The article discusses a simple zero drop or low drop solar charger controller circuit which can be modified in many different ways as per user preference.
A zero drop solar charger is a device which ensures tat the voltage from the solar panel reaches the battery without undergoing any kind of drop either due to resistance or semiconductor interference such as diodes etc in line.
The circuit here uses a mosfet as a switch for ensuring minimum drop of voltage received from the attached solar panel.
Moreover the circuit has a distinct advantage over other forms of zero drop charger designs, it does not unnecessarily load the panel making sure the panel is allowed to operate at it MPPT zone.
Let's understand how these features could be achieved through this novel circuit idea designed by me.
Referring to the proposed zero drop voltage regulator charger circuit diagram we see a rather straightforward configuration consisting of an opamp and a mosfet as the main active ingredients.
Here the opamp is wired as a comparator wherein its non-inverting pin is positioned as the voltage sensor via a voltage divider stage made by R3 and R4.
The inverting pin is as usual rigged as the reference input using R2 and the zener diode.
Assuming the battery to be charged is a 12V battery, the junction between R3 and R4 is calculated such that it produces 14.4V at a certain optimal input voltage level which may be the open circuit voltage of the connected panel.
On applying the solar voltage at the shown input terminals, the mosfet initiates with the help of R1 and allows the entire voltage across its drain lead which finally reaches the R3/R4 junction.
The voltage level is instantly sensed here and if in case it's higher than the set 14.4V, switches ON the opamp output to a high potential.
This action instantly switches OFF the mosfet making sure no further voltage is allowed to reach its drain.
However in the process the voltage now tends to fall below the 14.4V mark across the R3/R4 junction which yet again prompts the opamp output to go low and in turn switch ON the mosfet.
The above switching goes on repeating rapidly which results in a constant 14.4V at the output fed to the battery terminals.
The use of the mosfet ensures an almost zero drop output from the solar panel.
D1/C1 are introduced for maintaining and sustaining a constant supply to the IC supply pins.
Unlike shunt type regulators, here the excess voltage from the solar panel is controlled by switching OFF the panel, which ensures zero loading of the solar panel and allows it to operate at its most efficient conditions, quite like an MPPT situation.
The circuit can be easily upgraded by adding an auto cut off, and an over current limit features.
Parts List
R1,R2 = 10K
R3,R4 = use an online potential divider calculator for fixing the required junction voltage
D2 = 1N4148
C1 = 10uF/50V
C2 = 0.22uF
Z1 = should be much lower than the selected battery over charge level
IC1 = 741
Mosfet = as per the battery AH and the solar voltage.
Adding a current control feature to the above zero drop solar charger circuit
The above circuit looks quite an efficient design however lacks a current control feature.
The diagram below shows how the above circuit can be upgraded with a current control feature by simply adding a BC547 transistor stage across the inverting input of the opamp.
R5 can be any low value resistor such as a 100 ohm.
R6 determines the maximum allowable charging current to the battery which may be set by using the formula:
R(Ohms) = 0.6/I, where I is the optimal charging rate (amps) of the connected battery.
Note: A P-channel mosfet may not work correctly, therefore the mosfet in the above zero drop solar circuits must be replaced with N-channel mosfets as shown in the folowing diagrams. Readers are requested to do the modifications as per the following diagrams.
A zero drop solar charger is a device which ensures tat the voltage from the solar panel reaches the battery without undergoing any kind of drop either due to resistance or semiconductor interference such as diodes etc in line.
The circuit here uses a mosfet as a switch for ensuring minimum drop of voltage received from the attached solar panel.
Moreover the circuit has a distinct advantage over other forms of zero drop charger designs, it does not unnecessarily load the panel making sure the panel is allowed to operate at it MPPT zone.
Let's understand how these features could be achieved through this novel circuit idea designed by me.
Referring to the proposed zero drop voltage regulator charger circuit diagram we see a rather straightforward configuration consisting of an opamp and a mosfet as the main active ingredients.
Here the opamp is wired as a comparator wherein its non-inverting pin is positioned as the voltage sensor via a voltage divider stage made by R3 and R4.
The inverting pin is as usual rigged as the reference input using R2 and the zener diode.
Assuming the battery to be charged is a 12V battery, the junction between R3 and R4 is calculated such that it produces 14.4V at a certain optimal input voltage level which may be the open circuit voltage of the connected panel.
On applying the solar voltage at the shown input terminals, the mosfet initiates with the help of R1 and allows the entire voltage across its drain lead which finally reaches the R3/R4 junction.
The voltage level is instantly sensed here and if in case it's higher than the set 14.4V, switches ON the opamp output to a high potential.
This action instantly switches OFF the mosfet making sure no further voltage is allowed to reach its drain.
However in the process the voltage now tends to fall below the 14.4V mark across the R3/R4 junction which yet again prompts the opamp output to go low and in turn switch ON the mosfet.
The above switching goes on repeating rapidly which results in a constant 14.4V at the output fed to the battery terminals.
The use of the mosfet ensures an almost zero drop output from the solar panel.
D1/C1 are introduced for maintaining and sustaining a constant supply to the IC supply pins.
Unlike shunt type regulators, here the excess voltage from the solar panel is controlled by switching OFF the panel, which ensures zero loading of the solar panel and allows it to operate at its most efficient conditions, quite like an MPPT situation.
The circuit can be easily upgraded by adding an auto cut off, and an over current limit features.
Parts List
R1,R2 = 10K
R3,R4 = use an online potential divider calculator for fixing the required junction voltage
D2 = 1N4148
C1 = 10uF/50V
C2 = 0.22uF
Z1 = should be much lower than the selected battery over charge level
IC1 = 741
Mosfet = as per the battery AH and the solar voltage.
Adding a current control feature to the above zero drop solar charger circuit
The above circuit looks quite an efficient design however lacks a current control feature.
The diagram below shows how the above circuit can be upgraded with a current control feature by simply adding a BC547 transistor stage across the inverting input of the opamp.
R5 can be any low value resistor such as a 100 ohm.
R6 determines the maximum allowable charging current to the battery which may be set by using the formula:
R(Ohms) = 0.6/I, where I is the optimal charging rate (amps) of the connected battery.
Note: A P-channel mosfet may not work correctly, therefore the mosfet in the above zero drop solar circuits must be replaced with N-channel mosfets as shown in the folowing diagrams. Readers are requested to do the modifications as per the following diagrams.
0 Response to "Simple Zero Drop Solar Charger Circuit"
Posting Komentar