- 18 Feb 2026
- 6 min read
I Built a Powerbank-Sharing Startup Alone — and Today I'm Shutting It Down
ChargeBro: the idea, the build, the lessons
Today I'm switching off the server. This is the end of the journey for ChargeBro — and a good moment to recap and write down the lessons learned.
The idea
In December 2019, while traveling in Thailand, I first heard about powerbank sharing. I've never tried it before, but the idea stuck: scan a QR code, take a charged powerbank, and return it later — sometimes somewhere else. It solved a small but real problem at the exact moment you needed it.
Back in Ukraine, I couldn't stop thinking about it. At the time, we didn't have anything like that locally. The idea sat in my head until COVID lockdowns arrived and private life slowed down. I needed some inspiration. Something messy and real.
That's how ChargeBro started: a powerbank-sharing "startup" built by one developer, mostly at night, during a year when the world was paused.
My first Git commit is dated June 10, 2020. I didn't know native iOS or Android development, but I was reading a book about building an Uber clone with Codename One, and it inspired me so much that I decided to build the whole thing myself. I believed I could ship a mobile app without becoming a Swift/Kotlin developer first. That belief was naïve in some ways, but it removed the biggest obstacle: hesitation.
Naming it made it real
The first working name was takeAndCharge. Then I shared the idea with a group of friends and, in a very informal setting, we started brainstorming names and slogans. Nothing structured — just jokes, ideas, and "what if we call it…?"
"ChargeBro: charge in time, no stress to find"
I checked domain availability. It was free, so it won. I did the initial design in Figma myself and came up with this super simple logo:
The hardware: six powerbanks and a SIM card
I searched for hardware and ended up ordering a powerbank station from China. No screen — just a compact unit with six powerbanks, each with multiple built-in cables, plus a SIM-based internet module.
A sample arrived. I installed a local prepaid SIM, modified the device configuration and firmware so it would call my server instead of the vendor's default endpoint, and started writing the backend that could speak the station's protocol.
This is when it became real.
Backend was fast
Backend Software developer is my full time job. I had already a good experience so it took me a few weeks to build working draft.
As hosting, I considered AWS first because I knew it well from work. But for a pet project it was overkill — both in cost and complexity. I rented a small Hetzner server, used Dokku, and deployed a Spring Boot service. Swagger became my "control panel." When you're operating alone, being able to test and tweak quickly matters more than elegance.
The full system diagram, code structure, and deeper engineering notes are in the backend repo README
The stations had random reconnections. I never fully proved why — carrier conditions, firmware instability, power issues, "all of the above."
But the important part is what that forced me to build: online/offline status with a small delay, a map overlay so users wouldn't walk to a dead station, and automatic admin alerts to my phone whenever something happened. I didn't plan to build ops tooling. The hardware forced it.
The mobile app: where 80% of my time went
Backend was familiar. Mobile was new, and honestly more fun.
The app centered around a map: find stations, scan QR, unlock, and track the rental. I started with Figma mocks, showed them to a couple of friends who do UI/UX, made fixes, and then started coding.
At one point I spent two weeks polishing a splash screen animation: logo appears, grows, fades into the map, other elements appear. I proudly showed it to my girlfriend.
She watched it and said: "Okay… so where is it?"
I said: "That was it."
She laughed. "So that's what programmers do," she said.
The first pilot
By December 8, 2020, I installed the first working station. The first real pilot happened through the most startup-like channel possible: I talked about the project to friends, and a friend-of-a-friend worked with a gym administration in Kyiv.
No official partnership. No payments at first. Just: "Let's try it."
I installed one station at the front desk for gym members. Soon the gym's other two locations wanted stations too.
That's when it stopped being "a hobby project" and started acting like a startup. I monitored logs daily, watched every rent and return, fixed issues on the fly, and treated every weird station reconnect as my problem — because it was.
Mutual trust
So even though I started as a fun non-profit experiment, I had to design for fraud from day one. My solution was intentionally small: 50 UAH pre-authorization hold, released automatically after return. Amount was less than the powerbank itself. The point wasn't full insurance — it was friction against casual fraud and a "don't do something stupid" signal.
But theft prevention has a cost: trust. People didn't know this product category. Many didn't want to enter card details into a new app or register for "another useless app." In the gym pilot, usage was modest — around 1–2 rentals a day.
People don't adopt your product because it works; they adopt it because it feels safe and effortless.
If I built it again, I would simplify onboarding aggressively: phone number + SMS login (no email/password), deposit via Apple Pay / Google Pay, and probably a web-first experience — because apps add install friction, update friction, and store policy friction.
iOS was stricter (and shorter-lived)
Android felt easier. iOS was slower to approve and earlier to remove. In the end, both disappeared because I wasn't maintaining them and store policies evolve.
That's another practical reality of "shipping a product": publishing is not a one-time event. It's a long-term maintenance commitment.
Shipping was possible. Scaling alone wasn't.
Technically, ChargeBro worked. I integrated hardware, ran a TCP station protocol server, built a backend, shipped a cross-platform app, deployed stations, and operated a pilot.
But while I was engineering, I wasn't doing the other half: partnerships, distribution, sponsorships, fundraising. And then the market moved. A competitor later launched with broader coverage and real marketing, and I understood the truth:
You can build a product alone. You cannot build a company alone — especially when it depends on physical deployment, venue relationships, and user trust at scale.
Why I made the repos public
ChargeBro is no longer active, but it's still one of the most educational projects I've ever built — because it forced me into reality: reconnecting hardware, trust issues, and the gap between a working demo and a working business.
I'm publishing the code not because it's perfect, but because it's honest. If you're a developer thinking about building something physical, this is your reminder: you can. You will learn fast. The backend covers custom binary protocol handling, a two-phase payment flow, and real-time TCP-to-WebSocket bridging — things you rarely see in tutorials. Just don't confuse shipping with scaling.
Repos: chargebro-mobile and chargebro-backend
