10.26.2009 03:20 PM
The Pros and Cons of Lithium Ion Batteries
Lithium-ion battery packs are a videographer’s dream. Extended run times mean fewer battery changes and Lithium-ion batteries are lightweight so shooters aren’t overly burdened, even if they carry a spare. But these features come at a price. Lithium-ion batteries have their own shortcomings and operating requirements. Here’s how to treat them right:
Avoid heat. Storage anywhere where the temps get above 120 degrees is very bad. Direct sunlight, closed cars, and tropical climates are all hostile environments that can lead to battery failure.
Treat them gently. Lithium-ion batteries are more likely to suffer life-threatening injuries from accidental drops and rough-handling than their predecessors. Cushion them with cardboard or foam during storage and transport. And try really hard not to drop them.
Be partial to partial-discharge. Lithium-ion batteries are not susceptible to memory-effect and will be helped, not harmed, by frequent recharging after partial use. Fully discharging a Lithium-ion battery on a regular basis will shorten its life.
Don’t store them fully-charged. Batteries that will not be used for 30 days or longer should be stored at a charge level of 40%-50%. Storing fully-charged Lithium-ion packs for extended periods will shorten their useful life.
Use them or lose them. Unlike their Ni-cad and NiMH cousins, Lithium-ion packs have a useful life of two to three years from the date of manufacture, whether or not they are used. Don’t buy spares. Order replacements when they are needed. Check the manufacturing date stamped on the pack when you receive them to be sure you are getting fresh stock.
Don’t demand too much power. Lithium-ion packs aren’t able to supply as much current as other camera bricks and will fail if repeatedly asked to operate beyond their rated capacity. The smallest camera batteries, much-favored by folks who shoot handheld, should never be used to power an on-board light that draws more than 15 or 20 watts.
Retire that tired battery. Replace a Lithium-ion pack as soon as there is a noticeable decrease in run-time. This is almost certainly an indication that one of the pack’s cells has failed. A defective cell is likely to develop an internal short and that spells trouble for the entire pack.
A word of caution. Lithium-ion packs have been known to fail in a spectacular manner. They can explode, catch fire, and generate great quantities of noxious white smoke. Internal circuits are designed to prevent faults like over-charging and overuse from causing problems by automatically disconnecting the battery, but only the user can prevent damage from external forces.
Recognizing the potential hazard presented by a Lithium-ion battery failure, the airline industry forbids the transport of these packs in checked luggage. (A fire in the baggage hold is potentially much worse than one in the passenger compartment.) And there are significant limits to the number, size, and manner of packaging for Lithium-ion packs that are carried aboard an aircraft. Consult your battery manufacturer for advice about which of their products are eligible for air transport and any documentation that may be needed.