UPDATE: NEW BATTERY TECHNOLOGIES -
1999
Since the very first portable cameras, cameramen have asked for lighter and more powerful batteries.
There continues to be a lot of "talk" regarding new battery types in the market. Smaller, lighter, more powerful, less expensive - who hasn't heard these wishes from a battery user. Or as claims from a battery manufacturer? In fact, in all battery powered markets, batteries are the number one area in which customers would like to see improvements. In the computer and cellular telephone markets, requests for improvements in battery life (runtime) and weight/size come before processing speed and cellular coverage. Of course, the broadcast and professional video industry is no exception.
Unfortunately, the quest for the "perfect" battery has led to many unsuitable battery types being marketed over the years.
Some manufacturers have offered (and still offer) batteries of incorrect voltage, unsuitable size and insufficient packaging to meet the requirements of a video professional. Because these batteries were touted as "smaller, lighter, cheaper" and because the uninformed view is often that "a battery is a battery", these products were purchased thinking that they would be suitable for a professional. Many of these, such as NP-types, were brought up by equipment manufacturers from consumer products to allow the manufacturer to offer a turn-key camera package. Professionals soon found out that problems with these batteries were insurmountable. Terms like "memory" (which, if you refer to the enclosed copy of The Video Battery Handbook, does not exist in practical application) were coined to explain the inadequate operation of poorly designed and/or misapplied batteries.
Once these batteries were in operation, users looked for ways to salvage their NP investments. For example, we are all familiar with the variety of rejuvenators, reconditioners, de-memorizers, revitalizers and other such gadgets marketed in an attempt to salvage the large inventories of NP batteries in the marketplace. Well after investing thousands of dollars and hundreds of hours of maintenance time on their NP batteries, users found out too late that poor design and misapplication problems never really go away. Thus, an NP user typically carries up to 4 times the amount of batteries that should actually be needed and replaces them twice as often.
For a dozen years since the NP battery was introduced on a the first BetaCams, users were looking for a way to "fix" them. Over the years this exercise has prompted many products which unfortunately was like trying to fix a mis-registered camera by buying a new lens.
The quest for the "Holy Grail" of video batteries has taken its most recent turn in the introduction of exotic cell types introduced into the cellular and computer markets. Alas, were these applications only the same as a professional video camera. These new cell types addressed many of the size and weight issues for mobile communications and computing products. Rightfully so since the market drivers for these
products are several orders of magnitude greater than all camcorders, consumer to broadcast, put together. The cell manufacturer who could design a cell which could be used in a battery for notebooks and cell phones was designing a product for the largest growth markets the battery industry has ever seen. Size and weight are paramount to the exclusion of all other considerations. Furthermore, batteries designed for these applications typically have one product to operate - not the wide range of requirements in today's video professional operations. The publicity these new technologies - Nickel Metal Hydride and lithium ion - have received for mobile communications and computing have made them seem like the answer to all battery problems.
Now it seems, since we have heard so much about them, that the impression is that all new batteries are NiMH or Li-Ion. Not so....Let's look at a few irrefutable facts:
(1) NiCd technology has been commercial for over 40 years with real viability for about 25 years. Everyone remember their first "dustbuster"? 20 years ago, lead acid was the predominant technology in video. In 1994 about 1500 million cells were shipped; 1996 1650 million cells. Today, NiCd still accounts for about 70% of the world's total of rechargeable cells produced (well over 250 million cells each day !) Recent improvements have improved capacity in NiCad cells of 10% or more in all sizes.
(2) NiMH cell technology was commercialized less than 10 years ago with real viability less than 5 years. In 1994, 200 million cells shipped; in 1996, 450 million cells shipped. Today, NiMH technology represents more than 20% of the total cells produced for the world's consumption.
(3) Lithium ion technology has been commercialized for about 5 years with any real viability for about 3 years. In 1994, only about 15 million cells were shipped; 1996 140 million cells. Today, lithium ion represents a mere 10% of the world's total of rechargeable cylindrical cells.
(4) NiMH has taken over the computer industry, perhaps the closest application to video in the mobile communications market. In the US, for example, NiMH accounts for an estimated 70% of all notebook batteries. Lithium ion accounts for less than 30%.
(5) About 60% of all cell telephone batteries are NiCd. About 10% are lithium ion. The rest are NiMH.
(6) A typical notebook computer draws less than 1 amp (with hard drive and back lit color LCD screen) usually at 12 volts or about 10 watts.
(7) A typical cell phone draws less than 1/2 amp at typically 5 volts or well less than three 3 watts.
(8) There is a big difference in cells versus batteries. The largest capacity NiMH cell applicable in video today has a capacity of about 8 watt hours.
The largest lithium ion cell has a usable capacity of 9 watt hours. The largest NiCd cell is 6 watt hours. However, when these cells are put into a 14.4 volt series configuration and discharged at 50 watts (a camcorder and light) look at how the runtime numbers are different:
NiMH: 2 hours Li-Ion: 3/4 hours NiCd: 1.5 hours
Wait a minute. Doesn't lithium ion have more capacity than the other two technologies??? Doesn't NiCd have the least? The answer simply... is no. Lithium ion has a voltage advantage of 3.6 to 1.2 per cell for nickel based cells. Very simply this means that lithium ion needs only four cells to power a 12 volt device where nickel based technologies require 10 to 12. But its capacity in the same cell size is virtually the same as a NiCd. The nickel metal hydride and lithium ion cells are typically available only in small sizes which, although greater in capacity than a NiCd cell of the same size, are limited in their ability to discharge at the same rates as the NiCd and therefore are de-rated in actual use.
The cell sizes that can be effectively and safely constructed in NiMH and lithium ion are limited. Therefore, the batteries which can be made from them are limited because they must use the smaller cell sizes. To obtain the capacity of the same voltage NiCd battery, for example, 2 or 3 lithium ion cells must be paralleled or "stacked". By paralleling cells, theoretically, "larger" cells can be created from smaller cells, matching the capacity of the nickel based technologies, then put into a series configuration to obtain the voltage necessary. But the volume (smaller size) advantage is all but lost.
Paralleling or stacking cells "theoretically" creates larger cells, but manufacturing consistency, both in cell and battery assembly, is critical to this practice. However, in a young technology such as lithium ion, given its track record since its introduction, given the totally new manufacturing techniques , and given the controls required to safely charge and discharge this technology, no one in the battery industry assumes that today this practice is viable to all product applications. Recently, NiMH cells have been introduced in larger sizes to power high current applications in electric vehicles and power tools. These cells do not have to be stacked. It is the performance of these cells which has allowed Anton/Bauer to introduce the high performance HyTRON 100.Now let's understand some of the criteria for professional video batteries:
(1) A typical DVCPRO or SP-Beta camcorder draws about 2 amps at 12 volts or about 24 watts in record. (As an aside, "save" modes don't usually save all that much; even if someone uses it - which they usually don't). Many versions of new format cameras (disk, Digital-S, SX and others) as well as the high definition equipment, draw almost double (45 watts or more) of the state of the art SP camcorder.
(2) The typical on-camera light used today draws 25-50 watts. The typical focusable or dimming type light will always draw 50 watts.
(3) New formats have recording times on a single medium of 60 to 120 minutes or more (versus the 20-30 minute standard recording time of SP-Beta) an increase of 3 to 6 times. Therefore, the power necessary to record a single tape has increased by 3 to 6 times.
(4) Nearly 2/3 of the weight of a camcorder (with lens) is forward of the center of gravity point. Balance NOT weight is an overriding ergonomic design consideration on a camcorder. Compensating for this unbalanced weight has been determined as the cause of fatigue and back strain for cameramen. Although cameras are getting smaller and lighter, camera lenses must remain out front, unbalancing the camera. A 3-5 pound (2kg) battery actually balances today's camcorders perfectly while a lighter battery can actually add to the fatigue factor.
The answer to the question, "Why aren't all these new battery types used for my camcorder?", should now be clear:
A camcorder used by a video professional has different power and ergonomic requirements than a cell phone used by a soccer mom. Let's look at what is happening with each technology and how it is applicable to professional video:
Lithium Ion
Of all rechargeable chemistries, theoretically, lithium ion offers the future promise of smaller lighter batteries to match up with small low power equipment. For over 40 years cell manufacturers have been attempting to harness the energy potential of exotic metals such as lithium. Every early attempt was disastrous, leading to catastrophic and costly failures of batteries and equipment. Lithium ion chemistry, which does not use lithium metal in its pure form, has been successful in recent years in small two-cell batteries for low power equipment.
The single major disadvantage of this chemistry is made obvious by the absolute requirement for on-board "protection"
electronics to prevent overcharge (which results in catastrophic failure) or over-discharge (which renders the battery useless). Lithium ion chemistry is being employed, primarily in 2 cell configurations in the cellular industry and in the computer industries, where primary
considerations are weight and size. Moreover the devices they are used with (computers and telephones) have additional battery monitoring programs which can improve performance and reliability.
While lithium ion cells can retain their charge for a somewhat longer time than other technologies, lithium ion batteries stored for any time irreversibly lose capacity. The storage of lithium ion batteries, even for the time it takes to reach a customer from the factory, results in a loss of capacity which can never be restored. In practice this means that the clock starts on the life of a lithium ion cell from the time it is made - and continues to run whether the battery is used or not. No amount of "conditioning" cycles can bring back the lost capacity.
Another drawback to lithium ion technology as a video battery is its ability to address high rate discharge. In practice this means that no lithium ion battery on the market is capable of powering both a camera at 25 watts and an on camera light at 50 watts. In fact, the battery itself or the camera must be fitted with electronics to limit the current which can be drawn from the battery. Either the protection circuitry (required to protect the cells from over-current) will operate or the voltage regulation of the camera will limit the draw of the light rendering it virtually useless. Since the camcorder and light configuration is the most popular and economical operating arrangement in professional video, the practicality of existing lithium ion technology is limited.
The chemistry of lithium ion differs dramatically from any other rechargeable technology due to the nature of its electrolyte.
Much of the technical discussion in the battery industry regarding lithium ion has to do with some well founded concerns of reliability and safety.
The electrolyte (the liquid medium which allows the transfer of electrons from the positive to the negative plates) and the volatility of lithium metal (which can be formed under certain abuse situations) are the characteristics in which most of the R&D efforts by the cell manufacturers is seeking to improve. Current lithium ion cells use an organic electrolyte which is highly flammable. This means that the cell itself can support a fire, unlike other chemistries which use an aqueous (water based) potassium hydroxide electrolyte. The battery industry is actively pursuing this concern and development efforts are underway to address this issue.
Continuing developments in lithium ion design, manufacturing and construction will improve this chemistry in the future. Anton/Bauer continues to work with cell manufacturers to determine a suitable lithium ion cell for its Dionic(r) system, developed three years ago.
Cell manufacturers working on lithium ion have been focusing on developing different electrolytes, especially in the area of inorganic (non-flammable) and fire retardant electrolyte formulations. These changes when made, will be followed by improvements in volumetric and gravimetric energy density , thereby paving the way for an appropriate design for professional video. The electronic controls necessary for lithium ion are already a part of the Anton/Bauer InterActive DIGITAL battery. However, our view of the current benefit, dependability, compatibility and application of lithium ion chemistry available in configurations and usage required for professional video remains unchanged at this time.
Nickel Metal Hydride
Advancements in NiMH have improved this technology to offer the highest the watt hours per unit of volume. The weight of a lithium ion cell is less, but this is offset significantly by the complication of controls required for safe operation and the incompatibility with nickel based charger designs. NiMH cells have the same voltage as their NiCad cousins with the ability to store more energy due to the porous metal hydride electrode.
In practical application no conventional NiCad charger can handle the stricter charge controls required by NiMH technology. C-rate charging with TCO, -?V, and/or timed cutoffs are not acceptable methods to terminate charge. NiMH cells are not "drop-in replacements" for NiCad cells in any battery application. NiMH cells have a lower tolerance for high rate charge (excessive heat buildup lowers charge acceptance) and overcharge (degrades performance and cycle life). In fact, the cutoff methods employed for NiCad products by conventional chargers will not protect NiMH cells from damage (for example the -?V requirement for cutoff is twice as stringent as with NiCad). The only precision cutoff methodology for NiMH is a dT/Dt (change in temperature over a specified period of time). This cutoff methodology has been implemented in the computer industry since the early 90's (such as the type developed by Anton/Bauer for Apple computer based on the video InterActive(tm) Digital battery) and sophisticated
processing of temperature information supplied by the battery. Every Anton/Bauer InterActive charger possesses the ability to perform the dT/Dt calculations necessary to handle NiMH effectively and safely.
The operating characteristics of NiMH cells have been dramatically improved in recent years. Early NiMH cells were restricted by limited low temperature performance as well as high temperature cycle-life limitations. However recent improvements in NiMH chemistry, as well as the high voltage design of Anton/Bauer HyTRON batteries have virtually eliminated these concerns. HyTRON 50 batteries last year were the only power source for an expedition from Death Valley to the top of Mount Whitney experiencing operation temperatures ranging from around 100°F (38°C) to 15°F (-10°C). In fact, the cells used in the new HyTRON 100 battery were specifically designed for high current applications such as electric bicycles and power tools.
Unlike any other new technology, HyTRON batteries do not require the purchase of a new charger to take advantage of the
battery's performance. Any Logic Series charger with full communication capability can be upgraded with software to safely and reliably charge HyTRON. Any lithium ion batteries introduced thus far, require the purchase of a new charger. Moreover, if and when an improved generation of lithium ion technology becomes available, the new PowerChargers and late model Logic Series chargers will be able to address them transparently - with no need for a new charger.
Unlike any other new technology battery introduced, the battery can be mounted to any camera using a Gold Mount, factory standard on all DVCPRO and many other new camera models. HyTRON instantly assesses the InterActive Digital Battery viewfinder fuel gauge display, standard on new camcorders from all manufacturers, and the uninhibited ability to power on camera lighting.
Nickel Cadmium
Continued development of higher energy NiCad formulations, improved manufacturing techniques keeps this technology in the mainstream of portable power, especially in high power applications such as power tools and professional video.
With the advent of worldwide recycling and reclamation programs, the environmental concerns of the 1980's regarding the disposal of nickel cadmium cells have been addressed by the battery industry. Today NiCd cells are handled in recycling programs around the world similar to recycling glass or cardboard.
Charge times for NiCd batteries of about 1 hour are up to 3 times faster than either NiMH or lithium ion, making NiCd
indispensable to a fast paced professional. In the many applications of greater than 40 watt power requirements (such as a camcorder and on-camera light), NiCad remains the only acceptable rechargeable technology for reliability, runtime and service life.
The service life of NiCad batteries is unmatched by any other cell chemistry. In typical operation, especially in professional use, NiCad technology offers as much as three times the cycle life of any other chemistry. While NiMH and Lithium ion may offer equivalent runtime at a lighter weight, this advantage is offset by higher operating cost, the requirement for new chargers and a significantly shorter service life.
"Memory" is long forgotten. The only talk of memory is from manufacturers who offered poorly designed batteries and chargers or from users who based their operations on now obsolete box style batteries. The proper voltage batteries (no camera/camcorder has ever been designed to operate on a 12 volt battery such as NP or 90 types) have given rise to the poor cold temperature performance, short runtimes and short service life associated with the term "memory". A full discussion of NiCad's so-called "problems" long solved by Anton/Bauer charging and battery construction techniques, can be found in the Video Battery Handbook. Issues claimed to be "solved" by new technology battery products have been solved for video professionals years ago by Anton/Bauer.
So in the end, how does one determine which battery is "best"?
It is important to recognize that choosing a battery system today is as important a decision as deciding on a recording format. In most cases the choice of batteries outlasts the choice of cameras. Many broadcasters who started with NPs when the very first BetaCams appeared (because they got them "with the cameras") are still dealing today with problems which were successfully eliminated by Anton/Bauer a dozen years ago.
The "best" battery is one which can be consistently and dependably used every way the operator wishes to use his equipment. The battery to power a 40 watt digital format camera with an on-camera light is not necessarily the same battery to power a 25 watt camcorder without a light.
A battery system, with features adopted by every major equipment manufacturer, consisting of batteries of multiple sizes, chemistry and cost that can all be addressed on a single upgradeable charger is the only "universal" solution. Ultimately, each application and operation is different and should demand different battery types. No one battery in video, or in any industry, today can be called "universal".
Ask the right questions:
Which battery format offers the most flexibility and compatibility with today's equipment?
What sizes and types fit the type of shooting that I do? Do I only do one type of videography?
Can I mix different sizes and chemistries on the same charger?
Can I operate on-camera lighting?
Which format and battery type is the most cost efficient?
Which battery format can adapt to new technologies as they arrive?
When asking the right questions, Anton/Bauer can offer the right answers with a wide range of products comprised of a system of the latest technological advancements.
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