Friends:
I am still working on getting the E-vaults to play nice with the Sunny Islands and Sunny Boys. With Open loop I was getting significant discrepancies in the reporting of SOC in the e-vaults versus that reported by the SI inverters. This discrepancy did not diminish over time. The discrepancy caused unacceptable charging and generator operations. I got Closed loop hooked up, but I found that every few days the SI inverters would shut down due to a battery over-voltage condition. I believe that when the e-vaults are near 100% SOC the BMS units increase the battery impedance which means any charging current applied will cause the voltage spike I have been seeing. I was able to measure these conditions myself on site, although they were very fleeting and required recording with the Fluke87 Min-Max function (love this meter!). I was able to extract log files from the Sunny Island primary inverter and perform some analysis. It appears when I turned on remote BMS on the SI (as part of the Closed loop protocol) it disabled the Frequency-Shift Power Control. This means the SI inverters have gone from having poor control over battery charging to having no control over battery charging. I have documented my research here <https://millersolar.com/MillerSolar/case_studies/36_SIFortress/36_SunnyIslandFortressIntegration.html#Inhibit>. There is a table of contents to take you to the latest information. I appreciate pertinent comments any of you might have. By the way, if anyone has called SMA tech support for help on a Sunny Island system, you have likely been asked to extract log files, zip them up and send them off for review (and waited a long time for a reply). I am the kind of guy who does not like to wait for solutions and who likes to figure out things for himself. I have taught myself how to evaluate those log files. I will be posting a web page on the subject. In the meantime, if you are interested, two of my analysis Excel sheets are linked in the case study. I will be expanding on this and providing resources to any integrator that wants that knowledge. Thanks in advance for any insight. I hope I am wrong about this and I am just missing something. I also hope revealing my headaches will help someone someday… William Miller Solar 17395 Oak Road, Atascadero, CA 93422 805-438-5600 www.millersolar.com CA Lic. 773985
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