Series AND parallel?

[New England Rhinoceros]

I am new to solar and am 100% off grid. I have Eighteen 370 watt panels, two lv6548 inverters and two 9.2kw Big Batteries. My panels are wired 2 sets of 4 in series going to one inverter and 2 sets of 5 in series going to the other. This is what was recommended for wiring for my system. I am a home inspector by trade but being new to solar there is a lot I still don't understand. It looks as though I could use the two communication cables to connect my inverters and that would give the inverters the ability to function in parallel as well? Are the inverters able to figure out what my needs are and change that function for me? Do my panels need to be wired in parallel for this to work? I'm confused, have a LOT invested in this system and am terrified of messing it up. Its almost Halloween and winter is closing in on northern NH and I need the power for my heat and my water. HELP!

 

[MisterSandals]

What is the Voc of each panel and what are the solar input range and MPPT (optimal) range of the lv6548?

The panel configuration needs to meet the SCCs limitations first, and if possible, hit the MPPT range as well. Array voltage too low and your SCC will not startup; too high and you fry the SCC..

 

[MisterSandals]

Messing with numbers:
370W x 18 = 6660W
Avg solar day 5h x 6660W = 333000Wh
2x 9200Wh batteries = 18400Wh. (Lead acid? divide by 2 for usable)
18400Wh / 6660W = 2.7h to recharge from empty if 18400Wh usable

NH “may” be more like 2h solar day in winter. Also depends on how well array positioned and tilted.

 

[New England Rhinoceros]

What is the Voc of each panel and what are the solar input range and MPPT (optimal) range of the lv6548?

The panel configuration needs to meet the SCCs limitations first, and if possible, hit the MPPT range as well. Array voltage too low and your SCC will not startup; too high and you fry the SCC..

The Voc per panel is 41.0. The range for the lv6548 is 90Vdc-230Vdc. Each inverter can handle two strings of 6 panels in series, I only have 2 strings of 4 and 3 strings of 5. The inverters need 80Vdc to start up. What is SCC?

 

[rodrick]

Scc solar charge controller

 

[Bud Martin]

What is the max PV input Voltage spec of the LV6548? 250V?

 

[New England Rhinoceros]

What is the max PV input Voltage spec of the LV6548? 250V?

Max PV input is 250Vdc.

 

[New England Rhinoceros]

The Voc per panel is 41.0. The range for the lv6548 is 90Vdc-230Vdc. Each inverter can handle two strings of 6 panels in series, I only have 2 strings of 4 and 3 strings of 5. The inverters need 80Vdc to start up. What is SCC?

*2 strings of 4, 2 strings of 5. Not three. Clumsy typing...

 

[rodrick]

120 amp 250 v make sure to calculate temperature adjustment for the cold temps in winter

 

[New England Rhinoceros]

120 amp 250 v make sure to calculate temperature adjustment for the cold temps in winter

does the parallel connection cable make the system run in parallel even though the panels are wired in series? Or does that just allow the two inverters to communicate with eachother?

 

[MisterSandals]

The Voc per panel is 41.0. The range for the lv6548 is 90Vdc-230Vdc

4 or 5 in series work well with plenty of room for temp compensated (increases when colder) voltage.

does the parallel connection cable make the system run in parallel even though the panels are wired in series?

Not sure what parallel connection cables you are referring to. You have 4 salar strings and 4x solar inputs so no paralleling necessary.

I think the primary benefit of connecting the lv6548s (in parallel?) would be to work together charging batteries. Maybe someone here has experience with that.

 

[New England Rhinoceros]

4 or 5 in series work well with plenty of room for temp compensated (increases when colder) voltage.


Not sure what parallel connection cables you are referring to. You have 4 salar strings and 4x solar inputs so no paralleling necessary.

I think the primary benefit of connecting the lv6548s (in parallel?) would be to work together charging batteries. Maybe someone here has experience with that.

I am thinking that too. It seems like odd phrasing to call them "parallel cables" given the capacity with solar to wire in series OR parallel. I believe its just a communication cable so the inverters can work together. Every example I have seen with two or more of this type of inverter shows them using those cables. There is an example of it in this forum under the 48v blueprints section. Thanks for your input, I appreciate it.

 

[rodrick]

The parallel cable phases the inverters for 240 volt or to run them in 120 volt sharing the load is my understanding at least that’s what it does for the 2424mds also made by mpp

 

[New England Rhinoceros]

The parallel cable phases the inverters for 240 volt or to run them in 120 volt sharing the load is my understanding at least that’s what it does for the 2424mds also made by mpp

Thank you Rodrick, that is what I'm figuring out. I appreciate the feedback.

 

[rodrick]

Hey we are all learning here Will made a great site for all of us to benefit from we owe him many thanks!

 

[New England Rhinoceros]

Hey we are all learning here Will made a great site for all of us to benefit from we owe him many thanks!

You aren’t kidding.