50W Photovoltaic Solar Battery Regulator [080305]
This circuit was originally designed to power a small weather station but it is perfectly suitable for any other low-power application.The regulator was designed for a 10W to 50W 12V solar panel bit the electronics can be easily adapted for higher power.
The regulator was designed for a 10W to 50W 12V solar panel bit the electronics can be easily adapted for higher power.
A switching power supply (SMPS) module was added to reduce dissipated power and to improve efficiency (the original circuit was based on a 7805). This SMPS enables also the use of a 24V input voltage.
The charging of the battery is controlled by a microcontroller (MCU) that also cuts off the load when the battery gets discharged too much. When the battery is charged up to at least again 12V the load is automatically reconnected.
Discussie (3 opmerking(en))
ClemensValens 11 jaar geleden
Final PCB revision 1.3c to correct some minor details.
Software revision 2.5.1, almost completely in English with many comments. This version expects T2 and T4 to be mounted.
Here are the lab notes:
P3, IC4, R16, C7 are for future use and are not handled by the software. If they are mounted, the ADC reference and thus the voltage measurements will be incorrect.
Switches
Name
Function
S1
MCU reset (pushbutton)
S2
Configuration (4x DIP switch)
S3
Power On (pushbutton)
DIP switches S2
Name
Off
On
S2-1
Use hardcoded threshold & target voltages
Threshold & target voltages controlled by P1 and P2
S2-2
User load controlled by MCU
User load controlled by external (remote) control
S2-3
Gel battery
Lead-acid battery
S2-4
Count charge cycles
Reset charge cycle counters
Variable resistors (S1 = on)
LEDs
Name
Function
LED1
Solar panel connected (green)
LED2
Charge mode indicator (bicolor)
LED2
Color
Speed (duty-cycle)
Solar panel
User load (S2=off)
Battery
Orange
Slow (33%)
Disconnected
Connected
Charged
Green
Slow (2%)
Connected
Connected
Charging
Orange
Fast (10%)
Connected
Connected
Low
Red
Slow (2%)
Connected
Disconnected
Discharged
Off
-
Connected
Disconnected
Too low
At power-up a short sequence red-orange-green-off-red-orange-green-off is played, then it lights green during two seconds after which it will start indicating the functional mode from the table.
When this LED goes off because the battery level becomes dangerously low (10.8V), the 5V power supply is switched off and the MCU is switched off.
Connectors
Name
Function
K1
1x 1x8 or 2x 1x4 or 4x 1x2 connectors, 5.08mm pitch
Pin 1,2: solar panel (pin1=positive)
Pin 3,4: battery (pin3=positive)
Pin 5,6: user load (pin6=positive)
Pin 7,8: optional temperature sensor (NTC)
K2
1x3 pin header, 2.54mm pitch
Remote control input for user load (S2=on)
K3
2x5 pin header, 2.54mm pitch
AVR ISP connector
Jumpers
Name
Function
J1
Allow serial port to power the board (use with care)
J2
Bypass S3 for automatic power-up
Serial port
Data format: 9600n81
Outputs status messages:
The serial port is for diagnostic purposes only and the FTDI-BOB module should be removed during normal operation to save power.
Example output (battery replaced by adjustable power supply):
Photovoltaic Regulator Ver 2.5.1, Elektor 2013
Lead-acid Battery
Number of completed cycles: 0
Number of charge cycles: 0
Voltage = 13.19 V
Voltage = 13.19 V
Voltage = 13.24 V
Voltage = 13.19 V
Voltage = 13.17 V
Voltage = 12.19 V
charge cycle 1
Voltage = 11.58 V
Voltage = 11.15 V
Voltages
Type
Power-down
Discharged
Low
Charging
Max
Lead-acid
≤ 10.8
10.8-12.6
11.3-12.6
12.6-13.2
14.7
Gel
≤ 10.8
10.8-12.6
11.3-12.6
12.6-13.7
14.2
Note: when the battery voltage drops below 11.3V the circuit enters “discharged mode” (flashing red). To exit this mode either the voltage must drop further to enter “power-down mode” (off) or the voltage must increase to at least 12.6V to enter “charging mode” (flashing green). The “low battery mode” is skipped (fast flashing orange) in this case.
ClemensValens 11 jaar geleden
Nice2Know 11 jaar geleden
ClemensValens 11 jaar geleden
We have modified the PCB a little to make it fit nicely in the enclosure the author had chosen: Fibox MNX PC 150-50 LT. Also, we merged the connectors into one to make connections cheaper. Now you can use one 8-way or two 4-way or four 2-way (or two 3-way plus one 2-way but why would you want that?) plugs.
Regards,
Clemens
lelion95 11 jaar geleden
pascal.tours 12 jaar geleden