I notice in the release notes of firmware 505 for the Multiplus II:
Is this perhaps a measure to survive the frequent connects and disconnects due to loadshedding here in SA?
If so, how urgent is it that all inverters be updated?
No sense of urgency from Victron HQ for SA installers to apply this update.
• Some precautions were taken which help to increase the lifetime of the backfeed relays.
Is there more info on this or more details… what have they done and the benefits?
I’ll ask. It might take some time to get an answer… this guy is incredibly busy 
Alright, I found out.
It has to do with inrush current. Right after the transfer switch closes, it may sometimes need to open again immediately. For example if immediately on connecting to the grid, the voltage sags out of acceptable range.
What this change does, is it will ignore the sagging voltage for a short time, if it measures that it is due to inrush current. That prevents opening the backfeed relay under high current conditions, which of course it is rated for, but does impact its life.
If your system doesn’t frequently have false connect events… that is if your voltage is nice and stable on reconnecting, this is probably nothing to worry about.
Also, if the inrush is particularly large (more than 150% the rated current), or if it is so bad that the AC waveform is distorted, the PLL will lose lock and it will disconnect anyway.
Thanks so much. Given loadshedding frequency and my small town location I guess the upgrade is a good thing for me then. Especially in this case… which we do have …
“For example if immediately on connecting to the grid, the voltage sags out of acceptable range.”
YEs thats something I have all the time…
As a precaution, a Victron dealer told me about that, and other repairs they are affecting because of Eskom woes, I had the Tripconnect installed on their advice.
The further benefit of it being on the main DB, the rest of the house is also protected. We tend to forget that. Unless the whole house runs off the inverter.
Tripconnect waits 5 min after LS before connecting the main DB, Victron ±66s after that, IF the volts are >215v and <250v from the street … as per the setting.
Just an idea to consider too.
I did the firmware update yesterday and it went without a hitch. I do think its a good thing to do that update if you have funny voltages in your area. We frequently have voltages as low as 200V - especially after load shedding.
