Free
Passport
Register any battery. The record that follows it for life — through sale, second life and recycling. The sticker, the QR, the public page.
Free to start
Start free. Stay free until a battery reports.
Register every battery you're responsible for, print its label, publish its passport — for nothing, for as long as you like. You pay only while we're reading one. £2 a battery a month, and it stops when the battery goes quiet.
No card. No contract. Registration is free forever, not for twelve months.
82%
- Pack voltage
- 51.4 V
- Temperature
- 24 °C
View example reading
# illustrative — one endpoint, any batteryPOST /v1/readingsgateway: gw_7f3a · bus: can · dialect: pylontechframe: 0x4210 0x0E 0x3C …# decoded, stored, evidence kept201 soc: 0.82 · pack_v: 51.4 · temp_c: 24source: measured · raw: retained
Products
Nine services. Use one or all of them. They share one record of the battery.
Ingest
One door for every protocol. CAN, RS-485, SunSpec, Modbus TCP, manufacturer clouds. Raw frames kept as evidence, never overwritten.
Decode
A growing library of decoders — JK, Pylontech, Victron, SunSpec, Daly. New ones are added for everyone.
£2 / battery / mo
Monitor
Live readings and rule-based alerts to webhook, email or Slack. A battery that goes quiet stops costing you.
Core
Proof
An independent state-of-health estimate, with a stated uncertainty and the measurements it rests on. Computed by us, not declared by the maker.
In development — the estimate, its range and its evidence.
£15 / 25
Labels
Printed QR labels on polyester, laminated, rated −20 to +85 °C, posted to you. Or print your own from the PDF.
Gateway
Credentials and policy for every device that reports. TLS only. Each gateway can publish only on its own topics, checked on every message.
Free
Export
Your data, out, in open formats. Passports and readings. No lock-in is a feature, not a promise.
Public
Lookup
Scan the QR, see the passport. For buyers, recyclers and regulators. Every figure shows where it came from.
How it works
- 01
Register
Type in the battery. Make, model, serial, chemistry. It gets a passport and a QR in seconds. Free.
- 02
Connect
Point what you already have at us — a gateway, a manufacturer cloud with the owner's permission, or a monthly CSV. Nothing to install.
- 03
Read
We decode what the battery reports and keep the raw frames as evidence. Every figure is marked measured, reported or declared.
- 04
Prove
Over time, an independent state of health with a stated uncertainty. The number a buyer, a lessor or a regulator can rely on.
Two plans. A battery is on one of them.
Not an account-level choice — every battery picks its own plan, by whether it's reporting. Most of yours will sit on the free one.
| Never reportedFreeforever | Reporting£2 / battery / month£20 monthly minimum | |
|---|---|---|
| Battery passport, QR and public page | Included | Included |
| Printable label PDF | Included | Included |
| Public lookup for anyone with the label | Included | Included |
| Unlimited users on your account | Included | Included |
| History kept when the battery goes quiet | Included | Included |
| Live readings from the battery | Not included | Included |
| Alerts to webhook, email or Slack | Not included | Included |
| Independent state of health, with a stated range | Not included | Coming |
| How a battery gets here | You typed it in | Its first reading arrived |
Printed labels are the one thing with a separate price — £15 per 25, posted — and you can skip them by printing the PDF yourself.
Always free
These don't expire, don't count against anything, and don't change when you start paying for monitoring.
- PassportsUnlimited
Register as many batteries as you're responsible for. Each gets a passport, a QR and a public page.
- Public lookupUnlimited
Anyone who scans a label reads the published passport. No account, no limit, no charge to you or them.
- UsersUnlimited
Add your whole team. We charge for batteries, not seats.
- Label PDFsUnlimited
Print your own labels, with QR and serial barcode, as often as you need.
- ExportAny time
Passports and readings in open formats. Leaving is free, which is how you know staying is a choice.
- Quiet batteries£0
A battery that stops reporting stops costing. Its history and passport stay for as long as the record exists.
When does the meter start?
The moment a battery sends its first reading. Not when you register it, not when you create a gateway. And it stops on its own.
- 01
Never reported — free
You typed it in. Passport, QR, public page, label. It can stay here forever.
- 02
Reporting — £2 a month
Its first reading arrives and it moves here on its own. Live readings, alerts, evidence, and over time an independent state of health.
- 03
Quiet — free again
After an hour without a reading, it moves here on its own. It reports again, it moves back. You don't touch anything.
With fewer than ten monitored batteries the £20 minimum applies instead of the per-battery rate. It covers your tenancy. Every price, on one page
What it doesn't do
The list of things we won't claim.
A record is not a safety certificate.
A passport shows what has happened to a battery. It does not certify that the battery is safe to use.
We don't read state of health on day one.
No battery reports it. We derive it over months from what the battery does report, and we say how sure we are.
We don't control the battery.
Read-only, always. We never send a command to a pack or an inverter.
We don't make batteries. We prove them.
A manufacturer grading its own battery's residual value is marking its own homework. We take no money from battery makers, we keep the raw evidence, and every figure on a passport says where it came from.
- Article 14 · in force since 18 Aug 2024
- Passport mandatory · 18 Feb 2027
- Raw frames retained · never rewritten
- No manufacturer money · ever
Questions people ask before they start
Is "free" really free, or free for twelve months?
Really free. A registered battery costs nothing for as long as it's registered. There's no clock on it and no card on file.
Do you take money from battery manufacturers?
No. Not for listings, not for referrals, not for anything. The people paying us are the people who own the batteries, and that's the only way the proof means anything.
From the journal
All articlesData access · 2 Feb 2027
Reading a Pylontech over CAN: what's actually there
The most common battery in a UK cupboard, frame by frame. What it sends, what it doesn't, and why your inverter may be mislabelling it.
State of health · 26 Jan 2027
Where a used battery's value comes from
A used car with no service history is worth scrap. With one, it's worth money. The same is true of a battery leaving an EV at 75%.
Regulation · 19 Jan 2027
What a battery passport actually is
A logbook for a battery. Who writes in it, who can read it, what goes on the sticker, and what happens when the battery changes hands.
Register your first battery. It's free until it reports.
Request an account, type in a battery, print the label. Connect it when you're ready — the meter starts then, not before.