Non-existant warranty
I purchased an HM-600 in 2022. The unit developed a progressive internal fault in May 2026, documented in detail with Home Assistant telemetry: warning escalation over two days, anomalous error codes, and complete failure afterwards. I contacted Hoymiles support with full diagnostic data including timestamps, error codes, grid voltage logs, and a comparison with a reference solar system confirming the fault is internal. The only response I received was a request to disconnect and reconnect the inverter — which I had already done multiple times and stated clearly in my email. Then that I had to disconnect home assistant from the inverter. After I did, I then sent a detailed follow-up with all telemetry. No response + The support line on the phone only tells you to open tickets, so this is not a viable solution either. The inverter is within its 10-year commercial warranty. The fault is intermittent and recurring — confirmed again on 8 June 2026 by direct comparison with a second system on the same balcony with the same orientation. It has now been over a month since the initial failure. I have provided more diagnostic documentation than most professional installers would, and I have received no warranty resolution, no RMA, and no substantive communication. The product may be decent when it works. The warranty support is nonexistent.