My first post on this forum.

I have a 3 phase DB, and a few years back I had an installer put my essential loads on a single phase 5k Mecer inverter with a 5k battery backup , and a few PVs.

I have now decided to upgrade the system myself (I'll get a sparky to do the AC work) and I'll do the battery and PV connections.

I'm putting in a 12k 3phase sunsynk with 20k of batteries, and 5000w worth of panels. 

My concern is that 20Kva / 400A of batteries is not going to be enough to get me through 4 hours of load shedding between 6-10pm, if the 2 geysers are on, and my teenagers are using all the hot water. 

Is there a way to switch off my geysers during loadshedding, so that they don't draw on the batteries ? I was thinking of putting them on a relay, so that if the grid power goes, the relay switches off the geyser? Is such a thing possible? or are there other ways of doing it?

Best is to read the manual and/or search this forum for more detailed info. But yes, the Sunsynk inverters in general allow you to separate your essential loads from non-essentials, feed power to all, but switch off the geyser during loadshedding. No real need to buy additional relays, just tell the installer which loads you want backed up as ups loads, and which can go off.

SONOFF ENERGY MONITOR POW R3

or

SONOFF ENERGY MONITOR POWR320D

bonus points for flashing tasmota to it.

7 hours ago, GreenFields said:

Best is to read the manual and/or search this forum for more detailed info. But yes, the Sunsynk inverters in general allow you to separate your essential loads from non-essentials, feed power to all, but switch off the geyser during loadshedding. No real need to buy additional relays, just tell the installer which loads you want backed up as ups loads, and which can go off.

If I understand the SunSynk 12k 3p manual correctly, I would put essentials (lighting internet TV) on the generator/auxilary connection, and the rest to run as non-essential. I can then control these using the battery percentage or voltage. In other words, run everything, including geysers during load shedding, until the batteries drop to say 50%, and then run the essentials down to say 40%, and then use candles and smoke signals when I get to <25%.  Is this right?

The next question, is then how do I rig a 3 phase DB so that the inverter does not cut off the essentials on one of the phases? Am I correct that all I need to do is put the essentials on 1 phase and then separate these with an isolator on the DB?

 

I monitor my Inverter (Sunsynk) and the moment the "Grid" is lost, i switch off all the "BIG" loads that is connected to my inverter.
As my house is very old and it is not easy to install additional wiring to separate some of the big loads from my normal circuits, for now, that is the only way i can do that. 

I use Home Assistant, communicate with the inverter via RS485 to get all the values and status.
I use the CBI Astute (30A) to switch off my well point pump and i also have 3x CBI wall sockets that switch off the Dish washer and some other loads while we are on loadshedding.
This way you can control individual circuits.