a design flaw or at least a mismatch of regulator to charging system with a lot of electrical noise.

Apostolos thank you.

ebrabaek, I still want to see what you measure, partially for another data point, but more because I am curious what kind of meter you use :)

Mike C. From tests I have now done with two Shorai LFX18 batteries, doing something seems warranted. Balance charging every couple of months will suffice and would be the cheapest solution, or replace R/R's.

I am still waiting for 3 R/R manufactures to get back to me. I talked to sales support at all 3 companies but what I need to speak to is an engineer for each. Took a bit to confuse each companies tech support and convince then I really did need an engineer and that allowing me at one would only take up 15 minutes of their time and could be profitable. Will update on what kind of a regulator will work best as well as exploring series regulators as soon as I learn something more.

Thanks all, finally got back my high current and accurate clamp from repair and calibration since my shunts demise, more on cranking, pulse, CA, and CCA soon, and expecting to receive an AntiGravity battery and toss it into the mix of tests soon.
Owned to date. Honda Aero 50, Honda Elite 80, Honda Elite 250x2, Suzuki Katana, Suzuki RF600, Yamaha YZF1000R, Kymco Xciting 500, Suzuki GS500, Suzuki Burgman 650, BMW F800GSx2, BMW S1000RR, Aprilia Scarabeo 200, Aprilia Caponord, Aprilia Sportcity 250
I love and miss you Jeneca and I'm sorry.
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