I’m getting this lately … I’m eliminating a possible cause, the UPS I’m running to protect against that what Eskom supplies, that passes through the inverters.
To note, the error occurs during LS.
New one here just now too… I was away, opened VRM to see if all was fine and noted no AC input, full battery, no AC loads. Just ESS #3.
Got home, had to switch the mpii off and on to get usage again (battery and gx were very much still alive and the inverter was just in bypass… But almost as if it was frozen)
On a side note… Best place to get an extra us3000c at the moment? Worth it to take the extra punch for up5000? Consequences of mixing them?
Overload on changeover is one of two things in my experience. Either it is an actual overload… or you need to update the firmware (there is a known issue on older firmware versions, although it affects only a small number of installations).
ESS #3 means the battery asked to please stop discharging. For CAN-bms battery that means the battery sent DCL=0, which for a Pylontech battery happens at 12% SoC. If I recall. If the grid is on, it sends the inverter/charger into passthru. If the grid is off, the inverter/charger turns off.
Not the same “alarm” as the topic but woke up this morning just after 3am in total darkness - LS kicked in at 03:00 and Inverter switched off - no alarms.
“Discharge short circuit protection” alarm on BMS. BMS would not switch back on until some PV was available around 7am - JKBMS but same “switch off” occurred in Feb with my old Daly BMS - Battery at 60%, loads roughly 1500w
Also happened 2 days in a row last week, early hours of the morning but with “Low Battery” alarms
Had LS at 03:00 yesterday morning and no issue, everything worked as expected.- battery at 57%, loads at 1500w
Quattro 48/10000, 2 x 150/100 MPPT, BMV700 - all devices have latest firmware
Any thoughts appreciated thanks
In your case it is probably the BMS that is to blame…
Think the ESS 3 was an old message… battery was fully charged, last message before the inverter completed restarting was ESS #4.
But 100% battery, Grid available… inverter just wasn’t communicating anything. (GX and BMS were still very much online and battery too).
On the positive side…
Managed to figure out my old random trips (they returned last night). Suspect it has to do with my backup loads being very light and rarely discharging past 80% SoC… so yesterday everytime we hit 73% the battery would have a “crisis” and shutdown everything. Switching on ALL the lights in the house seemed to clear this… so I guess I need to do another “deep” discharge to get the balancing a bit better.
Anyone have something like this “scheduled”? Like a once a month wake up the battery type thing?!?
@plonkster - that was my initial conclusion as well but same issue with 2 different BMS’s has me a little puzzled…
It is most likely the over-current protection in the BMS that is a bit too sensitive.
When the grid fails for load shedding, the inverter tries to power the entire grid for a few ms,
which causes a very brief but large current spike from the battery.
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Inclined to agree - once the system is down, disconnect grid to inverter and I try to bring it back up, BMS still goes into “protection alarm”.
Yesterday, installed spare BMS, turns out it is a much upgraded version, firmware etc
LS at 03:00 this morning - all good so far 
over-sensitive BMS over-current protection probably kicks in when grid goes down (as pointed by @Stanley ) shutting down the battery, causing the inverter to shut down. Then when you try to restart everything the capacitors on the inverter probably again causes the BMS over-current to have a fit… google pre-charge options for inverter (assuming you do not have something already)
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Correct. Inrush currents on the caps can even cause commercial batteries to throw a fit. One way around it, is turn on the Multi, if you have AC at the time, or the solarchargers, so it charges the DC bus and anything connected to it, and then connect the battery to the DC bus.
Thanks, suspected as much - the new BMS seems a bit more capable, time will tell
as I discovered
Storytime … years ago sparkie and I made sure everything was off before he started. One thing I do is to drain the caps in the inverter by switching it on when disconnected from the batts/AC. Just in case.
Lo and behold, it starts right up, with no battery or AC connected.
Sparkie and I, we look at each other in complete shock.
Forgot to switch off the panels, as the MPPT is connected directly to the inverters’ battery connection points.
So the overloads haven’t happened again but started getting a different issue where the switching isn’t super smooth… As if the UPS setting isn’t being used. This then causes all the UPS’s in the house to panic… Also sometimes causes the printer to restart. Battery trips are back. First at 73%… More recently we had a trip at 82%… I can only guess that the cells aren’t balanced - found another user with this issue and he was apparently instructed by pylontech to top balance by upping the settings in ve configure… So have now implemented those settings. Also swung for the fences and upgraded the inverter firmware (we are back online and now on 497:-) ). Guess the next move is to hook up powerview and get logs from the battery…
We haven’t done a really deep discharge this round of load shedding yet… Deepest has been to 35% SoC… Perhaps this also needs looking at. Opinions on what works best? Deep discharge at lower loads or deep discharge at capacity? Some combination of the above?
I’ve put three smallish APC UPSes (2 x 650VA and 1 x 1500VA) around for the devices that were sensitive to the speed of Victron changeover switch…
They are used only to bridge a second or less, so basically will last long time and they are not too expensive (bought used and replaced batteries) 
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I’ve also experienced this alarm when load-shedding starts, but only for the 20:00 slot. I think I’ve mitigated it successfully with a Scheduled Charge setting:
I’ve set it to start at 20:00 and last for 20m and stop on SOC of 5%. We’re always off between 5-15m past the hour. That way the Multiplus idles for 20m each day, and it seems to drop the grid faster, without an alarm, in this mode than when it’s in self-consumption mode. It won’t use battery during this time, but also won’t change from the grid, since the SOC limit is 5%.
When you don’t have the 20:00 slot for a while you can turn it off, but I’ll keep mine on until load-shedding is lifted.
There’s 5x slots, so you can do other windows too. I assume 18:00 might be problematic in some places too. Not sure if the schedule is accessible via dbus or Node-Red, could then maybe just keep moving the same slot forward, but would want to limit to actual LS windows, otherwise you’re probably losing too much by idling all the time.
Edit: Actually, if you’re looking at automation anyway, the “limit inverter power” setting in ESS may also be a good target: set it to 0W before LS starts and the inverter should drop the grid faster.
So I’m still hitting this same issue every once in a while, even with the Scheduled Charging thing I tried. Computers also dropped off last night and I’ll be damned if I need to buy a silly UPS for each of them (although that is the best answer so far).
Has anyone done something drastic that solved the issue, like a Voltage Protection Relay or so-on? I don’t have space in the Eskom part of the DB without a lot of work, so not too keen to go that direction unless someone has tried it.
I just setup a couple of assistants (Aux2 input → General Flag → Ignore AC1) wired to the Cerbo Relay 2, so my next step is to try and get the ESP API into NodeRed and trigger the relay 1 min before LS every time, resetting at some point. But man, that’s a lot.
Ideas?
If i remember correctly, you have a 10kva Multi 11
Yep, that’s me.
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