Siemens SP18 solar module: datasheet and specifications
18 Wrated power
17 VVmp
21.7 VVoc
2.7 kgweight
633 × 275 mmoutline
Siemens SP18: product photograph restored from the original low-resolution picture.
The SP18 is an 18 W module of 36 cells on a 633 × 275 mm frame (2.7 kg), offered in a 12 V version (Vmp 17.0 V) and a 6 V version (Vmp 8.5 V at twice the current). Siemens listed it for telecom and for gas and oil telemetry.
Electrical data
36 cells in series; silicon (sp series).
Parameter
SP18 (12 V)
SP18 (6 V)
Rated power Pmax (W)
18
18
Minimum power Pmin (W)
16
16
Current at Pmax, Imp (A)
1.1
2.1
Voltage at Pmax, Vmp (V)
17
8.5
Short-circuit current, Isc (A)
1.2
2.4
Open-circuit voltage, Voc (V)
21.7
10.9
Derived figures
Quantity
Value
How it was obtained
Outer area
0.174 m²
calculated from length × width
Power per area
103 W/m²
calculated; Pmax ÷ area at STC
Module efficiency
10.3 %
calculated on outer dimensions (cell efficiency is higher)
Power per weight
6.7 W/kg
calculated
Voc at −20 °C (SP18 (12 V))
25.2 V
calculated with the datasheet Voc coefficient
Voc at −20 °C (SP18 (6 V))
12.6 V
calculated with the datasheet Voc coefficient
Vmp with 60 °C cells (SP18 (12 V))
14.2 to 14.9 V
approximate range; see the note below the table
Rough daily energy
68 Wh
calculated: Pmax × 5 peak-sun-hours × 0.75 system efficiency; a planning figure, not a measurement
With 36 cells in series the Vmp is 17 V at 25 °C. With 60 °C cells it falls to about 14.2 to 14.9 V (the datasheet gives no Vmp coefficient: the lower figure assumes a typical −0.47 %/K, the upper scales the Voc coefficient), a margin of -0.2 to +0.5 V against 14.4 V. The margin is negative or marginal, so on hot days this module may not finish charging a lead-acid battery. In 5 peak-sun-hours the 12 V version adds roughly 4.1 Ah a day to a 12 V battery (Imp × 5 h × 0.75).
Full datasheet tables
Thermal
Parameter
Unit
Value
Nominal operating cell temperature (NOC)
°C
45
Change of Isc with temperature
+2.06 mA/°C (+0.04 %/K)
Change of Voc with temperature
-0.077 V/°C (−0.34 %/K)
Qualification tests
Parameter
Unit
Value
Temperature cycling range
°C
−40 to +85
Humidity, freeze, damp heat condition
% RH
85
Maximum system voltage
V
1000 per ISPRA (EC), 600 per UL 1703
Wind loading or surface pressure
N/m² (PSF)
2400 (50)
Maximum distortion (4)
degrees
1.2
Hailstone impact withstand (diameter @ velocity)
mm @ m/s (in @ mph)
25 @ 23 (1.0 @ 52)
Physical
Parameter
Unit
Value
Number of series cells
count
36
Length
mm (in)
633 (24.9)
Width
mm (in)
275 (10.8)
Depth
mm (in)
34 (1.3)
Weight
kg (lb)
2.7 (5.9)
Warranty (5)
Parameter
Unit
Value
Power ≥ 90 % of minimum power
years
10
Notes from the datasheet. (1) Electrical values at standard test conditions: irradiance 1000 W/m², cell temperature 25 °C, spectrum per ASTM E892 (air mass 1.5). (2) Nominal operating conditions: 800 W/m², ambient 20 °C, wind 1 m/s. (3) Qualification tests per CEC 503. (4) Diagonal lifting of a module corner with three corners fixed. (5) Warranty applies to the original consumer purchaser; see the full limited warranty for conditions. The tier percentages refer to the minimum power rating (Pmin), not the rated power.
Where Siemens recommended it
The Siemens application pages list this module for: telecom, gas and oil. See the case files for installations from those categories.
