Stick to the knitting

General Discussions
1

Looks like US politics is disrupting the task at hand.
Here’s a topic posted in the 4x4 forum by a guy in Okahanja:

I was wondering if such control systems is available to switch off the aircons, in the farm house, automatically once the grid is not available, during the night, that they don’t run from the batteries, if so chosen. I googled a bit, but was not quit successful, maybe because I know to little about these things.

The farm house is on the UPS port of the 12Kw 3 phase Sunsynk inverter. All the other buildings are non essential, and separately from the house. The inverter and batteries are in a separate room which part of the out buildings.

I see you getting all sort of remote wifi switches, but all of them work from an app?. What I need is something in the DB room that tells such a wifi switches to switch off once the grid is not available, or something similar?

Else I need to add something like 2 x 5kw batteries per aircon.

2

It strikes me that an installation like this is added to an existing home with no thought to redesign of the electrical reticulation.
So instead of having most of the loads on a non essential supply which will simply switch off when there is a grid outage they start chasing their tail by switching appliances individually with whizz-bang WiFi contactors.

3

Most of the inverters have build in functions to control loads like that. Victron takes it a bit further with Node red in the large image. When we talk about home automation on the forum, we talk about exactly this kind of control where we will use different 3rd party devices to switch off loads we dont want to run from battery or only want to run till the battery reach a certain SOC and then switch off.

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4

this is absolutely the fun part of it all. I would rather do this than redesign or even rewiring my home. It will cost a fraction of the rewiring process. You should see some of the houses we install for, up to 3 floors and multiple loose standing buildings. Rewiring that will cost more than the solar system and in cases like this we will start to control devices separately.

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5

On the Sunsynk, you should be able to wire those appliances to the AUX port and achieve very close to what he wants. AFAIK, you can configure it to only enable the AUX output when the batteries are above a set level - say 90%.

6

I presume a potential free contact?
This then needs to be connected to the contactors controlling the A/Cs.
I think his inverter is in an outbuilding just to complicate things :slight_smile:

7

Normally you would just take the output from the AUX port. Sunsynk has 3 ports - almost like a Multiplus - 1. Incoming Grid; 2. Outgoing Backup; 3. AUX - which can be used as A generator input or a controlled output. I guess you could wire it to control contactors - that would save copper in this case. Just remember to add overcurrent protection to the control wires.

8

Oh yes! That! So many people forget that. The other day I was watching this short video, and was horrified for a split second when I saw this…

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And then thankfully I noticed this before I made a complete fool of myself :slight_smile:

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eFixx is not a bad channel to follow. Lots of tips, tricks, tool reviews…

9

I’ve been thinking of what happened on this typical installation…
The client in Okahanja wants a solar system so he phones the local solar installer (who is maybe in Windhoek a mere 70km away)
The installer gets the job and installs the panels and inverters etc. in the outbuilding because that makes sense and the feed to the main DB in the house.
All loads in the house are then supplied by the inverter (via a changeover switch)
The contractor sends his bill and everyone is happy for a while…

10

I think what a lot of us is missing, there is no one size fits all solution in this industry. I can see that you base your line of thinking on your own requirements as well as your own ideas and knowledge of this industry. I can assure you, I have heard just about as much plans and ideas as I have clients. Everybody has some or other different perspective or end goal and we as installers must make that happen. Your last sentence is so true, everyone is happy for a while, then they see what the system is capable of, or not and how everything is fitting together, and then not everyone is happy anymore. This is where the upgrades and changes start. As your knowledge of the system and its working increase, so will your ideas expand leading to you wanting more and finding ways to make it happen. Very few clients just accept the system as is and be content with what they have.

EDIT: the happiest and most content clients are the ones that allow us to record data, design a system accordingly and install a total turnkey solution based on the data collected. They never look back and the need to change anything very seldom arise.

11

I want to use an example and i hope the person sees this in the light i put it.

There was this man called @TheTerribleTriplet on a forum years ago that based all his advice on his own experience up to that time. Small inverter , wants vs needs and all that. Over the years he sort of realised his own “mistakes” . He started maturing in the industry and if i can compare his previous advice to his advice lately, you would not believe it is the same guy talking. As his needs, experience and knowledge grew, his advice also became better. He is still a bit stuck on his 18 cell single brick self build battery banks with fewer failure points, but I can live with that.

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12

All of that is the honest truth.

Now back then, 2008, when I started thinking about shiite, shiite like how can I recharge a UPS battery after hours of LS using the sun, we knew nothing compared to today.

There was no cost effective answer.

Years later, salient good advices all over, but it was mostly from forums overseas. Not really for SA conditions per se.

Conversely, those advices at the time had one HUGE impact … Cost!!!

So I thought, ok, there is what I’m supposed to do, then there are NEEDS … who has actually dunnit in SA, NEEDS only?

Seeing how the winds blew, I understood, must have a clear upgrade path in mind, read, “smous en smokkel”.

Result?
Gained a deeper understanding of why not, as well as the converse, how you can make a smaller system work optimally.

Cause over all these years, ROI first, accidently sorted LS as byproduct.

Today I know that it boils down to these factors:

  1. Your personality type?
  2. Your budget?
  3. Can you adept to the system, or must the system adapt to you?

Hence why I am still on a 5kVA, 5.2kW array and my pride and joy, a 18 cell bank.

And that with 9.5 people on the property. :grinning:

NEEDS vs WANTS vs HOBBY … NEEDS and ROI works well together.