Tower Energy calculates exactly how long your battery or generator will last based on your actual devices and capacity. No guessing during a blackout.
Download Free — iOSSelect your bonus and claim it before the timer hits zero. New players only. Standard wagering applies.
Wagering requirements apply to all bonuses. Minimum deposit required where stated. New players aged 18+ only. Offers valid for 7–14 days as specified per card. Gamble responsibly.
Tower Energy is built around a watt-hour runtime engine — you input your battery or generator's total capacity in Wh, and the app tracks cumulative power draw from every device you add. The calculation is continuous: change a device's quantity or toggle it from Continuous to Intermittent mode, and the estimated runtime updates instantly with no server call required.
The Time Simulation slider lets you drag through hypothetical usage hours to see projected remaining energy at any point in the future. The orange "0.0h" counter tracks your simulation position against the calculated maximum of 6.7 hours at a 300 W load, giving a realistic picture of how long your setup holds. The remaining Wh readout on the left and max hours on the right keep the math transparent.
Offline-first architecture means every calculation runs locally — no network dependency during a real outage when connectivity is unreliable. The app ships at 6.1 MB, runs on iOS 15.6 and above, and stores your configured sources and device list in local device storage so your setup persists between sessions without an account requirement.
Enter your energy source by name — the app ships with presets like Fosibot — and specify capacity in Wh with optional voltage data. An efficiency slider (default 100%) accounts for real-world battery losses.
Add appliances with their wattage and quantity. Set each to Continuous or Intermittent mode, which changes how that device contributes to the total draw calculation against your stored energy.
The estimated runtime display shows hours and minutes in large neon-green numerals. At 2000 Wh and 300 W consumption, the output reads 6h 40m — recalculates immediately when any variable changes.
Drag the white-handle slider across the timeline to simulate usage at any future point. The orange time counter and remaining Wh readout update in sync, projecting energy state without running the device.
Two large circular gauges display Total Capacity (kWh) and Consumption (W) with cyan arc rings and dark-field backgrounds. A separate circular gauge on the consumption card shows the 15% load percentage with a red arc indicator.
Load a pre-built device set with one tap: Home (5 devices — Refrigerator 150 W, LED Lights 60 W, Router 15 W plus 2 more), Emergency (4 devices), or Camping (5 devices). Profiles populate the device list instantly.
Svitlana Kravchenko developed Tower Energy as a standalone iOS utility — no corporate platform behind it. The app targets iPhone users on iOS 15.6 and later, ships at 6.1 MB, carries a 4+ age rating, and is available at no cost. Copyright 2026. The Travel category listing reflects its core use case: keeping power needs calculated during field situations, camping, or grid-independent travel.
Free on iPhone. iOS 15.6 or later required. No account. 6.1 MB — installs in under 30 seconds.
Download for iOS — Free
Requires iPhone with iOS 15.6 or later. Free download — no in-app purchases listed.
Age rating: 4+. Designed for iPhone. Size: 6.1 MB. Developer: Svitlana Kravchenko.