VoltLog vs MainframeMonitor
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
VoltLog
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VoltLog is a field tool for FPV pilots who use LiPo, LiHV, and Li-ion battery packs without smart battery electronics. After a flight, log the pack voltage and VoltLog shows the safety status of each battery on a clear, color-coded dashboard. The goal is simple: know which packs are safe for storage, which need charging, and which should not be left full for too long. Built for FPV battery routines: - Track battery packs with name, brand, cell count, capacity, chemistry, and cycle count - Log voltage per cell with a large custom keypad - See STORAGE, CHARGED, FULL, FULL RISK, DISCHARGED, and CRITICAL states at a glance - Open full cycle history for every pack - Set global and per-battery alert timing - Use local notifications for risky full packs and low-voltage reminders - Work offline-first with local Drift storage - Secure or switch accounts with Supabase Auth when you want cloud-backed data VoltLog is not a charger, cell checker, or battery management system. It is a practical logbook for pilots who already measure voltage and want a faster way to keep track of many packs. Designed for the field, not a desk: - High-contrast dark dashboard - Large battery tiles - Fast voltage entry without the system keyboard - Battery archive for retired packs - English and Polish interface If your FPV case has more packs than memory can reliably track, VoltLog gives you one place to see what needs attention before battery degradation becomes expensive. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
MainframeMonitor
Transform your iPhone into a vintage mainframe with a nostalgic CRT display. Monitor live system stats like battery, CPU, and memory, all within an authentic retro console experience. Includes hidden classic text-based games.
- Live system monitoring (battery, CPU, memory, storage)
- Home screen widgets
- Authentic CRT effects (glow, scanlines)
- Retro boot sequence
- Hidden classic text-based games
- Customizable color themes (Green, Amber)
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MAINFRAME MONITOR: Your Device as a Mainframe Console Mainframe Monitor shows your device's real live data in the style of a 1980s IBM operator console: CPU, memory, storage, battery, network, thermal state and motion. All values come from your device. You also get green phosphor text, scanlines, key clicks and real MVS commands. REAL DATA, CLASSIC LOOK • Live CPU load per core, memory, DASD, battery, network and thermal state • Front panel lamp strip that flickers with the load • Seismograph as a moving paper strip. Knock on the table! • Compass, audio output, brightness and refresh rate (ProMotion) • Motion sensors with pitch, roll, yaw and G-vector • Capacity planning: battery time remaining and storage forecast • Session statistics (SMF) with averages and peak values • Clock with UTC, Julian date and 64-bit TOD register FIVE HISTORIC DISPLAYS Press PF5 to switch between green and amber phosphor, the IBM 3279 color terminal, the neon-orange IBM 3290 gas plasma display and the Tektronix 4014 storage tube. Each display has its own effects, from degauss to beam redraw, and a matching app icon. MVS CONSOLE WITH REAL COMMANDS In the syslog you enter commands like a real operator: D T, D A,L, D M=CPU, D U,DASD, D NET, D IPLINFO, D ENV, D CAPACITY, D M=MIPS (CPU benchmark) and many more. With PF8, a virtual IBM 1403 line printer prints a status report on continuous paper that you can share as an image. PARALLEL SYSPLEX Couple iPhone, iPad and Mac on your local network via Bonjour to form a sysplex. The sysplex panel shows CPU, memory and battery of all devices. TRACE ROUTE WITH WORLD MAP PF9 traces the path your data takes to any website. You see every hop with IP, location and round-trip time, plus an ASCII world map of the route. The optional latency panel measures ping, jitter, packet loss and clock drift. IPL, INTRO AND SCREENSAVERS At startup the system boots with an authentic IPL sequence. The screensavers show real values too: control panel, tape drives, core memory, punch cards, printer or oscilloscope. GAMES IN THE COBLIB Hamurabi, Void Patrol, Snake and Bagels: classics in terminal style. WIDGETS AND LIVE ACTIVITY • Widgets for the Home Screen and Lock Screen in three sizes • Control Center button • Live Activity in 3270 style on the Lock Screen and in the Dynamic Island FOR EVERY DISPLAY The layout adapts to iPhone, iPad, Mac and foldable devices like iPhone Duo, stacked or side by side. With a hardware keyboard, F1 to F12 work as PF keys. FULLY CONFIGURABLE Show, hide and reorder panels, or choose a preset: Default, Minimal, Performance, Network or Device. Under PF1, an operator guide in German and English explains every feature. PRIVACY No tracking, no ads, no analytics. The app works offline. Network features only start after you agree (message IEA910A), and you can withdraw consent at any time under PF7. The EXT lamp shows you when data goes to the internet. Note: Job names in the log are simulated. D M=MIPS is an estimate, not an official IBM rating.
Screenshots
Verdict
The clearest difference is in-app purchases: MainframeMonitor at none against VoltLog's 3. VoltLog's advantage is iOS requirement (16.0 vs 18.6). On price, update cadence, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. VoltLog sells 3 in-app purchases, starting at $9.99 per month. MainframeMonitor asks for nothing beyond the download.
VoltLog ships an update every 10 days, MainframeMonitor fortnightly. The most recent releases landed on November 9, 2026 and November 10, 2026 respectively.
| Parameter | VoltLog | MainframeMonitor |
|---|---|---|
| Price | Free | Free |
| Rating | — | 5.0 (2 ratings) — better |
| Number of ratings | — | 2 — better |
| Update frequency | Every 10 days — better | Fortnightly |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | — | Free |
| Devices | iPhone | iPhone, iPad — better |
| Requires iOS | 16.0 — better | 18.6 |
| Further details — not scored | ||
| Size | 54 MB | 22 MB |
| Age rating | 4+ | 4+ |
| Developer | Filip Rusin | Ralf Langhoff |
In-app purchases
VoltLog
- Monthly Pro$9.991 Month
- Yearly Pro$39.991 Year
- Lifetime Pro$99.99
MainframeMonitor
No in-app purchases









