Privacy notice

Version 2026-11-03

BYD Tracker is run by Mark Calleran, trading as Caltechnics ("we"). We are the data controller for the personal data described here. Contact: privacy@caltechnics.com.

We are registered with the Information Commissioner's Office (ICO), the UK's data protection regulator, as a data controller: registration number ZC285721 (opens our entry on the ICO's public register).

What we collect

Your account: first and last name, email address, a contact phone number if you choose to give one, how you sign in (Google or email and password), and when you agreed to these terms.
Country you live in: Australia, United Kingdom, Ireland or Rest of Europe, chosen when you register (accounts made before November 2026 are asked once). We collect it because BYD Tracker is now used outside the UK, so we can give you local support. All data, including this, remains stored in the UK.
Your BYD app login: the email/phone and password you use for the BYD app, so we can read your car's data. It is encrypted with a key held in Google Cloud Key Management Service and bound to your account, so it can only be decrypted to read your own car. Nobody, including the administrator, can view it in the service.
Your car's data, read from BYD: battery level, range, odometer, speed, charging status, tyre pressures and similar readings; from these we work out trips, charges and costs.
Location (GPS), only if you switch it on (Account → Your data, off by default): the car's position at each reading, used for route maps and location alerts. Following data protection by design and by default (UK GDPR Article 25), no location is collected or displayed until the account holder switches it on for their car; they then decide separately, for each person they share the car with, whether that person can see it. Location history can reveal where you live, work and travel, so it is treated as sensitive. You can switch it off at any time, and Clear personal location data permanently removes every stored position. This setting only controls what BYD Tracker reads and keeps: your car sends its location to BYD's own cloud service regardless, and BYD may store it under its own privacy policy. BYD Tracker has no control over that.
Things you enter: charging and fuel receipts, reminders, settings (including your car's registration number, if you add it: kept so that MOT and tax dates can be checked with the DVLA once that feature is added; and your postcode district, e.g. SW1A, if you add it: used to find the nearest Met Office weather station for the efficiency-by-temperature chart. Only the first part of a postcode is kept), a saved notification location.
Billing: your subscription status and dates. Card details are entered on Stripe's page and never reach us. If we've offered you complimentary (free) access, your email address and the date it ends, kept until a few weeks after it ends or until it's removed. When a free trial starts we keep a one-way coded form of the car's VIN (it can't be turned back into the VIN) for 2 years, so each car gets one free trial.
Notifications: the address emails are sent to, and push-notification subscriptions for your devices.
Usage: when you last signed in and last used the service (updated at most every 15 minutes), so we can give support and spot accounts that are no longer used.
Technical logs: sign-in and server logs kept by Google Cloud for security and troubleshooting.
Visits to our public pages (the join page, the FAQ, the sign-up page and the live demo), if you're not signed in: we count page views per day, where visitors came from (the other website's name, or a campaign tag on the link), how many different visitors there were, and, in the live demo, clicks on "Start your free trial" and how many demo visitors went on to the sign-up page that day. No cookies or similar are used and nothing is stored on your device. To count different visitors, your IP address and browser name are combined with a random value that changes every day and turned into a short code; your IP address is not stored, the codes are deleted when the day ends (only the number is kept), and they can't be linked to you or from one day to the next. We also count, as a number per day only, new accounts, requests for a link to finish setting up later, trials started and BYD logins that couldn't be checked, so the totals stay right if an account is later deleted. The daily counts are kept for 13 months.
Email updates: whether you're happy for us to email you about BYD Tracker (for example when the service is unavailable or a new feature is added), and when you chose. The box is ticked when you sign up and you can untick it there, or change it at any time on your Account page; every such email also lets you unsubscribe. We never pass your address to anyone else for marketing. Emails you need to use the service (such as confirming your address, trial and billing notices, and the notifications you choose) are sent either way.
Notice to the administrator: when you start a free trial, the administrator of this site is advised of your joining the trial and may welcome you with an email and offer any support needed to help you get the most out of the site. Likewise, if you create an account but haven't finished setting it up an hour later, the administrator is advised and may email you to offer help.
Why you left: when you delete your account we ask why, from a short list (and, if you choose "Something else", in your own words). It's kept for 2 years without your account id, name or email, together with the day, how long the account was open and whether it was on a trial or paid, so we can improve the service. Please don't include personal details in the explanation.
"Email me a link" in the live demo: if you ask for a link to start later, we use your email address once, to send that one email through our email provider. We don't keep your address or add it to any list; we keep only a one-way code made from it for 30 days, so the same address isn't sent the link again. Lawful basis: legitimate interests (sending what you asked for).
Gift subscriptions: if you buy a gift, your name and email address (for the receipt and the gift code) and the payment record, held as accounting records like any other payment. You also give us the name of the person it's for, an optional message and, if you ask us to email it to them, their email address: we use these only to deliver the gift (the gift email and the printable gift card) and erase them 35 days after the gift is redeemed, cancelled or expires. If you receive a gift, we record which account redeemed it and when. Lawful basis: contract (the gift you bought) and legitimate interests (delivering it to the person it's for).

Why we use it, and our lawful basis

To provide the service you subscribe to (reading your car, showing trips and costs, sending the notifications you choose): contract.
To take payment and keep accounting records: contract and legal obligation.
To keep the service secure, fix problems and prevent misuse: legitimate interests.
Emails about BYD Tracker's service and new features, if you leave the box ticked: legitimate interests, under the "soft opt-in" for people who sign up to a service (you can say no when you sign up, and unsubscribe at any time); and the reasons people give for leaving, to improve the service: legitimate interests.
Location (GPS) data, only if you switch it on: consent. You give it on your Account page and can withdraw it at any time by switching location off; that stops collection straight away and doesn't affect anything else in the service. If you share your car, the people you share it with see location only if you also switch it on for each of them.

We don't make decisions about you by automated means that have legal or similarly significant effects.

We don't sell your data, use it for advertising, or share it with anyone except the providers below.

Who can see it

Your name, email address, phone number and subscription status can be seen only by you and the administrator of the service (and your name, email address and phone number by a regional administrator, as explained below), never by other users. If you approve a shared account (for example for your partner), that person can also see your trips, charges and car status, view only, until you remove them. They see locations only if you switch location on for that person. The administrator can also view your trips, charges and notifications (and locations, if you've switched location on) read-only when needed to give support or investigate a fault; each viewing is logged. Nobody, including the administrator, can see your BYD password. Stripe also holds your name, email and phone number to take payments.

Second administrator: a second administrator helps users in Australia. They can see the name, email address, phone number, country and set-up progress (for example whether your BYD login check failed) of users who live in Australia, to help them get set up. From time to time, in an emergency, the administrator may let them see the same details for all users, to provide additional support; this is switched on and off only by the administrator, and each change is logged. They can't see subscriptions or payment details, your car's records or your BYD password. All data remains stored in the UK.

If you have a shared account (you view someone else's car), we hold your name, email address, optional phone number and sign-in, and the car owner can see your email address in their list of people who can see their car.

We never sell your data, never share it with advertisers, marketers or data brokers, and never use it to show you adverts or send you marketing. The service has no adverts. The providers below handle data only to run the service for you.

Providers who process data for us

Google Cloud / Firebase (hosting, database, sign-in, encryption keys; data stored in London, europe-west2).
Stripe (payments and invoices).
BYD (your car's data is read from BYD's servers using your login, under your own agreement with BYD).
OpenStreetMap / Nominatim (map tiles, which your browser loads only when location is on and a map is shown; and the nearest road name for a saved location, which sends those coordinates to Nominatim when you set it).
Cloudflare (cdnjs) and Google (gstatic) deliver the map and sign-in code to your browser, so they see your IP address when a page loads; no car data is sent to them.
postcodes.io (finds the centre of your postcode district) and the Met Office (finds the nearest weather station to that point, and supplies daily temperatures). Only the district or its centre point is sent, never your name, account or the car's position.
Outside the UK: OpenStreetMap / Nominatim (finds the point, to about 1 km, for the postcode, Eircode routing key or town you enter for weather) and MET Norway (hourly temperatures for that point). Only the postcode or town, or the point, is sent, never your name, account or the car's position.
A Better Routeplanner (ABRP, Iternio), only if you connect it on the Account page: your car's battery %, speed, odometer, range and charging status after each reading (and its position only if location is on), sent to your own ABRP account. Disconnect at any time.
Ohme, only if you connect your Ohme home charger on the Account page: your Ohme email and password are sent to Ohme once to sign in (the password isn't kept), then BYD Tracker reads your charger's status, schedule, energy and costs from your own Ohme account, read-only. Disconnect at any time.
Your browser's push service (Apple, Google or Mozilla, depending on your device) delivers push notifications, which are encrypted so the push service can't read them.
Our email sending service Brevo (based in France) (notification emails: your email address and the notification text).

Some of these providers may process data outside the UK; where they do, they rely on UK adequacy regulations or standard contractual clauses.

How long we keep it

Your account and car records: while your account is open. Delete your account at any time from the Account page and everything (including your encrypted BYD login) is deleted straight away.
Backups: a copy of the database is taken once a week, kept in London, and used only to recover from a fault or mistake. Each backup is deleted automatically after 4 weeks, so anything deleted from BYD Tracker (including a deleted account) is gone from every backup within 4 weeks. If we ever have to restore from a backup, we delete again any accounts that were deleted after it was taken.
If your subscription ends (or you never start one), we keep your account for 4 weeks so you can come back. A week before the end we email you a warning; then the account and all its records are permanently deleted and we email you to confirm. Subscribing again in the meantime keeps everything. Only records held by BYD Tracker are deleted; anything stored on BYD's own cloud is outside this service and not affected.
Detailed car readings (taken once a minute while driving, including positions if location is on): 90 days, then deleted automatically. The trips, charges and costs worked out from them are kept while your account is open; only route maps for older trips stop being available. Monthly battery-health averages (the car's range estimate per % of battery) are also kept while your account is open.
Invoices and payment records: 6 years (UK tax law), held by Stripe. The same for gift purchases (who bought which gift, and when it was redeemed); the gift recipient's name, email and message are erased 35 days after the gift is redeemed, cancelled or expires.
Technical logs, including the record of administrator actions: 30 days (Google Cloud's standard log retention).

Your rights

You can access, correct, download in a portable format (Account → Download my data) and delete (Account → Delete my account) your data, withdraw consent for location at any time (Account → Your data), object to or restrict how we use it, and complain to the Information Commissioner's Office (ico.org.uk, 0303 123 1113). Contact us first if you can, at privacy@caltechnics.com.

Children

The service is for car owners and drivers aged 18 or over; we don't knowingly hold data about children.

Changes to this notice

If we change this notice in a way that matters, we'll update the version date at the top and email account holders.

Cookies

We use one essential cookie to keep you signed in, and the sign-in page stores sign-in details in your browser while you sign in. No analytics or advertising cookies, so there's no cookie banner.