Low Panel Output

[PWB]

Hi All,

this is my first post here, I'm a bit of a noob in this field and hope to get some advice here to optimize my system.

I have 16 x 620W panels installed on my roof (=9.92kW). Unfortunately 11 of these are east-facing (+/- 25°) and only 5 are north-facing (+/- 30°).

I am currently only getting a maximum 5.5kW at around 11h00. By 13h00 this drops to around 4kW!

I only start having a bit of shade on 2 panels at around 15h00, so shade is not the problem.

Does this sound right? What is the maximum output that I should be expecting in this configuration?

Cheers,

Pete

 

[kommando]

How many strings and which panels are part of which string. What inverter, how many MPPT's does the inverter have.

 

[PWB]

How many strings and which panels are part of which string. What inverter, how many MPPT's does the inverter have.

Hi Kommando,

thank you for your quick reply!

I have a Sunsynk 12kW 3 Phase Hybrid Inverter, which has two MPPT's. The north-facing panels are on one string and the east-facing panels are on a second string. Each string is wired in series and connected to a separate MPPT.

• PV input Voltage (V): 550V (150V-800V).
• MPPT Range (V): 200-650V.

The panels are Jinko NEO N-Type 620W Mono-Facial Solar Panels (Opt. Operating Voltage (Vmp): 45.79V)

So 11 x 45.79 = 503.69V and 5 x 45.79 = 228.95V

Cheers,

Pete

 

[BentleyJ]

Link to system estimator based on geographic location.

PVWatts

Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations

pvwatts.nrel.gov

 

[kommando]

The 11 panels look fine but will suffer from pointing east and so drop output in the afternoon, the 5 panels look to be close to the 200V MPPT. I would check the voltage your inverter is recording from the 5 north panels and the wattage, if its low then can you get another panel on that string also pointing north to get the volts and power higher into the MPPT range.

 

[PWB]

The 11 panels look fine but will suffer from pointing east and so drop output in the afternoon, the 5 panels look to be close to the 200V MPPT. I would check the voltage your inverter is recording from the 5 north panels and the wattage, if its low then can you get another panel on that string also pointing north to get the volts and power higher into the MPPT range.

Thanks Kommando,

that makes sense, I will check that.

I should have given you my location, which is Johannesburg, South Africa.

Cheers,

Pete

 

[PWB]

Link to system estimator based on geographic location.

PVWatts

Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations

pvwatts.nrel.gov

Thank you Bentley, I'll check it out!

 

[kommando]

I got that as I had to check if your north was the same as my south

You are well south and its your winter so that will affect it to, hence the need to also check using the link provided by @BentleyJ to see what your area could provide. For me Winter is a washout with less than 20% of summer output.

 

[PWB]

Oh wow, so I shouldn't complain about "only" getting 55% I guess!

I also found a reference for Cape Town on another forum, which calculated 50% for east-facing panel on 1 July. Cape Town is a good 6° further south, so I'm in the ballpark.

I just wanted to be sure that there is nothing fundamentally wrong with my installation.

Thanks again for all the help!