EDIT
I have since managed to succesfuly replicate the overload event warnings by running a weed-eater (800W) on “AC LOADS” and “GRID LOADS” (this is not the only device that causes the issue). This causes an overload event warning within a minute or two. This seems to confirm my original assumption that the high impedance of the supply cable coupled with a voltage drop may be the root cause (maybe even some type of resonance). Disabling LOM and lower grid voltage under Country Code to 180VAC did not help either. The question:
Why an overload event warning & how to stop the warnings?
Hi everyone,
I’ve been struggling with this installation since it was first installed about a year back. It was a replacement of a 5KW Microcare system that ran perfectly for around 10 years. The main reason for replacement was the ESS feature.
EDIT 2025-02-07T22:00:00Z
I decided to edit the block diagram for clarity
- AC LOADS = Grid loads but measured by Carlo Gavazzi meter (Also suplemented with PV power)
- Critical Loads = AC Out 1 & AC Out 2 (AC Out 2 is programmed in assitans to supply upto battery 40% or turn on/off depending on input of temp connector)
- Heavy Loads = supply upstream / utility / grid
- Cable - Battery to busbar 50mm2 (3M max)
- Cable - Busbar to inverter 50mm2 (1M max)
- Cable - MPPT to Busbar 25mm2 (1M max)
- Cable - PV 6mm2 (20M max)
- The grid supply cable is very long 200M (4 core 25MM2 doubled up)
Device: VE.Bus System
WARNING: Overload
This is a more extreme example, but generally when a high load is drawn upstream from the inverter it generates this error.
This only happens when ESS is enabled. The assumption is that an input voltage drop at the Multiplus is what is responsible (although not everytime, this was monitored by GRAFANA for 6 months). It is at the best it can be with the long supply cable. The question is what can I do to stop the overload warnings? Somtimes it wil generate a warning with a critical load of 500W and an upstream load of 1KW with a small 1V drop.
I HAVE ATTEMPTED THE FOLLOWING:
- Disabled LOM (Loss Of Mains)
- Decreased inverter voltage to 220VAC (this seemed to lessen the warnings)
- Limited inverter output
- Had the whole PCB replaced by our supplier (THIS SORTED OUT THE REDICILOUSLY LOUD HUMMING NOISES)
- Replaced the Pylontech battery bank with BSL
- Replaced battery DC wiring with 50mm
- Disabled ESS (This is the only solution that works but defeats the purpose)