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LEADERS OF THE PACK
INTRO
For the second year running we’ve been
putting a selection of replacement cellphone batteries through their paces,
Rick Maybury reports on this year’s runners and riders
COPY
You can almost guarantee the low battery warning
on your phone will start bleeping just
as you’re about to make an important call. The good news is many of the most
recent phones can now get through a normal working day on a single charge, but
that’s a fat lot of use to the rest of us, stuck with phones, that rely on
cantankerous nickel cadmium battery packs. They rapidly loose their ability to
hold a charge after just a few months, and often need replacing after only a
year of moderate use. Their only redeeming feature is price, compared with
newer battery technologies they’re reasonably cheap
The cost of nickel metal hydride (NiMh) battery
packs has fallen in the past year. They’re now available for a lot of phones
and can be used instead of nicads. NiMh batteries are slightly smaller and
lighter than nicads of equivalent capacity, more eco-friendly when it comes to
eventual disposal and they’re far less prone to the dreaded memory effect,
which can reduce a battery’s capacity by up to 50% in a matter of weeks or
months.
The most common cause of the memory effect is
cell-imbalance, where the rechargeable cells that go to make up a battery
develop varying states of charge. The majority of cellphone battery chargers switch
off when they sense one or more cells are fully charged, so that the others in
the pack may only receive a partial charge. It’s not necessarily a permanent
condition though, and by carefully discharging the whole pack several times,
the cells inside can be put back on an equal footing, so they all get an equal
charge. A growing number of chargers, sold through accessory dealers, have a ‘refresh’
facility, though few chargers, supplied as standard with mobile phones, can do
this.
But we digress. The topic of this month’s
accessory feature is replacement batteries. It follows on from the survey we
carried out last year, where we tested batteries from a number of well known
accessory companies. We’ve stuck to the same basic format used last year, so we
can compare results, and hopefully spot any trends.
THE TESTS
Our tests centre on one type of battery, the
ones used to power Motorola Micro TAC, Flip and Flare models. This is still the
most popular family of phones, and that’s reflected in the number of companies
that supply replacement packs. We should point out that all of the companies
included also supply batteries for most other popular makes and types of phone
as well, and that in a lot of cases they use the same cells in other pack styles.
We originally intended to focus on two types
of battery: slimline packs, similar to the type supplied with a phones as standard,
and high-capacity or added-value packs. We’ve kept this second category as
broad as possible, giving accessory suppliers and manufacturers the opportunity
to supply us with batteries that they feel are in some way special, either in
terms of capacity, value for money, size or features. However, in the end not
all manufacturers were able to supply both types. Several companies pointed out
that phone users are become wise to the sometimes significant price differentials
between standard and high capacity packs, which are normally much better value
for money, in addition to giving longer running times.
The tests are conducted using the same test rig
we used last year, that replicates different usage patterns. Cycle one represents
medium to heavy use, equivalent to two, five-minute calls an hour. Cycle two simulates
four, five-minutes calls an hour. In response to comments from several battery
suppliers we’ve changed the way we present the results. Last year we gave
actual running times; it was felt by some that the figures could be taken to
represent real-life operating times, so now we’re just going to give each battery
a set of scores, from one to ten. You can take it as read that five means average,
with the best performances getting eight to ten. The overall rating take other
factors into consideration, including price, build quality and any extra
features.
Before we test each battery we subject it to
three charge/discharge cycles, to condition the cells in the pack and eliminate
any residual charge or memory effect. This year we’ve included a few more NiMh
packs, and it’s worth pointing out that may require special treatment. Many standard
nicad chargers will cut off, before a NiMh pack reaches full charge. We now use
chargers designed to accommodate these battery packs. If you’re using an
ordinary charger, the trick is to take
the battery off the charger when it says it’s charged, wait a few minutes, then
put it back on again, when it should go on to receive a full charge.
Last year we found at least one pack that was
misleadingly labelled, so once again we open up suspect batteries, to check
what’s inside. In addition to verifying the cells are what the manufacturer
claim them to be, we also check for the presence of safety devices, and the
quality of the contacts etc. We’re pleased to say we haven’t come across any rogue
packs this time. We’ve also noted a general improvement in the performance of the
batteries on test. There seems to be fewer cheapo or second grade cells about
this year, though you can probably still find them in street markets and some
accessory dealers, if you look hard enough. The best advice we can give is to
buy brand name products from a reputable source. It will usually work out
cheaper in the long run.
And so to this year’s round-up. There were no
nasty surprises and all of the packs tested have come close to the manufacturer’s
stated capacity. This has tended to put more emphasis on the relationship
between capacity and price. We’ve also weighted the results to take the higher
price of NiMh packs into consideration, and any additional features.
BATTERY PERFORMANCE TABLE
Make/model Type Cap ££s C1 C2 Overall Rating
ATEC BO80MT NiCd 800 20 8 8 8
ATEC BU0120MT NiMh 1200 40 8 8 8
DANIEL DESIGN IQ* NiCd 1700 50 7 7 8
GRM 1700 NiCd 1700 30 8 6 8
GRM Slim NiMh 600 40 8 8 8
HAMA 41039 NiCd 1700 40 8 7 7
ORA MBP7B NiCd 700 20 8 7 8
ORA MBPH1900B NiMh 1500 55 7 9 7
PAMA 1100 NiMh 1100 40 8 8 8
UNIROSS UCB 310S NiCd 1200 30 8 7 8
UNIROSS UCB 310HTE NiMh 900 50 6 8 6
VIVANCO 6546 NiCd 1200 20 8 8 8
VIVANCO 6538 NiMh 1200 35 8 8 9 Star Buy
VOCALL CPB1 ** NiCd 700 25 9 8 8
VOCALL CHB 1S ** NiMh 600 50 8 8 7
WESTAR EXTENDED NiCd 1300 20 7 7 8
WESTAR SLIM NiMh 600 28 7 8 8
KEY: Cap
-- capacity in mAh (milliampere/hour), ££s -- suggested/typical retail
price, C1 - -medium/high usage cycle, C2 -- high use cycle, * built-in discharger
and charge indicator; ** supplied with soft carry case
SUMMARY
This year’s batch of batteries have turned in
a generally good set of results, at least as far as performance is concerned, with
far less variation than last year. There are still some quite significant price
differences though, particularly when it comes to NiMh cells. In some cases they’re
only marginally more expensive than equivalent nicads. All of the batteries we’ve
tried were satisfactory, a couple stand out as being particularly good value, but
it’s up to you to sift through the data, and as usual, shop around for the best
deals as actual street prices can be a lot less.
CONTACTS
Contact
Atec -- Lemon Accessories, telephone (0973)
282104
Daniel Design -- Small Talk Communications,
telephone (01923) 218753
Hama UK, telephone (01256) 708110
Ora Electronics, telephone (01296) 415445
Pama, telephone (0161) 224 4444
Uniross Batteries (01275) 858101
Vivanco UK, telephone (01442) 231616
Vocall -- Apex Distribution, (01707) 266222
Westar Connections, telephone 0181-903 0202
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Ó R. Maybury 1996 0508
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