Howzit from muldersdrift - DIY install

Got my east panels up and so far working fantastic. By 10am batteries are charged and there is about 4 - 5,5kw on call for daytime loads.
So currently have 8 north 4 east 4 west

Now the big one I need to start is the second inverter install.

Something interesting which I didn’t expect is that the north panels are getting on average the same power as the east panels early in the morning. It will probably change more in summer as the rising sun angle changes. The north has 8 panels and east 4 so exactly half, might be picking up few watts from the 4 on the west but shouldn’t be much

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This part I enjoy.
Finding out how many panels you can actually have on that East/West MPPT.
( I presume East strings are in parallel with West strings).
My prediction: You’ll be surprised.

Yes correct, the east 4 panels are in series to give about 200V 11A and then paralleled with the other 4 panels on the west in same configuration. At mid day it pumps from both sides and then drops off slowly by mid afternoon.

Good man, that’s the way I do it.
I find the benefit of being able to have far more panels far outweighs any slight theoretical inefficiency that results from an imperfect MPPT voltage match between strings.
I am not even convinced there is an MPPT voltage mismatch.

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Question on home assistant or node red.

I’m not too keen on messing with my OCTO GX in case I screw something up and mess up the brains of my system and would rather use a dedicated device. Now I’m a total novice so what would you recommend, using a desk pc at home and trying on there first or getting a raspberry PI and setting it up. Whats going to be easier to manage in future. I’m guessing the windows pc is not ideal and the PI might be better or should I just suck it up and try using node red on the OCTO.

edit: or any other suggestions

If you are not a person who like to tinker, then I would suggest you wait a bit.

There is something coming with the VenusOS large image version (this is the version that include Node Red). I suspect that this will become the normal image, which means when this is applied you will have Node Red in your OCTO by just upgrading to the latest version of the firmware. Then it is as simple as activating the option in your OCTO and everything is already set up.

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So managed to install second inverter and update both inverters to the latest 485 version.
I used two P4000 unistruts to mount the inverter as I wasn’t sure of the height because the cables have a set length to match other inverter. As you can see I need to drop the inverter a bit so that cables bend nicely. Below the inverter I will put in a piece of board and mount fuse and then also the cables going down to the trunking.


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Regarding solar panel earthing I see the clips are the most common but they flippin expensive. Why not just lug some cable and tec screw it to the frame of the panel. Apart from voiding the warranty any thing else of concern? The edge clips are about R35 each so add up quickly.

probably getting 12 more panels soon so getting some quotes, but the price of the clips bugs me when a 13mm wafer head tec screw costs a few cents

Edit: found some clips at work that should work so no need for tec screws, but still welcome to comment on idea

There is a pre-drilled Earth hole half-way down both sides of the long side of the panel.
(at least there was on my panels).
Whilst on the ground I pre-fitted a lugged earth loop with nuts and washers tight on one side hole, and installed the nut and washers loosely in the other hole.
(Use those biting lock washers).
Then as the panels were installed it made it a lot easier, only a matter of fastening one side to the adjoining and all the bits were already there.
The cost was neglible and 90% of the work was done on the ground.

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I did the same like Phil did.

Just a tip, make sure you seal the lug end where the coper cable is going of to your ground spike or if you tapping it to your earth binding setup of your solar in your house. After taking my system off because we were moving, I founded a rust spot in my white trunking where my earth combiner was. Did a bit of closure investigation, I founded it came from my earth panel cable. Rain water was making slowly it’s way inside the earth cable.

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Not really part of my install but I get excited when I get delivered these type of things. This the equivalent of a kid getting sweets.

I have a two way switch that I want to automate but still have the function of the switches, this makes it possible. So cool.

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The only issue with those, is you need to have a neutral in the wall box or able to get one to the box, for it to work correctly. About 1/3 of my switches in my house don’t have that - so having to make a plan there.

Yes here is the diagram incase anyone is wondering.
I had a box in the ceiling with all wires attached so just added switch, works perfectly.

Good old British ceiling-rose type wiring.

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Next phase of “operation off grid”
Geyser is going in now, we tested it on weekend and it was impressive, hopefully it gives many years of good service. I still have my electric geyser used upstairs.

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So last night was the first time I could switch off schedule charge and night time geyser and run purely off battery. The test run was successful. Im still connected to grid so when I run higher than 4kw it takes from grid. Next step is the second inverter wiring and putting grid on changeover so that I will be off grid but with a backup for now until its finally disconnected at transformer.

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Finally got my last set of panels, 12x445w.
Could not find same as I bought before at previous supplier and it was a bit of a struggle to find stock locally. It really seems stock shortages are going to become a big problem.


Wow, those are monsters!

How many panels will you now have in total?

They are but there is already 5-600w panels available.
These are 2,1x1m so they still fairly easy to move around, i think any bigger is going to be a struggle

In total I will have 28 panels in north/east/west directions. Its 12,3kw of panels but because they different directions and also that is their peak rating so should get 75-80% of that. I should be getting a constant 3-4kw from morning till evening in sunny days and probably a constant 1kw when overcast. That’s the theory anyway.