How long will a 99 Wh battery run my camera rig?

About 10.5 hours with a camera alone at 8 W, 6 hours with a camera and monitor at 14 W, 3.8 hours once a wireless transmitter is added at 22 W, and 2.6 hours with a recorder as well at 32 W. Divide watt hours by total watts and multiply by about 0.85 for conversion losses to get your own figure.

How do I calculate battery runtime?

Runtime in hours equals watt hours divided by the total load in watts, multiplied by roughly 0.85 for conversion losses in the plate, cables and dummy battery. Add every device that runs continuously rather than only what is recording, since a wireless transmitter draws its full current from the moment it is switched on.

Can I run a video light from a V-mount battery?

Briefly. A 200 W fixture at full output drains a 99 Wh cell in about twenty four minutes and a 212 Wh cell in under an hour. The same fixture at quarter output draws around 50 W and runs about 3.6 hours on a 212 Wh cell. Continuous lighting is a mains job unless you plan deliberately for large cells and reduced output.

What are the airline rules for camera batteries?

Under 100 Wh they go in carry-on with no approval and usually no quantity limit for personal equipment. Between 100 and 160 Wh they need airline approval and are typically limited to two. Above 160 Wh they cannot fly. Lithium batteries are banned from checked baggage in every case, which is why so many camera cells are rated at 99 Wh.

Why does my battery last less than the chart says?

Cold reduces capacity sharply below about 5 degrees Celsius, cells lose capacity with age, storage at full charge accelerates that degradation, and devices with spiking draws such as focus motors consume more than their average figure. Monitor brightness is also the single largest variable draw on most rigs and can double a panel's consumption.

How should I store camera batteries between shoots?

At 50 to 60 percent charge, somewhere cool. Lithium cells degrade fastest when held at full charge, particularly when warm, so a battery left at 100 percent for six months loses noticeably more capacity than one stored half charged. Charge to full the night before a shoot rather than keeping everything permanently topped up.

V-Mount Battery Runtime Chart: Every Common Load and Capacity

Short answer

Divide watt hours by the total load in watts, then multiply by about 0.85 for conversion losses. A 99 Wh cell driving a camera at 8 W and a monitor at 6 W lasts about six hours. Add a wireless transmitter and a recorder and the same cell gives two to three hours.

Battery planning is one calculation repeated: watt hours divided by watts, times about 0.85 for conversion losses. The tables below give device draws, capacities and the resulting runtimes so a SmallRig VB99 Mini V-Mount, 99Wh can be matched to a real load rather than to an optimistic guess.

Device draw table

Device	Typical draw	Notes
Mirrorless camera	6 to 9 W	Higher while recording and in 4K 60
Cinema camera	15 to 25 W	Active cooling runs continuously
5 inch monitor at 1000 nits	5 to 7 W	Roughly doubles at full brightness
5.5 inch monitor at 1600 nits	7 to 10 W	Brightness is the dominant factor
7 inch monitor at 2000 nits	10 to 14 W	The biggest monitor draw
External recorder	10 to 20 W	Higher while writing to a drive
Wireless video transmitter	6 to 10 W	Continuous, not only while recording
Wireless focus motor	3 to 6 W	Spikes on each pull
Field recorder	2 to 4 W	Often runs on its own cells
Timecode box	Under 1 W	Runs on its own cell for a day
COB light at 25 percent	About 50 W	A different order of magnitude
COB light at full output	200 W and up	Not a camera battery job

Add the draws of everything that runs continuously, not just what is recording. The transmitter row is the one people miss: a wireless video link draws its full current from the moment it is switched on, whether or not the camera is rolling, so it contributes to the total for the entire shoot day.

Runtime by load and capacity

Total load	50 Wh	99 Wh	212 Wh	NP-F970 at 47 Wh
8 W, camera only	5.3 h	10.5 h	22.5 h	5.0 h
14 W, camera and monitor	3.0 h	6.0 h	12.9 h	2.9 h
22 W, plus a transmitter	1.9 h	3.8 h	8.2 h	1.8 h
32 W, plus a recorder	1.3 h	2.6 h	5.6 h	1.2 h
40 W, a full cine rig	1.1 h	2.1 h	4.5 h	1.0 h
50 W, a light at quarter output	0.85 h	1.7 h	3.6 h	0.8 h
200 W, a light at full output	0.2 h	0.4 h	0.9 h	0.2 h

The bottom two rows are the ones worth internalising. People buy a V-mount expecting to run a light from it and discover it lasts twenty minutes at full output. Continuous lighting is a mains job unless you deliberately buy large cells and accept a reduced output setting.

The calculation, in one line

Runtime in hours equals watt hours divided by total watts, multiplied by roughly 0.85. The 0.85 accounts for conversion losses in the plate, the cables and the dummy battery, and it is a reasonable approximation across the range of loads a camera rig presents.

A worked example. A 99 Wh cell running a camera at 8 W, a 1600 nit monitor at 9 W and a transmitter at 8 W is a 25 W total. Ninety nine divided by 25 is 3.96, times 0.85 gives about 3.4 hours. That is a plan: one cell covers a morning and a second covers the afternoon.

The battery runtime calculator does this with your own device list, which is worth doing once before a shoot rather than carrying spares and hoping. Knowing the number changes when you swap cells, which is the actual point.

The three capacities

$130 to $330. Fifty watt hours for a light rig, 99 Wh as the airline-legal workhorse, and 212 Wh for lighting when you are driving.

Carry-on safe $129.99

SMALLRIG

SmallRig VB50 Mini V-Mount, 50Wh

50 Wh is under every common airline limit, which is the deciding factor for a rig that flies.

Capacity: 50 Wh
USB-C: PD 45 W

Two of these beat one big one for travel.

Check price

Best value $159.99

SMALLRIG

SmallRig VB99 Mini V-Mount, 99Wh

99 Wh sits right under the usual 100 Wh airline ceiling, and PD 100 W out means it charges a laptop between setups too.

Capacity: 99 Wh
USB-C: PD 100 W

The default V-mount for a documentary kit.

Check price

All day $329.25

SMALLRIG

SmallRig VB212 V-Mount, 212Wh

212 Wh runs a camera, monitor and transmitter through a full day, at the cost of being unflyable in a carry-on.

Capacity: 212 Wh

Studio and vehicle work only.

Check price

The 100 watt hour airline rule

Capacity	Carry-on	Checked baggage	Quantity
Under 100 Wh	Yes, no approval needed	No	Usually unlimited for personal equipment
100 to 160 Wh	Yes, with airline approval	No	Typically two
Above 160 Wh	No	No	Cannot fly

This is why so many camera batteries are rated at 98 or 99 Wh. Manufacturers sit deliberately just under the threshold. If your kit flies, buy multiple 99 Wh cells rather than fewer large ones, and keep the printed rating visible so it can be shown at a checkpoint.

What reduces these figures

Cold. Below about 5 degrees Celsius, capacity drops sharply and a cell that reads full in a warm vehicle will not deliver its rating outside.
Age. Lithium cells lose capacity with cycles, and a three-year-old battery reading full will not run a load as long as it once did.
Storage at full charge. Cells held at 100 percent, especially warm, degrade faster than cells stored at 50 to 60 percent.
Peak draws. A device that spikes, such as a focus motor on each pull, draws more than its average figure suggests.
Cheap plates and cables, which lose more in conversion than the 0.85 assumption allows for.
Monitor brightness, which is the single largest variable draw on most rigs.

The storage point is the one most people get wrong. Charge to full the night before a shoot rather than keeping everything permanently topped up, and run cells down to around half before they go into a cupboard for a month.

Next, from here

Battery runtime calculator
Your own device list, calculated.
Best V-mount batteries
The cells behind these figures.
Camera rig power guide
Building one power system.
V-mount versus NP-F
Which format your rig needs.
Best on-camera monitors
The largest variable draw on most rigs.
Rig weight calculator
What the battery adds in mass.

Common questions

How long will a 99 Wh battery run my camera rig?: About 10.5 hours with a camera alone at 8 W, 6 hours with a camera and monitor at 14 W, 3.8 hours once a wireless transmitter is added at 22 W, and 2.6 hours with a recorder as well at 32 W. Divide watt hours by total watts and multiply by about 0.85 for conversion losses to get your own figure.
How do I calculate battery runtime?: Runtime in hours equals watt hours divided by the total load in watts, multiplied by roughly 0.85 for conversion losses in the plate, cables and dummy battery. Add every device that runs continuously rather than only what is recording, since a wireless transmitter draws its full current from the moment it is switched on.
Can I run a video light from a V-mount battery?: Briefly. A 200 W fixture at full output drains a 99 Wh cell in about twenty four minutes and a 212 Wh cell in under an hour. The same fixture at quarter output draws around 50 W and runs about 3.6 hours on a 212 Wh cell. Continuous lighting is a mains job unless you plan deliberately for large cells and reduced output.
What are the airline rules for camera batteries?: Under 100 Wh they go in carry-on with no approval and usually no quantity limit for personal equipment. Between 100 and 160 Wh they need airline approval and are typically limited to two. Above 160 Wh they cannot fly. Lithium batteries are banned from checked baggage in every case, which is why so many camera cells are rated at 99 Wh.
Why does my battery last less than the chart says?: Cold reduces capacity sharply below about 5 degrees Celsius, cells lose capacity with age, storage at full charge accelerates that degradation, and devices with spiking draws such as focus motors consume more than their average figure. Monitor brightness is also the single largest variable draw on most rigs and can double a panel's consumption.
How should I store camera batteries between shoots?: At 50 to 60 percent charge, somewhere cool. Lithium cells degrade fastest when held at full charge, particularly when warm, so a battery left at 100 percent for six months loses noticeably more capacity than one stored half charged. Charge to full the night before a shoot rather than keeping everything permanently topped up.

Totalling your own rig weight against your gimbal payload? The Camera Rig Build Planner is the paid version of these pages: 8 printable worksheets you fill in with your own numbers, plus the full PDF, $29.