@P1000 20A x 450V = 9000W so that sounds about right 

7 hours ago, Sc00bs said:

So, I learnt something new today about my inverter  

Sunsynk 8kw specs say 10400W Max solar power. 

I learnt that the 10.4kw limit is actually split between the MPPT's @ 5200Watts per MPPT

Saying this however, the max amount of power I have produced on one MPPT is 5400watts, perhaps since the firmware update, there does however seem to be a cap per mppt as mine pull back on the power at 5.4kw.

Not sure what the DEYE specs say but assume that there are similar limits to the amount of power you can put through each MPPT

 

Apparently you can't believe everything you read on Facebook, lol 

 

5 hours ago, Sc00bs said:

Ok, looks like the info I was given is actually incorrect

Here I am generating the maximum solar energy of 10.4kw

 

4.2kw from the East Panels and 8.18kw from the West Panes. 

 

So not sure what the actual power limit is on the MPPT controllers. 

 

 

Graphic shows 6.18kW from West but text is 8.18kW.

1 hour ago, Scorp007 said:

Graphic shows 6.18kW from West but text is 8.18kW.

yes, my mistake, sry, is 6.18kw

 

11 hours ago, Sc00bs said:

@P1000 20A x 450V = 9000W so that sounds about right 

I calculated (80% of 500)x22A = 8800W. Your Vmp of your panel is about 83% of Voc. So I just took 80% to give it some more margin. Is the current limit of the Deye 20A or also 22A like the Sunsynk?

35 minutes ago, P1000 said:

I calculated (80% of 500)x22A = 8800W. Your Vmp of your panel is about 83% of Voc. So I just took 80% to give it some more margin. Is the current limit of the Deye 20A or also 22A like the Sunsynk?

According to the Deye datasheet and label on the inverter, the max PV input current is 22A per MPPT but as per my original post, it seems as if my inverter is clipping at 20A. I'm not sure if anybody else with a 8kW Deye has seen currents higher than this??

On 2022/01/20 at 7:46 AM, Freakazoid said:

According to the Deye datasheet and label on the inverter, the max PV input current is 22A per MPPT but as per my original post, it seems as if my inverter is clipping at 20A. I'm not sure if anybody else with a 8kW Deye has seen currents higher than this??

FYI - my Sunsynk clips at 20A, not 22A  

Spec says 18A but since the firmware update is up to 20A.

Hi All

I sent Deye Technical support an email last week asking why the inverter is clipping the current at 20A and not the stated 22A as indicated on the technical datasheet. They came back to me stating that the inverter clips the current at 20A as a safety feature as too much current is not good... (as shown below) 

Not a very technical answer and it also doesn't answer my question as to why the clipping happens at 20A and not the stated 22A... But it confirms that it is current clipping that I am seeing in my PV data. 

Anyway, guess I'll just have to live with it... 

 

On 2022/01/11 at 7:31 PM, Freakazoid said:

I have two strings of 5 panels each (East and North facing respectively).

Hi @Freakazoid,
We recently installed the 8kw Deye also in PTA. My understanding is that the Parallel strings you connect onto a single Mppt still needs to be identical. i.t.o. size, specs, orientation even. Because the max Power point control applies to 1 string's best case curve, and cant cater the same setting for different facing strings to charge optimally.

So to compare, with your 8,75kw worth of panels, what is your winter (clear weather) daily KWH production?

(We have 8,5kw worth of panels all facing NNE, with a winter daily production of around 45KWh at the moment)

Kind regards,

Clinton

2 hours ago, C solar said:

Hi @Freakazoid,
We recently installed the 8kw Deye also in PTA. My understanding is that the Parallel strings you connect onto a single Mppt still needs to be identical. i.t.o. size, specs, orientation even. Because the max Power point control applies to 1 string's best case curve, and cant cater the same setting for different facing strings to charge optimally.

So to compare, with your 8,75kw worth of panels, what is your winter (clear weather) daily KWH production?

(We have 8,5kw worth of panels all facing NNE, with a winter daily production of around 45KWh at the moment)

Kind regards,

Clinton

Hi @C solar

Thanks for your feedback regarding how the parallel strings on an MPPT should be equivalent.  My panels are all the same and the two strings paralleled on MPPT1 both consist of 5 panels each. My paralleled strings are however facing different directions (N & E) but as far as I can tell this doesn't seem to be holding me back.

I am struggling a bit with production in winter as 2 of my west facing panels (part of the 6 panel string connected to MPPT2) see shadow until around 12:30. There is unfortunately nothing I can do about this, I have a trickey roof. This means that during a "perfect" production day the 2 x 5 panels on MPPT 1 produce approximately 75% of my daily production. My worst production period was early June where I am only able to produce around 26kWh per day even on clear days with my system running as best it can. Current production is a bit better and if my system were to run at full capacity (my usual daily consumption is only around 28kWh) I would probably get around 32kWh per day (my 2 problem panels are seeing sun sooner in the day than what they were 6 weeks ago).

That's an impressive system that you've got, shows you what a difference well orientated panels make! If your load (batteries, home consumption) has sufficient need to pull maximum production capacity from your panels you'll probably be able to produce around 55 kWh with your system on a clear summer day!

Regards,

Rudolph

Hi  @Freakazoid

Thanks for your detailed response.

No doubt your west facing panels is where your greatest potential is for improvement. Shadows is your enemy with solar no doubt.
However also if you could re-align your north, and east panels to face a similar direction, you would see a good improvement there also I think, simply because the Mppt would start working with greater optimization.

I do have an important question regarding your production curve for your PV1 Mppt (N & E), considering this Mppt is rated for 4000w (5200w max), what is your daily production for just this half, and how long does your production curve peak for during a typical day? ...I'm trying to assess whether there might actually be an advantage to combine the two parallel string (on a single) Mppt the way you did it. ... I.o.w. if both your mppts produced the same as your Mppt 1, would the Kwh daily production look good, great, or just okay? Especially if you 'mirrored' this 2 parallel string in a North and west format on your PV2...?

 

 

22 minutes ago, C solar said:

Hi  @Freakazoid

Thanks for your detailed response.

No doubt your west facing panels is where your greatest potential is for improvement. Shadows is your enemy with solar no doubt.
However also if you could re-align your north, and east panels to face a similar direction, you would see a good improvement there also I think, simply because the Mppt would start working with greater optimization.

I do have an important question regarding your production curve for your PV1 Mppt (N & E), considering this Mppt is rated for 4000w (5200w max), what is your daily production for just this half, and how long does your production curve peak for during a typical day? ...I'm trying to assess whether there might actually be an advantage to combine the two parallel string (on a single) Mppt the way you did it. ... I.o.w. if both your mppts produced the same as your Mppt 1, would the Kwh daily production look good, great, or just okay? Especially if you 'mirrored' this 2 parallel string in a North and west format on your PV2...?

 

 

Hi @C solar

Please have a look at the two attached graphs of my PV1 and PV2 production. You will see the first graph was from 2022-04-05, even though the production curve is jagged, you can clearly see the general trend for the max possible production. The blue curve is for my N & E string and red is for the W string (which sees shadow until around 11:00)

The second graph is from yesterday (2022-07-26). You can clearly see that it was a cloudless day, PV2 was also performing relatively well but only performing well from around 12:00.

On 2022-04-05 PV1 produced a total of 22.66 kWh but was only performing at around 70% of it's total capacity (estimated). On the same day PV2 produced 9.94 kWh

On 2022-07-26, PV1 produced a total of 20.54 kWh (estimated at 95% of maximum capacity) while PV 2 produced 7.91 kWh (estimated 70% of maximum capacity)

Regarding your question on whether it would make sense to parallel two strings. I think it definitely does make sense, especially if you have shadows on one of your strings at any stage during the day. I don't think I would get nearly the same daily production if I opted to put a 1 x 8 panel string on each MPPT vs 2 x 5 panels on MMT1 and 1 x 6 panels on MPPT 2.

 

Let me know what you think

 

Regards,

 

1 hour ago, C solar said:

considering this Mppt is rated for 4000w (5200w max)

There is no such limit.

On 2022/01/20 at 7:07 AM, P1000 said:

I calculated (80% of 500)x22A = 8800W. Your Vmp of your panel is about 83% of Voc. So I just took 80% to give it some more margin. Is the current limit of the Deye 20A or also 22A like the Sunsynk?

 

Hi Rudolph @Freakazoid,
If this blue curve is typical for a sunny day on your Mppt 1, then I'm surprised and impressed.
      1) Its a wiiide steady curve with strong production early in the morning already.
      2) In April you are getting very close to the 4kW (+-) upper limit of your Mppt for a good wide chunk of the day.
      3) It appears as though the two string directions is actually not affecting your Mppt's production bad at all. It actually looks benificial...

Would love to see a December curve on this blue Mppt. Guessing you are producing close to 30kWh/day on a sunny December day?

Fascinating!

Compare your april curve above width mine below from a few days ago.:

Edited July 27, 20223 yr by C solar

4 hours ago, Freakazoid said:

Hi @C solar

Please have a look at the two attached graphs of my PV1 and PV2 production. You will see the first graph was from 2022-04-05, even though the production curve is jagged, you can clearly see the general trend for the max possible production. The blue curve is for my N & E string and red is for the W string (which sees shadow until around 11:00)

The second graph is from yesterday (2022-07-26). You can clearly see that it was a cloudless day, PV2 was also performing relatively well but only performing well from around 12:00.

On 2022-04-05 PV1 produced a total of 22.66 kWh but was only performing at around 70% of it's total capacity (estimated). On the same day PV2 produced 9.94 kWh

On 2022-07-26, PV1 produced a total of 20.54 kWh (estimated at 95% of maximum capacity) while PV 2 produced 7.91 kWh (estimated 70% of maximum capacity)

Regarding your question on whether it would make sense to parallel two strings. I think it definitely does make sense, especially if you have shadows on one of your strings at any stage during the day. I don't think I would get nearly the same daily production if I opted to put a 1 x 8 panel string on each MPPT vs 2 x 5 panels on MMT1 and 1 x 6 panels on MPPT 2.

 

Let me know what you think

 

Regards,

 

You are spot on that the current 2 strings in parallel can never match what you get if the E and N would be put in series. In the morning the N panels would throttle the good output of the E string. In the midday the E would be blocking the good output from the N string.

A number of wrong inputs in some of the replies. Different directions and angles are not ideal but it is not true that you should never do it. One can just position it in the best way based on the space and different roof portions.

The MPPT will still get the maximum the combined strings can provide. The stronger one will provide most current and weaker one less. This will alternate during the course of the day.

5 hours ago, Freakazoid said:

Hi @C solar

Please have a look at the two attached graphs of my PV1 and PV2 production. You will see the first graph was from 2022-04-05, even though the production curve is jagged, you can clearly see the general trend for the max possible production. The blue curve is for my N & E string and red is for the W string (which sees shadow until around 11:00)

The second graph is from yesterday (2022-07-26). You can clearly see that it was a cloudless day, PV2 was also performing relatively well but only performing well from around 12:00.

On 2022-04-05 PV1 produced a total of 22.66 kWh but was only performing at around 70% of it's total capacity (estimated). On the same day PV2 produced 9.94 kWh

On 2022-07-26, PV1 produced a total of 20.54 kWh (estimated at 95% of maximum capacity) while PV 2 produced 7.91 kWh (estimated 70% of maximum capacity)

Regarding your question on whether it would make sense to parallel two strings. I think it definitely does make sense, especially if you have shadows on one of your strings at any stage during the day. I don't think I would get nearly the same daily production if I opted to put a 1 x 8 panel string on each MPPT vs 2 x 5 panels on MMT1 and 1 x 6 panels on MPPT 2.

 

Let me know what you think

 

Regards,

 

Hi Rudolph @Freakazoid,
I couldn't resist. Here I took your december MPPT 1 curve , and mirrored it as a theoretical MPPT2 facing West & North (mirroring your current eastern panel setup) and overlaid the two of them .The white (and black lines) shows the combination production curve. 

I reckon this April setup might deliver about 64kWh for the day.
This setup looks optimal for long productive sun hours.
What do think?

C

Edited July 27, 20223 yr by C solar

4 minutes ago, C solar said:

Hi Rudolph @Freakazoid,
I couldn't resist. Here I took your december MPPT 1 curve , and mirrored it as a theoretical MPPT2 facing West & North (mirroring your current eastern panel setup) and overlaid the two of them .The white (and black lines) shows the combination production curve. 

This setup looks optimal for long productive sun hours.
What do think?

C

Hi Clinton @C solar

I like what you've done with your maximum theoretical production curve. What's the total area under the "combined production" curve (total theoretical daily production) for such a system?

I think the ideal setup (with 16 panels) would be an East string (5 panels), a North string (6 panels) and a West string (5 panels) with the East & West panels paralleled on the one MPPT and the North string on the other MPPT (basically what you proposed in your theoretical calc). I actually think that this setup would produce a greater daily yield (in a typical home) than a system with all panels facing North. An East, North & West string split will tend to "flatten" but "widen" your daily production curve as you start producing earlier in the morning (East string) and produce until later in the afternoon (West string). The peak production around midday (predominantly North string) would be compromised but in my experience, we won't use the full production capacity during midday of an all north facing setup. Typically, our house would only use a maximum of around 6kW at any moment so a system that can deliver 8kW would be wasted capacity. I would rather have a system with a maximum production capacity of 6kW but with the "extra" 2kW capacity available for use in the late afternoon (when we are cooking or bathing the kids). This means we start drawing power off our batteries later in the afternoon.

On my system, during the summer months, my maximum daily consumption is much less than in winter which means that I probably only use between 40% and 50% (estimate) of my system's full installed production capacity. On most summer days, my geyser is warm and my batteries (15kWh) are full at around 10:00!! The benefit of being "overspec'd" on production capacity during summer is that we tend to have many cloudy or rainy days so with the extra capacity we always manage to fill up the batteries and warm up the geyser. You might only have 3 or 4 hours of sunshine on some days but with your production capacity spread over 3 directions it doesn't matter when you get some sunshine.

This has become a really interesting discussion!

Regards,

Rudolph

 

 

45 minutes ago, Freakazoid said:

Hi Clinton @C solar

I like what you've done with your maximum theoretical production curve. What's the total area under the "combined production" curve (total theoretical daily production) for such a system?

I think the ideal setup (with 16 panels) would be an East string (5 panels), a North string (6 panels) and a West string (5 panels) with the East & West panels paralleled on the one MPPT and the North string on the other MPPT (basically what you proposed in your theoretical calc). I actually think that this setup would produce a greater daily yield (in a typical home) than a system with all panels facing North. An East, North & West string split will tend to "flatten" but "widen" your daily production curve as you start producing earlier in the morning (East string) and produce until later in the afternoon (West string). The peak production around midday (predominantly North string) would be compromised but in my experience, we won't use the full production capacity during midday of an all north facing setup. Typically, our house would only use a maximum of around 6kW at any moment so a system that can deliver 8kW would be wasted capacity. I would rather have a system with a maximum production capacity of 6kW but with the "extra" 2kW capacity available for use in the late afternoon (when we are cooking or bathing the kids). This means we start drawing power off our batteries later in the afternoon.

On my system, during the summer months, my maximum daily consumption is much less than in winter which means that I probably only use between 40% and 50% (estimate) of my system's full installed production capacity. On most summer days, my geyser is warm and my batteries (15kWh) are full at around 10:00!! The benefit of being "overspec'd" on production capacity during summer is that we tend to have many cloudy or rainy days so with the extra capacity we always manage to fill up the batteries and warm up the geyser. You might only have 3 or 4 hours of sunshine on some days but with your production capacity spread over 3 directions it doesn't matter when you get some sunshine.

This has become a really interesting discussion!

Regards,

Rudolph

 

 

Rudolph a North only system does indeed deliver quite a bit more yield than E, W and N. You have the benefit of a good spread over the whole day. If you mention that having more PV during midday and wasted you are already wasting a lot by having a 15kwh bank fully charged by 10h. You might think of using a deeper discharge during the evening. It sounds as if you don't really need the boost from the W side just prior to sunset if batteries remain fully charged from after 10h each day.

Obvious I don't know what your profile is it is based on what I figure out based on details provided.

Edited July 27, 20223 yr by Scorp007

1 hour ago, Freakazoid said:

I think the ideal setup (with 16 panels) would be an East string (5 panels), a North string (6 panels) and a West string (5 panels) with the East & West panels paralleled on the one MPPT and the North string on the other MPPT (basically what you proposed in your theoretical calc). I actually think that this setup would produce a greater daily yield (in a typical home) than a system with all panels facing North.

@Freakazoid Rudolph, perhaps all theory, but if you could produce about 31kW on your Mppt 1 in April, the mirrored and combined curve for both Mppts together may deliver 63kW I suspect.

I actually don't agree with your assessment to keep North facing panels on a separate Mppt. The partial light (at minimum) that falls on both your  strings help the multiplication math in terms of watts and amps. My understanding is with parallel strings, You need some light on your one shaded string whilst the other is producing good watts so the "zero production" of one string don't compromise the other too much. You need "some" amps on your shaded string so the volts don't drop to zero. So East and west on one mppt wont work well at all I think.  The two strings on one Mppt does affect each other some.

Perhaps this 'math' may help us think about it. 
10(sunny string) x 2(somewhat shaded string) = 20(production), 

however 10(sunny string) x 0(very poor exposed string with no volts) = 0 (zero production). The difference between 2 and 0 is infinite.

again: 10 x2 = 20, but 10x0=0

I know in reality your sunny string would still produce somewhat, but this thought experiment shows that the setup might not be ideal facing two strings on the same MPPT in complete opposite directions.

Still curious about your December KWh/day production on Mppt 1?

Edited July 27, 20223 yr by C solar

I think I saw in one of Kieth's videos or read somewhere, that the "older" SunSynk" 8.8 kW machines were update to 22A via firmware, but proved to unstable, so were brought back down to 20A. This could be the same for Deye machines. The new machines released now, I don't know, maybe someone with a new machine can check and let us know.

I think we are dealing with the mis conception that extra "light" produces volts which will produce amps. Even at low light the volts are present but the panel cannot produce amps which gives the W=V*A. Just look at the volts early morning.

https://www.solarquotes.com.au/panels/direction/

4 strings on 8k dual mppt inverter.
See Solar Advice - How to Size An Array - Case Study 3
https://solaradvice.co.za/how-to-size-a-pv-array

28 minutes ago, system32 said:

4 strings on 8k dual mppt inverter.
See Solar Advice - How to Size An Array - Case Study 3
https://solaradvice.co.za/how-to-size-a-pv-array

A great resource to explain how to connect panels with clear calculations and pictures. 👌👌👌👌

Only lacking in the maximum current to MPPT if 2 parallel strings do exceed the maximum current of the MPPT.

Edited July 29, 20223 yr by Scorp007

On 2022/07/27 at 9:41 PM, C solar said:

@Freakazoid Rudolph, perhaps all theory, but if you could produce about 31kW on your Mppt 1 in April, the mirrored and combined curve for both Mppts together may deliver 63kW I suspect.

however 10(sunny string) x 0(very poor exposed string with no volts) = 0 (zero production). The difference between 2 and 0 is infinite.

again: 10 x2 = 20, but 10x0=0

 

This is a good example that you will never get ZERO volts during day time. Even during the night @Wannebe got a voltage of up to 80V. There will just be no current to flow as any current at night time will cause the voltage to drop big time. So the calculation cannot use a value times zero=0.

 

Edited July 30, 20223 yr by Scorp007

On 2022/01/11 at 9:37 AM, Freakazoid said:

that the current is being clipped at 20 Amps.

Hi @Freakazoid
I noticed now the same 20A limitation on my system. Also using 2x strings of the JA 540W panels, supposed to be providing 12,9 + 12,9 = 25,8 Amps.

My 16Amp DC fuse in the combiner box recently popped, and we since replaced it with a 20Amp fuse. However these graphs were always, and are still showing a Max of 20.1Amp on the MPPT, irrespective whether the 16 or 20Amp Fuses was installed.
Do you have the correct fuse rating in your combiner box?
25A I think is the correct rating actually.
Regards, C

 

Edited August 16, 20223 yr by C solar