I logged read-only Modbus telemetry every 15 seconds and ran controlled A/B tests, reading each setting back from the holding registers to confirm it applied. Two behaviors don't match the documentation/UI:

1) "Time + SOC" mode ignores the Stop-SOC target.
Expected: charge during the window and only up to the Stop-SOC, then stop.
Observed: it charges the entire window regardless of SOC, overshooting to full.

• Test A: Stop SOC set to 85% at 14:09 — 16 minutes BEFORE the 14:25 window opened (ruling out "changed mid-window"). Battery grid-charged straight through 85% to 99% by the window's end. Net solar (PV − load) was negative after ~15:15, so the whole 56% → 99% climb was grid charging.
• Test B (clean retest): Time+SOC, Stop 45%, set before the window, wide band. Charged straight through 45% → 47%+ at full rate, with no throttle at the target.

2) AC Charge Power (kW) setpoint is ignored.

• Set to 3 kW → charged ~8.6 kW.
• Set to 10 kW → charged ~8.4 kW.
  Identical. Actual rate tracked only the BMS charge-current limit (~150 A at 50% SOC, tapering), never the kW setpoint.

3) For contrast — "SOC"-based mode DOES stop correctly (same battery, same live SOC):
With Based On = SOC, Stop 53%, grid draw went 873 W → 0 exactly at 53% and stayed at 0 even as house load rose. This shows the inverter has correct SOC and can act on it — which points the Time+SOC failure at the charge-control logic, not the battery or its comms.

Questions:

1. Is the Time + SOC behavior (1) intended, or a firmware bug? I expected it to stop at the target within the window.
2. Is the AC Charge Power (kW) setpoint supposed to cap grid charge current? It appears ignored.
3. If (1) is intended, what's the supported way to grid-charge to a target SOC within a time window and then stop? (SOC mode stops at target but ignores the window, risking charging during peak-rate hours.)

Happy to share full 15-second logs, register snapshots, and charts. Anyone else on FAAB-2727 seeing the same?

2026-03-29

• Based on FAAB-2626/2525.
• Match LCD V25.
• 1. Improved. New England Grid Profile — added regional grid profile support for New England configurations, with Voltage-Active mode disabled by default.
• 2. Improved. Added RS485 BUS communication support on the Meter485 port for PPL Electric installations.
• 3. Improved. LUMA Grid Profile: Voltage-Active Power mode enabled by default.
• 4. Improved. HECO Grid Profile: Frequency-Active Power mode enabled by default; under-excited reactive power set as default.
• 5. Improved. Optimized charging power limitations when PV power is unbalanced across inverters in a parallel system.
• 6. Improved. LCD phase setting labels updated from R/S/T to A/B, B/C, C/A （LCD V25）.
• 7. Improved. Update fan logic to start fans at a lower temperature to optimize heat dissipation.
• 8. Bug Fixes. Fixed repeated switching between on-grid and off-grid modes on the secondary inverter triggered by off-grid cut-off voltage in parallel shared-battery and lead-acid battery mode.
• 9. Bug Fixes. Reduced probability of repeated state switching between PVBatGridOn and PVChgGridOn.
• 10. Bug Fixes. Fixed the inability to exit on-grid AC couple charging state and switch to battery discharge when load exceeds AC couple power in a parallel system.

2025-06-22

• Based on FAAB-2021
• 1.Add Weekly Setting function.
• 2.Add the function of Sporadic AC charge power function, it will cause the AC charge power to fluctuate randomly between the set AC charging power and 2% rated power.
• 3.Optimize the response speed and stability in zero export mode in meter mode.
• 4.Optimize the restart logic that modify the CT/meter, battery type and brand will not be restarted.
• 5.Improve the issue of reading the RGM settings.
• 6.Improve the issue of power display on Micro-Grid mode.
• 7.Improve the issue of not stopping at the Stop Discharge Volt of forced discharge.
• 8.Improve the issue where the LCD display on the load power side lacked Smart Load power when the Micro Grid plus Smart Load mode were enabled.
• 9.Improve the issue of increased charge power when setting the Charge Last mode.
• 10.Improve the issue of abnormal load display in web page flow chart during parallel mode.
• 11.Improve the issue of getting phase lost warning when switching from on-grid and off-grid in three phase parallel mode.

2025-09-28

Firmware Changelog – FAAB-2525 （Based on FAAB-2122）
1.Added support for BASCO battery protocol （Battery Brand Setting 22）.
2.Added support for SunSpec Modbus IEEE-1547 certification.
3.Added support for N-PE bonding setting – enables closing the N-PE relay only in off-grid mode.
4.Added support for displaying EG4 battery model information.
5.Improved download time for subsequent firmware updates.
6.Enhanced encryption for firmware update packages.
7.Improved stability of remote LCD firmware updates.
8.Added ability to configure generator exercise cycles even when grid power is available （keeps generator in idle operation）.
9.Improved MPPT behavior.
10.Adjusted the Absorb Voltage and Float Voltage lower limit from 50 V → 48 V.
11.Expanded the setting range of Stop AC Charge SOC （%） to 0–101%.
12.Expanded the configurable range of grid protection parameters for 127/220 V grid type.
13.Fixed issue where LCD communication fault could occur when the FlexBOSS LCD screen kit backlight was off.
14.Improved LCD display for PV input arrow:
- Single unit: arrow displays when PV power >100 W
- Parallel system: arrow displays when total PV power >300 W
15.Fixed issue where consumption power was not displayed on monitoring line chart during off-grid or parallel operation.
16.Improved stability when switching between on-grid and off-grid modes if the battery discharges to the On-Grid Cut-Off SOC/Voltage while running with GridBOSS and set to Off-Grid mode.
17.Improved SOC control mode:
- If battery voltage drops below the off-grid cut-off voltage, the inverter will force charge the battery up to （cut-off voltage + 2 V）.
- Prevents over-discharge in cases where BMS SOC reporting is inaccurate.
18.When inverter is set to lead-acid battery mode or no battery mode, the active W04: Battery BMS Status Alarm will now be cleared automatically.

I have a new support ticket w/ Signature Solar, but wanted to share this experience and see if anyone else has had this happen.

• 1. Add the new startup option "Soc/Volt + Time" for AC charge startup. （Compatible with LCD V20）.
• 2. Add two-time settings to the generator startup setting.
• 3. Add AC couple on EPS port function to Flex Boss that paralleled with Grid Boss.
• 4. Optimize when either ‘charge control’ or ‘discharge control’ setting changes, the settings for both will be updated synchronously.
• * synchronized Charge and Discharge. if a customer sets the charging control to SOC, the discharging control setting will automatically switch to SOC.
• 5. Changing the CT ratio on monitor site no longer requires a system restart.
• 6. Optimize the issues of flicker.
• 7. Optimize the standard voltage of BUS1 to 370V.
• 8. Optimize the communication fault logic when connecting to Grid Boss.
• *it has been modified to alert when disconnecting the communication line when on-grid or off-grid
• 9. Optimize the issue of switching and EPS output interruption when PV is weak
• 10. Optimize DCDC operation to make it more stable.
• 11. Fix the parallel phase error issue when connecting generator in split phase parallel system.
• LCD V20
• 1. Add the new startup option "Soc/Volt + Time" for AC charge startup.

• Same as fAAB-1E1E, changes based on the FAAB-1B1C and EAAB-1D1D. After updating, it cannot restore version of FAAB-1C1C and below.
• 1.Compatible with FlexBoss.
• 2.Support working with GridBoss.
• 3.Add Dark Start logic to disconnect the EPS load
• by using the dry contact 2 to control external relay or contactor
•  when the battery SOC/Volt is very low and there is no grid available and allows the connected grid-tied inverter or generator to prioritize charging the battery to dart start the system.
• 4.Add WattNode RGM protocol, CT ratio and direction setting.
• 5.Add Dry contact reuse function for configuring RSD, Smart load, Darkstart and Non-critical Load.
• 6.Optimize the ability to take the half wave load.
• 7.Optimize remote update process.
• 8.Optimize the protection of model settings.
• 9.Optimize the update process without power loss for the single, parallel, GridBoss parallel system. 
• 10.Optimize the charge and discharge current setting limit for parallel system.
• 11.Optimize the BUS1 issue when the battery voltage goes to 40V. 
• 12.Optimize the operation of non-shared battery mode for GridBoss parallel system.
• 13.Optimize generator dry contact logic in parallel system. The master unit summarizes the status of each dry contact. If any dry contact meets the ON conditions, the system is set to work. If all unit meet the OFF conditions, the system will be set to stop. 
• 14.Optimize the Lithium battery option 31 not being able to be set for 16 cell lithium battery without communication. 
• 15.Optimize the issue that AC charge power cannot be reduced to 0 when the load exceeds the set generator rating power in parallel system with generator. 
• 16.Optimize the frequency shift when AC couple power exceeding system requirements in single unit with GridBoss system. 
• 17.Optimize the logic of Grid Always On function in smart load setting that,
• keep the smart load working even if enable Off-Grid Mode as long as the grid exists.
• 18.Optimize the LCD power flow display of the parallel system to display the total system power and change the display of power unit from W to kW.
• 19.Optimize display of PV3 power on LCD. 
• 20.Optimize the display of three-phase load power in parallel system.
  
  2461

• Change based on the FAAB-1A1A.
• 1.Fixed an issue when inverter in off-grid mode, inverter can't use generator to take load and charge battery.
• 2. Optimized the logic of on-grid load taking.
  
  139