A solar panel has one operating point at which it delivers maximum power, and that point moves with irradiance and temperature. A simple PWM controller clamps the panel to the battery voltage and gives up whatever power lies between there and the maximum power point. This project builds a buck converter between panel and battery, runs a perturb and observe algorithm that continuously hunts the maximum power point by adjusting duty cycle, and measures the energy harvested against a PWM controller on an identical panel so the improvement is a measurement rather than a claim.
Not just the parts. Teams budget from a component list, then run out in week six on wire, connectors and the driver board they destroyed. These are the lines that catch them.
| Line | Cost |
|---|---|
Components and materials From the bill of materials | Rs 5,400 to Rs 13,040 |
Spares and replacements 15 % — you will destroy something | Rs 810 to Rs 1,956 |
Consumables and hardware Wire, connectors, headers, screws, heatshrink | Rs 648 to Rs 1,565 |
PCB fabrication | Rs 350 to Rs 900 |
Report, printing and binding Two or three bound copies, plots and the plagiarism check | Rs 400 to Rs 1,200 |
| Total | Rs 7,608 to Rs 18,661 |
| Each, split 3 ways | Rs 2,536 to Rs 6,220 |
Indicative bands last checked in August 2026 — a guide, not a quotation. Prices move and vary by seller, and anything you can borrow from the lab comes straight off the total. The 5.2 week figure assumes 12 person-weeks of work shared between 3; students past 4 add coordination rather than output, so the estimate stops improving there.
The same chain in words
The controller measures panel voltage and current and multiplies them to get instantaneous panel power.
It perturbs the duty cycle by a small step and measures power again. If power rose, the next perturbation goes the same way; if it fell, the direction reverses. That is perturb and observe, and it converges on the maximum power point without needing to know anything about the panel.
The buck stage steps the panel voltage down to battery voltage. Because it is a converter and not a switch, the panel can sit at its maximum power voltage while the battery sits at its own — which is exactly what a PWM controller cannot do.
A charge state machine runs on top: bulk at constant current, absorption at constant voltage, then float, with the setpoints temperature compensated.
Both controllers run on identical panels into identical batteries, and the harvested energy is logged for both.
This is the chapter that separates an engineering project from an assembly job. Every value below carries the formula that produced it and the assumptions it rests on — check them against your own ratings before you use them, because your motor is not this motor.
Imp = Pmax / Vmp
100 / 18 = 5.56 A. Voc is around 22 V and Isc around 6 A, and the MOSFETs have to be rated for Voc on a cold clear morning, not for Vmp.
D = Vout / Vin for a buck converter in continuous conduction
14.4 / 18 = 0.80. The whole point of MPPT is that this ratio is free to change: the panel stays at 18 V while the battery is charged at whatever voltage its stage demands.
L = (Vin - Vout) x D / (f x delta-IL)
Ripple current chosen as 30 percent of the 6.6 A output: (18 - 14.4) x 0.8 / (50000 x 1.98) = 29.1 uH. The core must not saturate at the peak, which is output current plus half the ripple, about 7.6 A.
C = delta-IL / (8 x f x delta-V)
For 50 mV of output ripple: 1.98 / (8 x 50000 x 0.05) = 99 uF. In practice the capacitor's ESR dominates the ripple, so choose a low ESR type and check the ripple current rating.
Trade-off between tracking speed and steady-state oscillation
A large step tracks a passing cloud quickly but oscillates around the peak, losing power in steady sun. A small step is efficient in steady sun and slow under changing cloud. Measuring that trade-off, rather than picking a number, is what makes this a final-year project.
Gain depends on the gap between Vmp and battery voltage
On a cold morning Vmp can be 20 V against a 12.5 V battery, and MPPT recovers most of that difference. On a hot afternoon Vmp falls toward 15 V and the advantage shrinks. Report the gain against panel temperature rather than as a single headline percentage.
| Item | Qty | Unit cost |
|---|---|---|
Solar panel 100 W, 12 V nominal, Vmp about 18 V | 1 | Rs 2,600 to Rs 4,500 |
Microcontroller board ESP32 or STM32 with hardware PWM and a fast ADC | 1 | Rs 350 to Rs 900 |
Power MOSFETs IRFZ44N or IRF3205, 55 V, low Rds(on) | 2 | Rs 40 to Rs 120 |
Gate driver IR2104 or IR2110 half bridge driver | 1 | Rs 90 to Rs 260 |
Power inductor 33 uH, saturation current above 10 A | 1 | Rs 180 to Rs 500 |
Capacitors 220 uF low ESR output, 470 uF input, film bypass | 1 | Rs 120 to Rs 350 |
Current sensors INA219 or ACS712 30 A, panel side and battery side | 2 | Rs 150 to Rs 400 |
Schottky diode MBR20100 for reverse blocking | 1 | Rs 30 to Rs 90 |
Battery 12 V 7 Ah SLA, or a 4S LiFePO4 pack | 1 | Rs 800 to Rs 3,200 |
PWM controller for comparison Commercial 10 A PWM controller | 1 | Rs 350 to Rs 800 |
Heatsink and hardware Heatsinks, thermal pads, standoffs, enclosure | 1 | Rs 250 to Rs 700 |
Fuses and wiring MC4 connectors, 4 sq mm cable, blade fuses | 1 | Rs 250 to Rs 700 |
Specifications are written as ratings rather than brands, so any equivalent part works. Where a line says to borrow from the lab, do — it is usually the largest number on the page, and the total drops to Rs 7,608 at the low end without them.
None of these blocks you — they are learnable inside a semester. Each one you do not have costs a couple of weeks, so count them into your plan.
Anything marked required is a blocker, not a difficulty. Arrange the access before you commit to the project, not after.
Use these when your guide says the scope is too small, or when you want something in the results chapter that nobody else in your batch will have.
The structure below is what a project report is marked against, with the mistake that costs marks in each chapter. There is no template to download and there will not be one: the writing is your work, and a site that did it for you would be helping you cheat rather than helping you pass.
A mini project report runs to about 40 to 50 pages, and the literature survey is usually brief. Guides expect one clear objective, met and measured. A final year report is normally 60 to 90 pages with a substantial literature survey, and many departments expect a paper submission alongside it.
The full report guide — front matter, conventions and page countsOne paragraph covering what the problem is, what you built, and what the result was. Written last, even though it appears first.
Loses marks: Describing the problem and the method but never stating a result. If there is no number in your abstract, it is not finished.
Why the problem matters, the context it sits in, and a clear statement of the objectives your project set out to meet.
Loses marks: Objectives written so vaguely that nobody can tell at the end whether they were met. Write objectives you can tick off in the conclusion.
What has already been done, what each approach achieved, and the specific gap your work addresses.
Loses marks: A list of paper summaries with no comparison and no gap. The survey exists to justify your design choice, so end it by saying what you chose and why.
The system as a whole: the block diagram, what each block does, and the signal or power path between them.
Loses marks: A block diagram copied from a datasheet or another report. Draw yours to match what you actually built, including the parts that are inconvenient.
Every component value and rating, with the formula, the assumptions and the arithmetic that produced it. This is the chapter that distinguishes an engineering project from an assembly job.
Loses marks: Component values with no justification. If a resistor is 10 kOhm, the report must say why it is not 1 kOhm.
The circuit as built, the PCB or wiring, the flowchart, and the parts of the code that carry the actual logic.
Loses marks: Twenty pages of pasted source listing. Include the flowchart and the few functions that matter, and put the full listing in an appendix.
What you measured, in tables and graphs, compared against what you predicted in the design chapter — including where they disagreed.
Loses marks: Photographs of the working model presented as results. A photograph is evidence that it exists, not evidence that it works. Results are measurements.
Whether each objective was met, what the measured performance was, and what the honest next step would be.
Loses marks: Future scope written as a wish list of unrelated features. It should follow from a limitation you actually hit.
Every source in a consistent style, plus datasheets, full code listings and the complete bill of materials.
Loses marks: Citing a blog or a video where a datasheet or a standard exists. Cite the primary source for anything you relied on.
The demonstration is half the assessment. These are the questions this project invites, and the answers are written the way you would give them out loud.
Because it is essentially a switch connecting the panel to the battery, so it forces the panel to operate at battery voltage. If the panel's maximum power voltage is 18 V and the battery is at 12.5 V, the panel operates at 12.5 V, and since it behaves as a current source in that region the current is roughly unchanged. The power difference between 18 V and 12.5 V at the same current is simply lost.
It changes the operating point by a small step and compares the power before and after. If power increased, it keeps stepping in the same direction; if it decreased, it reverses. On the power against voltage curve this walks uphill toward the peak. It never settles exactly on the peak — it oscillates around it by one step, which is the method's known cost.
Under rapidly changing irradiance it can be confused about cause and effect: power changed because the cloud moved, not because of its own perturbation, so it can walk in the wrong direction. It can also lock onto a local maximum when the array is partially shaded and the power curve has several peaks.
Because in continuous conduction the average inductor current is set by the load, but the inductance determines how much the current swings around that average during each switching cycle. That ripple sets the peak current the core must handle without saturating, and it sets the output voltage ripple, so ripple is the design variable and the inductance follows from it.
Because the open circuit voltage of a silicon cell has a negative temperature coefficient, around minus 0.3 percent per degree, while the short circuit current rises only slightly. So as the panel warms, the whole curve shifts left, the maximum power point voltage falls with it, and the panel delivers less power despite the same irradiance.
The freewheeling diode drops around 0.5 V, and at six amps that is three watts of loss in one component. Replacing it with a MOSFET whose on-resistance is a few milliohms drops the loss to a fraction of a watt. The cost is the need for a half-bridge gate driver and dead-time control so both devices are never on together.
Normally taken as a B.E. mini project (5th/6th sem) or B.E. final year project (7th/8th sem) project. If yours is a different course, the extensions above scope it up and the simpler half of the design scopes it down — the arithmetic does not change. Back to all projects.