bladerunnerpv
Well-known member
From comparing victron 250/85, 250/100, 450/100, my conclusion it that the 250/100 will handle the most PV panels [Edit...] in parallel and input power, the 450/100 will handle more panels as a single string but less input PV power than the 250/100
Have I got it right ? Please could someone cast an eye over the method for calculating string voltage and powers for different victron charge controllers please and let me know if I've made any howlers?
Thanks for taking a look
[Edit: I know there's an MPPT calculator on the victron site but you can't select one product and try different panel combinations on it !]
Panels 405W Qcell
https://midsummerwholesale.co.uk/pd...m-g11-series-390-410-30t-2022-06-rev02-en.pdf
I think:-
The 250/85 will take 6 panels in a string, or 2x5 in parallel, or 5panels into MPPT1 and 5panels into MPPT2
The 250/100 will take 6 panels in a string, or 2x6 in parallel, or 6panels into MPPT1 and 6panels into MPPT2, as it will cope with more PV power than the /85 model
The 450/100 will take 10 panels in a string, or 5panels into MPPT1 and 5panels into MPPT2,
It cannot be used for two strings in parallel due to PVmax of 18Amps
The Voc max is limited by the battery float voltage [Edit: to 8 x float voltage, which means it can be less than 450V]
String voltage at -10degC example calc, using STC of 25degC
e.g. Voc + Voc*((-0.27/100)*(-10-25))
e.g. 37.18 + 37.18*((-0.27/100)*(-10-25)) = 37.18+3.51 =40.69V
For the power limit then the panel's Pmpp and it's variation vs temperature is what to watch ?
Power at -10degC example calc
e.g. Pmpp + Pmpp*((-0.34/100)*(-10-25))
e.g. 405 + 405*((-0.34/100)*(-10-25)) = 405+48.195 =453.2W
Victron 250/85:-
[Edit...]
A) MPPT 250/85, 3x MPPT trackers
PV max power 4900W, Vmax 250V
70A max PV short circuit current, 30A per MPPT
https://www.victronenergy.com/uploa...oller-MPPT-250-70-up-to-250-100-VE.Can-EN.pdf
Victron 250/100:-
[Edit...]
B) MPPT 250/100, 3x MPPT trackers
PV max power 5800W, Vmax 250V,
70A max PV short circuit current, 30A per MPPT
https://www.victronenergy.com/uploa...oller-MPPT-250-70-up-to-250-100-VE.Can-EN.pdf
Victron 450/100:-
[Edit...]
C) RS MPPT 450/100, 2xMPPT trackers
PV max power 5000W, Vmax 450V, 30A per MPPT
https://www.victronenergy.com/solar-charge-controllers/smartsolar-mppt-rs-450-tr
https://www.victronenergy.com/upload/documents/Datasheet-SmartSolar-MPPT-RS-EN-.pdf
Have I got it right ? Please could someone cast an eye over the method for calculating string voltage and powers for different victron charge controllers please and let me know if I've made any howlers?
Thanks for taking a look
[Edit: I know there's an MPPT calculator on the victron site but you can't select one product and try different panel combinations on it !]
Panels 405W Qcell
https://midsummerwholesale.co.uk/pd...m-g11-series-390-410-30t-2022-06-rev02-en.pdf
I think:-
The 250/85 will take 6 panels in a string, or 2x5 in parallel, or 5panels into MPPT1 and 5panels into MPPT2
The 250/100 will take 6 panels in a string, or 2x6 in parallel, or 6panels into MPPT1 and 6panels into MPPT2, as it will cope with more PV power than the /85 model
The 450/100 will take 10 panels in a string, or 5panels into MPPT1 and 5panels into MPPT2,
It cannot be used for two strings in parallel due to PVmax of 18Amps
The Voc max is limited by the battery float voltage [Edit: to 8 x float voltage, which means it can be less than 450V]
String voltage at -10degC example calc, using STC of 25degC
e.g. Voc + Voc*((-0.27/100)*(-10-25))
e.g. 37.18 + 37.18*((-0.27/100)*(-10-25)) = 37.18+3.51 =40.69V
For the power limit then the panel's Pmpp and it's variation vs temperature is what to watch ?
Power at -10degC example calc
e.g. Pmpp + Pmpp*((-0.34/100)*(-10-25))
e.g. 405 + 405*((-0.34/100)*(-10-25)) = 405+48.195 =453.2W
Victron 250/85:-
[Edit...]
A) MPPT 250/85, 3x MPPT trackers
PV max power 4900W, Vmax 250V
70A max PV short circuit current, 30A per MPPT
https://www.victronenergy.com/uploa...oller-MPPT-250-70-up-to-250-100-VE.Can-EN.pdf
Victron 250/100:-
[Edit...]
B) MPPT 250/100, 3x MPPT trackers
PV max power 5800W, Vmax 250V,
70A max PV short circuit current, 30A per MPPT
https://www.victronenergy.com/uploa...oller-MPPT-250-70-up-to-250-100-VE.Can-EN.pdf
Victron 450/100:-
[Edit...]
C) RS MPPT 450/100, 2xMPPT trackers
PV max power 5000W, Vmax 450V, 30A per MPPT
https://www.victronenergy.com/solar-charge-controllers/smartsolar-mppt-rs-450-tr
https://www.victronenergy.com/upload/documents/Datasheet-SmartSolar-MPPT-RS-EN-.pdf
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