Cell Pack Designer
18650 21700 LiFePO4 Calc
Only for iPhone
$4.99 · Designed for iPhone. Not verified for macOS.
iPhone
Design DIY battery packs with confidence. Voltage, capacity, discharge current, weight, cost and BMS sizing, all in one offline calculator.
Cell Pack Designer helps you plan DIY battery packs built from 18650, 21700, or LiFePO4 cells, before you spend money on parts.
Pick a cell preset (or enter your own specs) and a series x parallel configuration, and instantly see:
- Pack nominal and full-charge voltage
- Total capacity in Ah and Wh
- Continuous and peak discharge current
- Estimated pack weight
- Estimated build cost (cells, BMS, nickel strip, wiring)
- Recommended BMS current rating, with a warning if your BMS is undersized
- Estimated voltage sag under load
Every default value, cell capacity, cost, weight overhead, is editable, so the numbers match the exact cells and prices you are actually using.
Save multiple pack designs and compare them side by side to find the configuration that fits your project, whether that is an e-bike, a solar storage bank, a power tool pack, or a robotics project.
Cell Pack Designer works completely offline. Nothing you enter ever leaves your device.
This app is a planning and estimation tool. Always follow proper safety practices, use a real BMS, and verify specs against your actual cell datasheets before building a physical pack. Lithium battery packs can be dangerous if built incorrectly.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Reliability and input fixes:
- Designs and in-progress edits are now saved the moment the app is backgrounded, so nothing is lost if iOS closes the app right after you type.
- Number fields now have a Done key, and a field left empty snaps back to the value actually being used instead of looking blank.
- Renaming a saved design updates its detail screen immediately.
- Compare no longer offers to compare a design that was deleted while selected.
The developer, Yoshifumi Sato, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Yoshifumi Sato
- Size
- 12.2 MB
- Category
- Utilities
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Cell Pack Designer
