EG4 18Kpv MPPT MAX 500 volt - Headroom?

[garybryan33]

The worst-case scenario brings me within 19 volts of max. What is the consensus?

• Total string OC voltage: 450.09
• Nominal maximum power: : 4050
• Worst case temperature: -1.1
• Temperature coefficient (Voc): -0.27
• Temperature coefficient (Pmax): -0.34

For these, your:

• Total worst case differential is: 26.1
• Your voltage increase (%) is: 7.047
• Your voltage increase (V) is: 31.7178423
• Your maximum voltage (V) is: 481.8078423
• Your Pmax increase is (%): 8.874
• Your Pmax increase is (W): 359.397
• Your total Pmax at this temperature is (W): 4409.397

 

[timselectric]

Too close for my comfort. But, maybe it will be OK.

 

[sunshine_eggo]

There is zero tolerance on exceeding Voc limits.

Check your record low temperature against this chart:



Apply the correction value and do not exceed that value, e.g., if your record low is freezing, divide your max Voc by 1.10, and do not exceed that voltage when summing STC Voc values.

 

[EG4_Jared]

The worst-case scenario brings me within 19 volts of max. What is the consensus?

• Total string OC voltage: 450.09
• Nominal maximum power: : 4050
• Worst case temperature: -1.1
• Temperature coefficient (Voc): -0.27
• Temperature coefficient (Pmax): -0.34

For these, your:

• Total worst case differential is: 26.1
• Your voltage increase (%) is: 7.047
• Your voltage increase (V) is: 31.7178423
• Your maximum voltage (V) is: 481.8078423
• Your Pmax increase is (%): 8.874
• Your Pmax increase is (W): 359.397
• Your total Pmax at this temperature is (W): 4409.397

Max DC input voltage range for the 18kPV is 600VDC. Operating voltage range max would be 500VDC.

https://eg4electronics.com/backend/wp-content/uploads/2023/04/EG4-18KPV-12LV-Spec-Sheet.pdf

 

[garybryan33]

Max DC input voltage range for the 18kPV is 600VDC. Operating voltage range max would be 500VDC.

I am a bit lost with the difference between the DC input range and the full-power MPPT voltage range. If I understand, the 18Kpv can support intake voltage from an array up to 600 volts.

 

[garybryan33]

Apply the correction value and do not exceed that value, e.g., if your record low is freezing, divide your max Voc by 1.10, and do not exceed that voltage when summing STC Voc values.

Using my case as an example, using freezing as a record low, I should keep my solar panel array at or below 409 volts?

 

[sunshine_eggo]

I am a bit lost with the difference between the DC input range and the full-power MPPT voltage range. If I understand, the 18Kpv can support intake voltage from an array up to 600 volts.

It wasn't clear your question was specifically about the MPPT operating range.

481V is under the 500V upper limit.

Using my case as an example, using freezing as a record low, I should keep my solar panel array at or below 409 volts?

No. You're confusing Vmp and Voc. Voc is the never exceed.

Vmp must be under 500V to get MPPT function. A 600V Voc array is going to peak at about 480Voc STC nominal.

Your array sounds fine to me.

 

[timselectric]

I agree
With this new information.