Radek99

Hello, I would like to ask about the possibility of modifying / patching the firmware for my Axpert MAX / MAX II 8000 inverter. My current firmware versions are: U1: 72.03 U2: 112.15 U3: 00.00 Model name: MKS2-8000 What I am mainly looking for is a modification of several battery-related parameter ranges, because I am using a custom battery pack with a higher voltage range than the standard 48 V settings allow. The first parameter I would like to change is the low DC cut-off voltage range. At the moment, the inverter allows this setting only from approximately: 42.0 V to 48.0 V For my custom battery, I would need to be able to set this value to around: 52.0 V and ideally up to: 54.0 V The second part is the charging voltage range. Both bulk/absorb and float charging voltages are currently limited to approximately: 48.0 V to 62.0 V For my battery, I would need to extend this range to at least: 66.0 V and ideally up to: 68.0 V Of course, I understand that the related protection thresholds would also need to be reviewed and adjusted accordingly. I am not looking to simply disable protections, but rather to move the relevant voltage limits consistently, if the hardware is actually capable of operating safely in that range. I have inspected the PCB and, from what I could identify, I did not find any obvious component in the battery voltage measurement / control path that would be clearly underrated for these voltage levels. That makes me suspect that these limits may be mostly firmware-imposed, but I would like to verify this with people who know these Voltronic/Axpert firmware branches better. My questions are: Is this type of parameter range modification feasible in the U1/DSP firmware for this generation? Is U1 72.03 / U2 112.15 a known branch, and is it related to the newer MKS2-8000? Are the battery voltage setting limits stored as simple constants/tables in the DSP firmware, or are they tied more deeply into the control/protection logic? Would it be possible to patch only the U1/DSP firmware and leave the U2 display firmware untouched? Is there any known rollback package for the original U1 72.03 / U2 112.15 firmware combination? Is anyone here able to help with such a patch, or point me to the correct firmware branch / tools / person to contact? I understand that increasing these voltage limits may have hardware and safety implications, so I would like to approach this carefully and not flash anything without first confirming compatibility and having a rollback option. Thank you for any guidance.