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Mppt voltage range

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ab1

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Hi,

I currently have 4 panels each 545w, all facing same direction. Is buying an inverter with lower mppt range like 100v to 460v, better than buying an inverter with mppt range like 120v to 450v.

Will I benefit from lower voltage range mppt in cloudy days, and will it start to harvest more solar power in early mornings?

Thanks in advance for your help.
 
There will be a rating plate on each of your panels, and that has all the information you need to select a suitable solar controller.

Maximum open circuit voltage (x4) will determine the required maximum input voltage rating of the controller, but there are two conditions where that voltage may increase "slightly" above that stated on the panel. Super cold freezing conditions, and cloud edge effect, might increase the voltage slightly, so allow a safe voltage margin of perhaps ten percent minimum.
You don't need a 400v controller for only four panels in series.

Likewise there will be a maximum power voltage rating for each panel. That is where the controller will spend most of its time under all operating conditions where the panels are supplying usable power.

Rated power and current of the controller obviously needs to be sufficient.
No need to over specify your controller, UNLESS you are planning future upgrades.
 
It depends on how much time you will be spending closer to the lower end of the range.
 
You have actually put the cart before the horse.
You should pic panels that match your SCC, not the other way around.
Solar panels should be the last decision, when designing a system.
 
timselectric said:
You have actually put the cart before the horse.
You should pic panels that match your SCC, not the other way around.
Solar panels should be the last decision, when designing a system.
Click to expand...
There is truth in that.
Trying to find a controller for 12v at 200 amps might be as difficult, as finding a 1,000 volt ten amp controller.
A sensible compromise of how the panels are connected and finding a pretty average controller to work with should not be difficult.
 
ab1 said:
Hi,

I currently have 4 panels each 545w, all facing same direction. Is buying an inverter with lower mppt range like 100v to 460v, better than buying an inverter with mppt range like 120v to 450v.

Will I benefit from lower voltage range mppt in cloudy days, and will it start to harvest more solar power in early mornings?

Thanks in advance for your help.
Click to expand...
You need to look at the specs for the panels. Something like JA Solar 545W bifacials will be around 50V for VOC rating. Times 4 panels in series comes to 200V plus temp coefficient in colder temps.

You might be better served with the lower voltage SCC, either one will probably work just fine. But you need to look at the panels specs first.
 

Here are my panels specs:​

  • Jinko 545w, not bifacial.​

  • Rated Power-P Max(STC): 545W​

  • Open Circuit Voltage-Voc (STC): 49.52V​

  • Short Circuit Current - ISC (STC): 13.94a​

  • Max Power Voltage - Vmpp (STC): 40.80V​

  • Max power Current - Impp (STC): 13.36A​

  • Module Efficiency: 21.94%​

  • Max Power - P max(NMOT): 405W​

  • Open Circuit Voltage - Voc (NMOT): 46.74V​

  • Short Circuit Voltage - ISC (NMOT): 38.25V​

  • Max Power Current - Impp (NMOT): 10.60A​

 
ab1 said:

Here are my panels specs:​

  • Jinko 545w, not bifacial.​

  • Rated Power-P Max(STC): 545W​

  • Open Circuit Voltage-Voc (STC): 49.52V​

  • Short Circuit Current - ISC (STC): 13.94a​

  • Max Power Voltage - Vmpp (STC): 40.80V​

  • Max power Current - Impp (STC): 13.36A​

  • Module Efficiency: 21.94%​

  • Max Power - P max(NMOT): 405W​

  • Open Circuit Voltage - Voc (NMOT): 46.74V​

  • Short Circuit Voltage - ISC (NMOT): 38.25V​

  • Max Power Current - Impp (NMOT): 10.60A​

Click to expand...
Four of those should be well beyond 120V with first light. Current will come as brightness increases. So in this case I don't believe you'll have any significant output advantage with a 100V minimum SCC versus a 120V minimum.
 
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