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MPPT HANGING (DISCONNECTS)


nevinvert
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As said before; I am rather new to the subject although I was an Electrical Engineer by profession many years ago. I am deeply appreciated and impressed by the support from this forum.

MY PROBLEM

At times my MPPT (SolarCharger) stops with the battery discharging and the sun is blazing.  I suspect this occurs after the battery had reached 100% SOC but only sometimes.
The MPPT will only resume operation after I first switch off the incoming supply from the PV and wait for the warning that PV is off, and then switch the PV supply back ON again.
My system consists of:
(A)a single hybrid inverter
Specs are:
Model Name: FCS-KING-5000W-MPPT
Main CPU version:        00071.90
Bluetooth CPU version    00000.24
SCC CPU1            00001.10
(B) 4 strings of 3 Peimar solar panels V(oc) = 46.73  
(C) One battery pack of 100AH 50V LiFePO4 by MERITSUN

If this problem is unique to this 71.90 firmware version, seems to be mentioned elsewhere on this forum, which version should I flash? and some guidance on flashing will be most appreciated. Especially the cable connections required. The WatchPower seems to have a good procedure. 


The instruction from Meritsun was not to use any signal cable between battery and inverter and to set the inverter to AGM mode which preloads all the remaining settings.

Are there user settings that could solve this issue.

 

Thanks in advance

Neville
 

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On 2021/02/28 at 3:45 AM, nevinvert said:

(B) 4 strings of 3 Peimar solar panels V(oc) = 46.73  

There's your problem. Total Voc is over 140V @ 25°C. PV power will have derated to less than 33% of rated at that point, and the SCC will be running hot as well.

As I say in my signature, never run 3S of 72-cell panels on a machine with 145V absolute maximum PV voltage. You'll have to rewire to 6 strings of 2 panels.

Edited by Coulomb
Added "less than"
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Thank you so much Coulomb. I think I was a bit in denial when reading your earlier response. 

So restringing is my next prject. Phase 1 will be 4 x 2 followed by purchasing more cable and connectors to convert remaining panels to 2 x 2.

How does the 6 x 2 configuration affect max power output achievable

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On 2021/02/28 at 8:25 PM, nevinvert said:

How does the 6 x 2 configuration affect max power output achievable

It's still the same, apart from a slight hit due to the extra voltage drop across the cables now carrying higher current. But this will be more than offset by the SCC not shutting down due to over-temperature or over-voltage.

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  • 3 months later...

Once again thankyou for responding Coulomb.

Unfortunately the problem persisted after converting to 6 strings x 2 panels. Voltage and current measurements  confirmed correct reconfiguration.

I do not have any monitoring feature installed to record any abnormalities at the time.  So whether MPPT is overheating is not known to me. (Any recommendation?)

It does appear to me the situation arises when a lot of sun is available and little or no load at the time.

 Need I be concerned that the inverter default settings are selected, implying Battery type = AGM?

The Meritsun 100ah LifePo4 inspires me to be equipped with a sophisticated BMS.

The FCS-KING-5000W-MPPT hybrid inverter does have a Battery Option "WECO" which seems equivalent to the Meritsun;

Without having any communication cable connected between battery and inverter would some user defined settings not be the better option.

Any comments will be highly appreciated.

Thanks again for earlier advice.

 

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On 2021/02/28 at 3:45 AM, nevinvert said:

Main CPU version:        00071.90

OK, that's your next problem; it's fairly old now, and there were some fixes for SCC issues in 71.94. You may as well go to the latest firmwares, 71.97 and 02.66, available from the files section of this forum:

https://powerforum.co.za/files

For uploading instructions, use these, but they require a little adaptation for the removable display models such as the Kings.

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  • 3 weeks later...
On 2021/06/12 at 3:40 PM, Coulomb said:

OK, that's your next problem; it's fairly old now, and there were some fixes for SCC issues in 71.94. You may as well go to the latest firmwares, 71.97 and 02.66, available from the files section of this forum:

https://powerforum.co.za/files

For uploading instructions, use these, but they require a little adaptation for the removable display models such as the Kings.

The main CPU update went well, but running the reflashtool for DSP  the message "dsp.hex cannot found! displayed and the com port closed.

I did not want to copy the file with the same name from the cpu reflash tool, or was that the right thing to do?

I notice more battery selection will become available with the update whic I was looking forward to. LIFEPO4 is now included.

Looking forward to uour response

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2 hours ago, nevinvert said:

The main CPU update went well, but running the reflashtool for DSP  the message "dsp.hex cannot found! displayed and the com port closed.

The DSP is the main CPU. The processor in the removable display is called the MCU (presumably, MicroController Unit or similar).

Quote

I did not want to copy the file with the same name from the cpu reflash tool, or was that the right thing to do?

No, never copy .hex files; always use them from the folder that they came in, via the reflash tool in that folder. The DSP and MCU reflash tools are different! This is despite the fact that one of them has the option to update the MCU or DSP (as in the last photo above).

The above is the MCU updater. Probably the only thing you're doing wrong is you're clicking on "Update DSP" when you need to click on "Update MCU".

I suspect that they intended to merge the two reflash tools into one, but never finished the job. Or decided that it was too confusing, but still left the second button there (which in my mind only adds to the confusion, as we can see here).

Edit: the other confusing thing is the "Baudrate" option: it defaults to 19200, which is wrong. Yet the code seems to correctly start at 2400 bps, and switches to 9600 bps, as do all the reflash tools. More unfinished code perhaps? So just leave that one alone. Hopefully, it actually doesn't do anything.

Edited by Coulomb
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IT WORKED!!  VOILA

 

 

 

image.thumb.png.69cd03a4c4d7449f0324a958e7fb257f.png

 

 

My Android App still displays displays the same 5 battery options as before.  My battery is LiPo4 ; any suggestion? If User is selected, where can one find the suitable settings.

Your support is appreciated

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10 minutes ago, nevinvert said:

My battery is LiPo4 ; any suggestion?

Unless it's a Pylontech or Weco and you have the correct communication cable you will need to select user define. Battery settings should appear in the settings menu after you select the user defined. We normally enter the settings manually as the app isn't great in our experience.

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A comment on this issue as a whole is that the King model, even with the updates and correctly wired panels, has still can have problems in certain cases but the changes made will improve matters. If you search for dip and freeze problems there are several posts that explore this in detail.

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19 hours ago, nevinvert said:

My Android App still displays displays the same 5 battery options as before.

Removable display firmware version 02.66 should have 5 BMS options, in addition to the 3 non-BMS options, for a total of 8 options.

I don't use Watchpower, either on a PC or on a phone, so I don't know how up-to-date it is. My guess is that it's well behind the times (last update was November 2019??), so perhaps try the PC application, or just try using the front panel for the battery type setting. You should be able to change most other settings from the phone.

If they haven't updated the phone app in over 18 months, then that is certainly poor.

Edit: there seem to be some glaring gaps, like not showing the removable display firmware version.

Edited by Coulomb
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My battery is a 15 cel MERITSUN battery.

All the new battery options are indeed listed, by scrolling through the battery options on the LCD Display panel.

So the conclusion is for me to use a better Android App version of Watchpower. Any suggested? (Entering settings through the LCD panel is so "yester-year". ) Nevertheless, does any of the new (SOL, LIB or LIC) apply to MERITSUN?

I'm still having to get Watchpower on my Laptop to connect to the inverter. Ironically the reflash tool connected without a problem but not Watchpower, using the same cable setup. Although my previous inverter connected without problems before it blew up. Any suggestions? This is quite embarrassing to say the least.

Much appreciated Coulomb and Shadders

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