MPP Solar LV6548 + 6 x 545W Canadian Solar panels

[khaledme]

I am going through the same thoughts as others about combining panels, I have LV6548 + 6 x 545W canadian solar. VOC is 49.4, ISC is 13.95.
If I configure them as 3S2P it will go over the ISC, and if they all 6S it will go over the voltage.
Any ideas on which way to go? or would be safer to use both charge controllers with 3 pannels each string to stay under the operating voltage and current of the inverter?

 

[pvgirl]

3 panels in series on each of the 2 MPPTs is the only thing you can do with those panels and that inverter.

 

[khaledme]

3 panels in series on each of the 2 MPPTs is the only thing you can do with those panels and that inverter.

This was my though. Thanks for confirming

 

[khaledme]

I just spoke to Ian from Watt247 and he recommended that I dont worry about the Isc limitation as long as the arrays stay within the 250Voc and total power of 4KW per MPPT. He said the unit will limit itself to the amount of current it can handle. In this case I can wire the panels 3S2P with total Voc of about 150VDC and total PV power of 3300W.

Does anyone else have an experience with LV6548 with this typer of configuration?

 

[Zwy]

I just spoke to Ian from Watt247 and he recommended that I dont worry about the Isc limitation as long as the arrays stay within the 250Voc and total power of 4KW per MPPT. He said the unit will limit itself to the amount of current it can handle. In this case I can wire the panels 3S2P with total Voc of about 150VDC and total PV power of 3300W.

Does anyone else have an experience with LV6548 with this typer of configuration?

It will clip when over the Isc, but that also is a waste of potential yield. With 3270W total potential yield you are limited considering the idle consumption of the LV6548 is about 80W. It will take 1920Wh just to run the LV6548 for 24 hours unless you have it connected on AC input, then it will draw the 1920Wh from the grid.

I'm running JA Solar 530W panels, VOC is 49.65V, ISC is 13.43A and I run 8S. I do not use the MPPT's in the LV6548's. Originally I had a pair of EG4 6500EX's and the max I could pull thru those MPPT's was 3.9Kw with the 4.24Kw strings. When I first installed the LV6548's, I ran 4S and noticed yield was better simply because I was keeping the amperage down. I ordered a pair of EG4 MPPT100-48HV and installed one with 8S while leaving one of the 4S strings on a LV6548. Array is 420 feet one way distance and I wanted to compare to see if the higher voltage made a difference. The 4S string was interesting and you have to remember the MPPT algorithm is different. In full sun with peak power, the 4S string would not output 1/2 the 8S string. In overcast or partly cloudy conditions, including low light morning/evening, the 4S would output more than 1/2 the 8s string. My guess is the amps were higher during peak sun and lower during other conditions and why I was seeing these results.

Since then I finished install of the second EG4 unit, my Youtube channel shows the setup. Both EG4 charge controllers are running 8S. I pulled 4.3Kw off each string during the summer with hazy skies at peak sun. Recently I was checking some things on a partly cloudy day and saw over 5Kw per string with cloud edge effect and with the clear skies I would see 4.6Kw per string for extended times other than cloud edge effect. Pretty amazing off 4.24Kw of panels.

I do recommend considering using a separate charge controller with those panels simply because they won't fit well with the LV6548 MPPT limits. If you decide down the road to add more PV, which I'm certain you will, then you could source panels that better fit the lower VOC limit of the LV6548 MPPT.

If I do add more panels, it will be closer to the house and I will find the best fit for the 250V limit. It's all about options and the EG4 unit is really a very good deal. You could add 2 more of your current panels and run it thru the EG4 unit. I purchased the JA Solar panels at the time because it was a deal I couldn't turn down but those higher VOC panels do not fit well with the 250V limits. Part of the reason I switched to the EG4 6500EX inverters which did not work out well. The EG4 charge controller on the other hand has worked quite well, I've had the one running since July 4th and the second unit since about August 1st. These units do have a firmware update available, it is to fix a phantom F01 code that sets in low light conditions.

 

[khaledme]

Thanks Zwy for the details. This is very helpful. I actually have not bought the panels yet but I am running into the same senario where they are a very good deal for $/w. As of right now 6 panels can be easily split between the 2 charge controllers for this inverter, which would work fine for now. In fact I can even put 5S panels on each string and would be okay with 2750W, 150VOC and 18.3A on each string (total 5500W). But I was thinking the same thing about the future of adding more panels to maximize the 8000W capacity of the MPPT.

 

[Zwy]

Thanks Zwy for the details. This is very helpful. I actually have not bought the panels yet but I am running into the same senario where they are a very good deal for $/w. As of right now 6 panels can be easily split between the 2 charge controllers for this inverter, which would work fine for now. In fact I can even put 5S panels on each string and would be okay with 2750W, 150VOC and 18.3A on each string (total 5500W). But I was thinking the same thing about the future of adding more panels to maximize the 8000W capacity of the MPPT.

If you are thinking of moving to 240V split phase down the road, then purchase the 2nd LV6548 now. If you have a pair of LV6548's, you could put 3S (or 4S as you have not purchased yet) per LV6548 and that leaves the other MPPT on each inverter available for more panels.

5S will let the magic smoke out, do not use 5S. At 4S, you need to run the calculations for VOC at the coldest temps your area historically reaches. If it ever hits -30F, then you need to run it thru the calculator. Input the data here and your desired string configuration. It will calculate the string VOC at the coldest temps. Do not exceed the 250V limit, it is a hard limit. https://www.midnitesolar.com/sizingTool/

 

[khaledme]

If you are thinking of moving to 240V split phase down the road, then purchase the 2nd LV6548 now. If you have a pair of LV6548's, you could put 3S (or 4S as you have not purchased yet) per LV6548 and that leaves the other MPPT on each inverter available for more panels.

5S will let the magic smoke out, do not use 5S. At 4S, you need to run the calculations for VOC at the coldest temps your area historically reaches. If it ever hits -30F, then you need to run it thru the calculator. Input the data here and your desired string configuration. It will calculate the string VOC at the coldest temps. Do not exceed the 250V limit, it is a hard limit. https://www.midnitesolar.com/sizingTool/

Thanks for the information. I checked and it looks like 5S will go up to 257V at the coldest temperature in record in my location . Not sure if 7 volts above limit is a big problem or not.

 

[Zwy]

Thanks for the information. I checked and it looks like 5S will go up to 257V at the coldest temperature in record in my location . Not sure if 7 volts above limit is a big problem or not.

Like I said, it is a hard limit.

Operating range of the MPPT is 230V.

 

[Ronnie B]

It will clip when over the Isc, but that also is a waste of potential yield. With 3270W total potential yield you are limited considering the idle consumption of the LV6548 is about 80W. It will take 1920Wh just to run the LV6548 for 24 hours unless you have it connected on AC input, then it will draw the 1920Wh from the grid.

I'm running JA Solar 530W panels, VOC is 49.65V, ISC is 13.43A and I run 8S. I do not use the MPPT's in the LV6548's. Originally I had a pair of EG4 6500EX's and the max I could pull thru those MPPT's was 3.9Kw with the 4.24Kw strings. When I first installed the LV6548's, I ran 4S and noticed yield was better simply because I was keeping the amperage down. I ordered a pair of EG4 MPPT100-48HV and installed one with 8S while leaving one of the 4S strings on a LV6548. Array is 420 feet one way distance and I wanted to compare to see if the higher voltage made a difference. The 4S string was interesting and you have to remember the MPPT algorithm is different. In full sun with peak power, the 4S string would not output 1/2 the 8S string. In overcast or partly cloudy conditions, including low light morning/evening, the 4S would output more than 1/2 the 8s string. My guess is the amps were higher during peak sun and lower during other conditions and why I was seeing these results.

Since then I finished install of the second EG4 unit, my Youtube channel shows the setup. Both EG4 charge controllers are running 8S. I pulled 4.3Kw off each string during the summer with hazy skies at peak sun. Recently I was checking some things on a partly cloudy day and saw over 5Kw per string with cloud edge effect and with the clear skies I would see 4.6Kw per string for extended times other than cloud edge effect. Pretty amazing off 4.24Kw of panels.

I do recommend considering using a separate charge controller with those panels simply because they won't fit well with the LV6548 MPPT limits. If you decide down the road to add more PV, which I'm certain you will, then you could source panels that better fit the lower VOC limit of the LV6548 MPPT.

If I do add more panels, it will be closer to the house and I will find the best fit for the 250V limit. It's all about options and the EG4 unit is really a very good deal. You could add 2 more of your current panels and run it thru the EG4 unit. I purchased the JA Solar panels at the time because it was a deal I couldn't turn down but those higher VOC panels do not fit well with the 250V limits. Part of the reason I switched to the EG4 6500EX inverters which did not work out well. The EG4 charge controller on the other hand has worked quite well, I've had the one running since July 4th and the second unit since about August 1st. These units do have a firmware update available, it is to fix a phantom F01 code that sets in low light conditions.

I bought panel’s according to the recommended configuration in the manual. I found out that their configuration only works if you live in the tropics. I think your idea of using EG4 MPPT charge controllers will allow me to utilize all my panels.

 

[Ronnie B]

It will clip when over the Isc, but that also is a waste of potential yield. With 3270W total potential yield you are limited considering the idle consumption of the LV6548 is about 80W. It will take 1920Wh just to run the LV6548 for 24 hours unless you have it connected on AC input, then it will draw the 1920Wh from the grid.

I'm running JA Solar 530W panels, VOC is 49.65V, ISC is 13.43A and I run 8S. I do not use the MPPT's in the LV6548's. Originally I had a pair of EG4 6500EX's and the max I could pull thru those MPPT's was 3.9Kw with the 4.24Kw strings. When I first installed the LV6548's, I ran 4S and noticed yield was better simply because I was keeping the amperage down. I ordered a pair of EG4 MPPT100-48HV and installed one with 8S while leaving one of the 4S strings on a LV6548. Array is 420 feet one way distance and I wanted to compare to see if the higher voltage made a difference. The 4S string was interesting and you have to remember the MPPT algorithm is different. In full sun with peak power, the 4S string would not output 1/2 the 8S string. In overcast or partly cloudy conditions, including low light morning/evening, the 4S would output more than 1/2 the 8s string. My guess is the amps were higher during peak sun and lower during other conditions and why I was seeing these results.

Since then I finished install of the second EG4 unit, my Youtube channel shows the setup. Both EG4 charge controllers are running 8S. I pulled 4.3Kw off each string during the summer with hazy skies at peak sun. Recently I was checking some things on a partly cloudy day and saw over 5Kw per string with cloud edge effect and with the clear skies I would see 4.6Kw per string for extended times other than cloud edge effect. Pretty amazing off 4.24Kw of panels.

I do recommend considering using a separate charge controller with those panels simply because they won't fit well with the LV6548 MPPT limits. If you decide down the road to add more PV, which I'm certain you will, then you could source panels that better fit the lower VOC limit of the LV6548 MPPT.

If I do add more panels, it will be closer to the house and I will find the best fit for the 250V limit. It's all about options and the EG4 unit is really a very good deal. You could add 2 more of your current panels and run it thru the EG4 unit. I purchased the JA Solar panels at the time because it was a deal I couldn't turn down but those higher VOC panels do not fit well with the 250V limits. Part of the reason I switched to the EG4 6500EX inverters which did not work out well. The EG4 charge controller on the other hand has worked quite well, I've had the one running since July 4th and the second unit since about August 1st. These units do have a firmware update available, it is to fix a phantom F01 code that sets in low light conditions.

If you don’t mind me asking, how much battery are you using with your two LV6548’s? You have a DIY battery setup right?

 

[Zwy]

If you don’t mind me asking, how much battery are you using with your two LV6548’s? You have a DIY battery setup right?

58Kwh DIY, but adding another 14Kwh soon using a Luyuan box. If you look at my signature at the bottom of my post, you will see the blue links to threads of my system.

We can go 5 days without limited sun in winter by cutting any unnecessary usage, thus the reason for the extra 14Kwh so we can go at least 6 days. For one full year, grid usage came to 3% of total Kwh used.