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PV Capped / Troubleshooting?


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Hi All,

I'm new here and just had an installation completed and the system seems to be performing very poorly!

2x 5kW Deye Hybrid Inverters (Master/Slave)
28x 420W Mono Panels - 10.15Amp / 41.6V, connected in series
4x 5.1kW Lithium Battery Bank (Connected through CAN communications & Parallel).

* PV Strings are wired with 6mm wiring at max 30 meter distance per string

From the outset things had been very weird, since I had an installer sent out to do the installation and it seemed a little sketchy at first as I could never push my PV beyond 3.5kW when my load was between 5kW and 7kW. I've let the load continue for about an hour on many occasions the past week and a half since installation.

I've raised these concerns with the solar shop, and they sent a second installer through to verify and re-wire where things may have gone wonky. The installer added 4x panels as I originally had 3x strings installed of 8x panels each (according to Deye - which was a 'No-No', as they suggested 7x max per string). They were then changed to 4x strings of 7x panels each - with the slave inverter now running 2x strings and not just 1x.

I've contacted Deye, who performed a full system upgrade relating to getting both inverters updated with the latest Firmware and Software versions (however I can't seem to confirm this as I don't have access to the devices - having requested access twice now), and who verified the remainder of my configuration (need access to confirm).

Now the issue I am stuck with is that no matter what I do I can't seem to push my PV beyond 3.8kW ... originally this used to be 3.5kW before having had the 4x panels added.

My installation is done on a IRB roof facing 5 degrees from North (to East), at a 10 degree angle. I don't have any trees, or obstructions that would interfere with the panels generation capabilities.

Technically, my system should be capable of generating at least 9kW during peak hours of the day (taking into account we are in the winter period and shaving off around 20% of efficiency), but it keeps on "capping" or limiting my input towards 3.8kW and drawing the remaining {X}kW from batteries!

I just cannot get the panels to push beyond 3.8kW and when we test them with the multimeter they produce 294V (exceeding their capacity of 289.4V); however the max amp rating I managed to get is 4 amps during the past week and a half (only 1x cloudy day, but even then it "capped").

I'm therefor puzzled as to why their output in operating conditions perform so poorly?

Any help and/or advice would greatly be appreciated, thanks!

Edited by RabidBunny
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35 minutes ago, RabidBunny said:

Hi All,

I'm new here and just had an installation completed and the system seems to be performing very poorly!

2x 5kW Deye Hybrid Inverters (Master/Slave)
28x 420W Mono Panels - 10.15Amp / 41.6V, connected in series
4x 5.1kW Lithium Battery Bank (Connected through CAN communications & Parallel).

* PV Strings are wired with 6mm wiring at max 30 meter distance per string

From the outset things had been very weird, since I had an installer sent out to do the installation and it seemed a little sketchy at first as I could never push my PV beyond 3.5kW when my load was between 5kW and 7kW. I've let the load continue for about an hour on many occasions the past week and a half since installation.

I've raised these concerns with the solar shop, and they sent a second installer through to verify and re-wire where things may have gone wonky. The installer added 4x panels as I originally had 3x strings installed of 8x panels each (according to Deye - which was a 'No-No', as they suggested 7x max per string). They were then changed to 4x strings of 7x panels each - with the slave inverter now running 2x strings and not just 1x.

I've contacted Deye, who performed a full system upgrade relating to getting both inverters updated with the latest Firmware and Software versions (however I can't seem to confirm this as I don't have access to the devices - having requested access twice now), and who verified the remainder of my configuration (need access to confirm).

Now the issue I am stuck with is that no matter what I do I can't seem to push my PV beyond 3.8kW ... originally this used to be 3.5kW before having had the 4x panels added.

My installation is done on a IRB roof facing 5 degrees from North (to East), at a 10 degree angle. I don't have any trees, or obstructions that would interfere with the panels generation capabilities.

Technically, my system should be capable of generating at least 9kW during peak hours of the day (taking into account we are in the winter period and shaving off around 20% of efficiency), but it keeps on "capping" or limiting my input towards 3.8kW and drawing the remaining {X}kW from batteries!

I just cannot get the panels to push beyond 3.8kW and when we test them with the multimeter they produce 294V (exceeding their capacity of 289.4V); however the max amp rating I managed to get is 4 amps during the past week and a half (only 1x cloudy day, but even then it "capped").

I'm therefor puzzled as to why their output in operating conditions perform so poorly?

Any help and/or advice would greatly be appreciated, thanks!

Hi Rapid. 
 

Please can you post screen shots of all settings on the inverters. 

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8 minutes ago, tetrasection said:

 

60A seems very low, that's only 15A per battery?

I confirmed with Battery manufacturer ...

House wiring is max 63A so I can't push beyond that in any case (for the discharge).

Charging is a little on the low side ... max 70A/80A recommend for 4x batteries in parallel (60A charges all 4 in around 2 hours) - extends battery life ... :)

Edited by RabidBunny
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59 minutes ago, RabidBunny said:

I confirmed with Battery manufacturer ...

House wiring is max 63A so I can't push beyond that in any case (for the discharge).

Your batteries don't feed into your house wire, they feed into your inverter. 60A battery discharge goes together with your battery voltage which is around 50V.

So 60A x 50V is a max discharge of around 3000W. Once that get's converted to 220V the current will be below 14A (3000W / 220V).

63A at 220V would be over 250A battery discharge...

 

59 minutes ago, RabidBunny said:

Charging is a little on the low side ... max 70A/80A recommend for 4x batteries in parallel (60A charges all 4 in around 2 hours) - extends battery life ... :)

60A x 50V = 3kw

3kw x 2 hours = 6kwh

How can you charge a 20kwh battery bank with 6kwh?

 

EDIT: I'm talking only about the battery charge/discharge settings here, not the inverter AC output current setting (which should not go higher than 60A).

Edited by tetrasection
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I have different inverter but I'm in a similar position I think. I have trees all around the house and you can literally see on the inverter when the sun rises above the trees and when it sets behind the trees a whole 4 hours before the actual sunset.

I also started with only 6 panels due to budget constraints then went up to 16(8s2p) I only have 1 mppt. The house is in a gated suburb so wife made it clear we are not moving nor can we cut the forest around us.

An inverter with 2 separate mppt's might help but it's not cost effective to get rid of a perfectly good inverter.

Here are screen shots of pv production with 6 panels and with 16 panels.

Screenshot_20210622-040730_ShinePhone.jpg

Screenshot_20210622-040847_ShinePhone.jpg

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4 hours ago, RabidBunny said:

I confirmed with Battery manufacturer ...

House wiring is max 63A so I can't push beyond that in any case (for the discharge).

Charging is a little on the low side ... max 70A/80A recommend for 4x batteries in parallel (60A charges all 4 in around 2 hours) - extends battery life ... :)

Hi Rapid 

Thanks for the pics. Please @Achmat will you have a look at his settings and confirm if all is ok. Is it possible that it’s the 10 degree tilt and being winter that his panels aren’t producing. 
 

Regarding the charging current, I hope your installer didn’t advise you about the 63A breaker therefore setting your charge and discharge current to 60A. The breaker is rated at 63A at 230V which is around 14000w. The charge current is 60A at 50V which is only 3000w. 
 

You can comfortably set the charge and discharge to 100A each. In that way you will only charge and discharge the battery at 0.5C. 

Edited by Leshen
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1 hour ago, Leshen said:

Hi Rapid 

Thanks for the pics. Please @Achmat will you have a look at his settings and confirm if all is ok. Is it possible that it’s the 10 degree tilt and being winter that his panels aren’t producing. 
 

Regarding the charging current, I hope your installer didn’t advise you about the 63A breaker therefore setting your charge and discharge current to 60A. The breaker is rated at 63A at 230V which is around 14000w. The charge current is 60A at 50V which is only 3000w. 
 

You can comfortably set the charge and discharge to 100A each. In that way you will only charge and discharge the battery at 0.5C. 

Pv generation in winter suffers a lot from low angled panels and I don't think the impact is explained enough. I knew beforehand going into my setup. 

On my setup I have 22 panels on MPPT 2 and 12 panels on MPPT 1.

MPPT 2 installed capacity = 6 710w. Peak winter pv output = 2 670w. That's 60% loss in installed capacity. 

MPPT 1 installed capacity = 3 660w. Peak winter pv output = 1 470w. Also 60% loss. 

My panels are installed almost exactly the same on an IBR carport so expecting a 60% to 65% loss in pv production in winter is normal .

Looking at some of the graphs it does not appear to be capping as it would have a flat top on the curves but they seem to be perfect bell curves similar to mine. 

Two pics. First one from a few days ago and second one from summer. My panels were less in summer but you can still see the difference between winter and summer. 

Screenshot_20210622-064158_SOLARMAN Smart.jpg

Screenshot_20210622-070039_SOLARMAN Smart.jpg

Edited by Achmat
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6 hours ago, RabidBunny said:

 

20210622_001438.jpg

20210622_001430.jpg

20210622_001425.jpg

20210622_001419.jpg

As mentioned. Your battery charge and discharge rates seem low. You need to configure this at the battery voltage of 48v and not the house voltage of 220v. 

Not sure if the BMS is communicating correctly with the inverter but if it is then these settings do not matter as the BMS will dictate the charge and discharge rates. At least that's what is happening with the pylontech and sunsynk combo. 

 

Edited by Achmat
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28 minutes ago, Achmat said:

As mentioned. Your battery charge and discharge rates seem low. You need to configure this at the battery voltage of 48v and not the house voltage of 220v. 

Not sure if the BMS is communicating correctly with the inverter but if it is then these settings do not matter as the BMS will dictate the charge and discharge rates. At least that's what is happening with the pylontech and sunsynk combo. 

 

BMS is communicating via CAN, batteries are communicating via parallel (their own internal protocol). My understanding is that the master battery (as per PIN configuration dictates where the charge is flowing).

I have confirmed with battery manufacturer that 4x batteries in parallel should be set to 70A/80A (manual say BAH/*units in parallel* ~ inverters are capped at 115AH), master/slave, both connected to banks to share loads, i.e. Battery 1 = master, slave 1 ... slave 3 (master battery connected to master inverter, slave 3 battery connected to slave inverter) - therefor my understanding of 60A × 2 both inverters charging at the same time should produce 120A charge / discharge - (correct me of I am wrong)?

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10 minutes ago, RabidBunny said:

BMS is communicating via CAN, batteries are communicating via parallel (their own internal protocol). My understanding is that the master battery (as per PIN configuration dictates where the charge is flowing).

I have confirmed with battery manufacturer that 4x batteries in parallel should be set to 70A/80A (manual say BAH/*units in parallel* ~ inverters are capped at 115AH), master/slave, both connected to banks to share loads, i.e. Battery 1 = master, slave 1 ... slave 3 (master battery connected to master inverter, slave 3 battery connected to slave inverter) - therefor my understanding of 60A × 2 both inverters charging at the same time should produce 120A charge / discharge - (correct me of I am wrong)?

What are the specs of your batteries 

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2 hours ago, Leshen said:

Hi Rapid 

Thanks for the pics. Please @Achmat will you have a look at his settings and confirm if all is ok. Is it possible that it’s the 10 degree tilt and being winter that his panels aren’t producing. 
 

Regarding the charging current, I hope your installer didn’t advise you about the 63A breaker therefore setting your charge and discharge current to 60A. The breaker is rated at 63A at 230V which is around 14000w. The charge current is 60A at 50V which is only 3000w. 
 

You can comfortably set the charge and discharge to 100A each. In that way you will only charge and discharge the battery at 0.5C. 

That makes sense in terms of amps vs 48V system (to calculate the kW), however 60 amps is 60 amps (regardless of voltage) - again correct me if I'm wrong?

The 10 degree tilt (not that far off from many other installations) is the roof itself running at this angle and I think may potentially affect the efficiency, but surely not as much as 60% ... that seems to be quite a lot?

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1 minute ago, RabidBunny said:

That makes sense in terms of amps vs 48V system (to calculate the kW), however 60 amps is 60 amps (regardless of voltage) - again correct me if I'm wrong?

The 10 degree tilt (not that far off from many other installations) is the roof itself running at this angle and I think may potentially affect the efficiency, but surely not as much as 60% ... that seems to be quite a lot?

60A at 48v is different to 60A at 220v.

Battery charge and discharge amps are at 48v.

60% reduction in pv output is normal. There are a number of website that you can use to determine the pv output based on your location, array size, orientation and angle. 

You can use this app https://play.google.com/store/apps/details?id=com.exigo.solcaster

Just enter your setup and it should give what the expected pv output is for the next few days. 

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3 minutes ago, RabidBunny said:

That makes sense in terms of amps vs 48V system (to calculate the kW), however 60 amps is 60 amps (regardless of voltage) - again correct me if I'm wrong?

The 10 degree tilt (not that far off from many other installations) is the roof itself running at this angle and I think may potentially affect the efficiency, but surely not as much as 60% ... that seems to be quite a lot?

What you misunderstand is that current (A) doesn’t flow without voltage (V). If 60A was just 60A then a 12V 60AH battery is the same according to you as a 48V 60AH and it’s completely different. 

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