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LRMS MPPT Solar Power Module - Test and Characterization
09/25/2022 at 03:34 • 0 comments
R1 used with a INA3221 voltage and current monitor as a prototype model for revision 2.Prototype for revision 2:
Weather conditions:
2022/09/22 : Sunny with occasional high thin clouds
2022/09/23 : Early morning thin overcast followed Sun with intermittent cloud coverage
Solar Panel Configuration:
Orientation: South
Latitude: 48°4’41”N
Panel Angle: 50 degrees
Panel Width: 221mm
Panel Length :257mm
MPPT Solar Power Module:
Battery : 2500mAh 3.7V LiPO 1S cell
MPPT Charge Current : 200 mA
Charge Control Termination: C/10
MPPT LiPO Cell maximum charge level : 4.15V
Boost Converter Efficiency :
3.3 Vin 6.0 Vout I_Load 10mA 80 percent
3.3 Vin 6.0 Vout I_Load 200mA 85 percent
4.2Vin 6.0 Vout I_Load 200mA 80> percent
4.2Vin 6.0 Vout I_Load 200mA 90> percent
Load Current : 20mA
V_Batt Load Voltage : 5.832V
Solar Panel : Voltaic Systems P109 6Volt 9 Watt
Panel Ratings
Nominal
Expected
Open-Circuit Voltage
Voc
7.67
7.28
V
Voltage at Max Power
Vp
6.50
6.18
V
Short-Circuit Current
Isc
1.56
1.50
A
Current at Max Power
Ip
1.46
1.39
A
Maximum Power
Wp
9.49
8.56
W
2022-09-23 07:20:50 : Battery level 3.872 V
2022-09-23 10:10:24 : 4.144 V
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LRMS Analog IO Board - R1
09/12/2022 at 23:36 • 0 commentsThe LRMS analog I/O board is intended for analog sensors or custom sensor designs that do not have digital interfaces. In addition to the analog I/O the board also supports I2C and TTL UART connections.
A high speed amplifier with a sample and hold peak detector with a DC boost converter has been included for photo detectors such as a silicon photo-multiplier.
Board Connectors:
J1 & J2 : Two Configurable nano power operational amplifiers, can be configured as Differential, Single ended Non-Inverting/Inverting. Each amplifier output is buffered with a unity gain amplifier to the ADC channels.
(6Kz unity gain, 350nA per channel)
J3 : One high speed non-inverting operational amplifier with sample and hold peak detector.
(250Mhz unity gain, 100Mhz GBW)
J8: DC boost converter up to 32 volts DC.
J6 & J7 : I2C bus interface connectors
J5 : RS-232 TTL UART Connector
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LRMS Monitoring Station R1 - Operating Status 8/19/2022
08/19/2022 at 22:11 • 0 commentsRevision 1 of the LRMS monitoring station has been continuously operating outdoors for 8 months beginning January 2022. The sensors for the station are the usual temperature and humidity sensors found on many projects but I added a UV sensor to make the R1 station more unique and test the hardware and software.
Here are a couple of screen shots showing the data collected from LRMS R1
The sensors used are a DS18B20 temperature probe, Si7021 temperature and humidity sensor, and a LTR390 UV sensor in a PVC T pipe fitting.
UV & Humidity Sensor Module
The UV sensor has a 20mm x 20mm fused silica window epoxied in front of the LTR390 sensor (right side of photo)
to protect from weather and for maximum transmission of UV to sensor.The Si7021 located inside of PVC L fitting.
The DS18B20 is a water proof module and is shielded from direct solar exposure with a PVC pipe section.
March 15 2022 14:50PST
August 05 2022 14:19 PDT
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LRMS Revision 2 PCBs - Initial Route Complete
08/17/2022 at 23:00 • 0 commentsInitial PCB routing is competed and I am working cleaning up traces and adding text to silkscreen for headers etc.
All three boards pass design rules checks.
LRMS LoRa Transceiver R2
LRMS LoRa Gas Sensor R2
MPPT Solar Power Module R2
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LRMS Revision 2 PCBs - 3D models
08/11/2022 at 23:19 • 0 commentsI have been working on revision 2 of the LRMS boards. Component placement is completed and I will be routing
Transceiver and gas sensor boards.- All board dimensions have been updated to 90mm x 70mm (LxW). This supports inexpensive 70mmx90mm prototyping boards.
- Connectors have been changed to 2x10 row connectors and aligned on 2.54mm spacing from board edges.
- Added a new board - LRMS Environmental Gas Sensor. This a design based on my original Rev 1 test board.
LRMS LoRa Transceiver R2
Revision 2 :
uSD card connector for data logging
JST connector for connection to LRMS MPPT Solar Power Module
- Reverse power polarity protection
LRMS Environmental Gas Sensor
- Ultra low power op-amps for
- I2C bus connector
- UART connector
LRMS MPPT Solar Power Module
- J7 & J8 JST connectors changed to 5 pins. J7 is for I2C bus interface and J8 is for INA3221 status.
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Update to LoRa_RMS on GitHub
08/03/2022 at 19:06 • 0 commentsLoRa_RMS on Github has been updated to include initial release of code and installation instructions. See Software directory for details. LoRa_RMS is the directory for the system.
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Design files now on Github
08/02/2022 at 22:43 • 0 commentsThe design files for the LoRa Remote Monitoring system are now on GitHub.
I am in the process of working on revision 2 of the PCB board set and documentation.