June 11, 20242 yr I'm trying to work out how I can optimise my solar panels for less sun in winter by increasing the voltage and current of the 2 x solar arrays, as well as switching to mono panels which should be more efficient on cloudy winter days. My current setup looks like this: 20 x 250W poly solar panels Vmp: 30.1V Imp: 8.31A 10 x facing east 10 x facing north Sunny Boy 5000TL inverter 2 x MPPT charge controllers Max input voltage: 750V Rated input voltage: 400V Max input current: 15A x 2 Victron Multiplus 48V/5000/70 inverter 1380Ah flooded batteries According to my calculations I should be able to replace my 250W poly panels with the following 410W mono panels without blowing up my inverters 😉 22 x 410W mono solar panels Vmp: 31.2V Imp: 13.15A 11 x facing east 11 x facing north That will give me 342.2V at 13.15A per array in ideal conditions - still well within the Sunny's limits. Furthermore, since my panel placement isn't optimal I should never come close to the 750V limit. Does this make sense or am I missing something interpreting the limits of these devices? What worries me is that this will result in substantially more than 5KW of solar in summer, potentially damaging the inverter.
June 11, 20242 yr 17 minutes ago, drjeep said: I'm trying to work out how I can optimise my solar panels for less sun in winter by increasing the voltage and current of the 2 x solar arrays, as well as switching to mono panels which should be more efficient on cloudy winter days. My current setup looks like this: 20 x 250W poly solar panels Vmp: 30.1V Imp: 8.31A 10 x facing east 10 x facing north Sunny Boy 5000TL inverter 2 x MPPT charge controllers Max input voltage: 750V Rated input voltage: 400V Max input current: 15A x 2 Victron Multiplus 48V/5000/70 inverter 1380Ah flooded batteries According to my calculations I should be able to replace my 250W poly panels with the following 410W mono panels without blowing up my inverters 😉 22 x 410W mono solar panels Vmp: 31.2V Imp: 13.15A 11 x facing east 11 x facing north That will give me 342.2V at 13.15A per array in ideal conditions - still well within the Sunny's limits. Furthermore, since my panel placement isn't optimal I should never come close to the 750V limit. Does this make sense or am I missing something interpreting the limits of these devices? What worries me is that this will result in substantially more than 5KW of solar in summer, potentially damaging the inverter. For the Vmax you should be looking at 11xVoc plus 8% for a lowest temp of about 0°. You will be very far from the 750V Edited June 11, 20242 yr by Scorp007
June 11, 20242 yr Author 5 hours ago, Scorp007 said: For the Vmax you should be looking at 11xVoc plus 8% for a lowest temp of about 0°. You will be very far from the 750V Thanks @Scorp007 So really what makes the Sunny a 5KW inverter is the fact that it can output 5KW but that limit doesn't apply to solar input - as long as you stay within the input voltage range it's safe? Should I be concerned about amps at all or does it regulate that by itself? Edited June 11, 20242 yr by drjeep
June 11, 20242 yr 2 hours ago, drjeep said: Thanks @Scorp007 So really what makes the Sunny a 5KW inverter is the fact that it can output 5KW but that limit doesn't apply to solar input - as long as you stay within the input voltage range it's safe? Should I be concerned about amps at all or does it regulate that by itself? It has the max indicated as 15A per MPPT so you are good on that too. One can normally go over as we only get a 100% irradiance for short periods in most parts of SA. Yes it would limit the PV input based on the wide level of the PV string voltage. The Vmp of panels you want to pitch below 400V and can even exceed but you then loose a % or 3 in efficiency. No train smash.
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