DIY OG Solar install

lexity said:
To tell you the truth, this is as much for my own future install as it is for theirs.

But thanks for your input. I'm sure I will learn a ton from anyone who's done some hard yards.... if they are generous enough to contribute to the thread.

p.s. Well done, btw. That is excellent-going.
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on your learning curve ,make sure you have a big flat snow shovel with you at all times so you can shovel all the bullshit infront of you and throw it to the side and carry on.dont rely on utoob just watching that one you posted made my skin crawl .that inverter may give 1000 watts if youre lucky ,boet on a 12 volt system thats gonna hurt .
 
soulie said:
on your learning curve ,make sure you have a big flat snow shovel with you at all times so you can shovel all the bullshit infront of you and throw it to the side and carry on.dont rely on utoob just watching that one you posted made my skin crawl .that inverter may give 1000 watts if youre lucky ,boet on a 12 volt system thats gonna hurt .
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How come all your commas are preceded by a space?
 
Here are some links to assist in your endeavors:
https://app.opensolar.com/#/home - great free app to simulated an install project.
https://powerforum-store.co.za/ - trusted supplier, good prices
https://cleversolarpower.com/how-to-calculate-fuse-size-for-solar-system/ - fuse sizing calculator
https://www.opengreenenergy.com/solar-dc-cable/ - wire sizing calculator

that's as far as I've gotten. I'm not doing a DIY, but enjoy trying to understand what's going on, and also check an installer isn't BSing me.

*edit*
Added change in Voc for temp. variances link: https://www.alternative-energy-tutorials.com/photovoltaics/temperature-coefficient.html
 
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schuits said:
Here are some links to assist in your endeavors:
https://app.opensolar.com/#/home - great free app to simulated an install project.
https://powerforum-store.co.za/ - trusted supplier, good prices
https://cleversolarpower.com/how-to-calculate-fuse-size-for-solar-system/ - fuse sizing calculator
https://www.opengreenenergy.com/solar-dc-cable/ - wire sizing calculator

that's as far as I've gotten. I'm not doing a DIY, but enjoy trying to understand what's going on, and also check an installer isn't BSing me.
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Mucho gracias, amigo.
 
Its pretty easy to do, although looking at your specs - you need far more solar than that.

First up - what type of roof do they have, as mounting is important.

How much roof do they have thats not in shade?
Ideally you want as much PV as you possibly can fit within budget. Go with 120% of inverter capacity.
So if you have a 5KW inverter, 6KW of panels

Panels will need to be wired up in "strings". Strings are connected to MPPT inputs on your inverter. Or if you have a system with split MPPT and inverter, to your MPPT hardware (eg Victron)

Panels can be connected in series - in which case you add the voltages up for your final voltage, or in parallel, where the amps will go up. You can mix / match putting panels in series and parallel, but i'd suggest keep it simple for now.

You'll need to look at your inverter choice to see what voltages it supports, and where its sweet spot is.
You'll design your strings of PV to fit around those values. Never exceed the voltage, or you'll kill the inverter.
My strong suggestion is to not even come close to that value, even with VoC, safe is to keep panel voltage under 75% of the max voltage on the inverter. Panel voltage can rise during cloudy weather, and there are plenty of people who've killed (shitty but cheap) Axperts with overvoltage here in SA.

I'd suggest Deye inverter or Sunsynk, Deye's stuff is decent (Sunsynk is rebranded, slightly diff firmware, but same OEM deye hardware).

Back to voltages

Eg, if you have an inverter that says it likes 350v, with a max voltage of 500v, the max i'd suggest feeding it would be 500 * 0.75 = 375v +-20v

Panels will come in various options. You really just need to look at R/kW pricing, unless you have a small roof, and need the space.


Right now 405W panels are 2323.85 incl. (R5.7/KW), 550w 3064.35 incl (R5.57/KW) 650w 3743.73 incl (R5.75/KW) from a sample from an email I got this morning from SolarSolved

So, looking at that... I'd probably go for the 550W panels, as the price is cheaper...


Anyway, looking at their data sheet, 42.57v and 51.44v VOC @ 13-15A

Assuming your 350v sweet spot, that would be 7 or 8 panels in series per string. Probably 8 is best, as its an even number.

That would give you 4.4kW per string.

I'd probably lean to getting an 8kW inverter though vs the 5kW

8KW inverter Sunsynk - 35k
16 x 550w panels 49k
IBR Mounting x 6 5000 + Clips (4 per panel) 1500 = 6.5k
PV cabling 20M, DC breaker, DB Board, other misc bits 2k electrician to sign off 2k? call that 5k
5kWhr Battery / 25k
------------------
+- 120k there if you do your own labour.

If its not IBR mounting, add another couple of k on top.
 
lexity said:
I'm a novice when it comes to solar installation, and am helping someone size a solar system which is going be completely off-grid. It's a small 3 bedroom house and they are a couple who have a fairly modest-consumption lifestyle. They use somewhere in the region of 450kwh/month depending on time of year.

They are looking at spending in the region of R100k-120k. They want to know if that could include solar-powered hot water with their existing geyser(150 liters). They would prob leave connection to the grid for hot water if necessary, but knowing them, I'd say they would look for a complete OG solution before very long.

The quote I saw came in at R155k odd but I'm hoping I could do much/some of the labor which would knock around R30 -35k off. Also hoping to shop around with him for components to try to get them the best deal but the quote is for:

2 kW solar(Art), 5.4 kW battery and Deye 5kW inverter. Plus the bits in between.

Hopefully I can get some advice from those with some solar-install mileage under the belt.
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Unfortunately thats not going to get you offgrid.

With that budget, and some DIY though, you can go 8KW inverter, 8.8KW of panels, and 5KW battery (i priced that above for you).

Ideally, you'd want at least 20KW of battery, and more PV. I'd start with the 5KW and add more battery later though (recommend that as a newbie, you keep to same brand of battery otherwise gets a bit painful, although completely doable).
 
itareanlnotani said:
Unfortunately thats not going to get you offgrid.

With that budget, and some DIY though, you can go 8KW inverter, 8.8KW of panels, and 5KW battery (i priced that above for you).

Ideally, you'd want at least 20KW of battery, and more PV. I'd start with the 5KW and add more battery later though (recommend that as a newbie, you keep to same brand of battery otherwise gets a bit painful, although completely doable).
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Wow... a thousand thank-you's... you've given me a lot to chew on.

Will get back to you soon.
 
soulie said:
i think you need to look at the first places building plans to see if it can hold all those 30 kg panels you want to install ,engineers reports arent cheap and insurance company will want to know why there are roof tiles, beams and trusses in the lounge once its collapsed.no malice squire ,you asked you got .
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Not that hard... my wife makes me buy those 15kg cat litter bags.

Would 10 of them fit on my n-facing roof, spaced out evenly, without collapsing the roof?

Boom... next problem. :giggle: :thumbsup:
 
I was doing a concept setup and I though I'd use 600w panels on a 5Kw inverter. Then I found little caveat. The inverter takes a max current of 11A per MPPT, while a panel operates at 17A. While the inverter will clip the current that's just a waste, so that's another thing to consider.
 
Recently helped a lady who already had a modest solar system to upgrade her geyser to a solar-powered one

Kit needed

2 x 550 watt PV panels - about R8900
Geyserwise ECO kit and PTC dual voltage element - R3300
Hiring a plumber to change the existing element - R800
What we charged to fit everything - R3000

Total - R16000

On sunny days like today, the panels heat the water to 59 deg
On the 3 weeks of cloud, it did not work well at all
 
schuits said:
I was doing a concept setup and I though I'd use 600w panels on a 5Kw inverter. Then I found little caveat. The inverter takes a max current of 11A per MPPT, while a panel operates at 17A. While the inverter will clip the current that's just a waste, so that's another thing to consider.
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You never see the quoted voltage or current from a PV panel. The best I've seen with north-facing 560 watt panels is 505 watts, that is 92 volts and 5.5 amps

Wire them in series, then you'll see 190 volts and 5.5 amps
 
schuits said:
I was doing a concept setup and I though I'd use 600w panels on a 5Kw inverter. Then I found little caveat. The inverter takes a max current of 11A per MPPT, while a panel operates at 17A. While the inverter will clip the current that's just a waste, so that's another thing to consider.
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The SunSynk/Deye 5kw is now 13A. It'll only be above 13A for a short period of the day, so losses are actually minimal
 
lexity said:
Oh yes, ofc... there are 2 busbars. I remember now from an example setup I saw.

So, whether + or + when it hits the bus bar it just floods all the wires and - clearly - there is no ill effect on anything else connected.
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Hypothetical question for anyone who understands the flow of current.

In the design of the 12v setup(the 12v sponsored video) you can see there is a 12v fuseblock, connected to the negative busbar.

I see there's a positive cable coming from that fuseblock which is then connected to the postive battery terminal.

What would happen if it was instead connected to the positive busbar?
 
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schuits said:
I was doing a concept setup and I though I'd use 600w panels on a 5Kw inverter. Then I found little caveat. The inverter takes a max current of 11A per MPPT, while a panel operates at 17A. While the inverter will clip the current that's just a waste, so that's another thing to consider.
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How many CCs are you using for your thought experiment?

If there are two, is that for the purpose of experimenting with your panel configuration? Or is there some other benefit to splitting the CC into two?
 
2 so as not to exceed the limits per CC., also scalability etc.
The experimentation is around placement, angles and output related to those.
 
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