Millard Posted April 22, 2022 Posted April 22, 2022 Good day, My solar system consists of: 1x KODAK Solar Off-Grid Inverter VMIII 5kW 48V (PV array up to 5000w) 4x Pylontech US3000C 14x Canadian Solar 330w solar panels (7 panels in 2 sets) = 4 620w On a normal clear sunny day the inverter only absorbs +- 3 300w (+-59 amps) even when the load is 3 500w. At first I wanted to buy another inverter since when the inverter is turned off I might get, lets say 340volts from the panels. As soon as the inverter is turned on it would regulate the voltage from 200volt to 260v but never beyond that. What also irritates me is that it does this even when cloudy. The inverter MPPT says optimal voltage is from 120vdc to 450vdc (500vdc Max) ,but the startup is 150vdc????? So when it's cloudy the batteries barely charge if they charge due to the inverter dropping the voltage and the clouds as well. I have looked at it a few times. The one specific time the voltage was 250vdc on the panels side ,but as soon as you connect the inverter it was 150vdc. It did not charge since the start-up voltage is 150vdc (+-10vdc). But then, Yesterday I was at my mothers house. I installed / added 3x 340w to her existing 6x 330w solar panels. She has a Growatt 5KW low voltage inverter with 4x Pylontech US 2000 B batteries. I noticed the same problem. The inverter would limit the charging to 25amps (+- 1300w) and there is no way to change it because of the BMS. When I changed the battery type to User Defined and set the Parameters it would charge much faster. It was cloudy and early morning. It changed from 1200w to 2050w with no problem. Changed the batteries back to Lithium and I was back at 1200w. The only difference from the Kodak and Growatt inverter was that the Growatt did not drop the voltage. I have never changed my inverter and will do it tomorrow since I have the time then, but the obvious problem here seem to be Pylontech batteries tend to charge very slowly. From what I read and know about batteries myself is that the slower you charge a battery the longer it lasts. I do not what the inverter to decide when the batteries are full. I want the battery to decide. That is what the BMS is there for. Now the question is. Has anyone noticed this and is there a way to change this without changing the settings on the inverter and still use the BMS? I live in some of the sunniest areas you can get in the world but logic tells me that the battery should charge when it can and not take the whole day. Usually the batteries are 60% in the morning and at 13h they are full. What if it becomes cloudy at 11am and they can't charge due to taking their time to charge. What is the point in having 14 solar panels or 9 solar panels when it only use 10 solar panels or 4-6 solar panels? Any help would be appreciated. If you don't understand, then I don't know Kind regards, Millard Quote
FixAMess Posted April 22, 2022 Posted April 22, 2022 Have you checked what the max Amps your inverter can charge at? My Goodwe can charge at a max of 100A, even if the BMS reports that it can take 148A max. Also, the inverter may be providing the house with power and then only the reminder is sent to the batteries. Usually the pylontechs only charge at C/2... Quote
0012 Posted April 22, 2022 Posted April 22, 2022 Maybe only one batt's BMS is talking to the inverter, then the charge rate is limited to 37A for the US3000... who knows, more investigation required Quote
Millard Posted April 22, 2022 Author Posted April 22, 2022 15 minutes ago, FixAMess said: Have you checked what the max Amps your inverter can charge at? My Goodwe can charge at a max of 100A, even if the BMS reports that it can take 148A max. Also, the inverter may be providing the house with power and then only the reminder is sent to the batteries. Usually the pylontechs only charge at C/2... The inverter is can be set to 80A ,but ultimately it is decided by the BMS. it will set itself back down to 50A even if I say 80Amp. Please see below screenshots. You should see by the time that it changed back to 50A. No, the PV input is =- 3200w. From that the load gets deducted and the rest is send to the Batteries. I am no expert, so may I ask what is "only charge at C/2..."? Thanks. Quote
Millard Posted April 22, 2022 Author Posted April 22, 2022 19 minutes ago, 0012 said: Maybe only one batt's BMS is talking to the inverter, then the charge rate is limited to 37A for the US3000... who knows, more investigation required I set it up according to the manual from Pylontech. 1x master and 3x slaves. Sometimes the charging is 60A so I do not think this can be the problem unless 2 communicates, and yet they are being charged and stay level. Quote
0012 Posted April 22, 2022 Posted April 22, 2022 Maybe what you're seeing is this... When the batt is over 90% full, the charge current limit set by the BMS comes down to 59.2A for 4xUS3000. From your screenshots, your batt was at 97% SOC. Nexuss 1 Quote
Millard Posted April 22, 2022 Author Posted April 22, 2022 13 minutes ago, 0012 said: Maybe what you're seeing is this... When the batt is over 90% full, the charge current limit set by the BMS comes down to 59.2A for 4xUS3000. From your screenshots, your batt was at 97% SOC. It is quite possible that this can be the cause ,but it remains the same even when at 60%. I have never really looked below the 50% mark since it just does not go that low. What might be the reason I have not noticed this can be that it does this below 90% (Perhaps 80%) and at that time of the day I would not know. Is it possible that I can load an app like the one you have? My inverter only has Bluetooth connection. Perhaps another way? My biggest concern is the Voltage drop I get from the PV to the inverter when the batteries are charging ,but I guess that can be because of the BMS slowing down the charge rate. I just checked and seems like when the Batteries are full there is no voltage drop. Quote
hoohloc Posted April 22, 2022 Posted April 22, 2022 let me chip in on the growatt, your issue of 25A is because of your settings. On program 05, select LI, it will take you to program 36, then select option4 for Pylontech Quote
Millard Posted April 22, 2022 Author Posted April 22, 2022 (edited) 21 minutes ago, hoohloc said: let me chip in on the growatt, your issue of 25A is because of your settings. On program 05, select LI, it will take you to program 36, then select option4 for Pylontech Your Growatt seems to be the same, is possibly. However being a person with little to no patience when it comes to being in a rush and struggling to get a setting correct after you changed the battery type. Option Li4 (like in the manual) I had Error code 4 and 20. Option L04 also Error code 04 and 20,but perhaps you have never firmware. This was the only solution that worked (Below). For Pylontech Batteries and BMS comms Reset it after each firmware upgrade and then shut down the inverter and batteries completely, and then reboot it all. After both firmware updates have been applied and you've reset it twice, go and change setting 5 to Li, and pick profile L02 for Pylontech. Apply that, exit the settings menu, then go back into the settings menu and check that it remembered your change. Now shut the inverter down one last time, batteries off, and then fire it all up again. And now you should have full BMS comms working, assuming you have the comms cable plugged into the RS485 port (NOT the CAN port) on the master battery and the dip switches on the battery set to 1000. I will be sure to try your setting. Can you please tell me step by step. setting 05 -> Li Setting 36 -> option 4 in the manual like, Li4? or what is it set on? I still think the BMS is the big issue here. Slowing the charge as the batteries fill up like 0012 said. Edited April 22, 2022 by Millard Quote
Nexuss Posted April 22, 2022 Posted April 22, 2022 (edited) 3 hours ago, Millard said: I still think the BMS is the big issue here. Slowing the charge as the batteries fill up 0012 said. That is how they are supposed to work . Your main problem here is probably the inverter and not enough solar . Edited April 22, 2022 by Nexuss Quote
hoohloc Posted April 22, 2022 Posted April 22, 2022 1 minute ago, Millard said: Your Growatt seems to be the same, is possibly. However being a person with little to no patience when it comes to being in a rush and struggling to get a setting correct after you changed the battery type. Option Li4 (like in the manual) I had Error code 4 and 20. Option L04 also Error code 04 and 20,but perhaps you have never firmware. This was the only solution that worked (Below). For Pylontech Batteries and BMS comms Reset it after each firmware upgrade and then shut down the inverter and batteries completely, and then reboot it all. After both firmware updates have been applied and you've reset it twice, go and change setting 5 to Li, and pick profile L02 for Pylontech. Apply that, exit the settings menu, then go back into the settings menu and check that it remembered your change. Now shut the inverter down one last time, batteries off, and then fire it all up again. And now you should have full BMS comms working, assuming you have the comms cable plugged into the RS485 port (NOT the CAN port) on the master battery and the dip switches on the battery set to 1000. I will be sure to try your setting. Can you please tell me step by step. setting 05 -> Li Setting 36 -> option 4 in the manual like, Li4? or what is it set on? I still think the BMS is the big issue here. Slowing the charge as the batteries fill up 0012 said. OK, You need to get your communication first, Error code 4 and 20 means no comms. Once that is right, change program 5 to USE and go out of the program, then go to program05 again and change back to LI, then you will be able to see program 36 again, select option 4. You have to make a new comms cable, because the one that came with Pylons is a straight cable. You need PIN7 and PIN 8 from the batteries to go to PIN 2 and PIN 1 on the inverter, i .e PIN8 -to -PIN1 and PIN7 to PIN1 Quote
Millard Posted April 22, 2022 Author Posted April 22, 2022 13 minutes ago, hoohloc said: OK, You need to get your communication first, Error code 4 and 20 means no comms. Once that is right, change program 5 to USE and go out of the program, then go to program05 again and change back to LI, then you will be able to see program 36 again, select option 4. You have to make a new comms cable, because the one that came with Pylons is a straight cable. You need PIN7 and PIN 8 from the batteries to go to PIN 2 and PIN 1 on the inverter, i .e PIN8 -to -PIN1 and PIN7 to PIN1 The system is running correct. There is communication from the battery to the inverter. Can you please send me a picture of your Program 36? My mothers program 36 is set to L02. As per your recommendation I am not sure if your setting 4 is, "L04" or "L14 (Like in the growatt user manual)". I have tried "L14" and it did not communicate. Quote
Millard Posted April 22, 2022 Author Posted April 22, 2022 30 minutes ago, hoohloc said: OK, You need to get your communication first, Error code 4 and 20 means no comms. Once that is right, change program 5 to USE and go out of the program, then go to program05 again and change back to LI, then you will be able to see program 36 again, select option 4. You have to make a new comms cable, because the one that came with Pylons is a straight cable. You need PIN7 and PIN 8 from the batteries to go to PIN 2 and PIN 1 on the inverter, i .e PIN8 -to -PIN1 and PIN7 to PIN1 I see. I followed the other route. I updated the firmware and followed these instructions from SIliconkidd. I didn't have to change the cable. Just used the normal Growatt cable and the communication worked fine on program 05 ->"Li" and Program 36 -> "L02". Due to the changes in the cable that might be what is allowing your option 4 to work. Quote
hoohloc Posted April 22, 2022 Posted April 22, 2022 1 hour ago, Millard said: I see. I followed the other route. I updated the firmware and followed these instructions from SIliconkidd. I didn't have to change the cable. Just used the normal Growatt cable and the communication worked fine on program 05 ->"Li" and Program 36 -> "L02". Due to the changes in the cable that might be what is allowing your option 4 to work. Program 36 has to be Li4 Quote
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