More project photos (2)
The problem
An electric vehicle battery swapping station exchanges a discharged battery for a charged one instead of waiting for a charge. The idea only works if a charged battery is already waiting: a station with no ready stock saves nobody any time, so the real problem is inventory, not charging speed. Riders also need a fair way to reserve a charged battery in advance, and the station must know who took which battery. This project demonstrates the loop at laboratory scale: a four-bay model where a user books a slot online, taps a registered RFID card, and the controller unlocks only the reserved bay. The returned pack recharges in its bay while its level shows on an LCD and the dashboard. The build uses 12 V demo packs as stand-ins for EV packs, so it is a college-lab model. Builder note: the demo dashboard renders 24 bookable slots per day — 4 bays × 6 time slots.
The student books a time slot and bay on the dashboard.
Follow the working sequence
How it works
The complete swap takes four stages — book, authenticate, exchange, recharge — each handled by a different part of the system. A user first books a time slot and a bay on the web dashboard, which the ESP32 keeps as the day's booking list. At the station the user taps a registered RFID card on the MFRC522 reader; the Arduino checks the card against its registered list and the booking list, and only a valid card with a matching booking releases the servo lock on the reserved bay. The user places the discharged pack into the bay and takes the charged pack out, and a voltage sensor confirms a pack is docked before the bay locks again. The returned pack then charges at a 1 A current (design target) while its voltage is monitored, and once it reaches full charge the bay is marked ready on the LCD and dashboard for the next booking.
- The user books a time slot and bay on the ESP32-hosted slot-booking dashboard; the booking is stored with the card number and time.
- At the station, the user taps a registered RFID card on the MFRC522 reader (13.56 MHz, datasheet value).
- The Arduino verifies the card against the registered list and the booking list; an unregistered card or a card without a booking is rejected and the LCD shows the reason.
- On a valid tap, the servo lock on the reserved bay releases and the LCD names the bay to open.
- The user places the discharged 12 V demo pack into the bay and removes the charged pack; a voltage sensor confirms a pack is docked.
- The bay locks again and the returned pack starts charging at a 1 A current (design target) while its voltage is monitored.
- When the pack reaches full charge, the bay is marked ready on the LCD and the dashboard, and the swap is written to the activity log.
Tech stack:
- Arduino Uno (station controller)
- ESP32 (Wi-Fi slot-booking dashboard)
- MFRC522 RFID reader module
- 16×2 LCD with I2C adapter
- SG90 servo motors (bay locks)
- 4-channel relay module
- Arduino IDE
- HTML · CSS · JavaScript dashboard
| Parameter | Value |
|---|---|
| Battery bays | 4 bays |
| Demo battery packs | 4 × 12 V, 7 Ah sealed lead-acid packs (datasheet value) |
| RFID reader | MFRC522, 13.56 MHz (datasheet value) |
| RFID read distance | Approximately 3–5 cm (datasheet value) |
| Controller | Arduino Uno (station) + ESP32 (dashboard) |
| Display | 16×2 LCD with I2C adapter |
| Bay locks | 4 × SG90 servo motors (design target) |
| Charge current per bay | 1 A (design target) |
| Full recharge time per pack | Approximately 7–8 hours for a fully discharged pack (design target, not measured) |
| Swap time (tap to pack out) | Approximately 4 minutes (design target) |
| Bookable slots per day | 24 slots (4 bays × 6 time slots, demo build) |
| Power supply | 12 V, 5 A DC adapter (design target) |
| Scale | Demonstration model for lab/college use only |
Project features
A battery swapping station earns its time saving from charged inventory, not from charging speed, so this build is organised around four ideas: always having a charged pack ready, proving who the user is before any bay opens, letting the user reserve that pack in advance, and keeping an honest record of every swap. RFID authentication (MFRC522, 13.56 MHz datasheet value) checks each card against a registered list, a servo lock releases only the bay that matches the booking, and a 16×2 LCD plus the web dashboard show bay status, charge level and recent activity, so the whole station can be demonstrated end to end — book, tap, swap, charge — without any step being faked or hidden. The activity log records every authentication, booking, swap and rejection with its time, card and bay, and the safety interlocks keep a bay locked unless a valid card and a matching booking are both present.
- [RFID authentication] An MFRC522 reader (13.56 MHz, datasheet value) reads the user's card and the Arduino checks it against a registered card list before any bay can open; unregistered cards are rejected and the rejection is shown on the LCD.
- [Slot booking dashboard] A web dashboard shows the 4 bays and 6 time slots per bay — 24 bookable slots per day in the demo build — and records each booking with the card number, bay and time.
- [Four-bay swapping rack] Four bays hold one 12 V demo battery pack each, with a charging dock, voltage sensing and a servo-operated lock per bay, so a discharged pack can be exchanged for a charged one in a single visit.
- [Automatic recharge of returned packs] A returned pack starts charging in its bay at a 1 A charge current (design target) and its voltage is monitored until it is marked ready on the LCD and dashboard.
- [LCD status display] A 16×2 LCD shows system status, the number of charged bays and the result of the last card tap, so the station can be demonstrated without opening the dashboard.
- [Swap activity log] Every authentication, booking, swap and rejection is recorded with time, card number and bay, giving a clear audit trail for the viva demonstration.
- [Safety interlocks] A bay lock releases only after a valid card tap for a booked slot, and a bay with no docked pack stays locked; the charging circuit is fused and the demo runs on low-voltage 12 V packs only.
What is included
- Working four-bay battery swapping station prototype with RFID reader, LCD and servo bay locks
- Arduino firmware (RFID authentication, bay control, LCD status, charging monitor)
- ESP32 slot-booking web dashboard with bay status and activity log
- Circuit diagram and wiring documentation
- Component list with part numbers
- Project report PDF (background, methodology, architecture, results, future scope)
- PPT presentation for final review
- Viva Q&A preparation document (RFID, relays, charging, slot-booking logic)
- Demonstration guidance and setup instructions
Timeline
- Week 1: component procurement, bay rack fabrication and circuit assembly
- Week 2: Arduino firmware (RFID check, servo locks, LCD, voltage sensing) and bench testing
- Week 3: ESP32 booking dashboard, booking-to-controller link and full swap-loop testing
- Week 4: documentation, report, PPT and final demonstration rehearsal
Support
- Build and setup guidance over WhatsApp during the project period
- Help with demonstration rehearsal and viva questions on the swapping logic
- One round of minor changes (bay count, slot timings, dashboard labels) on request
Limitations & prerequisites
- Demonstration scale only: the station uses 12 V demo packs and is not a certified public EV charging or swapping station, and it must never be connected to a real vehicle battery.
- Only 4 bays and 24 bookable slots per day in the demo build, so a busy station would need more bays, which is listed as future scope.
- Full recharge of a fully discharged returned pack takes approximately 7–8 hours (design target), so a bay is only as useful as the charged stock it holds.
- RFID read distance is approximately 3–5 cm (datasheet value), so the card must be held close to the reader.
- The dashboard runs on the ESP32 over local Wi-Fi; it is not a cloud-hosted booking service and needs the station network to be reachable.
- The demo packs are sealed lead-acid stand-ins, not lithium EV packs, so no lithium battery-management behaviour is demonstrated.
- Charging uses a simple constant-current design target; no cell balancing or thermal management is implemented.
Frequently Asked Questions
Is this project suitable for a final-year project?
Yes, it is well suited to Electrical, Electronics and E&TC final-year projects because it combines power electronics, embedded control and a web dashboard in one demonstrable system. It covers battery charging and handling, Arduino-based RFID authentication, servo-driven bay locks and ESP32 slot booking, and the report documents a clear problem, a working prototype and honest limitations to discuss in the viva.
Does it work with a real electric vehicle?
No, it does not work with a real electric vehicle, and it must never be connected to one. This is a demonstration-scale station model built with 12 V demo battery packs for a college lab, and its purpose is to prove the swapping, authentication and booking logic at a safe low voltage. It is not a certified charging station and it is not intended for road use.
How does the RFID authentication work?
The MFRC522 reader (13.56 MHz, datasheet value) reads the card at approximately 3–5 cm, and the Arduino checks the card ID against a registered list and the day's bookings before any bay can open. Only a registered card with a matching booking unlocks its reserved bay, while unknown cards are rejected and the LCD shows "Card not registered" so the failure is visible during the demonstration.
How does slot booking prevent two users taking the same battery?
Slot booking prevents double allocation because each booking reserves one bay for one time slot, and the dashboard shows 24 slots per day across the 4 bays and 6 time slots. A bay unlocks only for the card that booked that slot, so another user cannot open a bay that is already reserved even with a valid registered card, and the activity log records who booked which bay.
What happens to the discharged battery after a swap?
The discharged battery is not discarded: the returned pack stays in its bay and charges automatically at a 1 A current (design target) while its voltage is monitored. Recharging a fully discharged pack takes approximately 7–8 hours (design target), after which the bay is marked ready on the LCD and dashboard, so the next booked user receives a fully charged pack.
Can this project be customized?
Yes, the bay count, the number of daily slots, the RFID card list and the dashboard labels can all be changed on request to suit a college's requirements. A payment record, an SMS notification or a cloud-hosted booking page can be added as an optional extension, and a larger bay count is listed as future scope in the project report.
Components & software requirements
- Arduino Uno (station controller)
- ESP32 (Wi-Fi slot-booking dashboard)
- MFRC522 RFID reader module
- 16×2 LCD with I2C adapter
- SG90 servo motors (bay locks)
- 4-channel relay module
- Arduino IDE
- HTML · CSS · JavaScript dashboard
Delivery information
Built-to-order project. Delivery timeline is shared after order confirmation based on current queue.
Support terms
Complete documentation, setup guide, and viva preparation included. Support for setup and explanation provided.
Download free synopsis (PDF)
Enter your name and WhatsApp number — the synopsis PDF downloads immediately. We may send occasional project updates on WhatsApp; no spam.