# SOLAR SYS vs WattCheck

The clearest difference is in-app purchases: SOLAR SYS at none against WattCheck's 3. SOLAR SYS also leads on iOS requirement (11.0 vs 17.0). WattCheck's advantage is update cadence (every 3 weeks vs every 6 months) and device support. On price there is nothing between them.

Both are free to download. WattCheck sells 3 in-app purchases, starting at $1.99 per 7 days. SOLAR SYS asks for nothing beyond the download.

SOLAR SYS ships an update every 6 months, WattCheck every 3 weeks. The most recent releases landed on September 10, 2026 and September 20, 2026 respectively.

## The numbers

| Metric | SOLAR SYS | WattCheck |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | — | No |
| Update frequency | Every 6 months | **Every 3 weeks** |
| Size | 14 MB | 17 MB |
| Requires iOS | **11.0** | 17.0 |
| Devices | — | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [文 周](https://appshunter.io/developer/1071506295) | [SUN TEAME PTE. LTD.](https://appshunter.io/developer/941073095) |

## What reviewers say

### SOLAR SYS

[App page](https://appshunter.io/ios/app/solar-sys/id6596742875)

**In-app purchases:** none


### WattCheck

[App page](https://appshunter.io/ios/app/wattcheck-cable-tester/id6790480866)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| WattCheck Premium Weekly | $1.99 | per 7 days |
| WattCheck Premium Monthly | $5.99 | per month |
| WattCheck Premium Yearly | $29.99 | per year |


## Frequently asked questions

### Is SOLAR SYS free?

SOLAR SYS is free to download, with no in-app purchases.

### Is WattCheck free?

WattCheck is free to download, with in-app purchases available.

### Which is updated more often, SOLAR SYS or WattCheck?

SOLAR SYS ships an update every 6 months, and WattCheck every 3 weeks. Most recently, SOLAR SYS was updated on September 10, 2026 and WattCheck on September 20, 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.*