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Deye/Sunsynk 5kW MPPT Limited to 9.9A?


recre8

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Hi Guys

I'm struggling with an issue with my Deye-branded 5kW inverter that seems to limit the PV current to exactly 9.9A, which severely degrades the maximum power I can get from my PV string. I live in a small townhouse on a very narrow (8 meters) plot so I opted for the most powerful PV panels that still operate within the 11A MPPT limit most inverters have (datasheet attached). 

My setup: I installed my 6x 450W JA Solar panels (within 5 degrees of north at 14 degrees tilt) and 2.5kW Solis grid-tie inverter for a hybrid inverter with battery setup over November 2020 and easily drew the maximum 2700W from the panels, sometimes even exceeding it. The Solis started giving DC Injection alarms and was returned under warranty and replaced with a 5kW Deye with a battery system. Only one MPPT is in use currently and I'm planning on adding another 6x 450W panels in the near future. But unfortunately, I noticed that my maximum power from the string only ever reaches around 2.42kW instead of the rated 2.7kW. Upon closer investigation I noticed that the PV power seems to plateau around midday. I then noticed that the Deye oddly seems to artificially limit the  PV current to 9.9A despite the datasheet and manual clearly stating 2x 11A MPPTs. I'm losing more than 10% of my power due to this limit.

My question is, is this a firmware issue or should the inverter be returned since it isn't performing according to the datasheet?

Can I ask you guys with Deye or Synsynk 5kW (not 8kW - the 8kW has a higher rated MPTT) to confirm whether your inverter PV current ever exceeds 9.9A and also which version of firmware you are running.  

Mine:
Control software: V2.1.3.8  CPU Software: VC.3.3.9

image.thumb.png.17ce404c6798673e7a77f63e9cf16e32.png

166 JAM72S20 440-465 MR Global_EN_20200706A (1).pdf

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Ok, specs for panels says short circuit current is 11A and not max power current.

Pass the salt with the 2.5kW grid tied Solis exceeding 2.7kW from the panels, are you certain of this?

Also did you factor in temperature derating? midday would presumably be warmest and panels presumably not exactly producing as much as they could if temperature was lower... my suggestion would be to talk to Deye or the branded outfit for a look and possible firmware upgrade, I'm guessing, assuming you could under circumstances squeeze more out of the panles, that the MPPT algorithm would need some changing...

My panels, heck, I better check, but never come close to even 9A, but have higher voltage and panels are only 280 or 290W. Ok, my current seems to top out at 9.5A for just shy of 2.3kW on the one and just over 2kW on the 2nd string, but, I thin, my JA Solar panels are hitting their max current on my Sunsynk 5kW Deye branded Hybrid unit.

BTW mine says:

Control Software Version 1 : V2.1.5.3
Communication CPU Software version : VE.4.1.3

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9 minutes ago, Kalahari Meerkat said:

Control Software Version 1 : V2.1.5.3
Communication CPU Software version : VE.4.1.3

Thanks for the info. Did you ask to have your firmware upgraded at some point or is this a brand new unit? Seems newer than mine. 

I found a post by @Vassen which also seems to point to MPPT being limited at 9.9A. Really hoping it's a firmware issue now. I sent email to Deye's support now as well. 

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4 minutes ago, Kalahari Meerkat said:

@recre8 I commissioned my unit end June or early July last year, can't remember, the firmware it came with looked totally different than current, I requested a firmware upgrade, in December, V2.1.3.7 was the original version.

Ah ok, how did you go about requesting the firmware upgrade? 

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2 minutes ago, Vassen said:

You also need to bear in mind that the angle of the sun right now is very different compared to what it was in nov/ Dec. With your panels being at such a low angle, it’s very good for summer sun as it’s directly above the panels. Now it’s moving lower so could impact a bit. 
 

Im not saying that this is the reason but it’s worth investigating. You winter generation is going to be a lot lower though. 
 

With my first string I used 420w Canadians and experienced the 9.9A limit. So on the second string I just found mono panels with a lower current ratings and now I don’t hit the limit on the second string. 
 

 

I also factored the angle of incidence in, but it seems the 9.9A limit is in fact built into the firmware or hardware. That definitely means the MPPT isn't working as it should and won't be able to get the full power out of any panel with an Imp of more than 9.9A. This is definitely a big issue. I received email from Deye this morning about the issue. Seems they are aware of it. 

"1, as you said, the inverter doesn't support the Max. 10.84A DC input current."

If they can't fix it in firmware, I'm going to have to return it under warranty since it isn't performing according to the specs. 

This really is a serious oversight on their part. 

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I have 16 panels (JA Solar 380W mono percs), 8 on each MPPT.

My 5.5k Sunsynk is running e410 (yes its a few months old, but it works and I love my UPS --don't want the hassle of re-setting the microwave clock and have a reset of all my other computing stuff ).

My roof angle is at 26 degrees, facing just slightly off North.

I do not seem to get near the panels' STC Max Power current of 9.5A, I think that the highest has been 8.1A. Then again, I have very little utilisation (10kWh per day), so I hardly ever max it out like you do -- have you got some seriously heavy loads, or are you feeding into the grid?

Another question, (I am curious that way): with such heavy loads, why did you originally opt for the 2.5kW Solis?

JAM72S01 PR 365-385 Global_EN_20180726A.pdf

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2 minutes ago, YellowTapemeasure said:

Have you got some seriously heavy loads, or are you feeding into the grid?

Another question, (I am curious that way): with such heavy loads, why did you originally opt for the 2.5kW Solis?

 

Hi

My base load is around 600W during the day, but I wanted to also cover my 2kW element in my geyser using the little Solis. The system worked really well and the Solis everyday without fail managed to get about 2800W+ out of the panels. When the Solis started giving DC Injection warning and Solis recommended returning the unit for a credit, I opted to change the system to a hybrid system with batteries since the solar was working so well. That's when I got the Deye. 

I really like the Deye. Everything works well, except that I can't get anywhere close to the maximum power from my PV string because of the current clipping. If you check the datasheet for my panels, when the current is limited to 9.9A they will always perform as if shaded, or in other words, as if having experienced about 10 years of aging. That's my really big concern at this point. Basically I'm losing about an entire panel's worth of power because of this, despite the string still being well within the MPPT spec as per the datasheet. Consequently, I can't fully cover my baseload and the geyser with the inverter anymore. But more important, I also can't charge the batteries at the rate I planned, considering 15% of the power is being left on the table. 

The MPPT according to the datasheet should be able to draw up to 11A from the panels (same as the little Solis), but for some reason it seems the firmware is limiting/clipping the current at a much lower point. I want to say it is firmware related because 9.9 seems to be too a very specific number. 

Incidentally, Deye upgraded my firmware for me yesterday, but they only upgraded the control software, not the communication cpu software. Mine is still stuck on C.3.4.6. I'm not really sure what the communication CPU does though. 

Control Software Version 1:V2.1.5.5
Communication CPU Software Version:VC.3.4.6

All in all, I'm currently in contact with Deye to figure out if they can fix the issue in firmware, since the unit clearly isn't performing up to the published specifications as is.

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22 minutes ago, recre8 said:

Hi

My base load is around 600W during the day, but I wanted to also cover my 2kW element in my geyser using the little Solis. The system worked really well and the Solis everyday without fail managed to get about 2800W+ out of the panels. When the Solis started giving DC Injection warning and Solis recommended returning the unit for a credit, I opted to change the system to a hybrid system with batteries since the solar was working so well. That's when I got the Deye. 

I really like the Deye. Everything works well, except that I can't get anywhere close to the maximum power from my PV string because of the current clipping. If you check the datasheet for my panels, when the current is limited to 9.9A they will always perform as if shaded, or in other words, as if having experienced about 10 years of aging. That's my really big concern at this point. Basically I'm losing about an entire panel's worth of power because of this, despite the string still being well within the MPPT spec as per the datasheet. Consequently, I can't fully cover my baseload and the geyser with the inverter anymore. But more important, I also can't charge the batteries at the rate I planned, considering 15% of the power is being left on the table. 

The MPPT according to the datasheet should be able to draw up to 11A from the panels (same as the little Solis), but for some reason it seems the firmware is limiting/clipping the current at a much lower point. I want to say it is firmware related because 9.9 seems to be too a very specific number. 

Incidentally, Deye upgraded my firmware for me yesterday, but they only upgraded the control software, not the communication cpu software. Mine is still stuck on C.3.4.6. I'm not really sure what the communication CPU does though. 

Control Software Version 1:V2.1.5.5
Communication CPU Software Version:VC.3.4.6

All in all, I'm currently in contact with Deye to figure out if they can fix the issue in firmware, since the unit clearly isn't performing up to the published specifications as is.

But what load do you have running that causes the bellcurve that you are getting in your graph? That's not a 600W load...

 

Edited by YellowTapemeasure
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That would be the batteries charging. The plateau in the curve is the inverter clipping the current. It should be a proper curve as you mentioned, not flattened like that.  

Edited by recre8
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14 minutes ago, recre8 said:

That would be the batteries charging. The plateau in the curve is the inverter clipping the current. It should be a proper curve as you mentioned, not flattened like that.  

Agreed on the curve clipping. OK, so I guess that batteries take until around 13H30 to charge, a small gap and then geyser kicks in at 14H00? Makes more sense.

Fully agree that your first call is to Dye to do some 'splainin about the 9.9A clipping on the MPPT vs the specified and published 11A limit. I would also suggest getting your supplier involved, after all they have specced the panels based on the 5.5k Dye's proclaimed capabilities, and under the circumstances would probably face a return of the panels / inverter/ both in favour of something more suited to your setup. They should add their weight to your (very valid and reasonable) argument.

Which brings me to my second point: Because you do not know how long this could take, you need to consider negotiating now already in the event that for some reason this drags on for too long. You may want to negotiate a return of the panels to your supplier in favour of ones with lower amperage. Do you have sufficient roof space for 16-20 panels?  If not, you need to consider a swop for the 8.8K Sunsynk, which is a pity because your base load of is only about 150W more than mine, and I am very, very happy with my 5.5k Sunsynk. Then again, I had the benefit of the experience and competence of the Powerforumstore, who specced and advised me on my system.

I still don't understand why you would have opted for the 2.5k Solis in the first place because it is half the rating of the 5.5k Dye? Or has this just been a protracted learning exercise?

 

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11 minutes ago, YellowTapemeasure said:

Agreed on the curve clipping. OK, so I guess that batteries take until around 13H30 to charge, a small gap and then geyser kicks in at 14H00? Makes more sense.

 

Well spotted. Absolutely correct yes. Unfortunately, I live in a small townhouse on a plot that is only 8 meters wide, so getting the maximum out the panels is paramount. Which is why I opted for the 450W panels in the first place - their max power point is just below 11A as found most commonly in smaller inverters.

Likely the best course of action would be to eventually swop out the 5kW for a 8kW if I can't get this resolved. My plan was initially to add another 6x450W panels on the 5kW's 2nd MPPT. If Deye can't fix the bug with the MPPT, and I swop it out for the 8kW, then at least I can fully use the 18A MPPT (holdings thumbs it is actually 18A) and add 550W panels. Unfortunately that also means shelling out another 12K for the price difference between the 5kW and 8kW 😟

Quote

I still don't understand why you would have opted for the 2.5k Solis in the first place because it is half the rating of the 5.5k Dye? Or has this just been a protracted learning exercise?

My plan was initially to only do grid-tie since my budget didn't allow for batteries. Things changed a bit and I took some money out of the bond to fund the batteries and the Deye. The longer term plan being to add another PV string in the next year or so. Reasoning also, I live in a complex where our electricity is resold to us at a flat rate of R3.20 per unit. They recently tacked on another 15% so the hybrid/battery route started making much more financial sense in the longer run. 

Edited by recre8
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3 minutes ago, recre8 said:

Well spotted. Absolutely correct yes. Unfortunately, I live in a small townhouse on a plot that is only 8 meters wide, so getting the maximum out the panels is paramount. Which is why I opted for the 450W panels in the first place - their max power point is just below 11A as found most commonly in smaller inverters.

Likely the best course of action would be to eventually swop out the 5kW for a 8kW if I can't get this resolved. My plan was initially to add another 6x450W panels on the 5kW's 2nd MPPT. If Deye can't fix the bug with the MPPT, and I swop it out for the 8kW, then at least I can fully use the 18A MPPT (holdings thumbs it is actually 18A) and add 550W panels. Unfortunately that also means shelling out another 12K for the price difference between the 5kW and 8kW 😟

I hear you, agreed. That is why I believe that you need to hold your supplier accountable, 12k with a 15-20%% discount would be good, considering this is what they sold you (as per the CPA) as fit for purpose. It may also spur them on to get Deye going on the explanation.

The 8.8k Sunsynk performs beautifully, just look for some posts by @Achmat for some awesomely round bellcurves ❤️ Maybe he can post graphs of his PV amperage to confirm?

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8 minutes ago, YellowTapemeasure said:

The 8.8k Sunsynk performs beautifully, just look for some posts by @Achmat for some awesomely round bellcurves ❤️ Maybe he can post graphs of his PV amperage to confirm?

I really like the Deye, it works beautifully other than my issue. I paired it with the new Pylontech Force L1 battery system, although rebranded as Kodak in SA. I'll write a proper review post after evaluating it for a week or two. 

1188571766_IMG_0257(2).thumb.jpg.de4dfd3a71a03ef22e35a2ca79b604ef.jpg

Ignore the dangling cables behind the battery please, I'm just waiting for stock of white spiral cable wrap to come in. Also the white board on top the battery is a offcut piece of postform top I had cut because I was worried my cleaning lady might put something wet on top the battery.

Edited by recre8
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11 minutes ago, recre8 said:

I really like the Deye, it works beautifully other than my issue. I paired it with the new Pylontech Force L1 battery system, although rebranded as Kodak in SA. I'll write a proper review post after evaluating it for a week or two. 

1188571766_IMG_0257(2).thumb.jpg.de4dfd3a71a03ef22e35a2ca79b604ef.jpg

Ignore the dangling cables behind the battery please, I'm just waiting for stock of white spiral cable wrap to come in. Also the white board on top the battery is a offcut piece of postform top I had cut because I was worried my cleaning lady might put something wet on top the battery.

It's a neat install, I really like the galvanised trunking, personally would not go with white plastic sprague, but rather galvanised sprague for the last bit, a lot more professional IMHO, plus it is harder wearing and a more "industrial" look. 🙂

Also like the postform top, very fitting.

 

 

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10 hours ago, YellowTapemeasure said:

I hear you, agreed. That is why I believe that you need to hold your supplier accountable, 12k with a 15-20%% discount would be good, considering this is what they sold you (as per the CPA) as fit for purpose. It may also spur them on to get Deye going on the explanation.

The 8.8k Sunsynk performs beautifully, just look for some posts by @Achmat for some awesomely round bellcurves ❤️ Maybe he can post graphs of his PV amperage to confirm?

Voltage and amps from MPPT 2.

2 strings of 11 x 305w panels per string. 

Screenshot_20210302-073412_SOLARMAN Smart.jpg

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54 minutes ago, Achmat said:

Voltage and amps from MPPT 2.

2 strings of 11 x 305w panels per string. 

I should probably consider swopping the 5kWfor the 8kW.

@YellowTapemeasure I received the following from Keith Gough at the Sunsynk forum:

Quote

The 5.5 kw invert has 2 x 2.75 kw mppts if the voc is high the current will clip

I wish this was disclosed in the datasheet. There is no way to extrapolate that restriction from the published specifications 5kW-Deye-Sunsynk-Hybrid-PV-Inverter-Datasheet.pdf

I also received this from Deye support:

Quote
From: [email protected]
HI,
sorry for this issue. currently the FW doesn't suport 11A. but now we are working on this. when the test completed, we will launch new FW to fix this problem.

So it definitely seems like there is an issue in firmware, but if Keith is accurate in that the MPPTs are only rated at 2.75kw, I'm still not sure how a firmware update is going to achieve the Max DC Input Power = 6500W in the datasheet?

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36 minutes ago, recre8 said:

I should probably consider swopping the 5kWfor the 8kW.

@YellowTapemeasure I received the following from Keith Gough at the Sunsynk forum:

I wish this was disclosed in the datasheet. There is no way to extrapolate that restriction from the published specifications 5kW-Deye-Sunsynk-Hybrid-PV-Inverter-Datasheet.pdf

I also received this from Deye support:

So it definitely seems like there is an issue in firmware, but if Keith is accurate in that the MPPTs are only rated at 2.75kw, I'm still not sure how a firmware update is going to achieve the Max DC Input Power = 6500W in the datasheet?

I am not sure that I understand Keith's answer. The 5.5K Deye's MPPT range is 125 to 425V, 6 of your panels in series is 298V (that's using VoC).

 

Edit: OK, I see now, 298V x 10.84 is 3230W. That means mine will clip as well, I am just not seeing it because my loads are too low.

 

But the Max DC input as per spec sheet is 6500 / 2 = 3250W per MPPT?

Edited by YellowTapemeasure
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6 minutes ago, YellowTapemeasure said:

Interesting mounting, I like the creative use of the wood, will need some maintenance though. I hope that you have earthed the panels properly?

To be honest with you I'm not all to confident in the earthing of PV arrays and I have found multiple conflicting views on the matter on this forum alone. The panels are all bonded electrically to the galvanized steel frame they are bolted to, which in turn is connected to the roof sheets. I don't live in an area where is there is any lightning (CPT), but are there other factors to consider?

Edited by recre8
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1 minute ago, recre8 said:

To be honest with you I'm not all to confident in the earthing of PV arrays and I have found multiple conflicting views on the matter on this forum alone. The panels are all bonded electrically to the galvanized steel frame they rest on, which in turn is connected to the roof sheets. I don't live in an area where is there is any lightning (CPT), but are there other factors to consider?

IMHO the panels need to be properly earthed, you will see the "grounding holes" on the panels' spec sheet. I have exactly the same IBR roof as yours and I used aluminum mountings, and all panels are properly earthed with three spikes in the ground. Poor earth makes working on your panels dangerous, I have heard of trickle shocks from panels mounted on wooden structures. My install is here.

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22 minutes ago, YellowTapemeasure said:

Poor earth makes working on your panels dangerous, I have heard of trickle shocks from panels mounted on wooden structures.

I really doubt this has any basis in fact the panels outer metal frame is not, from what I can tell linked in any way to the actual solar cells at all, in fact think about, it can *NOT* be linked...

Lets assume it was linked to the negative side of the cells, then all your panels could only ever work in paralell since all negative sides would be "earthed" in your scenario, everyone who would want to use their panels in series, like me, would have to mount them on a wooden structure and keep them insulated... and bang goes the poor earth theory... so, no, earthing will not make things less of more dangerous, but hey, I am willing to be edumacated....

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