VIDEO CAMERA 1996

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BATTERY MEGATEST 96

 

INTRO

Love ‘em or hate ‘em, we’re stuck with them...  Sooner or later you’re going to need a spare or replacement camcorder battery. We’ve been putting over sixty of them through their paces, in the annual Video Camera battery test...

 

COPY

If it wasn’t for a Swiss scientist called Carl Jungner we probably wouldn’t have camcorders. No, he doesn’t work for a major Japanese consumer electronics manufacturer, nor did he have anything to do with the development of video recording. In fact old Carl is long gone, he made his contribution almost one hundred years ago, in 1899 to be exact, when he figured out the chemistry for the nickel cadmium or nicad re-chargeable battery. Without the nicad the camcorder as we know it today, and a whole lot of other portable electrical and electronic gadgets, simply wouldn’t have been possible, or economic.

 

Nicads are still the cheapest and until recently, one of the most efficient re-chargeable power sources, but it’s also one of the most aggravating aspects of video movie-making, they always seem to go flat at the critical moment.

 

There’s nothing intrinsically wrong with nicad batteries, it’s just the way we use them. The pattern of camcorder usage is not conducive to long life or reliability. Most camcorders spend weeks or months doing nothing, interspersed with a few hours of intense activity, during which the battery pack is thoroughly mistreated. Consider this. A new nickel cadmium cell (a battery is made up of a collection of cells) should be able to withstand more than a thousand charge/discharge cycles, before there’s any significant reduction in capacity, due to irreversible chemical changes inside the cell. In practice most camcorder owners will be fortunate to get more than a few hundred cycles, before their battery packs become useless, so what’s going on?

 

There’s two problems. The first one is the way camcorder packs are charged. Nicads last longest when they’re charged gently at the C/10 or overnight rate, which takes around 14 hours. Ideally each cell in the battery should be carefully discharged, to no lower than 1 volt, before it’s recharged. That’s completely at odds with what happens to a typical camcorder battery pack. They’re charged on ‘fast’ high-current chargers, that take around an hour to charge a standard pack. Most chargers work on the principle -- called negative delta V -- that the battery is fully charged when it goes into an over-charge condition, which is indicated by a drop in voltage, and a rise in temperature. Overcharging damages a nicad cell, over time reducing its capacity. In effect, every time you fast charge a camcorder battery, you’re shortening its life.

 

There’s worse to come, camcorders have voltage sensors, that shut the machine down, well before the battery is fully discharged. That’s a safety feature, to ensure there’s always enough power left to unlace and eject the tape. But that means that when the battery is recharged there’s still a residual charge left in it, possibly as much as 25% of its normal capacity. The cells in a battery are not all the same, and over the course of a few weeks or months, they develop quite widely varying states of charge, but the charger has no way of know that. It decides the battery is fully charged when it detects the characteristic voltage dip, which can happen if only a few of the cells reach full charge, leaving the rest only partially charged. This is known as cell ‘imbalance’ and is one of the main causes of the so-called ‘memory’ effect. From the camcorder owners point of view a battery will appear to have shorter and short running times, with just a few months of purchase.

 

Time at last for some good news. It is possible to eradicate, or at least minimise memory effects by regularly subjecting nicad packs to a series of controlled  discharge/charge cycles. You may be lucky and have ‘refresh’ or ‘condition’ mode on your camcorder’s charger, if not it’s a good idea to get an accessory charger with that facility. It will help prolong the useful life of your battery.

 

So far we’ve only talked about nicads, they are still the commonest type of camcorder battery, but rival technologies are beginning to have an impact. Nickel metal-hydride batteries have been around for a few years, but just recently the price has begun to fall, to the point where they’re in the same ball-park, as nicads. They do not suffer from memory effects to anything like the same extent as nicads, and they don’t mind repeated top-up charges so much. They’re also a little smaller and lighter than nicads of equivalent capacity. Shop around, they’re worth considering.

 

However, the big news in camcorder power is Lithium Ion. This once exotic battery technology is now finding its way into mainstream video movie-making, thanks largely to the considerable efforts of Sony to standardise on this type of power source. Lithium Ion batteries have an even higher power density than nickel metal hydride, and they’re virtually immune from memory effects and tolerant of top-up charges. Their discharge characteristics are a lot more predictable, making it possible for camcorders to have accurate battery charge/time remaining  indicators. They probably make a damn fine cup of tea too but they are expensive, and the jury is still out, as far as longevity is concerned.  

 

So there you have it. That more or less brings us to this year’s camcorder battery  Super Test. It’s a little different from previous years; we’re still focusing on 6 volt ‘NP’ style packs, which are still the most common, and we’ve included a few more 4.8 volt packs, which are used on Panasonic camcorders, and clones. This year though it’s bigger, a whole lot bigger, with over 60 packs tested, and we’ve revised our testing procedures. Previously we’ve used actual camcorders to simulate real-life operating conditions, but the machines we’ve used are now all getting a little long in the tooth for this kind of marathon exercise.

 

This year the tests were conducted using a Hahnel Pro 9900 battery tester. It’s a professional measuring instrument that checks three packs at once, taking each of them through a predetermined number of charge/discharge cycles, giving a capacity reading for each cycle, when the test has been completed. We had hoped this new system might speed things up a little, though in the end it still took several weeks to complete.

 

SUMMARY

Most of the nicad batteries tested failed to reach their stated capacity within the first three charge/discharge cycles. This is normal, some batteries may not give their best until they’ve been through more than half a dozen cycles. To give them all a fair chance we repeated the tests. On the second run almost all of them all managed to come within 10% of their quoted rating, most managed to be within 5%, a couple even managed to exceed their spec. Overall we consider this year’s batch did very well. Unfortunately these tests are simply a snapshot and do not tell us anything about long-term reliability so we’re always grateful for any feedback that you can provide. The final star rating was based on a number of factors, including average capacity, price, added-value features, size and construction. Here’s how it worked out:

 

 

MAKE/MODEL

Type

(volt/style)

stated

cap mAh

 

Price

££s

Video Camera Rating

Bandridge VB364B

nicad 4.8/P

1300

 

30

****

Bandridge VB364D

nicad 4.8/P

2000

 

35

*****      SB

Bandridge VB366C

nicad 6/M

1800

 

30

***

Bandridge VB466E

nicad 6/M

2400

 

40

****

Bandridge VB866C

nicad 6/M

1800

 

30

***

Bandridge VB1866C

nicad 6/M

1800

 

40

***

Duracell DR10

NiMh 6/S

1800

 

40

***

Duracell DR11

NiMh 6/M

3600

 

60

****

Duracell DR12

NiMh 6/C

3000

 

60

****

Duracell DR14

NiMh 4.8/P

3200

 

60

***

DSM DPPS20

nicad 4.8/P

2000

 

24

****

DSM Ultimate H1

nicad 7.2/S

1900

 

35

****

Energiser CM1060H

nicad 6/C

1800

 

30

***

Energiser CCM2460

nicad 6/P

1800

 

30

***

Energiser CCM4060A

nicad 7.2/M

2000

 

40

***

GP VD103

nicad 6/M

2400

 

30

****

GP VP105

nicad 4.8/P

1200

 

16

***

GP VP107

nicad 4.8/P

2400

 

26

****

GP VD151

NiMh 6/M

1500

 

28

****

GP VD153

NiMh 6/M

3000

 

52

*****      SB

GP VP155

NiMh 4 8/P

1500

 

24

****

GP VP157

NiMh 4.8/P

3000

 

42

****

Hahnel Combi 2000**

nicad 6/S

2000

 

38

***

Hahnel M2000

nicad 6/M

2000

 

26

****

Hahnel ML 2400*

nicad 6/M

2400

 

50

***

Hahnel 3200

NiMh 6/M

3200

 

 

*****       SB

Hahnel Campack 4.8

nicad 4.8/P

2000

 

33

****

Hama CP407

nicad 6/S

2000

 

40

***

Hama CP408

nicad 6/S

2400

 

50

****

Hama CP409

nicad 6/S

3300

 

75

***

Hama CP451

nicad 4.8/P

2600

 

40

***

Hama CP452

nicad 4.8/P

2000

 

40

***

IQ BS20Ei *

nicad 4.8/P

2200

 

25

***

IQ SP77i *

nicad 6/M

2200

 

25

****

Keene NP 10-20

nicad 4.8/P

2000

 

23

*****       SB

Keene NP10-26

nicad 4.8/P

2600

 

30

****

Keene NP10-34

NiMh 4.8/P

3200

 

40

***

Keene FZ 171

nicad 6/M

2400

 

30

****

Keene FZ174

NiMh 4.8/P

3200

 

40

****

Millennium CM2360

nicad 6//H

1800

 

40

***

Millennium CM2560

nicad 6/S

1800

 

40

***

Panasonic VW-VBS20

nicad 4.8

2600

 

50

***

Sony NP68

nicad 6/S

1800

 

40

***

Sony NP-78

nicad 6/S

2400

 

50

****

Sony NP 90D

nicad 6/S

3000

 

70

***

Sony NP-98

nicad 6/S

3000

 

60

***

Sony NP 4500

nicad 6/S

4500

 

100

***

Sunpak RB-80L *

nicad 7.2/M

2700

 

50

***

Sunpak RB-80U

nicad 7.2/M

2700

 

44

****

Uniross VP66

nicad 6/S

1800

 

20

***

Uniross VP66S

nicad 6/S

2400

 

40

***

Uniross VP183

nicad 6/S

1800

 

30

****

Varta V111

nicad 6/M

2400

 

40

*****       SB

Varta V213

NiMh 6/M

3600

 

60

****

Varta V214

NiMh 6/H

1800

 

45

***

Varta V215

NiMh  6/C

3600

 

60

****

Varta V216

NiMh 4.8/P

3600

 

70

***

Vivanco BP2648

nicad 4.8/P

2600

 

40

****

Vivanco BP3006Y

NiMh 6/S

3000

 

50

***

Vivanco BP3248

NiMh 4.8/P

3200

 

50

****

 

 

Key: style, M= multifit (Sony/Panasonic/JVC), C = Canon, H = Hitachi/Minolta, P =  Panasonic, S = Sony

* built in power indicator, ** built-in video light hot shoe

 

 

SIDEBAR 1 -- INSIDE STORIES

Camcorder battery packs are made up from a collection of individual cells. There are basically two types, cylindrical ones, that look pretty much like regular pen cells; the commonest types are a little larger than an AA cell. The other sort are ‘prismatic’ cells, they’re usually rectangular or square in cross section, which means they can be packed more tightly together, in smaller cases.  Most types of rechargeable cell have a nominal output of 1.2 volts, which explains the sometimes odd voltages. For example, a 4.8 volt battery, of the type used by Panasonic on their ‘slimcams’, contains four cells. Six-volt packs contain five cells, or two (or three) banks of five cells, wired in parallel, and so on. Inside nicad and nickel metal hydride batteries there should be a set of safety devices, including a thermal fuse, a thermistor -- a device which changes its electrical resistance when it gets hot -- and a ‘polyswitch’, another type of fuse that protects against short circuits.

 

Rechargeable batteries should always be treated with care. Do not carry them in your pocket without a protective cover, exposed contacts can easily short-circuit on metal objects, like keys or coins. The metal can become red hot and it could lead to a rapid build-up of heat within the cells. In extreme circumstances they can burst, spewing caustic and toxic chemicals, and super-heated hydrogen gas, all of which can cause very nasty burns. Dispose of old batteries thoughtfully, especially nicads, which contain a particularly nasty and noxious mixture of chemicals. Take them to a video or photographic dealer, who should be able to send them for recycling. Alternatively, take them to your local authority amenity tip, most now have battery collection points;  on no account put them into household waste. 

 

 

---end---

© R.Maybury 1996 3110

 

 


 

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