The SDL-1 Solar Data Logger determines how much solar power can be produced from the available sunlight (solar insolation) at a location. It is a self-contained solar irradiance logger that combines a data logger and a solar radiation sensor (silicon pyranometer) to measure and record solar irradiance at regular intervals for up to 170 days at a time. The SDL-1 also reports the cumulative incident solar energy that it receives during deployment.
For a planned solar power system, the SDL-1 can help determine the best location and optimal tilt for the solar panels. For systems already in place, the SDL-1 is further useful for monitoring solar power system performance over time. A comparison of the cumulative incident solar energy (measured by the SDL-1) and the actual energy produced (measured by the systems production meter) provides a basis for tracking system performance.
The unit is housed in a weatherproof enclosure and is powered by a standard 9V battery with a typical battery life of two years. The SDL-1 is based on the Microchip PIC16F88 microcontroller and data is stored in non-volatile memory for later transfer to a computer for analysis.
Frequently Asked Questions
Q. How do typical measurements from the SDL-1 and the SIM Solar Irradiance Meter compare?
A. The graph below shows data from an SDL-1 near solar noon and two readings from a SIM. These measurements were taken with natural sunlight at normal incidence and clear sky conditions. The readings are in agreement to within 2%.
Q. What parts are included with SDL-1 kit?
A. The SDL-1 kit comes with a complete set of parts, shown below. See the
manual for more details.
Parts List:
Ref. Description Qty
C3 Cap, 0.01uF, SMD 1206 (Green) 1*
C1, C4, C8,C9, C10 Cap, 0.1uF, SMD 1206 (Orange) 5*
C6, C7 Cap, 47pF, SMD 0805 (Yellow) 2*
C11, C12 Cap, 18pF, SMD 0805 (Blue) 2*
C5 Cap, 10uF, 10V tantalum, SMD 1206 1
C2 Cap, 47uF, 25V Al electrolytic 1
D1 Photodiode, BPW34, clear plastic 2 lead DIP 1
D21 LED, red 1
D31 LED, green 1
FB1 EMI ferrite bead, SMD 0805 (Black) 1*
J1 Connector, USB type B 1
J2 Connector, 9V battery snap 1
Q1 MOSFET p-channel, Siliconix TP2104, SOT-23, P1LE 1
Q2, Q3, Q4 Transistor , NPN, BT3904, SOT-23, 1An 3
R1 Res, 510 ohm, 0.1%, SMD 0805, 511 1
R2 Res, 20K ohm, 0.1%, SMD 0805, 203 1
R30, R31 Res, 62.0 ohm, 0.1%, SMD 0805, 620 2
R17, R18 Res, 470 ohm, 5%, SMD 1206, 471 2
R7 Res, 1K ohm, 5%, SMD 0805, 102 1
R11, R13, R20 Res, 10K ohm, 5%, SMD 0805, 103 3
R12 Res, 47K ohm 5%, SMD 0805, 473 1
R4, R5 Res, 10M ohm, 1%, SMD 1206, "1005" 2
R6 Res, 22M ohm, 10%, SMD 1206, "226" 1
RN1, RN2 Resistor network, 10K, 8-lead SMD, 103 2**
SW1 DPDT slide switch 1
SW2 SPST-NO push switch 1
U1 IC, USB to serial interface, FTDI FT232RL, SSOP-28 1**
U2 IC, Dual op-amp, National Semiconductor LMC6482AIM, SOIC-8 1**
U3 IC, Voltage regulator (5V) National Semi. LM2936M-5.0, SOIC-8 1**
U4 IC, Programmed microcontroller, Microchip PIC16F88-I/P, 18 pins 1
U5 IC, 256k serial EEPROM, 24LC256-I/SN, SOIC-8 1**
X1 Crystal, 32.768KHz, 4-lead SMD plastic package 1
MISC SDL-1 printed circuit board 1
MISC Posts for photodiode D1 2
MISC Socket for U4, 18 pins 1
MISC 9V battery holder 1
MISC 2-56 machine screw, 3/16" length 2
MISC 2-56 nut 2
MISC #2 lock washers 2
MISC 4-40 machine screw, 1" length 4
MISC Aluminum spacer, #4 hole, 3/8" length 4
MISC 4-40 nut 4
MISC #4 flat washer 4
MISC Rubber O-ring 4
MISC #8 sheet metal screws, 5/8 (to attach cover to base) 4
MISC #8 sheet metal screws, 3/4" (to mount PVC enclosure) 4
MISC PVC enclosure, 4x4x2" (includes cover and base) 1
MISC Glass plate, 1x1x0.039" 1**
* These parts are identified by the color code on their containers.
** These parts are pre-installed.
Solar Power Basics
The higher efficiency and lower cost of todays solar panels has caused renewed interest in converting sunlight into electricity. The increasing cost of utility electric power is making
solar power even more attractive. The cumulative global photovoltaic capacity was 5,000
MW in 2006 and is growing by about 22 percent each year.
To take full advantage of solar
power for a given application, the generating capacity must be sized appropriately
according to the expected load and the amount of solar resource available. The amount of
solar resource tends to vary greatly depending on factors such as atmospheric conditions, time of year, latitude and local terrain. Quantifying the solar resource is key to the proper sizing of
a photovoltaic installation to meet the expected energy demands of the system.
For more about the basics of solar power, click here.
