3KW or 5KW setup - please advise

Rouxenator said:
Very good point - I did not take seasonal changes into account.

Perhaps I should just go with my gut feel and stick to the 3KW idea I initially had.
The benefits are it is more affordable, albeit partly due to sticking to AGM batteries for now, and with only 3 panels the 3KW should work with a bigger margin for seasonal and weather variances.
The downside being it will not provide as much power and the AGM batteries will wear out sooner than Lithium but at that point I can revisit the situation.
Storage capacity will be almost the same since I will be adding another 200Ah to the one I have giving 4.8Kw in total.
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Most of these decisions boil down to personal choice and experience, the forum can only provide guidelines. Clearly you can't mix and match two systems, so its a big leap to a 5kW/48V/lithium setup. It also depends on how you expect load shedding to go in the future, and what your risk threshold is.
 
Rouxenator said:
Yes - since I already have 1 nearly new 200Ah AGM if I do go 3kW the easiest way to reach 24volt is to buy another. For 5kW it makes more sense to just go lithium.
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Isn't it better to wait until the new 200Ah AGM is finished and then go 3kW with a 24V LFP? Should be about 6 months.
 
Rouxenator said:
Very good point - I did not take seasonal changes into account.

Perhaps I should just go with my gut feel and stick to the 3KW idea I initially had.
The benefits are it is more affordable, albeit partly due to sticking to AGM batteries for now, and with only 3 panels the 3KW should work with a bigger margin for seasonal and weather variances.
The downside being it will not provide as much power and the AGM batteries will wear out sooner than Lithium but at that point I can revisit the situation.
Storage capacity will be almost the same since I will be adding another 200Ah to the one I have giving 4.8Kw in total.
Click to expand...
Also keep in mind that your useable capacity will be half for AGM. If you have 4.8 kWh total then you'll only be able to use 2.4 kWh.

With the 5 kWh Lithium you can use most it...
 
With a few panels you may land in no solar production at all

The 5kw with higher startup voltages is a problem/tricky
The moment you go 5kw the lowest startup mppt you can go is 60v

So lets take the 145v voc max
If you use 50v panels you can use max 2 panels
That would put its max power viltage at 41ish volt

So 2 panels would be 82v nicely into the mppt range

If a total of 2 sections is shaded irespective of panel ie lets say you have a section on each that is shaded

Then the voltahe will drop by 26v as its bypass kicks in dropping you below the 60v mppt startup voltage and you get only a few watt like 15w

So you think ok lets try a lower voltage panel ie a 41.3v panel that would land in 120v voc and a vmp of about 34.6 vmp but in reality closer to 30v when panel is hot so then you can lose 2sections and still produce power lose a third and most likely you drop out of mppt range
And get nothing

Half cut panels can see you still produce power if you have enough half panels to still satisfy the voltage to fall in mppt range

If you have more panels you can endure more shading as long as the voltage of the string exceeds the mppt startup voltage (pay atterntion to vmp not voc and keep in mind it will be lower if panel is hotter) hence if you have more panels 5kw startup isn't a big deal with few panels especially if you get shade it is a big deal

Naturally the max voc plays an important part in selecting panels but vmp on low panel count or low voltage mppt is a bugger if you have any shade

In this regard the 3kw system with a much lower mppt startup voltage (thanks to the lower voltage of battery) will be more forgiving
 
Pineapple Smurf said:
Go big
Inverter will run cooler
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1685518293203-jpeg.1533371
 
Benedict A55h0le said:
It does not seem like you have the required roof space to have a 5kw inverter. You really do need at least a 5kw inverter. A Sunsynk 5kw needs 4 panels per array. Splitting the array is not a good idea with Sunsynk type inverters. You can try find smaller panels that could fit 4 in the space. I would sell the house and buy a place with proper solar capability.
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That is the weirdest advice I have ever seen on this forum regarding solar installations where someone says sell the house and buy a proper place for solar.

If it were me I would rather just divorce the gorgeous wife and kick her out and therefore I now only require half the solar capacity and still get to keep my house.
It's confirmed, you Sir are an absolute total idiot :p
 
Pineapple Smurf said:
That is the weirdest advice I have ever seen on this forum regarding solar installations where someone says sell the house and buy a proper place for solar.

If it were me I would rather just divorce the gorgeous wife and kick her out and therefore I now only require half the solar capacity and still get to keep my house.
It's confirmed, you Sir are an absolute total idiot :p
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Nah, it's an inside joke :laugh: me and Benedict go back more than 20 years, working hard or hardly working at Swist(ika) in Stellenbosch. Swist being short for Somerset West Idiots Stand Together.

But I could never move out of Stellenbosch because we have the best mountain bike trails on Earth. Something which Benedict is missing out on.

In the long term we will be moving out of Stellenbosch to a much bigger house on the West Coast where my parents are retiring. Plans are underway to get a big solar install done that side, I just need to sort out my tiny Skelmbos house first.
 
Rouxenator said:
I am happy with the work of this guy, and I like the deal he put together for me:
  • 5kw Hybrid Inverter Lux Power SNA5000 ( Used ): R8,000.00
  • 5Kw Battery ( Lithium ): R26,460.00
  • Powit 550w solar panel x 2: R8,500.00
  • Sub D.B. Board: R1,800.00
  • Installation: R5,000.00
Total: R49,760.00
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That's a great deal. The Luxpower SNA5000 has a rep for being bulletproof, and it blends, unlike most Axperts. Moreover, it is on the COCT's approved list.
The only thing that concerns me is the Powit panels, never heard of them. I would stick with the 1st tier JA Solars, or maybe even consider other panels that are higher voltage. Brands like JA Solar, Canadian Solar, Longi, Seraphim, and Cinco are more mainstream brands.

You also need to get a bit more creative regarding panel mounting space. There are no rules that say that you must use the roof, so if you are out of space, consider:
1. A carport if you have one (or maybe it's time for one?);
2. A pergola, or patio roof (or create the one that you always wanted);
3. Window and door awnings. A MyBB member made his own awnings over windows, and placed panels there.
4. Ground mounted structure. This takes up space, and panels are fair game for thieves, but better than nothing.

Any wall that is somewhat North-facing is fair game.
 
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Pineapple Smurf said:
That is the weirdest advice I have ever seen on this forum regarding solar installations where someone says sell the house and buy a proper place for solar.

If it were me I would rather just divorce the gorgeous wife and kick her out and therefore I now only require half the solar capacity and still get to keep my house.
It's confirmed, you Sir are an absolute total idiot :p
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And then again, maybe not, it's exactly what I did in 2019. An empty North-facing roof was a non-negotiable requirement in my search for a new home.
 
RonSwanson said:
And then again, maybe not, it's exactly what I did in 2019. An empty North-facing roof was a non-negotiable requirement in my search for a new home.
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So you threw the wife and kids and benedict away?
 
Getting a good deal on a 5kw is hard to pass on though

Having 5kw is nice in the sense that you could actually run the whole house with some scheduling around high draw items

And the blend capabilities makes a big difference to actually save on electricity bill while trying to still have the battery capacity avail for shedding

While the off grid axperts not so user friendly for that with smaller array

So if no shading problems i would try the 5kw (good price)

Could always go a shorter wider panel ie like the 455w canadian that is 1.9 x 1.13and mount portrait with 600 overhang on the top then could go 5 if needed
If you left some space as dipicted in drawing the overhang will be less

Upping the total to 2275W vs 1650w of 3x 550w

If leaving the space that isn't enough for a 6th panel where the other roof valley cuts in you may be able to drag panels a bit lower meaning the overhang will be less
 
I thought it is not advisable to mix lead acids of different age/usage etc?

How do you determine if it will be okay? Voltages?
 
TheChamp said:
Yes it is not, who is mixing batteries?
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I think the confusion comes in with the batteries I plan to use.

If I go 5KW it will require 48volt DC so I will buy a new lithium battery.
If I go 3KW it will require 24volt so I will just add another AGM to a 12V 200ah I already have.

I spent a lot of time thinking about this and I think it may be time to actually buy a ladder and get on top of the roof and do some measurements. It sure would be a pity if I go with 3KW and there would have been space for 4 panels with a little rooftop tetris.

Edit - the green is the one I have, the black below it is the geyser panels (below that is the stoep afdak in the shade). If I can fit 3x 550w in the layout of the blue blocks it would be awesome.

1689576710009.png
This is a very tiny plot, especially with the pool in the back. I think out house floor space is 1.7x that of the erf.
 
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Rouxenator said:
I think the confusion comes in with the batteries I plan to use.

If I go 5KW it will require 48volt DC so I will buy a new lithium battery.
If I go 3KW it will require 24volt so I will just add another AGM to a 12V 200ah I already have.

I spent a lot of time thinking about this and I think it may be time to actually buy a ladder and get on top of the roof and do some measurements. It sure would be a pity if I go with 3KW and there would have been space for 4 panels with a little rooftop tetris.

Edit - the green is the one I have, the black below it is the geyser panels (below that is the stoep afdak in the shade). If I can fit 3x 550w in the layout of the blue blocks it would be awesome.

View attachment 1558015
This is a very tiny plot, especially with the pool in the back. I think out house floor space is 1.7x that of the erf.
Click to expand...
Get rid of the solar geyser.
 
Pineapple Smurf said:
That is the weirdest advice I have ever seen on this forum regarding solar installations where someone says sell the house and buy a proper place for solar.

If it were me I would rather just divorce the gorgeous wife and kick her out and therefore I now only require half the solar capacity and still get to keep my house.
It's confirmed, you Sir are an absolute total idiot :p
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Getting a house with proper solar capability is the best advice ever. The only issue being cost for drunk losers like you. But Rouxenator is not like you.

You are an ANC voter and NHI supporter. Fokkof dronkie.
 
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