LV6048 Max (Amp) for PV String Question?

[diysolar81]

All, while I understand the Max voltage on a PV String is there a Max Amperage. I bought a LV6048 a couple years ago but haven't pushed it much. Originally had 2 x JA Solar panels ( 48.86 VOC with 1039 Isc) connected per MPPT. Now I have 3 APTOS 370W Bifacial Connected (41.4 VOC with 11.26 Isc) per string.

The LV6048 is 4000W input per MPPT with a total of 8000W Max PV input. I'm not trying to max out the system I would just like to add 6 more APTOS 370W panels to the system. I want to run a 2P3S configuration to add to my pergola. In the 2P3S configuration I would be at 125V VOC at 23A rounding up. I'm thinking 4000/145(Max Voltage of the PV String) gives about 27(A) rounding down. While I should be good increasing my system, what I'm really asking is does Amperage come into count besides the Max VOC for the PV Input?

 

[sunshine_eggo]

All, while I understand the Max voltage on a PV String is there a Max Amperage. I bought a LV6048 a couple years ago but haven't pushed it much. Originally had 2 x JA Solar panels ( 48.86 VOC with 1039 Isc) connected per MPPT. Now I have 3 APTOS 370W Bifacial Connected (41.4 VOC with 11.26 Isc) per string.

The LV6048 is 4000W input per MPPT with a total of 8000W Max PV input. I'm not trying to max out the system I would just like to add 6 more APTOS 370W panels to the system. I want to run a 2P3S configuration to add to my pergola. In the 2P3S configuration I would be at 125V VOC at 23A rounding up. I'm thinking 4000/145(Max Voltage of the PV String) gives about 27(A) rounding down. While I should be good increasing my system, what I'm really asking is does Amperage come into count besides the Max VOC for the PV Input?

I would do 3S2P (two strings of 3S in parallel).

This is a "low voltage" MPPT at 145Voc max. They do not have the Imp/Isc limit like the high voltage (250-500V) MPPT. Generally speaking, as this is a ~60A output MPPT, if your Isc is below 60A, you're good unless otherwise specified. At 60A, you'd likely be well over the 4000W limit, so little risk there.

I would be very okay with 3S4P of those panels per MPPT (4,440W)

 

[42OhmsPA]

I'd run some cold weather VOC calculations before going 3S.

Thread 'Maximum open circuit voltage calculator'

Feb 19, 2020

I'm posting this in a thread here since it might be useful for people. Please keep in mind that the below calculator contains bugs and doesn't do error checking - it's literally been 5 minutes to put together. Ok, so what does it do? It calculates the maximum open circuit voltage you would see on your solar panel string when the temperature drops. You just enter your Voc at 25C, the temperature coefficient (both should be available for panels in their datasheet, the former per panel and should be multiplied with the total panels per string in series, the latter is given as a percentage)...

• upnorthandpersonal
• Replies: 25
• Forum: Frequently Asked Questions

• 
• 

 

[sunshine_eggo]

I'd run some cold weather VOC calculations before going 3S.

Thread 'Maximum open circuit voltage calculator'

Feb 19, 2020

I'm posting this in a thread here since it might be useful for people. Please keep in mind that the below calculator contains bugs and doesn't do error checking - it's literally been 5 minutes to put together. Ok, so what does it do? It calculates the maximum open circuit voltage you would see on your solar panel string when the temperature drops. You just enter your Voc at 25C, the temperature coefficient (both should be available for panels in their datasheet, the former per panel and should be multiplied with the total panels per string in series, the latter is given as a percentage)...

• upnorthandpersonal
• Replies: 25
• Forum: Frequently Asked Questions

• 
• 

Assuming the very conservative -0.4%/°C, good down to -15°C (5°F).

Guessing this isn't a common low in Florida.

 

[42OhmsPA]

Assuming the very conservative -0.4%/°C, good down to -15°C (5°F).

Guessing this isn't a common low in Florida.

Hopefully not but it might help others later on.

 

[diysolar81]

I would do 3S2P (two strings of 3S in parallel).

This is a "low voltage" MPPT at 145Voc max. They do not have the Imp/Isc limit like the high voltage (250-500V) MPPT. Generally speaking, as this is a ~60A output MPPT, if your Isc is below 60A, you're good unless otherwise specified. At 60A, you'd likely be well over the 4000W limit, so little risk there.

I would be very okay with 3S4P of those panels per MPPT (4,440W)

Thanks for information I barely have enough space for the 3S2P configuration per string. With my 20 KWH of Batteries and Florida Sun this might just curve my 30 KWH daily usage.