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Configuring panels for my inverter

mnakkach

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Feb 3, 2022
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I am configuring the right panels for my inverter

Can you please help in finding the right panels for my inverter?

Inverter is Voltronic Infinisolar V IV with followig specs:
Maximum PV input power: 6000w
Maximum PV DC voltage: 450VDC
MPP voltage range: 120VDC – 430 VDC

Current panel I found in the market
Longi 545 Hi-MO5
Pmax STC:545w
Pmax NOCT: 407w
Voc STC : 49.65V
Voc NOCT: 46.55V

If I configure 9 in series I will get
446.85V which is good, close and less than 450v of the inverter’s max PV
4905w, which is way lesser than 6000w of the inverter’s max PV input power

If I configure 10 panels, 5 in series, 2 sets in parallel, I will get 5450w, not high enough but lower volts. 12 panels is overkill on watts.

Shall I look at other panels or any other suggestions with the above Longi panel?

Thank you
 
If I configure 9 in series I will get
446.85V which is good, close and less than 450v of the inverter’s max PV
No, you need to have 15-20% volts leeway in case it gets colder than 25C (77F) where the panel voltage is rated.

What is the battery(s) that you are charging? What will your system voltage be?

Have you looked for big cheap panels in your area on craigslist for example?
 
No, you need to have 15-20% volts leeway in case it gets colder than 25C (77F) where the panel voltage is rated.

What is the battery(s) that you are charging? What will your system voltage be?

Have you looked for big cheap panels in your area on craigslist for example?
ok, so i keep 15-20% volts leeway, what about watts? is it ok to configure panels at 99% of max pv input of inverter? I haven't yet purchased batteries but looking for 48v 200ah-300ah lithium
 
is it ok to configure panels at 99% of max pv input of inverter?
Yes, its called over paneling and helps maximize SCC capabilities in low light conditions; morning, evening, cloudy.

Have you done a power audit to see how much energy and number of panels you need?

48V x 200Ah = 9600Wh

9600Wh / 5h solar = 1920W solar to recharge battery 100%
 
Yes, its called over paneling and helps maximize SCC capabilities in low light conditions; morning, evening, cloudy.

Have you done a power audit to see how much energy and number of panels you need?

48V x 200Ah = 9600Wh

9600Wh / 5h solar = 1920W solar to recharge battery 100%
Yes, the mentioned formula should be fine with me, also, the inverter is hybrid, i can use the grid to charge the batteries if needed.

My main worry is up to what % to configure panels for inverter? 80% on volts and 99% on watts? as per the inverter's manual it says 99% on volts and 99% on watts. We are talking about STC only, not NOCT.
 
2 strings of 12 x 240 or 250 watt panels, puts you in the sweet spot.
 
My main worry is up to what % to configure panels for inverter? 80% on volts and 99% on watts? as per the inverter's manual it says 99% on volts and 99% on watts. We are talking about STC only, not NOCT.
80% of max input voltage is a good estimate. If you know the lowest temp your panels will be in (record lows), this can be more precisely calculated. Its about .35% voltage increase for every degree below 25C.

Some folks over panel 25-50% of max usable watts. (which is max charging amps x charging volts).
 
Keep in mind that it's good to use the panel specs as a guide to configure your array. Bearing in mind that you don't live in the perfect conditions of the testing lab. It's unlikely that you will see more than 85% of the rated output.
 
80% of max input voltage is a good estimate. If you know the lowest temp your panels will be in (record lows), this can be more precisely calculated. Its about .35% voltage increase for every degree below 25C.

Some folks over panel 25-50% of max usable watts. (which is max charging amps x charging volts).
But again we are talking about STC where the 49.65v is measured in lab with optimum environment, at 0c and 1000w/m. which means if i won't be getting this voltage on earth, but, even if i reached this peak it won't be above the max of inverter. isn't?
 
Keep in mind that it's good to use the panel specs as a guide to configure your array. Bearing in mind that you don't live in the perfect conditions of the testing lab. It's unlikely that you will see more than 85% of the rated output.
ok, but i wanted to make sure if it is ok to put pv together to match voc with max pv of inverter and watts to max watts of inverter measured at STC.
 
My inverter has the same specs. I have 2 strings of 11 x 250 watt panels currently connected. But, they are on an east facing roof. My system has been up and running for the last month. I'm waiting for summer to see how my max production is. Currently I have see a max of 388v, 14a, and 4kw. (Not recorded at the same time together) I am planning to add a 12th panel to each string, after I see how it goes, this summer.
And probably another string on the west side of the roof.
 
My inverter has the same specs. I have 2 strings of 11 x 250 watt panels currently connected. But, they are on an east facing roof. My system has been up and running for the last month. I'm waiting for summer to see how my max production is. Currently I have see a max of 388v, 14a, and 4kw. (Not recorded at the same time together) I am planning to add a 12th panel to each string, after I see how it goes, this summer.
And probably another string on the west side of the roof.
what is the voc of your panels?
 
Ok, i conclude I can do over paneling for watts but volts i should remain under by 10-15%?
 
My PV is 49.65v , 545 w, planning to configure 6 in series 2 strings. This will give 297v in STC and 279v in NOCT.

Isn't low volts? I heard PV will not perform well in low light since MPP range is 120v to 430v
 
You're in the range. But, I prefer to be at the top of the range. It helps on cloudy days.
 
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