Combiner box limits?

[BackTOschool]

Hello, I would be really grateful for experienced persons thoughts / input as I'm trying to avoid a mistake....


I have a 2S4P system that I am installing.
8 identical Panels, each panel: 330W, 32.6V (VMP), 10.2A (IMP) 10.9 (ISC)

My array is East / West, as a result I am over-panelling.
My 2S4P array "should" produce a maximum 64V, 40A, and 2,560 Watts.
My system is 12v.

My MPPT will limit the Watts input to 1000 watts.
I am thinking of using The Eco-Worthy 6 string combiner box, which has a "max input solar wattage limit for 12v systems of 1080W"

My thinking (which may be flawed) is that the MPPT will only draw 1000w limit, which is below the 1080w limit of the box

Question:
Can I use the combiner box for my system?

kind regards
Steve.

 

[Hedges]

Combiner box does not have a watts limit, mostly an amps limit. Possibly order of connecting wires can let that be doubled, if connections are made so only half the current travels in any portion of a busbar.
Also a volts limit, any fuse or breaker likely the limiting factor.

MPPT typically limits its draw to some output current. What is that spec? What is max battery voltage? How many watts is that? What is lowest Vmp of your array, and what current do deliver such watts?

East/West facing means peak current available will be lower than about 40A (varies with lighting).
Consider any conditions of short circuit that would not blow a fuse, rather put continuous current through combiner.

6 String PV Combiner Box with Lightning Arrester & 10A Rated Current Fuse & Circuit Breakers for On/Off Grid Solar System | ECO-WORTHY

ECO-WORTHY 6 String PV Combiner Box is suitable for photovoltaic grid-connected and off-grid power generation systems. 6 String Configuration, Max current of single PV input array is 10A. Each String Continuous Duty Rated at DC 250V. Single PV input array installs with high voltage fuse, its...

www.eco-worthy.com

That sounds like 10A per string, not a watts limit.

"10.9 (ISC)"

Fuse size should be at least 10.9A x 1.56 = 17A. How does that compare with what PV panel label says?

Does combiner box spec/manual name a maximum size fuse? I can't find it.

I would consider wire gauge, see if it is sufficient for 17A.
And I would consider changing order of wires in busbars so 2x PV inputs feed one end, 2x feed other end, and output breaker taps the middle. So only half the current flows through cross section of busbar (if not already ordered that way.)

 

[Mattb4]

May not be an issue but you need to use Voc and not Vmp for max voltage. Regarding the combiner box. Its max limit is the limit of how much it will handle before a fuse blows or the breaker trips. Since solar panels only give as much as the load demands (and the sun can provide) you will have to ensure your SCC and subsequent loads do not exceed the max rating. This can be deceptive because if your SCC is 80amp at 12v and 80a at 14.5v you have a different wattage to deal with (960w vs 1160w)

 

[BackTOschool]

Combiner box does not have a watts limit, mostly an amps limit. Possibly order of connecting wires can let that be doubled, if connections are made so only half the current travels in any portion of a busbar.
Also a volts limit, any fuse or breaker likely the limiting factor.

MPPT typically limits its draw to some output current. What is that spec? What is max battery voltage? How many watts is that? What is lowest Vmp of your array, and what current do deliver such watts?

East/West facing means peak current available will be lower than about 40A (varies with lighting).
Consider any conditions of short circuit that would not blow a fuse, rather put continuous current through combiner.

6 String PV Combiner Box with Lightning Arrester & 10A Rated Current Fuse & Circuit Breakers for On/Off Grid Solar System | ECO-WORTHY

ECO-WORTHY 6 String PV Combiner Box is suitable for photovoltaic grid-connected and off-grid power generation systems. 6 String Configuration, Max current of single PV input array is 10A. Each String Continuous Duty Rated at DC 250V. Single PV input array installs with high voltage fuse, its...

www.eco-worthy.com

That sounds like 10A per string, not a watts limit.

"10.9 (ISC)"

Fuse size should be at least 10.9A x 1.56 = 17A. How does that compare with what PV panel label says?

Does combiner box spec/manual name a maximum size fuse? I can't find it.

I would consider wire gauge, see if it is sufficient for 17A.
And I would consider changing order of wires in busbars so 2x PV inputs feed one end, 2x feed other end, and output breaker taps the middle. So only half the current flows through cross section of busbar (if not already ordered that way.)

Combiner box does not have a watts limit, mostly an amps limit. Possibly order of connecting wires can let that be doubled, if connections are made so only half the current travels in any portion of a busbar.
Also a volts limit, any fuse or breaker likely the limiting factor.

MPPT typically limits its draw to some output current. What is that spec? What is max battery voltage? How many watts is that? What is lowest Vmp of your array, and what current do deliver such watts?

East/West facing means peak current available will be lower than about 40A (varies with lighting).
Consider any conditions of short circuit that would not blow a fuse, rather put continuous current through combiner.

6 String PV Combiner Box with Lightning Arrester & 10A Rated Current Fuse & Circuit Breakers for On/Off Grid Solar System | ECO-WORTHY

ECO-WORTHY 6 String PV Combiner Box is suitable for photovoltaic grid-connected and off-grid power generation systems. 6 String Configuration, Max current of single PV input array is 10A. Each String Continuous Duty Rated at DC 250V. Single PV input array installs with high voltage fuse, its...

www.eco-worthy.com

That sounds like 10A per string, not a watts limit.

"10.9 (ISC)"

Fuse size should be at least 10.9A x 1.56 = 17A. How does that compare with what PV panel label says?

Does combiner box spec/manual name a maximum size fuse? I can't find it.

I would consider wire gauge, see if it is sufficient for 17A.
And I would consider changing order of wires in busbars so 2x PV inputs feed one end, 2x feed other end, and output breaker taps the middle. So only half the current flows through cross section of busbar (if not already ordered that way.)

Thank you, for your time in answering my questions.
kind regards
Steve