FoxESS Community - Owners & Installers Forum

I have a 7,5kW system with an H3 inverter and an EQ battery, installed last December. So far it's worked flawlessly, but yesterday for the first time I had a burst of fault alerts.

It started with a "234: BMS Alarm" and "64: DC Bus volt is high", and the error light on the battery flashing. I powered everything (inerter and battery) down for 15m or so and brought it back up, but then for the next 6 hours there were sporadic "64: DC Bus volt is high" alerts. Aside from the alerts, everything was working exactly as I would expect it to.

The first fault came in at roughly the time when I'd expect peak yield, but the later ones were happening while the panels are shaded by a tree shadow, so the yield drops off dramatically.

After about 6 hours the faults stopped, and everything seems OK now.

Is this something worth following up, or could it be related to temperature? Yesterday was the hottest day on record here, with the air temp over 40 degrees, but if I understand the physics right, panel output should drop with higher temperatures?

Less likely to be due to temperature, as you say battery volts are higher when cells are cold and panel output is also higher - we are in peak summer with the sun reaching its highest so it is possible that if your panels are not all pointing in the same direction / elevation that they would be generating their highest output simultaneously.

Have you done a deep discharge cycle on your battery recently ?, if not it would be worth allowing them to drop down to minSoC and then allow them to charge again.

Also worth asking Fox to update your battery firmware and then monitor.