Good day, I have a bit of experience with Home Automation but I am completely new to the solar game. I have an electrician busy installing my 5KW Deye inverter and I have some concerns with how the wiring is set up and want to see if I can solve my problems without spending a fortune on tearing up the driveway.

We have an outbuilding (A garage that was converted into a flat) that has its geyser and connects to the pool pump and only one DB Board. The inverter + battery + solar is set up in the main house with the home load being set to the main geyser + stove and the essential load is configured to be the plugs+light+outbuilding. I have noticed that when the aircon in the outbuilding is on and the geyser is on together with some appliances in the main building it trips the inverter, I believe it's exceeding the AC passthrough (8400w?).

I want to ask if my idea for solving my dilemma sounds feasible and if anyone has any pointers / alternative suggestions.

1. Install Sonoff Smart loadshedder
2. Set the pool pump, secondary geyser and aircons on smart (din) switches to turn off when the power fails.
3. Install an automatic transfer switch to only enable the Inverter essential loads connection once the grid fails.
4. Set the Deye inverter to Zero Export to CT so that the solar is still effectively used to reduce my electricity bill when the grid is connected and the essential load is connected to the grid instead of the inverter.
Thus when the grid is connected, the inverter will not do any AC passthrough and focus on charging the battery and then pushing excess solar back into my home load. When the grid fails, the ATS kicks in and the Sonoff switches will run automation to turn off all the non-essential devices during loadshedding.
 
I've also thought about installing the ATS only on the power that goes to the outbuilding so my essential loads on the main DB will still be using AC passthrough when necessary, but the outbuilding will only use the grid when Eskom is working.

I hope my idea makes sense. Otherwise, I'll need to either install a second inverter + battery or have an electrician install a second DB, tear up the brick paving and lay new cables to split the essential and non-essential outbuilding loads so that AC passthrough doesn't exceed the max.

Edited March 11, 20232 yr by Vakie
Spelling fixes

Hi @Vakie to me the most reliable solution would be to move the outbuilding feed onto the non-essential side, and introduce seperate 2.5mm or 4.00 mm surfix feed  to the outbuilding from the inverter essential side, in order to feed the flat's essentials (lights and plugs). Of course that feasible if the distance between house and flat is not a mile long!

The problem with an aircon and geyser on the essential side is that of racing conditions. Once the grid fails and these loads are on, the inverter will trip in battery mode before you have the time to switch them off via automation techniques. 

EDIT: ok, I get your proposal, you want to keep the flat on  nonessential by default when grid is available, via auto xfer switch. Then when grid fails, you switch the geyser and aircon off via smart switch first , then command the xfer switch to essential. Yes that should work. 

Only small downside is a short interruption on plugs and lights in the flat, but i am sure that may not be a problem for you. 

Good thinking, as long as the cost of automation does not exceed the cost of a seperate 2.5mm cable feed. 

Edited March 11, 20232 yr by BritishRacingGreen

Thanks @BritishRacingGreen, I'm going to ask the electrician for an estimate on running a separate cable and compare it to the automation solution. It's not that far, probably 20m from the inverter location and 10m from the main DB. He would likely have to remove some bricks from the paving and I have no idea how difficult / expensive it is, but it sounds like a pain.

A small interruption isn't an issue for my use case, it's much better than a full 2 hours of loadshedding and it's mostly just for running some lights and a tv in the outbuilding which can just start up again without causing any major issues and since I went for a more expensive Deye (I'm glad I did since I was planning on going Luxpower but they didn't have stock) I should be able to still use the excess solar to offset the grid usage of the outbuilding load when the grid is connected even though it's connected to the nonessential load at that time. Now I just need to force the electrician to install the CT...

Any recommendations for alternatives to the Sonoff smart loadshedder or tips / tricks with it? Does it play nicely with Home Assistant?

23 minutes ago, Vakie said:

Thanks @BritishRacingGreen, I'm going to ask the electrician for an estimate on running a separate cable and compare it to the automation solution. It's not that far, probably 20m from the inverter location and 10m from the main DB. He would likely have to remove some bricks from the paving and I have no idea how difficult / expensive it is, but it sounds like a pain.

A small interruption isn't an issue for my use case, it's much better than a full 2 hours of loadshedding and it's mostly just for running some lights and a tv in the outbuilding which can just start up again without causing any major issues and since I went for a more expensive Deye (I'm glad I did since I was planning on going Luxpower but they didn't have stock) I should be able to still use the excess solar to offset the grid usage of the outbuilding load when the grid is connected even though it's connected to the nonessential load at that time. Now I just need to force the electrician to install the CT...

Any recommendations for alternatives to the Sonoff smart loadshedder or tips / tricks with it? Does it play nicely with Home Assistant?

Great, please keep us posted as you introducing the solution. 

I am more old school and would prefer the CBI Astute. But lately Sonoff have 3kw switches for, inter alias, geysers. The sonoff representative is actually active on our forum, contact him, very helpfull and friendly. @Sonoff Africa

I have a particular interest in HA, i am new to it, so please please share if you do go this route.

 

 

Edited March 11, 20232 yr by BritishRacingGreen

2 minutes ago, BritishRacingGreen said:

Great, please keep us posted as you introducing the solution. 

I am more old school and would prefer the CBI Astute. But lately Sonoff have 3kw switches for, inter alias, geysers. The sonoff representative is actually active on our forum, contact him, very helpfull and friendly. @Sonoff Africa

I have a particular interest in HA, i am new to it, so please please share if you do go this route.

 

 

And of course you must not select a automatic xfer switch, you need to introduce a manual but electrically operated arrangement. Because you need to give a window of time for the smart switches to switch off first, before you command the xfer switch onto the essential output of the inverter. 

Summary note to self.

Vakie wants to multiplex  the essential and nonessential  feeds , within COC rules of engagement, where there may be limitations of existing copper feeds. Use case : remote  outbuildings. 

An idea to remember in future.