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Topic starter
August 7, 2025 8:22 pm
After months long diagnostics, replacing inverter (6000xp), investigating other members experiences I came to conclusion that the BMS of EG4 indoor wall mount battery has serious comms issues preventing the battery to be used in closed loop mode (inverter setting to battery type Lithium). I believe it is the time I rise it up so EG4 can pick it up and address in next firmware update and provide affected users with tools/gear to actually perform their BMS firmware updates on their batteries.
Here is the issue with BMS.
It appears that randomly Battery BMS loses the comms to the inverter resulting in the inverter acts like there is no battery connected to it. The instances are 1-2s only - basically not able to be captured by EG4 web monitoring (which samples the system every 4-5min only). it can happen few to several times a day.
The result is that inverter goes to by-pass mode and conveys grid power until it senses the battery is present. So if one has grid connected setup it is almost unnoticeable as the inverters transfer switch provides seamless power supply transition between battery/grid/battery.
For those folk who are in off-grid mode (no grid connected) it is obviously noticeable it results in power frequent 2-5s power losses with consequences potentially more severe (surge affected electronics, fridges, etc.). Basically I had to invest in multiple UPSs and whole house surge protection installed to prevent comms disruption and equipment damage (lost two subwoofers and AVR due to those power blips while off-grid)
To make the story short:
It doesn’t matter which inverter one is using. Once the wall mount battery comms is lost - bypass to grid, interrupted battery chagrin or short blackout for those off-grid
Related posts:
statements from:
@scottmr808, @BPorter , @frankorth
Supports my conclusion that EG4 wall mount battery can be reliably run ONLY in open loop mode (run as Lead Acid)
Here is the data from my system supporting my above statements.
I gave up more testing and run EG4 Wall-mount indoor battery in open loop mode (set up as as Lead Acid type).
It is inconvenient yet it works. A temporary solution until EG4 fixes the BMS firmware and provides tolls to rectify the flaw.
@EG4
ball is in your court.
Brgds
K
