Best Place To BuildHow they make the world's fastest EV chargers | Exponent Energy CEO gives factory tour! BP2B S2 Ep.7
CHAPTERS
- 0:00 – 1:18
Inside Exponent Energy’s mission: a full-stack energy company for commercial EVs
From the factory floor in Bengaluru, Arun Vinayak frames Exponent as an energy company—not merely a charger or battery company. The focus is commercial vehicles, where electrification impact is largest and energy transactions must be fast, reliable, and economical.
- •Exponent sits at the intersection of energy, automotive, and financing for commercial fleets
- •Commercial vehicles are ~10% of vehicles but consume ~70% of on-road energy in India
- •Exponent positions the future of energy as “batteries + chargers,” delivered as one stack
- •Goal: make energy seamless so EV adoption becomes the obvious choice
- 1:18 – 3:12
World’s fastest charging claim: 15-minute charging from 3-wheelers to buses (1.5 MW)
Arun explains Exponent’s headline capability: 15-minute fast charging across vehicle classes, including buses. The host sees Exponent’s “ePump” concept as an EV equivalent of a fuel pump for quick, repeatable public charging transactions.
- •15-minute charging designed for commercial uptime and earnings continuity
- •ePump concept mirrors refueling: pull in, connect, charge, leave
- •Coverage spans 3-wheelers, LCVs, and even buses
- •1.5 MW bus charger described as the world’s highest power charger built in India
- 3:12 – 6:42
Origin story: building a (brakeless) car at 16 and the “builder switch”
A personal detour sets the tone for Arun’s maker mindset—he built a car from scrap parts as a teenager. The experience cemented a lifelong focus on mobility and the joy of building real, working systems.
- •Sourcing parts from Bengaluru’s scrap markets and using workshop tools to fabricate
- •Real-life “Junkyard Wars” prototyping with limited budget and lots of iteration
- •The car drove well but lacked brakes—highlighting raw experimentation
- •This early success hardwired a commitment to building mobility products
- 6:42 – 9:22
Why EV adoption stalls: energy experience, not the vehicle
Arun argues EVs are already superior machines when you ‘remove the battery equation’; what holds adoption back is the energy ecosystem. The chapter reframes EV scaling as an energy transaction problem—where, how fast, and how reliably you can charge.
- •EVs are faster/cheaper/longer-lasting; adoption bottlenecks are energy questions
- •Key anxieties: charging location, charging time, battery longevity
- •History lesson: petroleum ecosystem enabled ICE dominance; EV needs its own ecosystem
- •Mobility equals freedom/flexibility—energy must deliver those traits
- 9:22 – 11:07
Why “1-hour fast charging” isn’t fast enough for India’s commercial reality
The conversation turns practical: many users can’t charge at home and already live with daily refueling routines. Exponent targets sub-15-minute transactions to make public charging viable for drivers who can’t afford long waits or unpredictable queues.
- •Many owners (especially commercial) park away from home and depend on public energy
- •CNG refueling can take 1–1.5 hours; repeating this with EV charging is unacceptable
- •15 minutes enables ~10-minute top-ups in typical usage (arrive with 20–30% SOC)
- •Future roadmap: aiming toward ~5-minute charging in a few years
- 11:07 – 13:26
Charging infrastructure economics: throughput per square foot is the real battle
Arun explains why charger businesses struggle when charging is slow: land and parking costs dominate, and low daily utilization kills unit economics. Faster charging boosts energy sold per station, enabling sustainable pricing for commercial customers.
- •Stations must make money for charging to proliferate—investors need returns
- •Real estate/parking costs make low-throughput charging unviable
- •Commercial users are price-sensitive, so pricing headroom is limited
- •Solution is 10–20x higher energy throughput via much faster transactions
- 13:26 – 19:55
Why you can’t ‘just push more current’: lithium plating, entropy, and cell damage
The host asks the naive-but-crucial question: what happens if you simply dial up current? Arun breaks down electrochemistry limits, explaining lithium crowding/plating and why charging (not discharging) is what most stresses and degrades cells.
- •Charging stresses cells; driving/discharging is comparatively gentle
- •Fast charging creates lithium-ion ‘traffic jams’ at the anode (crowding)
- •Lithium plating is irreversible and triggers the degradation ‘knee’
- •Heat rises with I²R, but thermal issues are secondary to electrochemical damage
- 19:55 – 23:20
Exponent’s approach: closed-loop, cell-level intelligence + digital twins in the cloud
Exponent replaces probabilistic CCCV charging with a deterministic, feedback-controlled system. The stack senses cell behavior in real time, predicts precursors to plating, and dynamically adjusts (even reverses) current using per-cell models that improve over time.
- •Industry norm CCCV is open-loop and ‘bets on probability’ across varying cells/aging
- •Exponent uses high-accuracy sensing and fast response to manage each cell
- •Predicts lithium crowding before it becomes plating; adapts charge profiles dynamically
- •Maintains a ‘digital twin’ for each cell/battery pack that learns with every session
- 23:20 – 26:45
Thermal breakthrough for India: move HVAC/cooling from vehicle to the charger via fluid coupling
To handle massive heat during rapid charging, Exponent rethinks where cooling lives. Instead of expensive, bulky onboard HVAC (hard to justify on low-cost vehicles), Exponent shifts cooling/heating to the charger and delivers it through the connector using fluid lines.
- •15-minute charging implies ~16x current and ~256x heat vs 4-hour charging
- •EV batteries need 25–40°C; India’s ambient can exceed that → negative gradient
- •Onboard HVAC is expensive and bulky (e.g., passenger-car scale systems)
- •Exponent’s connector carries power + data + fluid; charger pumps coolant and can heat too
- 26:45 – 31:22
Engineering with economics: making rapid charging affordable for commercial EVs
Arun ties technical choices to cost structure and adoption: great engineering that can’t scale economically is a science project. By relocating expensive subsystems off-vehicle and maximizing fleet uptime, Exponent aims to improve total cost of ownership and accessibility.
- •Tech matters only if it disrupts performance, price, and accessibility at scale
- •Removing vehicle HVAC reduces upfront vehicle cost, especially for 3-wheelers
- •Downtime is lost earnings; rapid charging restores operational freedom for fleets
- •Queues/power outages become less painful when transactions are faster
- 31:22 – 34:24
Where Exponent is today: deployment scale, investors, and the Series B story
Arun shares Exponent’s operational footprint—team size, chargers deployed, and pilot vehicles—plus the company’s funding journey. The host references Exponent’s Series B announcement video and brand-building efforts despite being B2B.
- •~200-person team; ~150 chargers; 2,000+ vehicles in early pilot (primarily 3-wheelers)
- •Bengaluru deployment comparable to LPG/CNG station counts; ambition to scale further
- •Raised ~$44M from investors including Lightspeed, Eight Roads, and TDK
- •Series B launch video messaging: EVs need freedom; slow charging is the ‘horse’ era
- 34:24 – 37:21
Battery tech is not one-size-fits-all: metrics differ by phones, cars, and commercial fleets
Arun explains how battery design priorities change by application. Consumer electronics optimize energy density and tolerate shorter life; commercial vehicles prioritize long life and fast public charging over compactness.
- •Phones/laptops: energy density and thinness; less emphasis on life/charge time
- •Passenger vehicles: balance of density and charging; home charging often possible
- •Commercial vehicles: 8–15 year asset life, high cycle count, and fast charging critical
- •Prediction: charging splits into ‘slow at home’ vs ‘ultra-fast in public’ models
- 37:21 – 43:31
IIT Madras, CFI, and Raftaar: learning to build, competing globally, and forming the talent pipeline
The conversation rewinds to Arun’s IIT years: initial academic shock, then finding CFI as a maker haven. Raftaar’s Formula Student experience—getting outperformed abroad—became a catalyst for building serious hardware in India and seeded future founding teams.
- •CFI as a ‘safe space’ to build without success pressure; prototyping budgets changed mindsets
- •Raftaar global competitions exposed the gap: others built better even without elite theory
- •Many Ather/Exponent team members trace roots to Raftaar/CFI networks
- •Exponent continues to hire from the student community and supports current teams
- 43:31 – 58:19
From Ather CPO to founding Exponent: why energy infrastructure became the next building block
Arun explains his decision to leave Ather after helping shift India’s EV narrative toward ‘best product, electric by default.’ By 2020, he saw energy systems—not vehicles—as the limiting factor, and recognized the commercial segment needed a dedicated platform company.
- •Ather’s achievement: proving EVs can be faster and better, changing public perception
- •By 2020, OEM capability improved; missing ‘building blocks’ were in energy ecosystems
- •Attempting a platform within Ather faced conflict/competitor concerns
- •Key realization: rapid charging is primarily a commercial vehicle problem → new company
- 58:19 – 1:09:49
Factory tour: India-specific product design, testing at speed, and precision battery manufacturing
The episode culminates in a hands-on tour: connector management for messy real-world parking, accelerated lifecycle testing in thermal chambers, and a tightly integrated HQ+lab+factory setup. Arun showcases automation, laser welding, adhesive assembly (“Stickinator 3000”), and tolerance control needed for high-rate charging reliability.
- •Induct ePump and connector management: heavy cables + fluid lines + misaligned parking realities
- •Remote monitoring, CCTV, and station management tailored for public infrastructure behavior
- •Accelerated life testing: thermal ovens + cyclers; 3,000+ 15-minute cycles; compressed discharge profiles
- •Manufacturing: 6-axis laser welding, adhesive-based assembly for consistency, uniform thermal extraction, and tight cell-to-cell tolerances
