9H1LO

on my 2KVA model the 1M smd voltage dividers are just above the fan and in high humidity condensation was building up on them, eventually they failed due to corrosion, i only noticed after inverter kept shutting down saying (i think error 09) and high battery voltage and reading was >30v even though batteries were at 26V (2kva  is 24V) 
I cleaned up the board and replaced the 1M resistors, and also put a small 1M preset instead of one of them to calibrate the reading as the divider is not that precise in my opinion then I sprayed some varnish over the area after drying it properly to avoid this condensation building up as my inverter is outside in a cabinet but in my country it could be 25C with 99% humidity and the fans make the situation worst due to venturi effect i think