Why Camera Batteries Fail: Core SWX CEO Ross Kanarek Explains Watt Hours, Voltage, and Amps

Battery News

by Johnnie BehiriApril 7^th, 2026

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Battery specs are among the most misunderstood aspects of professional filmmaking rigs, and the consequences of getting them wrong range from a flickering light to a hard shutdown mid-take. In a new easy-to-understand educational video, Core SWX CEO Ross Kanarek breaks down exactly what watt hours, voltage, and amperage mean in practice, and why confusing them is one of the most common and costly mistakes on set.

Core SWX has been one of the leading names in professional cinema and broadcast power solutions for over two decades. Ross himself has spent that time working directly with major productions, directors of photography, and equipment manufacturers on real-world power problems, which makes his no-fluff breakdown unusually grounded. The video is aimed at anyone who has ever had gear shut down unexpectedly, but the depth of the explanation makes it relevant for experienced professionals as much as newer filmmakers.

We covered the Core SWX Apex 360 V-Mount battery lineup when it launched, and it directly addressed one of the pain points Ross discusses here: the mismatch between what a battery’s label says and what it can actually sustain under real production loads.

Watt hours: your fuel tank

The starting point is watt-hours, the capacity figure printed on virtually every professional battery. Kanarek’s framing is useful: watt-hours represent the total energy a battery can store, not the rate at which it delivers power. The confusion, he explains, arises because watt hours and wattage sound similar but measure entirely different things. Watt hours describe the tank; wattage describes how fast your equipment is draining it right now.

The math is straightforward on paper: a 98Wh battery can theoretically deliver 98W for one hour, or 49W for two hours, and so on. The critical caveat is that this only holds true if the battery is actually capable of sustaining that output in the first place. That “if” is where most rig problems originate.

Watt hours are calculated by multiplying a battery’s nominal voltage by its design amperage, which is why the figure alone doesn’t tell you the whole story. Understanding it properly requires looking at voltage and current handling together.

Voltage: not a number, a range

Of the three concepts Ross covers, voltage is arguably the most misunderstood and the one with the highest potential for hardware damage. He describes it as electrical pressure, the force pushing current through a circuit. The key point that many filmmakers miss is that a battery does not operate at a single fixed voltage. It moves across a range depending on its chemistry, cell configuration, and current charge state.

Nominal voltage, the figure most commonly cited on labels and in spec sheets, represents the midpoint of that range during typical use. A standard lithium-ion cell, for example, sits at 4.2V when fully charged and drops to around 3V when depleted. Its nominal voltage of 3.6 to 3.7V is simply the average across the discharge cycle. Scale that up to a four-cell series pack, which is the basis of a 14.4V V-mount battery, and the actual operating range runs from approximately 12V at the low end to 16.8V fully charged.

This range matters in both directions. Too low and the gear may refuse to power on. Too high and the components can be damaged. The discharge curve adds another layer of complexity: voltage holds relatively steady through most of the runtime, then drops sharply toward the end. A 14.4V pack may still be reading close to nominal voltage halfway through a shoot, but once it enters that tail-end drop, the performance degradation is rapid. Flickering monitors, glitching cameras, and sudden shutdowns are the symptoms.

Ross also highlights a gap in how manufacturers communicate acceptable voltage ranges. Many lights and monitors use fixed DC inputs tied to the power adapters they shipped with, and when third-party battery plates are added without clear voltage range labeling, operators are left to piece together compatibility on their own. That ambiguity, he notes, is far too common.

Amps, amp hours, and load handling

The third variable is current: amperage, which describes how much electrical flow is moving through the system at any given moment. Ross draws a clear distinction between amps (the flow rate right now) and amp hours (the total volume of current the battery can deliver over time). Both are frequently conflated, and both are incomplete without the third element: load handling.

Load handling, sometimes expressed as a C rating or as a continuous amp rating, defines how much current the battery can reliably deliver without degrading performance or triggering a protective shutdown. A battery may have a large amp hour rating but a limited ability to sustain high-current loads, which creates problems specifically with power-hungry equipment. LED lights, in particular, require constant and often high current draws, and not all batteries rated for cinema use are actually built to handle them cleanly.

Ross uses the analogy of a car: amp hours are the fuel tank size, amps are the fuel flowing right now, and load handling is the size of the engine required to manage that flow. Pushing more current than the battery was designed to handle generates excess heat, causes voltage sag, accelerates cell wear, and, at worst, produces exactly the kind of mid-take shutdown that disrupts a production.

For operators building power budgets for complex rigs, the formula Ross lays out is practical: if gear is rated in watts, divide watt hours by wattage to get runtime. If gear is rated in amps, divide watt hours by nominal voltage to convert to amp hours, then divide by the current draw. The arithmetic is simple; the challenge is gathering accurate specs from manufacturers who don’t all speak the same language.

He also flags the consumer power bank market as a particular case of misleading labeling. Products citing 10,000 or 30,000 milliamp hours rarely state the voltage at which that capacity is measured or the sustained current they can actually deliver. That’s not accidental. Most cannot handle the kind of continuous, real-world loads that professional filmmaking gear requires.

Why this matters beyond theory

The through line across all three concepts is that battery specs only tell you what you need to know if you understand what questions to ask. A battery with 300Wh of capacity and poor load handling will fail just as dramatically as an undersized one. A 14.4V-labeled battery connected to gear expecting a narrower input range can damage components. And a runtime calculation based on watt hours alone, without accounting for sustained output capability, will produce numbers that don’t survive contact with a real production day.

For those specifying power on high-draw rigs, a previous CineD article on the Core SWX Apex 360 illustrated how separating camera and lighting batteries can solve exactly these voltage and load compatibility issues in practice. The Apex lineup was designed specifically around the sustained high-current demands of modern LED panels, a problem Ross’s explainer now helps to articulate from first principles.

Have you encountered unexpected shutdowns or voltage issues on a production rig? What has been your approach to speccing power for high-draw equipment like LED lights or large-format cinema cameras? Don’t hesitate to let us know in the comments below!