Power Calculator

Power Calculator

Calculate battery runtime and power draw for camera packages

Overview

The Power Calculator helps you estimate how long your batteries will power your camera package on set. Select your camera, monitor, wireless video, and other accessories, and the calculator shows total power draw and estimated runtime per battery type.

Requirements

Functional Requirements

Non-Functional Requirements

Data Requirements

• Device database: Bundled JSON with camera bodies, monitors, transmitters, and accessories (power draw in watts)
• Battery database: V-Mount and Gold Mount batteries with capacity (Wh)
• Persistence: the live selection is not restored on its own, but Saved setups are — they ride the synced preferences blob (preferences.powerCalcPresets), so they survive a reload and follow the account across devices. This page said "Calculator state is not saved between sessions" until 2026-09-07, contradicting its own Save the Setup section three screens below.
• Inputs: Device selections and custom watt values

Constraints & Limits

• Available to all tiers. The diagram is not a Pro feature — nothing in the calculator is tier-gated. What is limited is the number of calculations: a signed-out or unsubscribed user gets FREE_CALCULATOR_LIMIT = 5, after which an upgrade overlay covers the results and the diagram together. Subscribers are unlimited. This page called the diagram Pro-only until 2026-09-07.
• Power draw values are manufacturer-rated nominal draws — actual draw varies
• Battery runtime is an estimate; real-world conditions may differ

Offline Behavior

• Fully available offline — all device data is bundled with the app
• No network dependency

Dependencies

• Requires: None — self-contained feature
• Required by: None

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Accessing the Power Calculator

Navigate to Additional Tools → Power Calculator in the sidebar.

Using the Calculator

Step 1: Select Devices

Choose from the dropdown menus:

Step 2: Review Power Summary

The summary shows:

• Per-device power draw (watts)
• Total power draw across all devices
• Estimated runtime per battery

Step 3: Connection Diagram

Everyone sees an interactive diagram showing:

• Power paths from battery to all devices
• Signal paths (video, data)
• Drag nodes to rearrange the layout

Step 4: Save the Setup

Under the device selections, Saved setups keeps named copies of the rig on screen:

Saved setups are stored with your account preferences, so they follow you to every device you sign in on, ride along in a full backup, and appear in a preferences export. Up to 24 are kept.

Saving under a name that already exists replaces that setup rather than adding a second entry with the same name — re-saving means "update this one". Renaming onto a name already in use behaves the same way, so the list always answers "which rig is A-cam?" with exactly one entry.

A setup stores the same configuration the shareable ?pkg= link carries, so loading a saved setup and opening a shared link arrive at exactly the same rig.

Calculations

Runtime formula:

Runtime (hours) = Battery Capacity (Wh) / Total Power Draw (W)

Example:

• Total draw: 120 W
• Battery: 98 Wh V-Mount
• Runtime: 98 / 120 = 0.82 hours (~49 minutes)

A package drawing nothing reports unlimited runtime, and any result above 100 hours is clamped to 100 — an overflow guard, not a real estimate.

Batteries needed (ten-hour day):

Runtime pools every source of energy in the package. The battery count cannot, because a hot-swap plate's internal buffer — and, in gimbal mode, the gimbal's own pack behind a ring grip — is charged once and stays on the rig. A spare battery adds only its own capacity. So the count is sized in energy rather than by dividing the day by the pooled runtime:

Batteries = ceil( (10 h x Total Draw - Fixed reservoir Wh) / Swappable Wh )    (minimum 1)

Example:

• Total draw: 74 W → 740 Wh for the day
• Battery: 150 Wh V-Mount, hot-swap buffer: 50 Wh
• The buffer covers 50 Wh once; the remaining 690 Wh comes from 150 Wh batteries
• Batteries: ceil(690 / 150) = 5

"Swappable Wh" is the battery minus any capacity declared fixed on it, not the battery's rated figure. The two are the same for an ordinary battery — which is why the example above divides by 150 — but a pack that declares part of its own capacity as fixed contributes only the remainder per swap. In the source that divisor is swappableWh = batteryCapacity - declaredFixed.

Dividing the day by the pooled runtime instead — ceil(10 / (200 / 74)) — gives 4, one battery short. Until v0.703.63 that is what the app did, and the number flows straight into the gear list's battery quantity. Packages with no hot-swap were never affected: with no reservoir, the two formulas are the same expression.

Tips

1. Plan for 80% capacity: Real-world battery capacity degrades — plan for 80% of rated Wh
2. Add accessories: Don't forget wireless follow focus, lens motors, and monitoring accessories
3. Compare batteries: Try different battery types to find optimal runtime
4. Use for budget planning: Runtime estimates help determine how many batteries to rent
5. Mind the hot-swap buffer: It shortens how many spares you need, but only once — don't multiply it across the spares you pack

Related Documentation

• Camera Tools
• Device Library
• Projects & Workspace

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Last Updated: 2026-09-07 Version: 0.790.2