BATTERIES

INTRO

A while ago a friend of the family gave me a Kiev 16u 16mm movie camera. Its a rather strange beast in that its not only a three turent camera (i.e three primary lenses screwed on a rotating turent) it runs on 12 AA size batteries. Stranger still it contains not a an 18 volt motor as you would expect, but a 9 volt motor. That is rather than connecting 6 batteries is series to obtain 9 volts, it seemed to rely on three banks of 4 batteries. Each bank contained a set of two batteries connected in series, in parallel with an another set of two batteries also in series. This seemed like an attempt by the designers to boost the current output from the batteries. The end result is 3 banks of 3 volts, adding up to the neccessary 9 volts.

To complicate things further it still seemed to be chewing through the batteries at a tremendous rate. This got me thinking about what 9 volt power supplies were available. It also got me thinking about other battery type problems that confronted the 8mm film maker. Problems such as the need for replacing the venerable mercury oxide exposure meter batteries, and the re-celling of Beaulieu Super 8 camera, quickly spring to mind

Classification

As always when one confronts problems such as these, one turns to the web for the answers. This therefore is the result of my wanderings.

It seems that batteries can be placed into two broad categories:

Primary: or one time use and dispose, and

Secondary: or re-chargeable.

Each category can be further split according to the chemical composition of the battery, whether it be Alkaline, Lithium, etc, etc... The performance characteristics of each battery is very much dependent on its chemical composition. The following is a brief outline of current battery technology that may be of use to the average 8mm film maker.

DISCLAIMER: The author accepts no responsibility for any errors or omissions contained in the following information. Information on a particular battery should be obtained from the manufacturers website, or the manufacturers themselves.

© Copyright INTO 8MM FILM 2007.
The Author accepts no Responsibility or Liability for errors or omissions contained in this article.

Zinc-Manganese Dioxide:

The ubiquitous Alkaline battery, particularly the AA size, probably accounts for 90% of super 8 camera battery usage. Invented nearly 40 years ago, its simple chemical composition based on a Zinc Anode, Manganese Dioxide Cathode, and an "Alkaline" electrolyte of Potassium Hydoxide, has except for minor improvements, changed little. In high drain continuous usage such as a typical super 8 camera, it out performs ordinary Carbon Zinc batteries. Its availability, and performance when compared with Carbon Zinc, more than counter acts its price differential. Hence it is the first battery of choice for the super 8 film maker. Indeed, many manufacturers of Super 8 Sound cameras particularly specified that their cameras should be operated with Alkaline batteries. Alkaline batteries also had better leakage protection than their Carbon Zinc counterparts. All the same, batteries should be removed from the camera when not in use.

© Copyright INTO 8MM FILM 2007. DISCLAIMER: The author accepts no responsibility for any errors or omissions contained in the following information. Information on a particular battery should be obtained from the manufacturers website, or the manufacturers themselves.

Zinc-Mercury Oxide:

From the mid 60's to the early 80's, the humble Mercury Oxide button cell was the preferred battery of choice amongst designers of 8mm movie camera exposure systems. Its Anode was composed of either Zinc or Cadmium, while its Cathode was made up of Mercury Oxide. It belongs to the Alkaline family because its electrolyte was typically Potassium Hydroxide. The reason that it was the preferred battery was because unlike Zinc-Manganese Dioxide Alkaline batteries which tended to have a gentle downward sloping voltage output, it maintained a stable voltage output for nearly its entire usable life. Its stable output voltage of around 1.35 volts (for a single cell) and 2.7 volts (for a dual cell) and long shelf life meant that it was used by other photographic equipment that required these characteristics for their exposure systems. However its high toxicity, especially when released in the environment, meant that eventually its manufacture had to be phased out completely.

This inevitably caused problems amongst the millions of users of photographic and 8mm equipment that relied upon these batteries for proper use. Many made do with their Alkaline counterparts, and manually adjusted their exposure system to compensate for the higher (1.5 volts) voltage. Others, however, were able to adapt other members of the Alkaline battery family that had stable output voltages.

Zinc-Air:

One of the closest to matching the Mercury Oxide battery in its stable output voltage, is the Zinc Air cell. Its output voltage of 1.4 volts remains relatively stable for its usable life. It comprises of a Zinc Anode and Carbon/Oxygen Cathode. Holes in the battery allow air to enter through the cathode. The Alkaline Electrolyte of Potassium Hydroxide, aids in both the transfer of electrons and the trapping of Oxygen. They originally come with the air holes sealed. In this state, they have a long shelf life.

However, once the seal is removed the chemical reaction starts, and typically the battery has a very short life. The chemical reaction continues, even though the battery is not in use. It can only be halted by covering the holes. Therefore the cell needs access to air for it to operate. In a closed environment like a battery compartment, it may either fail to operate properly, or not at all. Another problem to overcome is their small size, when compared with Mercury Oxide cells. Special adapters are needed here, not only to fit them into battery compartments, but also to properly stack them to obtain voltages greater than 1.4 volts. This is because as mentioned earlier, in order for the the Zinc Air cell to operate it needs access to air through a number of small holes. If these holes are covered by stacking, the cell may fail to operate properly, or not at all.

Zinc-Silver Oxide:

The other battery cell that comes close to matching the output characteristics of the Mercury Oxide cell is the Zinc Anode, Silver Oxide Cathode battery. In size it is almost the same as a Mercury Oxide cell, however, it has a higher output voltage (typically 1.5 volts) under load conditions, than its Mercury Oxide counterpart. Therefore it requires special adapters to lower its voltage down to around 1.35 volts. Unlike Zinc Air cells once removed from operation they do not continue to be as chemically active. With moderate use and good care, they have the same shelf life as other "Alkaline" batteries.

CYLINDRICAL

Lithium-Iron:

A recent addition in the marketplace, the Lithium Anode, Iron Sulfide (or Iron Disulfide) Cathode battery stands out from the rest of the Lithium based Primary batteries in that its voltage output is typically 1.5 volts and comes in standard AA size. It also has for a Primary Lithium based battery uncommonly high capacity and high drain characteristics, typically higher than normal Zinc Manganese Dioxide Alkaline batteries. However their cost, when compared with normal Alkaline batteries has to be taken into consideration, especially when a lot of the simpler silent Super 8 cameras tend to have low to moderate drain characteristics.

BUTTON

Lithium-Manganese Dioxide:

The most commonly available Lithium based button cell type battery, it consists of a Lithium Anode, Manganese Dioxide cathode and typically an organic electrolyte. It, however, cannot be used for replacing a Mercury Oxide battery because of its size, voltage (typically 3 volts) and its sloping output voltage characteristic under mid to high drain applications.

RECHARGEABLE ALKALINE

One of the new technologies that has emerged, it is distinguished from other Alkaline batteries by its acronym of RAM. This battery essentially has the same chemical composition, output voltage and sizes as Primary Zinc Manganese Dioxide Alkaline Batteries. However, RAM batteries should never be confused with, nor used with ordinary Primary Alkaline batteries. RAM batteries typically come with their own charger, so the manufacturers instructions should be followed to achieve best results. At the time of writing they are the only re-chargeable battery that comes close to matching the typical output voltage (1.5 volts) of primary batteries. This is important especially with 8mm cameras that either combine the film advance motor and exposure system or use separate 1.5 volt alkaline cells for their exposure system. Therefore as they gain acceptance into the wider market, RAM batteries may become an interesting alternative to the 1.5 volt Primary Alkaline cell.

NICKEL METAL HYDRIDE

The early 90's saw the emergence of a battery technology that was set to overtake the venerable Nickel Cadmium cell. It has a Cathode of Nickel Oxyhydroxide and an Anode that is composed of a Metal Hydride. This Metal Hydride is capable of storing Hydrogen atoms, which participate in the charging/discharging process. Their high capacity, high drain characteristics, and similar typical voltage (1.2-1.35 volts) make them a good replacement for Nickel Cadmium cells. Both Nickel Cadmium and Nickel Metal Hydride cells come in the same standard sizes as normal Primary Alkaline cells. Nickel Metal Hydride cells do not suffer as much from "Memory Effect" which is a slight drop in voltage output that occurs when a cell is partially discharged then fully charged a number of times. To avoid this phenomenon it is advisable to follow the manufacturer's charging instructions. Unfortunately their sloping voltage output and low typical voltage mean that Nickel Metal Hydride cell should not be used to replace 1.5 volt Alkaline cells. However they seem to be the battery of choice when it comes to "Re-celling" certain Beaulieu Super 8 cameras. A German company named Emmerich have produced a battery that is shaped like an oversized button cell, that people are using for this purpose.
However, before attempting any "Re-celling" or external power supply designing, it is highly recommended that the Battery manufacturer should be consulted first.

SEALED LEAD ACID

Most people are aware of the 6 and 12 volt Sealed Lead Acid batteries that come in mono blocks. They come in various capacities , with the 6 volt Sealed Lead Acid battery being the one which probably is of interest to the 8mm film maker. They can be useful as an external power source, where cameras have provision for connecting to an external power supply. The Battery manufacturer should be contacted before attempting to design an external power supply. However, there is also a cylindrically shaped Sealed Lead Acid battery, the typical output voltage of which is around 2 volts. These maybe combined to produce voltages higher than the single cell voltage of around 2 volts. Information on these batteries can be obtained from the Manufacturer Hawker Energy.
The Battery manufacturer must be consulted on which is the best method of charging. The Battery manufacturer should also be consulted before designing an external power supply.

RECHARGEABLE LITHIUM

An interesting addition to the Secondary cell market. Its structure is composed of a Lithium Oxide Compound Cathode and a special Carbon compound Anode. The Carbon compound Anode stores Lithium Ions during the charging process, and releases these Ions to recombine as the Lithium Oxide compound at the Cathode. The end result is a battery that is light, has a typical output voltage of around 3.6 volts and high drain characteristics, (similar to high capacity Nickel Metal Hydride). However, at the moment, they are not as common and as cheap as the Nickel Metal Hydride cell. Should improvements be made, and they become more common and cheaper, then they may become of some use to those seeking an alternative to the Nickel Metal Hydride cell, particularly in "Re-celling" Beaulieu cameras.
Once again it is strongly advisable that the Battery manufacturer be consulted before attempting to design a power supply, and also to obtain information on the best method of charging these cells.

PRIMARY CELLS
ALKALINE
Cylindrical
Button
LITHIUM
Miscellaneous
SECONDARY CELLS
Miscellaneous