Feature spec
Goal: Send a clear invoice after finishing a job.
- Add a client, line items, a due date, and payment instructions.
- Preview the total before exporting a PDF.
- Keep an editable draft if export fails.
App Overview
Battery Grapher
Battery Grapher graphs your historical battery levels and learns your habits to make smart predictions on what your future battery levels will be
$1.99 · In-app purchases
PRICE
$1.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.3
151 ratings · Top 30%
Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.
Build your own version
Build Kit
Make this idea yours
A product spec, screen plans, and build steps for your coding agent.
First kit free with a verified email
Add to a Remix
Combine features and design from your favorite apps.
Kit ready. Verify your email to download it.
Generating… usually about a minute.
Make it yours Optional
What should your app do differently? Your note travels with the kit so your coding agent builds around your idea.
What's included15 files
A product spec, phased build plan, differentiation notes, and screen references.
- START_HERE
- AGENTS
- EVIDENCE
- SPEC
- BUILD_PLAN
- DIFFERENTIATION
- skills/
- screens/
Preview a sample Build Kit No email needed
Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.
Screen plan
Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.
States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.
Differentiate and validate
Hypothesis: Contractors need faster repeat invoices more than more templates.
First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.
The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.
Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.
JavaScript is required to complete mailbox verification.
Free quick prompt For a smaller starting point
Quick prompt
Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
// RORK SYSTEM PROMPT
Rork plan preview for Battery Grapher: map the core Utilities workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
Preview ready. Verify your email to reveal and copy the full prompt.
JavaScript is required to complete mailbox verification. Return to this prompt preview.
Continue in Rork >
Affiliate link: CloneChart may earn a commission at no extra cost
Opportunities
AI-GENERATED OPPORTUNITY HYPOTHESES
These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.
Hypothesis 1
Include additional metrics like screen on/off time or app usage.
Assumption to check: Limited tracking options (only battery percentage)
Validate with people who use this workflow before building.
Hypothesis 2
Implement CSV or PDF export for user data.
Assumption to check: Data export options are limited
Validate with people who use this workflow before building.
Hypothesis 3
Add customizable alerts for battery levels.
Assumption to check: No notifications for low battery alerts
Validate with people who use this workflow before building.
Hypothesis 4
Provide tutorials or tooltips to help users understand data.
Assumption to check: Difficult to interpret graphs for new users
Validate with people who use this workflow before building.
App evidence
Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.
App Store description
Battery Grapher graphs your historical battery levels and learns your habits to make smart predictions on what your future battery levels will be. Developed specifically with energy consumption in mind, Battery Grapher has almost no impact on battery life. SMART PREDICTIONS Battery Grapher uses historical battery levels to intelligently predict what your battery level will be throughout the rest of the day, allowing you to plan when to next charge your device. The longer you have Battery Grapher installed, the more accurate future battery level predictions will be. LOW ENERGY CONSUMPTION Battery Grapher is made for people who want to extend the battery life, meaning that low energy usage is a priority. The app runs a background task only once an hour, and doesn't require a network connection, which keeps energy consumption extremely low. CUSTOMIZABLE NOTIFICATIONS Battery Grapher allows you to set notifications that fit your needs. You can get the app to notify you when you battery drops below a preset percentage, or if you only have a certain number of hours left before your battery runs out. (currently only available on watchOS) ALL COMPLICATIONS & WIDGET SIZES SUPPORTED Battery Grapher supports all complications & widget sizes. Complications can show hours before needing to charge, or battery %. Both complications and widgets are customizable from within the app.
Written user reviews are not shown here. Check current App Store reviews >
Screenshots
< Scroll to see more >
Build scope
Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.
Define the first version
Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.
Set boundaries
Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.
Check the hard parts
Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.
SUGGESTED BUILD STACK
React Native
Expo
react-navigation
react-native-chart-kit
@react-native-async-storage/async-storage
redux
BUILD KIT DIFFICULTY
Intermediate
From the Build Kit assessment.
A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.
