RedEarth BlackMax - Page 10

BlackMax – Installation and Operation Manual
Page 10 of 36
Issue date: 24/11/2023. Version 13.0
Note that the BlackMax has two MPPTs, so PV panels can be installed facing in two different directions.
Example calculation of maximum number of solar panels in the array:
Below are the specifications of a typical 400W panel that RedEarth supplies in the complete BlackMax PowerStation kit (as of
December 2023).
Electrical characteristics
400W panel
Mono-Crystalline Module (HiE-S_____UF)
Maximum Rating Power (Pm)
W
400
Open Circuit Voltage (VoC)
V
49.5
Short Circuit Current (Isc)
A
10.12
Maximum Power Voltage (Vmp)
V
41
Maximum Power Current (Imp)
A
9.76
Module Efficiency
%
21.3
Maximum System Voltage
V
DC 1,500
Temperature Coefficient of Pmax
% / °C
-0.340
Temperature Coefficient of Voc
% / °C
-0.270
Temperature Coefficient of Isc
% / °C
+0.040
Maximum number of panels in series (Max. PV array voltage):
For the 400W panel shown above, Isc is 10.12 Amps at 25degC. If the highest expected temperature is 50degC then the
temperature correction is +25degC x +0.040% = +1.00%. This means that at 50degC the Ioc is 1.00% higher than at 25degC =
1.010 x 10.12 = 10.22Amps.
As the temperature increases the Ioc Increases which is why the highest temperature is important for Ioc calculations.
The Isc rating of the BlackMax Is 19.5A per MPPT. In Australia the Isc rating is decreased by 1.25x to get the usable Isc. This
means a maximum of 19.5/1.25 = 15.6 Amps Is allowed according to the Australian standards.
This means that a maximum of one (1) string can be connected in parallel.
Total maximum number of panels:
This means that a total of 18 x 400W panels with these specifications can be connected to the BlackMax. This is 18 x 400W =
7.2kW.
To achieve closer to the maximum 7800W rating of the BlackMax inverter is recommended to seek lower voltage panels that
remain within the short circuit current limit of 15.6A Isc.
An example of this is the Tindo Karra 410W, specs below:
Electrical Characteristics
108 Cell Module
Karra – 410G2H
Item
Unit
*STC
*NMOT
Max. power (Pmax)
Wp
410
301
Max. power voltage (Vmp)
V
31.11
28.6
Max. power current (Imp)
A
13.18
10.5
Open circuit voltage (Voc)
V
37.11
34.3
Short circuit current (Isc)
A
13.93
11.3
Panel efficiency
%
20.6
Positive power tolerance
W
0 + ~ 5
*STC (Standard Test Condition): 1,000 W/m
2
, AM 1.5,25
°
C/ *NMOT (Nominal Module Operating Temperature): 800W/m
2
, 20°C, wind speed 1m/s,
Tolerance of Pmax, Voc &Isc ± 3% within each watt class at STC.
WARNING
The Solar DC circuit breaker on the BlackMax must be in the
off position before any solar panels are connected