In the MPPT RS range of products, on the product brief present on the Victron website, PDF dated April 15, 2025, so about one year and a half ago, it says:
PV Isolation fail level (4) - 100 kΩ
Note 4: The SmartSolar MPPT RS will test for sufficient resistive isolation between PV+ and GND, as well as PV- and GND. If the resistance falls below the threshold, the unit will report an error and send an error signal to the GX device (if connected) for audible and email notifications. Despite the error, the product will continue charging the battery.
Also, on all RS range on the Error code overview section, for Error 41, it says:
Error 41 - Inverter shutdown (panel isolation resistance too low):
PV panel isolation resistance too low. Check the PV array cabling and panel isolation, the inverter restarts automatically once the issue is resolved.
But on the VictronConnect changelog, on 6.50beta9, from September 30, 2026, it says:
MPPT RS: Added error #41, “PV isolation failure” (requires an upcoming firmware release)
So, in the end…
Was the error 41 reporting feature present one year ago (or is it even in the current release version), or not???
As the “upcoming firmware” remark for sure is referring to the MPPT RS and not VictronConnect, I suppose…
The resistance value is shown, indeed, but I was talking about the error itself and its reporting.
Based on the resistance, the error is generated or not.
Did you tried to put a 50K resistor between PV+ or PV- and ground and see if the value is changing accordingly AND if the error is generated and reported?
For example, on Multi RS Solar, even if the manual is talking about the isolation resistance, that resistance is NOT shown on VictronConnect as in your MPPT RS case and if I do the above it’s NOT generating the error.
I haven’t checked the VC/VRM notification system itself like that, but for me, seeing the telemetry values and how they change depending on the weather conditions is quite enough.
So there is, indeed, a discrepancy between written and fact…
Some will argue that the MPPT RS series have the PV side galvanic isolated from battery side and therefore it’s not so important, but for others the PV isolation is a certification issue/condition.
True.
It would be for me also, if it would be reported…
But for Multi RS Solar VictronConnect doesn’t report it, despite the fact that’s 95% the same hardware for MPPT side…
