Hello everyone,
Thought I read in the manual for the SmartSolar MPPT RS that the minimum isolation resistance below which it will shutdown is 100 kOhm, is that correct?
For my setup, VictronConnect shows me only 1.3 kOhm (see attached picture) but it happily operates, no issues. It does not shut down. Is this a bug in VictronConnect maybe?
Hi Bartholdl,
Yes, you’re right. The PV Isolation fail level is 100 kOhms.
What you see in VictronConenct must be a bad read from the device, that’s why it works properly. Can you confirm the firmware version of your MPPT RS and the VictronConnect version?
Sorry, but I am having hard time to understand this after decades of writing embedded firmware…
Communication is supposed to have some sort of error checking scheme, e.g. CRC, right? So bad packets/values are discarded…
So, the bad value is before sending.
That means that the read value from the “sensor” is either bad, and that will mean that the MPPT should shutdown, because that “bad” value will be used internally and trigger things, or the firmware is with errors and will send different values from the one read…
Is there some other variant?..
Hi Mauricio,
Thanks for confirming the 100 kOhm! This is a MPPT RS 450/200. It happened on both version 1.16 and after I updated to 1.19. VictronConnect in both cases was at 6.11. VictronConnect shows the 1.3kOhm both with a direct bluetooth connection to the RS and with the indirect connection through VRM (in VictronConnect). There are three strings of panels attached to the RS, the fourth input is not in use, in case that helps.
Maybe the real value is 1.3 MOhm, and there’s a simple display error in VictronConnect?
