Apple-notarized · v1.2.12 · macOS 14+

Your Mac. Your battery. Your rules.

ThunderVolt works out what your battery actually needs — from its measured degradation, your Mac's temperature, and what's on your calendar — then sets the charge ceiling to match and holds it at the hardware level. Companion apps for iPhone and Apple Watch.

From €2.99/mo · No credit card required · Cancel anytime

Apple-notarized & signed
Zero data collection
SHA-256 published for every build

Most MacBooks lose 20% battery capacity within 2 years.

Every charge cycle above 80% accelerates electrochemical aging, and heat does more damage than cycle count. macOS can cap charging — but it can't tell you what your battery's real capacity is doing, or move the ceiling when your Mac runs hot, or lift it the night before a 7am flight.

Setting a limit is the easy part.
Knowing what it should be is the product.

From your calendar and thermal sensors down to the SMC. No terminal, no config files.

Free
Adaptive Mode
Reads thermal state, time of day, and your calendar, then picks the charge ceiling to match. Hot desk drops it to 65%. A 7am flight on the calendar takes it to 100% the night before.
  • Calendar-aware charging: tops up before flights
  • Thermal-aware throttling when Mac runs hot
  • Time-of-day scheduling with custom rules
Pro
Thermal Guard
Pauses charging when your Mac runs hot. Heat does more damage to lithium-ion capacity than cycle count does. Monitors CPU proximity, battery, and ambient sensors in real time.
Pro
BMS Calibration
Your Mac's reported battery health drifts, because the battery management system's own estimate drifts. ThunderVolt scores six signals to catch that, then runs a full guided calibration cycle to reset it — so the number you're reading is the number that's true.
  • 6-signal scoring detects when calibration is actually needed
  • Automated 5-phase cycle with live time estimates
  • Tracks full-charge-capacity drift over the battery's life
Pro
Health Trends
macOS shows you a number today. ThunderVolt shows you the curve — capacity, cycles, and temperature history over months, so degradation is something you can see coming.
Free
Live Power Flow
Watch exactly how many watts are going into your Mac in real time. Monitor AC adapter draw, battery charge rate, and system consumption from the menu bar.
Pro
Travel Intelligence
Spots calendar events with airport codes and pre-charges your Mac to 100%, only when you actually need it. Returns to your limit after landing.
Free
Hardware Control
Whatever ceiling it decides on, ThunderVolt holds it — writing to the SMC directly and driving macOS's own Charge Limit where the system owns it. Re-checked every 60 seconds.
Pro
Companion Apps
Control your Mac's charging from your iPhone or wrist. Native iOS and watchOS apps with push notifications, remote mode switching, and live power flow.
Explore All Pro Features

Your Mac battery,
on every screen you own.

Adjust limits, check health, and override modes from whichever device is closest.

THUNDERVOLT · MENU BAR
Charge Limit Adaptive · Active
80%
205080100

The control room.

Live charge gauge, slider for instant overrides, scheduled rules, and a thermal heatmap, in a menu bar app under 12 MB.

  • Menu-bar app, no dock icon
  • SMC writes every 60 seconds
  • Scriptable via Shortcuts & CLI

Quiet alerts that matter.

Notifications when Adaptive Mode shifts gears. Tap to override, swipe to dismiss, never spam. Full charge-control lives one tap deeper.

  • Native iOS app with push notifications
  • Remote-trigger one-tap modes
  • End-to-end encrypted handoff
THUNDERVOLT now
Adaptive Mode adjusted
Limit lowered to 65% · CPU 78°C, heat protection active.
65%
CHARGE LIMIT

Your battery on your wrist.

Glance at battery health, toggle modes, and confirm charging status without pulling out your phone or walking over to your Mac.

  • Complication support for watch face
  • Digital Crown scroll to adjust limits
  • Haptic feedback on mode changes

One license. All your devices.

Every plan includes Mac, iPhone, and Apple Watch. 7-day free trial. No credit card required.

Monthly
€2.99/mo
Billed monthly
  • All Pro features
  • Mac + iPhone + Watch
  • Up to 3 Macs
  • 7-day free trial
Buy Pro

All plans include a 14-day refund window. Compare all features on our Pro page.

Before you install.

Is ThunderVolt safe? What permissions does it need?

Yes. ThunderVolt is Apple-notarized, signed with a verified Developer ID, and undergoes automated malware scanning. It requires Accessibility access to write charge limits to your Mac's SMC (System Management Controller), the same hardware interface macOS uses. No data leaves your device, ever.

How is this different from other charge limiters?

Other limiters set a ceiling and stop there. ThunderVolt decides what the ceiling should be: BMS Calibration scores 6 signals to keep your health reading honest, health trends show the capacity curve over months, and Adaptive Mode reads heat and your calendar so flights are handled without manual scheduling. It also has native iOS and watchOS apps, where most limiters are Mac-only, and one license covers up to 3 Macs.

Does it work on my Mac?

ThunderVolt works on all Apple Silicon Macs (M1–M4) and Intel Macs with a T2 chip or later, running macOS 14 Sonoma or newer. This includes MacBook Air, MacBook Pro, iMac, Mac Mini, Mac Studio, and Mac Pro. iPhone requires iOS 18+. Apple Watch requires watchOS 11+.

Can I cancel anytime? What's your refund policy?

Yes. Cancel anytime from your account. Subscriptions have a 14-day refund window. Your 7-day free trial requires no credit card.

Does ThunderVolt collect my data?

No. Zero. ThunderVolt processes all battery data locally on your Mac. We don't have servers to send it to. Calendar access is read-only and stays on-device. iPhone-to-Mac communication is end-to-end encrypted over your local network or iCloud.

How does the 7-day trial work?

Download the app and start your trial. No credit card needed. Full access to all Pro features for 7 days. After the trial, subscribe to continue. If you don't subscribe, the app reverts to Free tier with basic charge limits and monitoring.

Ready to protect your battery?

7-day free trial. No credit card. Works on up to 3 Macs.

Download ThunderVolt Free

For macOS 14+ · Apple Silicon & Intel · 100% private