<div dir="ltr"><div dir="ltr"><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Redundancy is so important, and it seems like some manufacturers have not thought this through and implemented a truly redundant or failsafe system.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">I am somewhat interested in the direction that Enphase is headed with allowing fully off-grid systems. The "no single point of failure" concept is attractive, but in practice, it is not really true since there are obviously central components that can fail to perform. The Tesla PW3 concept is interesting in that you can just feed essentially independent Powewall units into a Gateway, and failure of one will not cause failure of others (I believe this to be true, but I am not certain). Sadly, they do not support off-grid systems.</div><br clear="all"></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">With the issues I am having at this particular site, I am contemplating reconfiguring it to use an automatic transfer switch to turn on the generator and directly power loads when inverter power is lost (through faults or otherwise). I have not completely thought this through to determine how it can work to both serve this redundancy function while remaining a potential battery charging source during normal conditions.</div></div><div><br></div><div><div dir="ltr" class="gmail_signature"><div dir="ltr"><br>Jason Szumlanski<div><span style="color:rgb(51,51,51);font-family:Roboto,RobotoDraft,Helvetica,Arial,sans-serif;font-size:13px">Principal Solar Designer | Florida Solar Design Group</span><br style="color:rgb(51,51,51);font-family:Roboto,RobotoDraft,Helvetica,Arial,sans-serif;font-size:13px"><span style="color:rgb(51,51,51);font-family:Roboto,RobotoDraft,Helvetica,Arial,sans-serif;font-size:13px">NABCEP Certified Solar Professional (PVIP)</span><br style="color:rgb(51,51,51);font-family:Roboto,RobotoDraft,Helvetica,Arial,sans-serif;font-size:13px"><span style="color:rgb(51,51,51);font-family:Roboto,RobotoDraft,Helvetica,Arial,sans-serif;font-size:13px">Florida State Certified Solar Contractor CVC56956</span></div><div><font color="#333333" face="Roboto, RobotoDraft, Helvetica, Arial, sans-serif">Florida Certified Electrical Contractor EC13013208</font></div></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, Nov 9, 2024 at 10:55 AM Michael Morningstar via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">I wish I didn't know what you were talking about! : )</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, Nov 9, 2024 at 7:16 AM Jason Szumlanski via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div style="font-family:arial,helvetica,sans-serif">I wrote in another thread about an off-grid quad Sol-Ark system that was shutting down due to parallel stop when one of the four inverters experienced a DC PV fault, and how that shutdown is far from ideal. The same system is down once again, this time due to an AC fault code.</div><div style="font-family:arial,helvetica,sans-serif"><br></div><div style="font-family:arial,helvetica,sans-serif">The homeowner started getting repeated F18 and F34 AC overcurrent faults on one of the slave inverters. This, in turn, shut the entire system down due to parallel stop faults (F41). None of the other units had AC overcurrent faults, and the load is nowhere near requiring all four inverters for even the most demanding circumstances. It was designed this way for redundancy, which I am quickly finding out is not Sol-Ark's strong suit. </div><div style="font-family:arial,helvetica,sans-serif"><br></div><div style="font-family:arial,helvetica,sans-serif">To diagnose the issue remotely, I had the owner turn off all four load breakers, all DC PV input, and the AC microinverter input on the GEN terminals. I had them restart everything (several times). Every time, the same inverter would have repeated AC overcurrent faults, and the others would have parallel system faults. Since there were no loads connected by virtue of the load breakers being open, I suspected this had to be an internal fault. </div><div style="font-family:arial,helvetica,sans-serif"><br></div><div style="font-family:arial,helvetica,sans-serif">I went to the site, and Sol-Ark Tier 1 tech support had me shut off all inverters and take the suspect inverter out of parallel operation mode. As a standalone master it was able to power up and support the entire house load without issue. Then we reprogrammed it for parallel operation again and turned everything back on. We were unable to stay on the phone long enough to determine if this was successful, but ultimately, the fault returned. I was told to call and ask for Tier 2 next time if it happened again, which I intend to do on Monday. At this point, the issue can only be internal to the unit, and I intend to demand warranty replacement of suspect components or the whole unit.</div><div style="font-family:arial,helvetica,sans-serif"><br></div><div style="font-family:arial,helvetica,sans-serif">I had to get the system running, so I wanted to take the bad inverter out of the parallel system. I was hoping that simply shutting it down would work. This is the third of 4 inverters in the Modbus chain. When turning it off completely (all AC and DC switches disconnected), the 4th inverter would fault, presumably because the Modbus signal was not being relayed, but inverters #1 and #2 worked fine. However, I wanted #4 to also continue working while taking #3 out of service. So then I turned on the battery disconnect for #3 but left it in the off mode by not pressing the on/off button, thinking that it would allow relay of the Modbus signal from #2 to #4. That allowed the system to work momentarily, but then everything faulted out due to parallel system stop. In other words, I was going to have to physically take #3 out of the Modbus daisy chain to make this work.</div><div style="font-family:arial,helvetica,sans-serif"><br></div><div style="font-family:arial,helvetica,sans-serif">Of course, I didn't have a long enough Cat5 cable with me, nor a Cat5 splice connector. So I had to rig something, which I did successfully to jumper from #2 to #4. But when I turned everything back on, #4 still would not work. I eventually realized that you have to change the Modbus address from 04 to 03 in the settings. Apparently, the addresses need to be sequential for it to work. Once I did this, I was able to get the system up and running again as a triple-inverter parallel setup. No faults were observed. So the theory was proven that #3 has an issue internally.</div><div style="font-family:arial,helvetica,sans-serif"><br></div><div style="font-family:arial,helvetica,sans-serif"><br></div><div style="font-family:arial,helvetica,sans-serif">Anyway, bottom line, I am disappointed at how one inverter fault takes down the whole paralleled system, and also how taking a faulted inverter out of the system requires physical and programming changes. Turning it off should be sufficient. This is a very poor way to implement a parallel system that should provide the peace of mind that redundancy implies. Now I have a customer who thought they were getting a system with failsafe redundancy that actually requires a service call every time one of the paralleled units decides it does not want to play nicely with others.</div></div><div><br></div><div><div style="font-family:arial,helvetica,sans-serif">Jason Szumlanski</div><div style="font-family:arial,helvetica,sans-serif">Florida Solar Design Group</div></div><div><div dir="ltr" class="gmail_signature"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><b><div style="text-align:center"><table border="0" cellpadding="0" cellspacing="0" style="color:rgb(34,34,34);font-weight:400;text-align:start;font-family:"helvetica neue",helvetica,arial,sans-serif"><tbody><tr><td rowspan="2"></td><td rowspan="2"><br></td></tr></tbody></table></div></b></div></div></div></div></div></div></div></div></div>
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<p style="margin:0px;font:18px Helvetica">Michael Morningstar </p><p style="margin:0px;font:18px Helvetica"><br></p><p style="margin:0px;font:18px Helvetica">Morningstar Electric Inc</p><p style="margin:0px;font:18px Helvetica">PO Box 1494</p><p style="margin:0px;font:18px Helvetica">Mount Shasta, CA 96067</p><p style="margin:0px;font:18px Helvetica">530-921-0560</p><p style="margin:0px;font:18px Helvetica">CSLB 1116835</p><p style="margin:0px;font:18px Helvetica"><a href="mailto:mjmorningstar@gmail.com" target="_blank">mjmorningstar@gmail.com</a></p><p style="margin:0px;font:18px Helvetica"><br></p></div></div>
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