May 8, 20233 yr Three sets of panels, each with 3 panels in series and all 48 volts with a combined output of 3 555 W have been working perfectly, producing up to 4 000 W on occasion. A while ago I noticed a drop in wattage output, where total output would have been expected to be around 3 000 W, only about 1 800 to 2 000 W was being produced. Investigation thus far indicates that two of the sets, when isolated from the rest, are producing the expected 140-150 volts while the third set is only producing approximately 100 volts. When the sets are combined, the total output drops to around 100 volts, indicating that some weaker sets may be affecting the others. Tests on the three panels in the set producing 100 volts, when isolated, show 55 volts on one and 35 and 38 on the other two adjacent to each other. The panels are two sets of 3 x Canadian 365 W monos and one set of 3 x 455 W Haitai monos. The Canadians were installed in January 2022 and the Haitais eight months later. They feed to a Growatt 5 Kw inverter and 3 x Growatt Hope 3,3 Kw batteries. There is no visual indication of a suspect connection, but it seems surprisingly co-incidental for two relatively new Canadian panels to malfunction in similar fashion. Any thoughts and suggestions would be welcomed.
May 8, 20233 yr 11 minutes ago, Langjan said: Three sets of panels, each with 3 panels in series and all 48 volts with a combined output of 3 555 W have been working perfectly, producing up to 4 000 W on occasion. A while ago I noticed a drop in wattage output, where total output would have been expected to be around 3 000 W, only about 1 800 to 2 000 W was being produced. Investigation thus far indicates that two of the sets, when isolated from the rest, are producing the expected 140-150 volts while the third set is only producing approximately 100 volts. When the sets are combined, the total output drops to around 100 volts, indicating that some weaker sets may be affecting the others. Tests on the three panels in the set producing 100 volts, when isolated, show 55 volts on one and 35 and 38 on the other two adjacent to each other. The panels are two sets of 3 x Canadian 365 W monos and one set of 3 x 455 W Haitai monos. The Canadians were installed in January 2022 and the Haitais eight months later. They feed to a Growatt 5 Kw inverter and 3 x Growatt Hope 3,3 Kw batteries. There is no visual indication of a suspect connection, but it seems surprisingly co-incidental for two relatively new Canadian panels to malfunction in similar fashion. Any thoughts and suggestions would be welcomed. The set producing 100V are pulling down the 2 sets that are at 140-150V. Disconnect the set showing 55, 38 and 35V and check how the other 6 are doing. This set is it the Haiti monos?
May 9, 20233 yr Author 6 hours ago, Scorp007 said: The set producing 100V are pulling down the 2 sets that are at 140-150V. Disconnect the set showing 55, 38 and 35V and check how the other 6 are doing. This set is it the Haiti monos? Yes they are all monos. Thanks for the feedback guys, now to complicate matters - both of the other sets of three are producing 140-150 V when tested individually but when connected together in parallel production goes down to 105 V. My understanding is that different wattage does not matter as long as voltages are the same but could this be incorrect and be leading to incompatibility?
May 9, 20233 yr 2 hours ago, Langjan said: Yes they are all monos. Thanks for the feedback guys, now to complicate matters - both of the other sets of three are producing 140-150 V when tested individually but when connected together in parallel production goes down to 105 V. My understanding is that different wattage does not matter as long as voltages are the same but could this be incorrect and be leading to incompatibility? There is a problem and needs a step by step approach. Connect the 1st 3 to the inverter and check what output you get on the inverter and also check the voltage. Then disconnect them and connect the next 3. Check the same. Then disconnect and try the last 3. Post the results and may be we can make sense of the readings to try and help.
May 9, 20233 yr 2 hours ago, Langjan said: Many thanks Scorp007, will get back to you soon. Good. For now those 3 with the 35, 38 and 55V readings also are not OK. Don't connect them accept to do checks. I presume they are the 3 x Haitai.
May 9, 20233 yr Author Here are the readings taken from the inverter at about midday today: Set 1 - 3x365 W panels: 90 V, 9 A and 870 W Set 2 - 3x365 W panels: 94 V, 10 A and 800 W Set 3 - 3x455 W panels: 117 V, 11 A and 940 W At 16:15 I connected sets 1 and 3 to test in weak sunshine: 115 V and 450 W Your inputs and assistance is appreciated. Have I been expecting too much from the wintry sunshine days? We also had quite a bit of rain and clouds lately, but we were away for almost three months so I was unable to monitor the effect of the coming winter and the full set was only completed in August so it's my first winter using it.
May 9, 20233 yr Author The three with the previous 35, 38 and 55 V readings are set no. 2 - Canadians. However, these were not taken at the inverter and might not be very accurate, using a cheap multimeter. I tested them with the multimeter again and they all tested at 36-37 V. Edited May 9, 20233 yr by Langjan
May 9, 20233 yr 2 hours ago, Langjan said: The three with the previous 35, 38 and 55 V readings are set no. 2 - Canadians. However, these were not taken at the inverter and might not be very accurate, using a cheap multimeter. I tested them with the multimeter again and they all tested at 36-37 V. It remains a puzzle. Please give the model of inverter. Afternoon sun can vary so one can not read much into the figures supplied.
May 10, 20233 yr Author Considering that all three of my panel sets are producing more or less the same result, I have put these questions to AI and received these replies: What voltage is a typical 48 V solar panel in the 350-500 W range supposed to generate in normal sunlight? ChatGPT A typical 48 V solar panel in the 350-500 W range is designed to generate a voltage range of around 40-60 volts in normal sunlight conditions, depending on factors such as the type of solar cells used and the temperature of the panel. It's important to note that the actual voltage output of a solar panel can vary depending on a number of factors, including the angle and intensity of sunlight, the temperature of the panel, and any shading or obstructions that may be present. Additionally, the voltage output of a solar panel may fluctuate throughout the day as the angle and intensity of sunlight change. Would 36 to 37 volts in winter sun conditions be regarded to be too low? ChatGPT A voltage output of 36-37 volts from a 48 V solar panel in winter sun conditions is within the normal range of expected output. During the winter, the angle of the sun is lower in the sky, and the daylight hours are shorter, which can result in reduced solar panel output. Additionally, colder temperatures can also impact solar panel performance, as solar panels are typically more efficient at converting sunlight into electricity at lower temperatures. Many thanks for your inputs, do you have anything to add or do you think that I should stop being concerned?
May 10, 20233 yr Author Scorp007 many thanks for your inputs, do you have anything to add or do you think that I should stop being concerned?
May 10, 20233 yr 41 minutes ago, Langjan said: Scorp007 many thanks for your inputs, do you have anything to add or do you think that I should stop being concerned? Your inverter is meant to work in the 60-115V MPPT range and Voc 145V. You should connect them only as 2xseries per string. So I suggest you try 3 strings in parallel for a 2S3P system. See what output you get. Only once we can see the specs of the 2 brands of panels can one comment on how to if at all can one use them for up to 8 panels. I just hope your MPPT is not damaged after the 3 set of 3 in series.
May 10, 20233 yr 1 hour ago, Scorp007 said: Your inverter is meant to work in the 60-115V MPPT range and Voc 145V. You should connect them only as 2xseries per string. So I suggest you try 3 strings in parallel for a 2S3P system. See what output you get. Only once we can see the specs of the 2 brands of panels can one comment on how to if at all can one use them for up to 8 panels. I just hope your MPPT is not damaged after the 3 set of 3 in series. You are spot ON. I use the same inverter and also it is normal that your voltage will change at different times of the day. You will not always get the max voltage
May 11, 20233 yr Author Specs of the two brands of panels: Haiti Canadian Maximum power Pmp) 455 W 365 W Open circuit V (VOC) 49,68 V 47,2 V Short circuit current (Isc) 11,67 A 9,75 A Maximum power voltage (Vmp) 41,34 V 38,8 V Maximum power current (Imp) 11,13 A 9,18 A Module efficiency at STC (nM) 21,16% 18,4%
May 11, 20233 yr 24 minutes ago, Langjan said: Specs of the two brands of panels: Haiti Canadian Maximum power Pmp) 455 W 365 W Open circuit V (VOC) 49,68 V 47,2 V Short circuit current (Isc) 11,67 A 9,75 A Maximum power voltage (Vmp) 41,34 V 38,8 V Maximum power current (Imp) 11,13 A 9,18 A Module efficiency at STC (nM) 21,16% 18,4% Your inverter/ panels are wired wrong. You need to change your configuration to have only two panels in series and then parallel all the series connected panels. As for the voltages, what you are getting looks to be normal. Your panels will never produce maximum power Voltage through out the day. You can use Growatt server to check your voltages and you will see that at one point you were getting the expected max power voltage. But start with lowering your voltage, your MPPT voltage range is 60 to 115v. 140 to 150v is too much for your inverter MPPT, according to the specs
May 11, 20233 yr Author 55 minutes ago, hoohloc said: Your inverter/ panels are wired wrong. You need to change your configuration to have only two panels in series and then parallel all the series connected panels. As for the voltages, what you are getting looks to be normal. Your panels will never produce maximum power Voltage through out the day. You can use Growatt server to check your voltages and you will see that at one point you were getting the expected max power voltage. But start with lowering your voltage, your MPPT voltage range is 60 to 115v. 140 to 150v is too much for your inverter MPPT, according to the specs Thanks hoohloc. I am in the process of connecting them correctly. Now I need to confirm whether the Canadians and the Haitis are compatible.
May 11, 20233 yr 20 minutes ago, Langjan said: Thanks hoohloc. I am in the process of connecting them correctly. Now I need to confirm whether the Canadians and the Haitis are compatible. Looking at the specs, There is not much of a big difference between the two. Just note that you will be loosing out on the 455w performance as the lower wattage panels will be dominating. I.e, consider all your panels as being 365W, you now have 6 x 365w panels 😀
May 11, 20233 yr Author 2 hours ago, hoohloc said: Looking at the specs, There is not much of a big difference between the two. Just note that you will be loosing out on the 455w performance as the lower wattage panels will be dominating. I.e, consider all your panels as being 365W, you now have 6 x 365w panels 😀 You've lost me a bit here - I have six 365 W panels in any event. I intend to disconnect the third 455 W panel from the bank of 455's so then I will have three sets of 365's and one set of 455's and one spare 455 for which I may add a mate later on. As I understand it, the total wattage produced by different panels is the sum of their individual capacity as long as the voltage is the same. I don't agree that the lower wattage panels will in effect lower the output of the others. To illustrate the point in practice, the array has, at the height of summer, produced up to 4 000 W from a total rated capacity of 3555 W. Edited May 11, 20233 yr by Langjan Added the concluding paragraph
May 11, 20233 yr 53 minutes ago, Langjan said: You've lost me a bit here - I have six 365 W panels in any event. I intend to disconnect the third 455 W panel from the bank of 455's so then I will have three sets of 365's and one set of 455's and one spare 455 for which I may add a mate later on. Ok, thought you have three of each, so in that case, you will have 2S4P, your one set of 455w will be at the same voltage as that of the rest of the sets. Which is 77.6v. See an example below, in your case the current of the 455w will be 11.13A and the other three sets will sit at 9.18A each, so you can calculate from there how much you will be loosing. Edited May 11, 20233 yr by hoohloc
May 12, 20233 yr Author According to our calculation the 2s3p configuration will generate 24 amps. The inverter Max. PV Input Current is only 22 amps. Add the other 2s1p and the total amperage will increase to 30 amperes which exceeds the specified limit by a large margin. Please confirm if you agree and comment on the desirability of the proposed change.
May 12, 20233 yr 1 hour ago, Langjan said: According to our calculation the 2s3p configuration will generate 24 amps. The inverter Max. PV Input Current is only 22 amps. Add the other 2s1p and the total amperage will increase to 30 amperes which exceeds the specified limit by a large margin. Please confirm if you agree and comment on the desirability of the proposed change. I thought you are using Growatt SPF5000TL. The max current that your MPPT will take is 80A, please see the screen shot from the user manual below
May 12, 20233 yr Author Here is a screen shot of the Growatt SPF 5000TL HVM-WPV manual, shows Max. PV input current 22A: Edited May 12, 20233 yr by Langjan Added details
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