DIY OG Solar install

itareanlnotani said:
It's theoretical max you'll see per hour in an ideal world.

Realistically, you'll probably pull around 5hrs of that in summer (as Speedster says +-20kWh/day), and 1-2hrs of that in winter (4-8kWh/day) as an average in WC, better winter figures in other areas.

The actual output will increase during the day from sunrise on, peak at midday, then go back down to zero at sunset.
Your output curve will look something like this. Peak will be your 4400W less some conversion losses, and losses from heat in summer, as panels typically lose some < percent for every degree over STC (25c)


images



Some graphing of solar averages in different areas here - https://www.news24.com/news24/tech-...olar-output-in-every-province-in-sa-20230518#




Going back to your setup as stated.

Panels will be 50v each VoC x 4 = 200V (+-at worst)
Your Luxpower 5KW inverter is MPPT ranges 120V~385V

I'd lean toward 6 x 550W panels per string x 2, then voltage will be hit earlier in winter, vs later.
That will clip at peak in summer, but in winter will give you more output.
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the 50v voc in reality would mean about 40v vmp so if you lose more than one total panel to shading even split over all panels you end up with a voltage outside mppt range meaning the output is pulled closer to voc where the amps drop of and production drops drastically

he would still be in play as long as the shade loss is 1panel or less if 50v panels if lower voltage panels ie 41v voc you drop so close mppt startup to limit production to almost meaningless if any shading loss
 
leon.davibe said:
the 50v voc in reality would mean about 40v vmI'p so if you lose more than one total panel to shading even split over all panels you end up with a voltage outside mppt range meaning the output is pulled closer to voc where the amps drop of and production drops drastically

he would still be in play as long as the shade loss is 1panel or less if 50v panels if lower voltage panels ie 41v voc you drop so close mppt startup to limit production to almost meaningless if any shading loss
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My concern is going over MPPT 385v max for his Luxpower inverter.
Using VOC + 20% is still under the 385v max for the inverter.
( Assuming 6 x 50 @ VoC = 300 + 20% = 360. 360 < 385v, so i'm happy with that margin of safety).

Too many idiot installers don't consider winter, and too many shitty inverters have been blown that way (usually Axperts...)

I haven't considered about shade losses; he hasn't talked about them either.

Shading loss should lower amp output though for the affected string, not voltage.

I think he has the can't fit sufficient panels on the roof issue though, as he mentioned 7 max, now 2 strings of 4...
I'd prefer more panels, so earlier output, later output..
 
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itareanlnotani said:
My concern is going over MPPT 385v max for his Luxpower inverter.
Using VOC + 20% is still under the 385v max for the inverter.
( Assuming 6 x 50 @ VoC = 300 + 20% = 360. 360 < 385v, so i'm happy with that margin of safety).

Too many idiot installers don't consider winter, and too many shitty inverters have been blown that way (usually Axperts...)

I haven't considered about shade losses; he hasn't talked about them either.

Shading loss should lower amp output though for the affected string, not voltage.

I think he has the can't fit sufficient panels on the roof issue though, as he mentioned 7 max, now 2 strings of 4...
I'd prefer more panels, so earlier output, later output..
Click to expand...
If a portion has more than 20% shading the bypass diode kicks into action

If a section gets bypassed you not only lose its watts contribution to the string you also lose its voltage

Example of string of 4 x 41v voc panels

So with 3 working panels on a hot day you would get the bottom red spot ie 3x40v panels
To meet the 120v

On a cold morning the voltage would lift thanks to the cold and you get the top red dot

And with the return of the panel lost to shadding the 120v would mean the mppt would fall at 120v bottom of mppt range pulling the voltage of the 4 panels to 30v each green dot each falling back on the peak output amps

The mppt decides the voltage in its range and if the unshaded panels can't get you there in their meaty amp output portion it may be in the drop off zone

So dropping out of mppt range is worse than normal shading

ie if the remaining panels voltage can see each panel still operating at its peak amps while over the startup voltage it's fine but if you drop out of range you get pulled into the drop off zone
 

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itareanlnotani said:
My concern is going over MPPT 385v max for his Luxpower inverter.
Using VOC + 20% is still under the 385v max for the inverter.
( Assuming 6 x 50 @ VoC = 300 + 20% = 360. 360 < 385v, so i'm happy with that margin of safety).

Too many idiot installers don't consider winter, and too many shitty inverters have been blown that way (usually Axperts...)

I haven't considered about shade losses; he hasn't talked about them either.

Shading loss should lower amp output though for the affected string, not voltage.

I think he has the can't fit sufficient panels on the roof issue though, as he mentioned 7 max, now 2 strings of 4...
I'd prefer more panels, so earlier output, later output..
Click to expand...
Right.... there is shading on the tiled roof. They are looking to see if they can simply cut the tree down. Otherwise they will put 8x 550s onto their double-garage roof which has no shading issues.

The IBR roof, however, will not allow a 30 degree panel position. More likely a 15 - 20 degrees.

I will update when I get more info.

Edit: Make that an 8 degree panel position. So not as much as hoped.
 
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itareanlnotani said:
Unless you're getting an amazing deal on R/kw stick with JASolar etc

Also - if you go Canadian Solar - make sure that they're not off the back of a facebook lorry haha.
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I did wonder why price recent drop..... hmmm.

Still.... 'new' the the market doesn't necessarily mean inferior.

It could be a case of he who dares wins.
 
lexity said:
I did wonder why price recent drop..... hmmm.

Still.... 'new' the the market doesn't necessarily mean inferior.

It could be a case of he who dares wins.
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The prices of silicone wafers dropped so there was a price drop on all brands

It does fluctuate from time to time
 
lexity said:
Right.... there is shading on the tiled roof. They are looking to see if they can simply cut the tree down. Otherwise they will put 8x 550s onto their double-garage roof which has no shading issues.

The IBR roof, however, will not allow a 30 degree panel position. More likely a 15 - 20 degrees.

I will update when I get more info.

Edit: Make that an 8 degree panel position. So not as much as hoped.
Click to expand...
The summer output will be better

Though with the longer days not really needed
the extra bonus of perfect alignment tends to be applied to winter by most to lift the dip of winter
 
itareanlnotani said:
View attachment 1586386


Ex vat dealer price at segen so you have a baseline. Pricing under R4/ kw now which is nice.
Click to expand...
So, the cheaper price is the ex vat, but what is the higher price? It looks like more than double in some cases, so that's not VAT ... at least not VAT alone.

For example, I can see :
Cinco 200w:

R1,700 odd

and

R8,000 odd
 
lexity said:
So, the cheaper price is the ex vat, but what is the higher price? It looks like more than double in some cases, so that's not VAT ... at least not VAT alone.

For example, I can see :
Cinco 200w:

R1,700 odd

and

R8,000 odd
Click to expand...
It's the price ex VAT on top. And then that price divided by panel size below.
 
lexity said:
Yes, I see that.

What happens to the flow of current when it hits the busbar?

Does it split up and go into all the connecting wires/cables?
Click to expand...
As long as the battery cables are equal long no problem.
Pylonetch battery cable are equal long, mine runs from battery to main battery fuse. Two sets of batteries.
Don't cut off let it be equal long.

Ease of installation. If you have multiple battery array. (BusBar)
 
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lexity said:
I had a question about the efficiency of the inverter.

It is said to be 85% to 90% efficient. I presume this means when current flows in at 100%, by the time it exits the inverter, it is at 85%.

There was someone describing how to work out what size fuse to insert after the inverter, and he described increasing the rating of the fuse.

Why, given the lower amps i.e. 90%, did he have to increase the rating, and not reduce it?

He said the amp rating would need to go up to 196 from 166 due to the inverter efficiency(which I would have thought is deficiency).

His calculation was 166 amps / 85% = 196 amps (resulting in him going for 200amp fuse).

I was expecting 166 x 85% = 141 (perhaps a 150amp fuse)

p.s. his system was a 12v bat, 2000w inverter, 400w panels system.
Click to expand...
Eff.jpg
If you are not technically inclined. Look at Sunsynk inverter, efficiency.
All electronics will have loses, will never be 100%.
 
lexity said:
I had a question about the efficiency of the inverter.

It is said to be 85% to 90% efficient. I presume this means when current flows in at 100%, by the time it exits the inverter, it is at 85%.

There was someone describing how to work out what size fuse to insert after the inverter, and he described increasing the rating of the fuse.

Why, given the lower amps i.e. 90%, did he have to increase the rating, and not reduce it?

He said the amp rating would need to go up to 196 from 166 due to the inverter efficiency(which I would have thought is deficiency).

His calculation was 166 amps / 85% = 196 amps (resulting in him going for 200amp fuse).

I was expecting 166 x 85% = 141 (perhaps a 150amp fuse)

p.s. his system was a 12v bat, 2000w inverter, 400w panels system.
Click to expand...
The inverter can put out x watts

ie if it says 5000w it will do it

But thanks to losses it will have to pull 5,882 Watts from the battery to supply that 5000 watt at 85 % efficiency

The varied efficiency depends on load ie you may find it is more efficient at higher amps and less so at lower or vice versa
 
leon.davibe said:
The inverter can put out x watts

ie if it says 5000w it will do it

But thanks to losses it will have to pull 5,882 Watts from the battery to supply that 5000 watt at 85 % efficiency

The varied efficiency depends on load ie you may find it is more efficient at higher amps and less so at lower or vice versa
Click to expand...
Thats a pretty shitty inverter if the efficiency is 85%.

Most will sit in the 94-97% efficiency range.


Don't forget about Battery efficiency in/out also. Thats on top of your inverter efficiency.
 
itareanlnotani said:
Thats a pretty shitty inverter if the efficiency is 85%.

Most will sit in the 94-97% efficiency range.


Don't forget about Battery efficiency in/out also. Thats on top of your inverter efficiency.
Click to expand...
yea just used his example
even a cheap axpert gives 93% efficiency

though lifep04 lithium efficiency is pretty good will most likely lose at most 1-2%
yet another reason to go lithium

love it if someone does the silly tests, this channel had to grow on me


 
leon.davibe said:
The inverter can put out x watts

ie if it says 5000w it will do it

But thanks to losses it will have to pull 5,882 Watts from the battery to supply that 5000 watt at 85 % efficiency

The varied efficiency depends on load ie you may find it is more efficient at higher amps and less so at lower or vice versa
Click to expand...
I will give you an example.
Washing machine on
Kettle on
Air Fryer on
Microwave on
More than 5kW usage.

This did not trip the inverter, because Esdom was still available. Esdom did supplement the rest of the power that was over my 5kW inverter.
But if Esdom was not available it would trip the inverter. (5kW inverter)
 
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