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Privacy policy

Last updated: 2 October 2026

The short version

The ChargeLog app records charging sessions on your phone and keeps them there. It needs no connection to do that, and it has no analytics, telemetry or crash-reporting code of its own. Your recordings leave only when you send them: an export you save, a watch syncing to your own phone, a support email you attach diagnostics to — or a charging curve you have opted in to contributing to the open dataset, which is off until you turn it on and described in full below. If you installed from Google Play, Google also collects crash and install counts on its own terms. This website uses no cookies, no analytics scripts, and no trackers.

Who we are

ChargeLog is developed and published by BluffWorks LLC, based in Virginia. For the purposes of data protection law (including the GDPR), BluffWorks LLC is the data controller for the personal data described on this page: what you send to our email addresses, and the connection data Cloudflare handles when it serves this site. The app itself sends nothing to us — see below. You can reach us at hello@chargelog.org.

The app

  • What it records: charging sessions — battery readings, charging phases, temperature, and physical context such as fold state, screen state, and whether the charge is wired or wireless — in a local database on your device. Between charges it also notes the battery level as it falls, with the screen state, so it can estimate how your phone drains. Both stay on the device, and both go with Delete all data.
  • What leaves your phone on its own: nothing. The app contains no analytics, telemetry or crash-reporting code, and makes no network request of any kind unless you have opted in to contributing. Anything that leaves is something you started: an export to a location you pick, a watch's sessions arriving on your own phone over Bluetooth, a support email — see Support email below — or a contributed charging curve, below that.
  • Contributing to the open dataset: the app asks, once, whether you would like your anonymized charging curves to join a public dataset of how devices really charge, shows you exactly what would go, and stores your answer on your phone. It is off unless you turn it on, one tap turns it off again, and nothing about the app works differently either way. When it is on, a rounded summary of a finished charge is sent over an unmetered connection to api.chargelog.org — never the raw recording, and never your own tags, notes or location. The service that would receive them is not running yet, so nothing is sent whatever you answer today. The dataset has a page of its own: the open dataset.
  • Google Play: if you installed ChargeLog from Google Play, Google may collect crash, ANR and install statistics on its own terms — see Google's privacy policy (opens in a new tab) — and show them to us through the Play Console, without anything that identifies you. That is Google's collection, not the app's: the app adds nothing to it. A review or testing feedback you leave on Play reaches us the way Google presents it, with whatever name Google attaches.
  • The Wear OS app: it records your watch's own charging on the watch — and, like the phone app, the battery level as it falls between charges — and, once you pair the two by hand, sends the charging sessions to your phone over Bluetooth. They go to that phone and nowhere else on their own; the watch app declares no network permission at all. A watch session that has reached the phone can be part of a diagnostics bundle you choose to send — see Support email below.
  • Your control: sessions can be deleted one at a time or all at once from within the app, a retention setting can prune old ones, and uninstalling the app removes everything it stored on that device. Files you exported yourself are yours and are not touched; a watch's sessions already synced to your phone stay on the phone until you delete them there.

This website

  • No cookies, no analytics scripts, no third-party trackers.
  • One form: the closed-beta sign-up at /beta/. It stores the email address you type, the phone model you name, whether you said you have a watch, the time, and — once your invite has been sent — the date it was sent, in Cloudflare's key-value store, and nothing else: no IP address, no browser details. It exists only to add you to the Google Play tester list and send you the invite. The list is read through a page only the maintainer can open, behind a sign-in. Every entry is deleted when the beta ends, or sooner if you email hello@chargelog.org. Nothing else on the site writes anything.
  • Your browser stores a single localStorage entry to remember your light/dark theme choice; it never leaves your device.
  • The site is served by Cloudflare, which as the host sees what any web server sees — your IP address, the page requested, your browser's user agent — keeps aggregate operational logs, and may ask your browser to report a failed connection back to it. All of that is under Cloudflare's privacy policy (opens in a new tab); we see traffic counts, not visitors.

Donations

Donations are processed by Liberapay (and the payment processors beneath it, Stripe and PayPal) under Liberapay's privacy policy (opens in a new tab). Liberapay shows us only what its own settings let you share with a recipient, and we never see your card or bank details.

Support email

If you write to support@chargelog.org, we hold what you send: your address, your message, and anything you attach. Settings → Help → Contact support pre-fills the subject with your app version, device model and Android version, and can attach a diagnostics bundle — a zip built on your phone, shown to you before it goes anywhere, and attached only when you turn it on yourself. It contains:

  • a device report — app version, Android version, device model, your settings, and the random per-install id (16 random bytes, tied to no hardware identifier) that tells your devices' sessions apart, with the watch-sync trust file and any stored token left out;
  • recent recorder service events;
  • the three newest session logs from each device — the phone, and any watch that has synced to it — trimmed to their most recent part when they are long;
  • the app's own log lines.

We keep support mail only as long as the ticket needs it, and at most twelve months after the last message; we delete it sooner on request — write to the same address and say so. Mail to either address is forwarded by our domain's email routing (Cloudflare) to an ordinary mailbox at a mail provider, each under its own terms; nobody outside BluffWorks LLC reads it, and a bundle is opened only to answer you and fix what you reported. Nothing in a bundle is published or sold, and nothing from it is ever pasted into a public issue. A bundle is never sent over the network: the only way this data leaves your phone is the mail you choose to send.

Your rights

The app sends us nothing unless you turn contributing on. If you do, your contributed charging curves are the one thing we hold, under a pseudonym that changes monthly and no account: delete them from the phone that sent them, in Settings → Contribute charging curves → Delete my contributions, and they leave the dataset's storage at once and its reports by the next nightly rebuild. Each day's manifest keeps a hash of what was accepted that day, which identifies no one. Everything else the app records stays on your device, under your control. The other exception is what you email us yourself, including a diagnostics bundle: see Support email above. For anything related to this website, a donation, or support mail, email hello@chargelog.org and we'll respond within 30 days. If you are in the EU, EEA or UK you can also complain to your data protection authority.

Children

ChargeLog is not directed at children, and we declare it to Google Play as an app for adults (18 and over). The app sends us nothing about anyone, of any age; the only personal data we ever hold is email, and we do not knowingly keep mail or a beta sign-up from anyone under 18. If you believe someone under 18 has written to us, tell us at hello@chargelog.org and we will delete it.

Changes

If this policy changes, the date at the top changes with it, and a change to what leaves your phone is spelled out here rather than just re-dated. What the app may send is bounded by the app itself, not by this page: contributing is off until you turn it on, one endpoint is compiled into the build, and Google Play lists the app's permissions on its own page for anyone who wants to check.