harryyking/powercalc

How to Calculate & Reduce Your ECG Electricity Units (kWh) in Ghana to Save Money # PowerCalc GH — React Native Expo App ## ECG Prepaid Electricity Estimator for Ghanaians --- ## Quick Start ```bash # 1. Create the Expo project (run this first) npx create-expo-app@latest PowerCalcGH --template tabs cd PowerCalcGH # 2. Install required dependencies npx expo install @react-native-async-storage/async-storage npx expo install @react-native-community/slider npx expo install react-native-safe-area-context npx expo install expo-sharing npx expo install expo-notifications # 3. Copy all files from this scaffold into the project # (types/, constants/, hooks/, store/, components/, app/) # 4. Start dev server npx expo start ``` --- ## Project Structure ``` PowerCalcGH/ │ ├── types/ │ └── index.ts ← All TypeScript interfaces │ ├── constants/ │ ├── tariffs.ts ← PURC tariff rates (update quarterly) │ └── appliances.ts ← All 25+ appliances with Ghana defaults │ ├── hooks/ │ └── useCalculator.ts ← Core calculation logic + formatters │ ├── store/ │ └── historyStore.ts ← AsyncStorage credit history │ ├── components/ │ ├── ApplianceCard.tsx ← Tap-to-toggle appliance tile │ └── ResultCard.tsx ← Days-left result + breakdown bars │ └── app/ └── (tabs)/ └── index.tsx ← Calculator home screen ``` --- ## Tariff Update Process (every quarter) PURC adjusts tariffs quarterly via the Automatic Adjustment Formula (AAF). When a new rate is announced, **only update `constants/tariffs.ts`**: 1. Check: purc.com.gh → Tariffs → Current Electricity Tariffs 2. Update `ratePerKwh` values in the `TARIFFS` object 3. Update `lastUpdated` date string 4. Submit an OTA update via `eas update` — no App Store review needed ```ts // Example: updating residential band residential: { bands: [ { minKwh: 0, maxKwh: 30, ratePerKwh: 0.8690, ... }, // lifeline { minKwh: 30, maxKwh: 300, ratePerKwh: 1.9688, ... }, // ← update this { minKwh: 300, maxKwh: null, ratePerKwh: 2.1500, ... }, // ← and th …