Make this Zero Drop Solar Battery Charger Circuit

The post talks about a basic zero drop or low drop solar charger controller circuit which is often altered in lots of alternative ways according to user choice. The circuit would not rely on microcontroller and can be developed even by a layman.

A zero drop solar charger is a device which guarantees tat the voltage from the solar panel reaches the battery without undergoing any kind of drop either due to resistance or semiconductor interference for example diodes etc in line.

The circuit here makes use of a mosfet as a switch for being sure 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 pointlessly shunt the panel ensuring the panel is permitted to work at its largest effectiveness zone.


Let’s know how all of these features could possibly be accomplished during this novel circuit idea created by me. Talking about the offered zero drop voltage regulator charger circuit diagram we observe a rather simple configuration comprise of an opamp and a mosfet as the main energetic components.

Right here the opamp is cabled as a comparator in which its non-inverting pin is placed as the voltage sensor via a voltage divider stage created by R3 and R4.

The inverting pin is as normal rigged as the reference input utilizing R2 and the zener diode.

Considering the battery to be imposed is a 12V battery, the junction between R3 and R4 is determined such that it generates 14.4V at a certain optimum input voltage level which can be the open circuit voltage of the associated panel. On making use of the solar voltage at the demonstrated input terminals, the mosfet is linked to with the aid of R1 and permits the whole voltage across its drain lead which lastly actually reaches the R3/R4 junction.

The voltage level is immediately felt here and if in the event it’s more than the set 14.4V, switches ON the opamp output to a high potential.

This activity immediately switches OFF the mosfet making certain no more voltage is able to achieve its drain. In spite of this along the way the voltage now has a tendency to decrease below the 14.4V mark across the R3/R4 junction which one more time encourages the opamp output to go low and in turn turn on the mosfet.

The above switching continues repeating quickly which ends up in a continuing 14.4V at the output given to the battery terminals.

The utilization of the mosfet assures a nearly zero drop output from the solar panel. D1/C1 are launched for sustaining and preserving a persisting supply to the IC supply pins.

As opposed to shunt type regulators, right here the excess voltage from the solar panel is managed by switching OFF the panel, which guarantees zero loading of the solar panel and enables it to generates its most effective problems, quite similar to an MPPT circumstance.

The circuit may be very easily improved by attaching an auto cut off, and an over current limit capabilities.



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 = ought to be much lower than the chosen battery over charge level IC1 = 741

Mosfet = in accordance with the battery AH and the solar voltage.

Including a current control characteristic to the above zero drop solar charger circuit

The above circuit appears quite an effective design in spite of this lacks a current control feature. The diagram below demonstrates how the above circuit could be enhanced with an existing control feature by simply including a BC547 transistor phase across the inverting input of the opamp. R5 may be any low value resistor for instance a 100 ohm. R6 decides the highest permitted charging current to the battery which might be set by utilizing the formula: R(Ohms) = 0.6/I, where I is the optimal charging rate (amps) of the attached battery.


Note: A P-channel mosfet might not function properly, consequently the mosfet in the above zero drop solar circuits needs to be restored with N-channel mosfets as presented in the folowing diagrams. Viewers are suggested to do the changes according to the following diagrams.



Tips on how to Begin the zero drop solar charger circuit


It really is very simple. You should not hook up any supply at the mosfet side. Upgrade the battery with a adjustable power supply input and adjust it to the charging level of the battery which can be allowed to be charged. Now cautiously change the pin2 preset until the LED just shuts off….flick the preset to and fro and check the LED reply it ought to also blink ON/OFF in the same way, definitely regulate the preset to a point where the LeD just shuts off totally….seal the preset. Your zero drop solar charger is set, and set. It is possible to verify the above by using a higher input voltage at the mosfet side, you’ll discover the battery side output generating the entirely controlled voltage level which was earlier set by you.