# Propeller Calc vs Epoch Li

The clearest difference is review sentiment: Propeller Calc at 100% against Epoch Li's 29%. Propeller Calc also leads on rating (3.0 vs 2.6). Epoch Li's advantage is update cadence (every 3 weeks vs every 21 months) and ratings volume (70 vs 1). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Propeller Calc holds the better App Store score, 3.0 against 2.6. That said, the two scores are not equally well evidenced: Epoch Li has 70 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 100% of Propeller Calc's written reviews are positive against 29% of Epoch Li's.

Propeller Calc ships an update every 21 months, Epoch Li every 3 weeks. The most recent releases landed on November 1, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | Propeller Calc | Epoch Li |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.0 (1 ratings)](https://appshunter.io/ios/app/propeller-calc/id478119478/reviews)** | [2.6 (70 ratings)](https://appshunter.io/ios/app/epoch-li-ion/id1640434817/reviews) |
| Number of ratings | 1 | **70** |
| Positive reviews | **100.0% of reviews** | 29.2% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 21 months | **Every 3 weeks** |
| Monetization | Free | Free |
| Size | 3 MB | 35 MB |
| Requires iOS | 17.0 | **13.0** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Frode Rørvik](https://appshunter.io/developer/478119481) | [EDG Sales International LLC](https://appshunter.io/developer/1546168152) |

## What reviewers say

### Propeller Calc

[App page](https://appshunter.io/ios/app/propeller-calc/id478119478)

This utility calculates propeller performance metrics like pitch, gear ratio, RPM, slip, and speed. Input any four values, and the app computes the fifth, helping users understand the relationship between propeller design and boat performance.

**Highlights:** Calculate pitch, gear ratio, RPM, slip, and speed, Enter any four variables to find the fifth, Understand propeller slip and its impact, Supports iPhone and iPad, Free to use

**Features:** macOS Compatibility

**In-app purchases:** none


### Epoch Li

[App page](https://appshunter.io/ios/app/epoch-li-ion/id1640434817)

Monitor your lithium-ion battery system in real-time via Bluetooth. View voltage, current, power, and internal resistance. Receive alerts for temperature, short circuits, and voltage deviations to extend battery life and enhance stability.

**Highlights:** Real-time voltage, current, power, and internal resistance display, Individual battery voltage and alarm status monitoring, Cell comparison and balancing display, Temperature and critical parameter warnings, Record of all warnings and protection events

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none

**What reviewers like**

- 🔋 Outstanding battery performance and capacity
- 📱 Excellent real-time battery monitoring
- 👍 Simple and clean app interface (mentioned by one user)
- ⚡ Fast and efficient charging performance
- 💡 Provides detailed battery information (SOC, voltage, current, temp, cells)

**What reviewers complain about**

- 🐛 Frequent Bluetooth connection issues (drops, doesn't auto-connect)
- 🐛 App crashes frequently
- 🐛 Clunky and unreliable Bluetooth connectivity
- 🐛 App disconnects when minimized or switching apps
- 🐛 Does not remember previously connected devices

**Reported bugs**

- Bluetooth does not auto-connect
- Bluetooth signal frequently drops
- App crashes frequently
- App disconnects when minimized or switching apps
- App does not remember previously connected devices

**Requested features**

- Filter Bluetooth devices by MAC address prefix
- Implement BLE non-exclusive connection
- Bring back old app features (time to charge/discharge)
- Document app data and features
- Provide password for advanced settings


## Frequently asked questions

### Is Propeller Calc free?

Propeller Calc is free to download, with no in-app purchases.

### Is Epoch Li free?

Epoch Li is free to download, with no in-app purchases.

### Which has better reviews, Propeller Calc or Epoch Li?

Propeller Calc is rated higher. Propeller Calc averages 3.0 out of 5 from 1 ratings, while Epoch Li averages 2.6 from 70 ratings.

### Do Propeller Calc or Epoch Li have ads?

Neither Propeller Calc nor Epoch Li shows ads.

### Which is updated more often, Propeller Calc or Epoch Li?

Propeller Calc ships an update every 21 months, and Epoch Li every 3 weeks. Most recently, Propeller Calc was updated on November 1, 2026 and Epoch Li on November 3, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*