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How they make the world's fastest EV chargers | Exponent Energy CEO gives factory tour! BP2B S2 Ep.7

Inside the factory that produces the world's fastest EV Charger! In this Best Place to Build Podcast episode, Arun Vinayak (Co-Founder & CEO, Exponent Energy, former CPO, Ather Energy) breaks down the hidden engineering challenges behind rapid EV charging and why the future of mobility in India requires a full-stack energy solution. 👉 In this episode, you’ll learn: — Why petroleum “dumb nozzle” model doesn’t work for EVs — The real reason fast-charging batteries are hard to build — Why energy is a transaction problem (like Visa: card + POS) — How Exponent Energy is building the entire stack — battery + charger + software — for 15-min charging — Arun’s early journey: building a brakeless car from Bangalore’s Shivajinagar scrap market — Key lessons from scaling Ather Energy and now Exponent Energy — The future of EV adoption in India and why mobility needs fresh thinking Whether you’re curious about EV startups, battery innovation, or India’s clean mobility future, this conversation offers a rare inside look from one of India’s leading energy entrepreneurs. Looking for something specific? Here you go: 0:00 Introduction 0:52 Meet Arun Vinayak: Co-Founder and CEO of Exponent Energy 1:30 Exponent Energy & the world’s fastest EV charger 3:23 Building a car at 16 years old 5:41 Building the future of Energy 7:10 What’s holding back EV adoption 11:07 The Real Challenge: Charging Infrastructure 12:36 The Energy Economics and EV vs Petroleum 16:12 Why you can’t just pass more current to a battery 19:55 How exponent solves fast charging 26:47 Economics & making EVs more accessible 31:24 Where is Exponent Energy now: team, progress, investors 33:30 Exponent’s Series B announcement video 34:40 Lithium-Ion Tech & how metrics differ by Industry 37:45 Arun’s Life at IIT Madras and Raftaar Formula Racing 42:07 Being CPO at Ather and starting Exponent 46:59 Building in India. Twice. 51:34 Mentoring CFI students and Hiring from CFI 52: 35 Arun’s tweets & being a Bangalorean 56: 30 Test Cricket and Startups 40:20 Scaling EV Infrastructure in India 45:15 Inside the Factory: Building the World’s Fastest Chargers 51:00 The Future of Rapid Charging & Global Expansion 56:20 Cricket & Startup Life 58:14 Exponent Energy Factory Tour

Arun Vinayakguest
Sep 4, 20251h 9mWatch on YouTube ↗

At a glance

WHAT IT’S REALLY ABOUT

Exponent Energy’s full-stack approach to ultra-fast EV charging in India

  1. Exponent Energy targets India’s commercial vehicles, arguing that although they are only ~10% of vehicles, they consume ~70% of on-road energy, making them the highest-leverage segment to electrify.
  2. The company claims “world’s fastest” 15-minute full charging from 3-wheelers up to buses, including a 1.5 MW charger built in India, to eliminate downtime and improve charging-station throughput economics.
  3. Arun explains why fast charging is a battery-chemistry and control problem (lithium crowding/plating, cell-to-cell variation) that cannot be solved by simply pushing more current, requiring closed-loop, cell-aware charging instead of open-loop CCCV.
  4. Exponent’s technical differentiators include real-time sensing and control, cloud “digital twins” per cell, and moving expensive HVAC/cooling off the vehicle and into the charger via a connector that carries power, data, and coolant.
  5. The episode weaves Arun’s builder origin story (scrap-built car at 16, IIT Madras/C FI/Raftaar, Ather CPO) with Exponent’s “engineering + economics” philosophy, current scale (150 chargers, 2,000+ pilot vehicles), and the challenges of building deep tech in India.

IDEAS WORTH REMEMBERING

5 ideas

Fast charging is fundamentally a two-sided “transaction” problem, not a charger-only upgrade.

Exponent argues that unlike petroleum (easy transaction, hard upstream), EVs have energy everywhere but a hard midstream transaction; rapid charging requires charger, battery pack, BMS algorithms, connector, and station to be designed as one system.

Open-loop CCCV charging is “probabilistic”; rapid charging needs deterministic, cell-aware control.

CCCV applies generic current/voltage profiles despite cell aging and pack differences; Exponent claims it senses cell behavior in real time, predicts crowding, dynamically adjusts (and can reverse) current per cell, and learns via cloud models.

Lithium plating is the degradation cliff that fast charging must avoid.

Arun describes lithium ions “traffic-jamming” at the anode during aggressive charging, triggering irreversible plating that removes active material and causes the familiar “knee” in degradation curves.

Thermals are necessary—but secondary to electrochemical control.

Even perfect cooling cannot prevent plating if charging is uncontrolled; however, once charging goes faster, heat scales sharply (I²R), so robust thermal systems are required for field reliability.

India’s commercial EVs can’t afford vehicle-integrated HVAC; move cooling to the charger.

Because many commercial vehicles in India heat up mainly during charging (low-speed duty cycles), Exponent relocates heating/cooling hardware to the charging station and pumps coolant into the battery through the connector, lowering vehicle cost and complexity.

WORDS WORTH SAVING

5 quotes

Commercial vehicles are just 10% of the vehicles on the ground, but they consume 70% of the energy.

— Arun Vinayak

One-hour charging… is not fast enough. Imagine going to a public spot and waiting one hour, twice a day.

— Arun Vinayak

If you just amp it up blindly, you will destroy the cell.

— Arun Vinayak

We’re going from this to a deterministic method, where we real-time understand what’s happening with every cell.

— Arun Vinayak

Engineering without economics is just a science project.

— Arun Vinayak

Commercial vehicle electrification leverage (10% vehicles, 70% energy)15-minute charging and station throughput economicsWhy “just increase current” fails (lithium plating, degradation)Closed-loop charging vs CCCV open-loop methodsThermal management and negative temperature gradient in IndiaCharger-to-battery coolant/heating via multi-service connectorFactory testing: accelerated lifecycle cycling and tolerance controlMake-in-India deep tech adoption and OEM trust gapFounder journey: IITM CFI/Raftaar, Ather to Exponent

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