Issue with Growatt SPF 5000 ES

fopoku2k2

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I have been using the Growatt SPF 5000 ES since September of this month. I recently noticed that solar generation goes off for an hr to 3 hrs each day. When this happens the inverter is able to read voltage from the panels but no current. I have 12 panels connected to the inverter in 3 strings of 4 panels each.

Total voltage of my PV setup ranges from 120vDC to 150vDC. Total current also ranges from 10amps - 35amps. I just went over the manual again and noticed that it is written on page 39 that the Max. PV input current is 18amps. Am I over heating the inverter with my 35amp panel configuration?

Thanks for reading and your contribution
 

FilterGuy

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I recently noticed that solar generation goes off for an hr to 3 hrs each day. When this happens the inverter is able to read voltage from the panels but no current. I have 12 panels connected to the inverter in 3 strings of 4 panels each.
Could it be that the voltage is dropping too low?

1637184926013.png
I have been using the Growatt SPF 5000 ES since September of this month.
Hmmmm, When is September of this month? :ROFLMAO: (Sorry, I could not resist...)
 

Struc

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Start up voltage is 150vdc. Why are you paralleling panel strings when you can put them all in series?

The working voltage of the Growatt is 120vdc - 450vdc. I would guess that your voltage is dropping too low.

And yes, you are sending too many amps to it.
 

FilterGuy

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I just went over the manual again and noticed that it is written on page 39 that the Max. PV input current is 18amps. Am I over heating the inverter with my 35amp panel configuration?
When I contacted Growatt about this they insisted the 18A as measured by array Isc is a hard limit. However a lot of people have reported that the growatt distributors are all saying that overpanneling like you are doing is fine.
 

FilterGuy

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Why are you paralleling panel strings when you can put them all in series?
We don't have the panel specs, but if he is getting 120-150V with 4 in series, all 12 in series is probably too much, particularly once you calculate for lower temperatures. However, 2 strings of 6 panels should work fine.
 

sunshine_eggo

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At a minimum, you're losing out on nearly 50% of your array.

Running at the absolute max current for extended periods might cause a temperature issue to cut charging.

Why not re-string from 4S3P to XS to raise the voltage and lower the current?
 

Struc

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We don't have the panel specs, but if he is getting 120-150V with 4 in series, all 12 in series is probably too much, particularly once you calculate for lower temperatures. However, 2 strings of 6 panels should work fine.
Don't disagree, but if he's pushing 35a on 3 strings, then each string is putting out about 11.5A, and a 6s2p configuration will be too high on the amperage side too. The specs are going to be closer in 12s config (or he needs to remove a panel or two).

fopoku2k2, need to see your panel specs to make a true recommendation.
 

FilterGuy

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Don't disagree, but if he's pushing 35a on 3 strings, then each string is putting out about 11.5A, and a 6s2p configuration will be too high on the amperage side too. The specs are going to be closer in 12s config (or he needs to remove a panel or two).

fopoku2k2, need to see your panel specs to make a true recommendation.
Good point about the current. I was only looking at voltage.

It is disappointing that grow-watt is so restrictive on over paneling. I have noticed that the stand-alone MPPT controllers seem to be a lot less restrictive on over-panneling than the All-in-one units are.
 

Struc

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Good point about the current. I was only looking at voltage.

It is disappointing that grow-watt is so restrictive on over paneling. I have noticed that the stand-alone MPPT controllers seem to be a lot less restrictive on over-panneling than the All-in-one units are.

I dunno.... They say you can put 6000w of PV into it, but also say 450v max and 18a max, which is 8100w, so it seems there is some ability to overpanel a bit if you can work out the panels to hit close to those max values.

In this case, a 12S config should be around 450v, 11.5A based on what we know. I'm sure the open circuit voltage is going to be way too high once we see the actual panel specs.
 

sunshine_eggo

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I dunno.... They say you can put 6000w of PV into it, but also say 450v max and 18a max, which is 8100w, so it seems there is some ability to overpanel a bit if you can work out the panels to hit close to those max values.

In this case, a 12S config should be around 450v, 11.5A based on what we know. I'm sure the open circuit voltage is going to be way too high once we see the actual panel specs.

I'm thinking 11S, and he'll actually get notably more than with 4S3P.
 

fopoku2k2

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At a minimum, you're losing out on nearly 50% of your array.

Running at the absolute max current for extended periods might cause a temperature issue to cut charging.

Why not re-string from 4S3P to XS to raise the voltage and lower the current?
I can not connect all 12 panels in parallels. If I do so I would go over the voltage limit. Find below the spec sheet for the panel. It is a 375w panel. I think I can only connect 10 of the panels in parallel.
1637240246408.png
 

fopoku2k2

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Don't disagree, but if he's pushing 35a on 3 strings, then each string is putting out about 11.5A, and a 6s2p configuration will be too high on the amperage side too. The specs are going to be closer in 12s config (or he needs to remove a panel or two).

fopoku2k2, need to see your panel specs to make a true recommendation.
375w panel spec attached above
 

sunshine_eggo

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I can not connect all 12 panels in parallels. If I do so I would go over the voltage limit. Find below the spec sheet for the panel. It is a 375w panel. I think I can only connect 10 of the panels in parallel.
View attachment 72681

No one has mentioned 12 in parallel. That would only be 41V and 132A.

10 panels in SERIES will produce more than your 4S3P array by about 80%.

As it stands, you're completely wasting almost half of your array. You will never get any power out of over 1/3 of it due to the 18A current limit, i.e., your 4S3P array can only produce, 4 * 34.41V * 18A = 2478W

To be explicit your 4S3P 4,500W array will NEVER produce more than 2478W. Period.

A 10S array will produce 10 * 375W = 3750W of power and be at 10 * 34.41V = 344.1V @ 10.90A. 10S Voc AND cold weather might put you over the 450V limit.

Your panels are not a good match for this inverter due to their higher current. ~350W 72 cell panels in a 8S2P configuration would meet both the voltage and current limits.

You're essentially limited to:
9S if cold weather is a concern
10S if it's never below freezing.
6S2P, but you're 2A over the current limit, and you might have the same problem.

You don't have any other options with those panels and that MPPT.
 

fopoku2k2

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No one has mentioned 12 in parallel. That would only be 41V and 132A.

10 panels in SERIES will produce more than your 4S3P array by about 80%.

As it stands, you're completely wasting almost half of your array. You will never get any power out of over 1/3 of it due to the 18A current limit, i.e., your 4S3P array can only produce, 4 * 34.41V * 18A = 2478W

To be explicit your 4S3P 4,500W array will NEVER produce more than 2478W. Period.

A 10S array will produce 10 * 375W = 3750W of power and be at 10 * 34.41V = 344.1V @ 10.90A. 10S Voc AND cold weather might put you over the 450V limit.

Your panels are not a good match for this inverter due to their higher current. ~350W 72 cell panels in a 8S2P configuration would meet both the voltage and current limits.

You're essentially limited to:
9S if cold weather is a concern
10S if it's never below freezing.
6S2P, but you're 2A over the current limit, and you might have the same problem.

You don't have any other options with those panels and that MPPT.
Sorry, i meant to type series and not parallel.
I am in West Africa, very tropical climate so no freezing here YET!!
You are right. The most I have generated is 2237W
I'll reconnect the 10 panels in series later today and report back

I realized you used 34.41V Vmp for your calculations, shouldn't you use 42.15Voc instead?
 

sunshine_eggo

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Sorry, i meant to type series and not parallel.
I am in West Africa, very tropical climate so no freezing here YET!!
You are right. The most I have generated is 2237W
I'll reconnect the 10 panels in series later today and report back

I realized you used 34.41V Vmp for your calculations, shouldn't you use 42.15Voc instead?

I used 34.41V for power calculations. 42.15Voc is only used to determine if you're under the 450V limit OR if you meet the 150V minimum start voltage.

10S should be fine.
 

sunshine_eggo

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At 4S (42Voc) in a tropical climate, he's definitely going to be >150V if there's any juice to be had.
 

fopoku2k2

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The spec says the start voltage is 150V. If it only gets to 148 it won't start.
WOW!! that's crazy since mine starts generating way lower than 150v. see below.

With my 4S3P i hardly hit 150v. Maybe its because the 3rd string is of a mismatch panel. So I had 2 strings with 42.15Voc and the last string with 38.86Voc.

I think the reason why I did the 4S3S was because I read that connecting mismatched panels in series would not work. So I connected the mismatched cells in parallel as the last/3rd string with a combiner box

1637261416889.png
 
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sunshine_eggo

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WOW!! thats crazy since mine starts generating way lower than 150v. see below.

with my 4S3P i hardly hit 150v
View attachment 72706

The MPPT needs to SEE a voltage of 140-160V before it will start charging per the spec. Your 4S panel's allow >160V, so that's covered. It does NOT need to operate above 150V.

Once the MPPT starts operating, current flows and voltage drops closer to Vmp. Per the spec, it's MPPT range is 120-450V. Even below 120V, you'll still get charging, but it will probably be much less productive.
 
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