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455w or 540w panels?


Terminal3k

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Hi guys,

Im busy looking at what panels to buy.  Panels are hard to source at the moment and very expensive.  

I dont have a problem with roof space.  The 455w are quite a bit cheaper than the 540w per watt.

I have a sunsynk 5kw and looking to install between 5000w - 6000w.

I would like some opinions of what panels to choose.  I know the voltage per watt is lower on the 540's and they are more efficient, but they are more expensive per watt.

Please give me some perspective?

thanks!

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1 minute ago, Terminal3k said:

really good, thanks! and in winter time? hows the production?

Hard to say as i only had 5 panels per string at that time , Production was about 200-300kwh a month with 10 panels in peak winter.

having higher string voltage will be allot better than the lower voltage you will be running at with the 540w panels. This morning my one string hit 11,9 amps@ 300~ volts. 

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2 minutes ago, Nexuss said:

Hard to say as i only had 5 panels per string at that time , Production was about 200-300kwh a month with 10 panels in peak winter.

having higher string voltage will be allot better than the lower voltage you will be running at with the 540w panels. This morning my one string hit 11,9 amps@ 300~ volts. 

does the higher voltage help with production?

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9 minutes ago, Terminal3k said:

540w 12.97

455w 9.93

please help me understand why is this important?

5kW Sunsynk Hybrid Inverter

  • Max power input – 6500W
  • Max V DC input – 370V (100V~500V)
  • Max current input – 11A + 11A

the Jinko 470w does 10-11A output and is R6.70 per watt

  • Nominal Max. Power (Pmax): 470W
  • Opt. Operating Voltage (Vmp): 43.28V
  • Opt. Operating Current (Imp): 10.86A

maybe consider 7x 470w per mppt, so 14x 470w in total

you'll run on 300v per mppt, and around 10A, total pv power 6580W

 

Edited by Nitrious
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Just now, Terminal3k said:

does the higher voltage help with production?

Yes , the mppt's run the most efficient with voltage as close to 370V as possible. Even with my 8 panels per string i only operate around 300 volts. 9 Panels would be ideal on a string but then you are oversizing the PV quite a bit and its less economical that way (unless you ran 18- 400w Panels) that would be the most ideal. At minimum i would go with 14 of the 455W panels-7 per string .

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5 minutes ago, Nitrious said:

Max power input – 6500W

Max V DC input – 370V (100V~500V)

Max current input – 11A + 11A

the Jinko 470w does 10-11A output and is R6.70 per watt

Nominal Max. Power (Pmax): 470W

Opt. Operating Voltage (Vmp): 43.28V

Opt. Operating Current (Imp): 10.86A

thanks, Where is the 470w Jinko available from for R6.70?

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The 5 kW is now rated at 13 amps, my inverter is over a year old, so had a firmware update done to achieve the 13 amps, but based on the cost and not having roof space issues, go with the 455's

the amps are relatively important, eg if the mppt was rated for 11 amps and you had 13 amp panels, mid day you would have clipping, which is not really a problem, but you would be wasting pv production

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2 minutes ago, YellowTapemeasure said:

The 540W panels are closer to the 13A limit of the 5K Sunsynk's MPPT. Optimised and simpler configuration.

Running at higher voltage and lower amps will allways be more ideal. My 455w panels hit almost 12 amps ,the 540w panels will definitely go over 13 ,so you are being clipped on amps and you are running lower string voltage with the 540W panels ,so its much worse.

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17 minutes ago, Nitrious said:

5kW Sunsynk Hybrid Inverter

  • Max power input – 6500W
  • Max V DC input – 370V (100V~500V)
  • Max current input – 11A + 11A

the Jinko 470w does 10-11A output and is R6.70 per watt

  • Nominal Max. Power (Pmax): 470W
  • Opt. Operating Voltage (Vmp): 43.28V
  • Opt. Operating Current (Imp): 10.86A

maybe consider 7x 470w per mppt, so 14x 470w in total

you'll run on 300v per mppt, and around 10A, total pv power 6580W

 

thanks, this sounds like a good plan.

my summer usage is about 20kw and my winter is about 25-30kw.

Im going to have 1 x 5.5 hubble battery installed now, with the hopes of putting in another one in winter time.

Will this 14 x 470w be too much for me now? bearing in mind i would like to save as much as i can during winter too

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7 minutes ago, Nexuss said:

Running at higher voltage and lower amps will allways be more ideal. My 455w panels hit almost 12 amps ,the 540w panels will definitely go over 13 ,so you are being clipped on amps and you are running lower string voltage with the 540W panels ,so its much worse.

 

Clipping of the amps will only occur when there is no load, so that power is wasted in anycase, 12.9A is current under load, so it (theoretically) won't be clipped.

Agreed that higher voltage is generally better, as long as it is within the operating range. 

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4 minutes ago, Terminal3k said:

will this 14 x 470w be too much for me now? bearing in mind i would like to save as much as i can during winter too

Its really hard having too much solar in winter ,that is how i ended up buying more panels haha . If all your panels are facing the same direction i would go for 14 , for east/west split go for 16 . 

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Just now, Terminal3k said:

If i were to get 8 x 455w (53.87v voc), then i would be running at 430v per MPPT. would that be safe?

Yes that is perfectly safe and its what i am running currently. Heres the specs from the inverter right now.

PV1
289.60V
10.70A
3.058kW
PV2
297.20V
10.70A
3.123kW
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59 minutes ago, Nexuss said:

I run 2 strings of 8 panels 455wJA solar on my 5kw Sunsynk. I made 48 kwh the other day.  Very happy with them.

 

2 minutes ago, Terminal3k said:

If i were to get 8 x 455w (53.87v voc), then i would be running at 430v per MPPT. would that be safe?

found the answer to my question, nevermind :)

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