• Have you tried out dark mode?! Scroll to the bottom of any page to find a sun or moon icon to turn dark mode on or off!

diy solar

diy solar

EG4 18Kpv MPPT MAX 500 volt - Headroom?

garybryan33

New Member
Joined
Aug 22, 2023
Messages
64
Location
California
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
 
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.


1713214531469.png
 
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.
 
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?
 
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.
 
Max DC input voltage range for the 18kPV is 600VDC. Operating voltage range max would be 500VDC.


View attachment 209512
Hi EG4 Team.

Please be advised that this link now bring us to a version of the document that doesn't have the optimum pv input range at all like your screenshot does ...this is causing problems for your customers with smaller strings as seen in a couple of threads:
1713214531469.png
Screenshot_20250203_084425_Samsung Notes.jpg
 
Last edited:
I don't see any confusion here.
I don't know what the semiconductors are rated for in the mppt but the capacitors are 630 volt.
The mppt will work between 140 and 500 volts, absolute best efficiency is at 360 volts.
Use the official string calculator here
The old spec sheet in yellow has the entry:
"Full Power MPPT Voltage Range 230V-500V"

The new spec sheet doesn't have that entry at all. Just the 140V-500V operating range entry.
 
The old spec sheet in yellow has the entry:
"Full Power MPPT Voltage Range 230V-500V"

The new spec sheet doesn't have that entry at all. Just the 140V-500V operating range entry.
The previous spec sheet is outdated, which is why we created an updated version. However, the operating voltage range remains between 140V and 500V, with a nominal MPPT voltage of 360V.
 
The previous spec sheet is outdated, which is why we created an updated version. However, the operating voltage range remains between 140V and 500V, with a nominal MPPT voltage of 360V.
In the previous spec sheet it was clear that one needed to design for 230V minimum string voltage for expected full performance. That's a full 90V over the operating minimum in the new sheets.

In the updated spec sheet for the 18kpv and Flexboss21 there is no entry for this so someone who doesnt go digging in the manual could put a string together that just hits 140V and get garbage performance.

You've taken away a valuable entry in the spec sheet and buried it in the manual for some reason.
 

diy solar

diy solar
Back
Top