I spoke with Emily from RM Stator this morning.
I explained what was happening with elevated Voltage jump with the series rectifier. She explained this was normal and voltages varied with throttle input.
As long as my voltage was between 13.8 -15V, everything is functioning fine.

My bike is parked for the season until spring (uncoming shoulder surgery). I inquired what my options were is I had a problem next riding season.
Emily told my I had a 2 year warrantee on my rectifier..

 

Since this appears to be literally plug and play for a quality series R/R "I assume that's also the case for my 2017", I may just have to add this to the list of things to buy.......appreciate all the info you've given while literally being the guinea pig for this.

 

Checked my rectifier today.

Note battery voltage with motor off. Battery should measure 12.0-13.0 Volts at rest. = 12.93V
• Start the motor, and let idle (~1000 RPM). Battery voltage should measure 12.0-13.5 Volts. = 14.5-14.6V
Increase motor speed to ~5000 RPM. Battery voltage should measure up to 14.6-14.8 Volts. = 14.4-14.5V
• If any of these tests fail, the regulator is faulty and should be replaced."

I rode for about 15-20 minutes today. Voltage on bike registered a constant 14.4V while ridng with occasional jumps to 14.3V and 14.5V depending on throttle position.

I sent my results to RMStator to see what they say. Other than higher idle reading, bike ran fine.

 

THis is the response I got from RMStator regarding the testing of my rectifier.

HI,

Thank you for your thorough test results,

Your charging voltage (14.4–14.5 V) is completely normal for a BMW R1200GSW (2014–2018).

BMW’s spec for the liquid-cooled R1200 series (LC/GSW) is typically 14.2 V ± 0.3 V, meaning 13.9–14.5 V is normal.

Many owners report that the factory regulator holds ~14.4 V steady, independent of RPM.

At idle, your voltage being 14.4 V is actually good — it means your stator and regulator are providing solid output even at low RPM. Some regulators wait until ~2000 RPM to reach 14 V, but the BMW system regulates early.

Stable charging while riding (14.3–14.6 V) is perfectly within tolerance and exactly how the after and/or OEM, Shindengen-type MOSFET regulators behave — small variations with throttle load are expected.

No overcharging concern: 14.5 V is below the threshold (15.0 V) where you’d start worrying about overvoltage or battery stress, even for AGM or LiFePO₄ batteries.

Your rectifier/regulator is functioning normally.
The readings are consistent with OEM BMW specs for a 2014 R1200GSW — stable, well-regulated output across the rev range.

Please let us know if you have any further questions.
Sincerely,Daniel

I spoke with Daniel this morning and am confident that my unit is good and I have confidence in RMStator's products