Battery Technology for Film and Video

Battery Technology for Film & Video

If you’re a cameraperson shooting video or film on a daily basis, you're always concerned with your batteries. Are they charged, about to go dead, or defective? Most modern cameras have various indicators either thru the lens or elsewhere that indicate the charge level. Batteries can be heavy. Often I wear a 12-volt pack (with interchangeable charge ability of 120 and 220) around my waist that looks like some kind of ammo pack. Sometimes, to reduce the maximum airline weight of 70 pounds per container, I’ll first take out the battery belts and wear them onboard which always gets stares.

Attempting to understand DC power supplies isn’t always easy today as there are so many variations on similar products. There are a lot of things to take into consideration such as the following:

Lead acid cells
Nicad cells
Lithium-ion batteries
Discharge aspects
Memory
Voltage
Capacity

Often camera personnel choose lead acid cell batteries since they handle bad charging methods fairly flexibly. What I mean by bad charging habits is that the battery has no memory and can be charged even when partially or nearly fully charged. They also have a long shelf life. In terms of their use for video cameras, they are fairly heavy when compared to other kinds of batteries. In terms of video, they discharge quickly and your camera usually shuts down quicker than other battery types. Also, if you store lead acid batteries fully discharged, your equipment may suffer internal damage due to sulfidation.

NiCad cell batteries deliver much better performance. They deliver more consistent voltage without the typical voltage discharge you find with lead acid cell batteries. If you use lead acid batteries for your lights, you loose your color temperature quickly because of the voltage drop. When using NiCad cells, color temperature stays about the same during discharge. NiCad batteries are also lighter weight.

Lithium-ion batteries represent the very best in batteries today and are costly. They are extremely light and have a very long and extremely stable discharge rate.

I live in California and energy conservation is on most Californians minds. Battery life is can be averaged out to a cost-per-charge. NiCads beat lead acid cell batteries in this judgment.

When you’re purchasing batteries you might want to look up the characteristics of their discharge rate. Most major film and video battery companies have this material online. In terms of cameras, this means that the camera will stop working before the battery is fully discharged. In terms of lights, it means a change in color temperature.

Choosing the voltage of your battery may also aid you if it is done with care. For instance, if your camera uses 12 volts, you can choose a 13.2-volt battery pack and also power your some lighting gear. At least when you use this slightly higher volt battery, you may prevent early shutdowns of your camera.

Many batteries have what is commonly referred to as “memory.” These types of batteries require that you must have them about 99% discharged prior to charging them. For years I used a 12-volt car lamp on location to make sure my batteries were discharged before recharging them every night. This is a result of the battery charger doesn’t react that the battery has a full charge and keeps charging.

Batteries are a big subject and a very expensive part of production. Understanding all aspects of how batteries work will truly aid your career in filmmaking.