IanThomson

Thanks for all the good work Coulomb, enjoy the coffee, when you get a break.

Thanks for the explanation, I am now back on the same path. I am not sure the display is removable. I hope I have not waisted your time. The RM inverters I am using are these "SOL-I-AX-5.RM" https://www.mecerpc.co.za/Mecer-SOL-I-AX-5-RM-p-249017.php

Thanks for the reply. You have lost me a bit there, here I take very small steps. Are you suggesting I should use your HEX route, as per your answer to the original post?

Hi Coulomb. Thanks so for making contact. Maybe I did not explain fully / clearly. I bought inverter 1 (SOL-I-AX-5.RM King 5K RM - 48V 4000W MPPT) about a year ago. I then wanted to add a second inverter in //, but needed to get the FW updated on the old so they would work in //. Once installed, I then noted that the voltage readings on inverter 2 (new) were low compared to inverter 1 (old). The VDC is my main concern, as it triggers a panic as the inverter sees the battery pack voltage going too low, I have program 05 set to usr. The inverter BMS did not want to talk to my Dyness 4.8 bats in PLY mode. I did try fixing the VDC reading using "Calibrating your inverter's battery voltage reading" but got 'nacks' using Weber's nudge method and Tera Term. I assumed when nudging the reading, I should send the command as ASCII and not HEX (i tried both). I have not tried using your HEX route. Thanks for the help.

Hi Guys. Could I revive this thread? I have a similar problem. I have 2 x RM Axpert Kings in // showing different VDC and VAC readings on the LCDs. I bought them about 1yr apart and had to get the FW updated so they were the same version number to work in //. When a check the VDC on the inverter terminals, both read the same ( within 0.1) vdc, but inverter 1 (HL) shows the correct (higher) voltage 48.9vdc while inverter 2 (SL) shows incorrect (lower) voltage 47.8vdc. The same happens on the VAC (grid) side, the multimeter gives 248vac on both sets of input terminals, while inverter 1 shows 247vac and inverter 2 shows 242vac. I note this ratio 47.8/48.9 = 0.98 and 242/247 = 0.98 Any ideas how I could correct this problem?