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LAPTOP COMPUTERS
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This tutorial contains three sections: travelling with laptops,
rechargeable battery care and use, resources for laptop users on
CompuServe. For additional information on purchasing a laptop
computer, see the section on laptop purchasing contained within
the chapter titled "Buying a Computer."
Laptops are made to travel. Their small size and potent features
make computing on the road a snap. Consider using this
assortment of tips which seasoned laptop owners have come to
rely on....
Airports are a frequent transit point for laptop owners. Be sure
to be prepared for a SPEEDY passage through airport security by
being aware that in most cases you MUST boot up the laptop so
that a DOS prompt, menu or other sign of visible activity is
displayed on the screen. Security officials do this for a
reason: if a laptop computer has been tampered with or hollowed
out to serve as an empty shell for explosives or weapons, the
machine will not boot up or operate. By forcing the laptop owner
to activate the machine, airport security is effectively
screening for tampered machines.
Once you know this, several important tips are quite useful.
Always carry a BOTH a fully charged battery and AC adapter with
the laptop. No power means no possibility of booting the machine
and your laptop might be forced to remain behind!
To speed the process on laptops equipped with hard drives try an
experiment. Prepare a bootable floppy disk with DOS system files
and a short AUTOEXEC.BAT program which boots the machine rapidly
since DOS usually tries to boot from a floppy first and then the
hard drive second. Now time how long it takes to boot from the
floppy as well as the hard drive. Whichever is faster is the one
you want to use to speed your trip through airport security. But
ALWAYS take the bootable floppy as well. Why? If your laptop
hard drive becomes damaged in transit - a possibility in today's
airport environments - then you have a floppy backup which will
also get you through airport security.
Cursor size and blink rate on many laptops are atrocious. Third
party software utilities are available which can alter both size
and shape of the cursor - we will discuss these in more detail
in the software section of the Laptop tutorial. However the
point to be made is that you might find one ideal cursor size
and blink rate for airplane use and a DIFFERENT cursor size and
blink rate better at the office or in the airport. Try various
combinations in various lighting. Several different cursor
configurations are quite handy when travelling under varying
lighting conditions. By the way in a pinch, The WordPerfect word
processing package has just such a utility you might want to dig
out if you own WordPerfect but have never used software cursor
control utility!
Did your portable printer malfunction and crash while you are on
the road? Or maybe you just don't want to carry your printer at
all. Here's an obvious idea: use your laptop and modem/faxboard
to fax your file to the hotel front desk fax machine and pick it
up there! If your modem lacks fax transmit capability, send the
file via modem to CompuServe and let them re-send it to your
hotel fax machine using their fax transmission capability.
Worried that the fax image might fade or curl with heat or
handling? Then xerox copy it onto standard paper which is a more
permanent material than fax paper.
Speaking of modems, the smallest and most "laptop useful" modems
are available from U.S. Robotics (call 708/982-5010.) Their
World Port modem is truly tiny, fully-featured and ruggedly
designed for travellers. Hayes has also produced the Pocket
Modem (call 404/449-8791.) Some of the most clever portable
modems do not even need battery power - they draw current from
the computer or telephone line.
Hotels and airlines always have carpeting. And carpeting is
productive of electrical static. Shuffle across the floor in
most travel facilities on a dry or cool day and you get a spark
when you touch the doorknob. This same static electricity
buildup can ruin the EPROM chip in your laptop keyboard when you
sit down to use the laptop. Be sure to first touch a bathroom
faucet with a coin. To eliminate static in your hotel room,
just take off your shoes and socks!
Carry extra charged batteries on long flights or international
flights. Seems like a simple tip, but that battery pack you
bought two years ago may finally decide it has a one hour life
somewhere over the Atlantic Ocean. Rechargeable batteries cannot
be recharged forever - after two to five years they begin to die.
Be sure you know how to turn off the speaker beep facility in
your laptop. Crowded airplanes indicate courtesy. Third party
software utilities exist which will provide this capability if
you own an older laptop without this software or hardware
feature. More about this in our software tutorial.
Conserve power on long flights. Turn down the screen brightness
to save power. Use the auto-resume feature if your laptop
contains the capability. Switch to slow mode or lower the
processing speed of your CPU chip. Your instruction book may
mention some or all of these features.
Some laptops have a variation of the auto resume feature that
even allows you to change batteries right in the middle of a
program. Check your manual. Might be a lifesaver on a plane
trip.
Save still more power when travelling by investigating software
ram disks or virtual disks which, unlike a spinning hard drive
or floppy, use far less power on long airline flights. DOS
itself comes with a reasonable although rudimentary ram drive
called VDISK which all laptop owners should check out. You can
also obtain third party shareware, commercial and public domain
ram disk software. Of course be sure to save your work to a
floppy or hard disk before you turn the machine off since a ram
disk operates purely in memory and MUST have power to maintain
your data.
If you travel out of the country, be sure to register your
foreign made laptop with U.S. Customs when you depart - so that
upon return you are not forced to pay duty on a machine you
bought in the U.S. but which customs officials will suspect was
purchased overseas. This can be a sticky subject. Contact a
local customs office for instructions on registering your
machine prior to departure.
Travellers should also consider etching your name, address,
telephone and social security number onto the machine in several
places. Although this may decrease the resale value of the
laptop, it also increases chances of recovery in case of theft.
Don't make the mistake of etching ONLY your social security
number onto your laptop. Federal privacy laws prevent release of
your social security records even to some law enforcement
agencies and in that respect having only your social security
number on valuable items is probably next to worthless as a
security item.
Hotels are getting better about providing modular plug in
telephone jacks for laptop users who need to hook up a modem.
But it seems the telephone jack on the wall is always ten feet
from the nearest table where you laptop sits. Solution? Always
bring a modem extension cord with in-line connector. Makes
laptop modem work a joy! Another tip: use the hotel's toll free
800 number to call ahead and doublecheck that your room is wired
with modular plug-in telephone jacks. Takes a moment and costs
you nothing! Speaking of plugs, investigate the new breed of
miniature surge supressing AC adapters if you travel to foreign
countries whose voltage can be less reliable than that in the
U.S.
You can obtain special anchor plates or straps which attach to
the bottom or side of a laptop with permanent glue. A flexible
steel cable and lock lets you secure your laptop to a hotel
radiator or piece of furniture and defeats all but the most
determined thief.
For those who absolutely need telephone links when travelling,
consider purchasing an acoustic modem coupler which works with
all telephones when you cannot plug your modem into the wall.
Acoustic couplers work by attaching directly to the mouthpiece
and earpiece of any standard phone and transfer data directly by
sound transmission. By the way, in overseas areas you will soon
find that you need a maddening array of special adapters to hook
your modem to the telephone line directly. An acoustic modem
coupler is the only truly "universal" adapter which will connect
to all telephones throughout the world.
Another modem tip when using hotel telephone lines: arrange with
the front desk or operator to ALWAYS put your call DIRECTLY
through without intervention. Many hotel system route your call
through a switchboard which prevents your modem from getting a
dial tone!
Diehard laptop users who communicate with the head office via
modem should also investigate remote computing software which we
will discuss later. Remote computing software allows you in your
hotel in New York to call San Francisco by modem and then
connect directly with your desktop computer or office LAN
network. Once connected, you can run your word processor, obtain
files, check figures on the office spreadsheet and more. In
essence your laptop functions as a remote keyboard for a
computer which is thousands of miles away. Shareware, public
domain and commercial software packages of this type are
available. But if you do this, here is one important tip many
travellers learn the hard way: ALWAYS leave a note for the
maintenance person or janitor which tells them not to turn off
what appears to be your idle office desktop computer. Oh, and
while you are gone, turn off the desktop monitor but leave on
the pc if you plan to compute remotely. This saves power and
prevents screen burnout!
Need to test if two files are slightly different as you check
newer document files against older ones? Or maybe just backup
all NEWER revisions of your files to a floppy or transmit them
by modem to the head office? Use the DOS XCOPY command to track
down differences between two files such as word processing
documents. DOS also previously had an older File Compare command
called FC which accomplishes the same thing. Sidekick version 2
has a reconcile feature and Lap-Link can transfer files between
to computers and check dates and times to make sure you are
obtaining the newest version of a file or to ensure that both
computers indeed have the latest file.
By the way, here is an example of how to use the DOS XCOPY
command to copy all files from ALL subdirectories on a laptop
hard drive named C: onto a backup floppy in the A: drive which
have been updated on or later than March 15, 1992. Very handy
when you are on the road and want to copy or prepare for modem
transmission all of your updated files for the head
office. At the DOS prompt type:
XCOPY C:\*.* A:/S/D:03/15/92
Consider travel insurance for replacement of your laptop in case
of theft. Contact Safeware at 800/848-3469.
Business travellers often have to present VERY important
presentations with their laptops. Essential job proposals,
contracts, crucial price schedules. If it is important to your
business, always make a backup copy on floppy disk. Seems
simple, but many business users discover that their hard drive
equipped laptop has crashed due to airport handling in transit.
A floppy can save the day and in a pinch you can rent a computer
or borrow one from your client. If data matters, put it on a
floppy.
Make sure you ALWAYS carry a null modem cable and file transfer
software with your laptop when travelling. You can probably
patch into another desktop computer to transfer files in
emergency, but without the null modem cable and software you are
stuck. Practice transferring files between several computers
before you travel so you have the process comfortably memorized.
For the truly worried traveller, also carry a pair of gender
changer plugs which allow hookup of male to male and female to
female cable connections. Also a 25 to 9 pin plug adapter.
Laptop computer die in transit? Carry a set of jewelers
screwdrivers and floppy disk cleaning kit. If a few simple
things such as this won't fix it, then grab the yellow pages and
look under computer rentals. By the way, many hotels maintain
rental laptops for business travellers. But the secret is that
the rate is far cheaper by renting from a local vendor than the
hotel. Make a few phone calls and get a laptop delivered to your
hotel suite in case of emergency. The smartest travellers call
ahead to their destination and reserve a backup laptop in case
of problems at a local vendor. If the laptop is not checked out
a small retainer fee is kept by the vendor. This can be done by
a charge card and a long distance phone call. Same goes for
renting LCD projection panels for business meetings.
Consider obtaining a CompuServe account for modem use if you
travel frequently. You can obtain online support for laptop
computer problems directly from the manufacturer, download
special software utility files, transmit important files to the
home office, send faxes when all you have is a modem which lacks
fax transmit capabilities (CompuServe converts your modem
transmission and sends it on via their fax equipment.) Lots of
good ideas and special laptop discussion forums for business
travelers. You can even book hotel and airline reservations
directly by modem using CompuServe, too. Laptops, travel and
CompuServe go together handsomely.
Did your ribbon die in your portable printer? Just not black
enough? Stick some fax paper in the printer. It is heat
sensitive and will frequently pick up an image without a printer
ribbon. Amazing but true. This works with dot matrix printers.
Do not try it with laser printers.
Check ahead for special regulations. Example: in Germany modems
are regulated under certain security laws - presumably spies
could use them to transmit data. You must have a "modem permit"
in that country or your equipment can be confiscated. In other
countries and some developing nations such as Africa and India
confiscation of computer equipment is common - even if all of
your registration and travel documents are in order! In those
cases you might be better off leaving your computer at home and
bringing a tape recorder or notepad. Just because you own a
computer does not mean you can use it in an unrestricted
fashion while you travel!
Tempted to use one of those inexpensive overseas power
convertors to adapt your AC plug in convertor to European
current? DON'T DO IT without first checking with the
manufacturer. Those inexpensive current convertors work fine
when changing high voltage overseas current to lower voltage US
current for things like shavers because they reduce the voltage.
The problem is that most of the world uses 50 cycle AC current
versus the normal 60 cycle AC current in the U.S. Computers CANNOT
run from these inexpensive convertors and damage may occur.
Find out what device the manufacturer supplies or recommends for
travel outside of your country of residence.
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RECHARGEABLE BATTERIES AND LAPTOP COMPUTERS
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No other topic seems to inspire more opinion and comment than
the proper care and handling of rechargeable laptop and notebook
computer batteries. Should you slow or fast charge them? What is
the true life of a rechargeable battery after which it must be
disposed? Do rechargeable batteries have a "memory" effect? Can
nickel-cadmium batteries explode when charging or discharging?
Although this tutorial may seem technical in places, try to read
ALL of it since battery power may be your only source of laptop
power on many occasions.
For many portable computers a variety of rechargeable battery
options exist today. But frequently it comes down to the old
standby: nickel-cadmium batteries. Ubiquitous in consumer
electronic items such as shavers, flashlights, toothbrushes and
radios, nickel-cadmiums or "nicads" are a reasonable balance of
power, cost and weight and are used by many computer
manufacturers as the portable power source of choice. Let's
scratch the surface on the topic since there is QUITE A BIT the
manufacturer doesn't tell you about nicads....
Glance at the following chemical equation which is at the heart
of the nickel-cadmium cell reaction. Don't get overly anxious
because high school chemistry was not your favorite subject.
We'll take things slowly....
<-----
Cd + 2 NiOOH + 2 KOH -----> Cd(OH) + 2NiO + 2 KOH
2
In this highly simplified reaction sequence, electricity is
generated when the reaction proceeds in the direction of the
right pointing arrow, the discharge cycle. If the reaction
proceeds in the left direction the cell is charging.
In simplest terms, a nicad cell (a battery is constructed of
several cells hooked together) has a positively charged plate of
nickelic hydroxide and a negative plate of metallic cadmium. The
liquid between the positive and negatives plates which
facilitates this chemical reaction is usually a dilute solution
of potassium hydroxide - similar to lye or the Draino (tm)
solution your pour down the sink to clean your plumbing. When
discharging and thus producing electricity, the nickelic
hydroxide is reduced to nickelous hydroxide as hydroxyl ions
from the potassium hydroxide electrolyte combine with the
cadmium metal of the negative plate of the cell to form cadmium
hydroxide. Cadmium is oxidized when this happens and electrons
are provided into the external circuit, such as your laptop
computer.
When charging, the process reverses and hydroxyl ions combine
with the nickel which accepts electrons from the external
charging circuit. Notice that the electrolyte, potassium
hydroxide is unchanged with two atoms or units produced on both
sides of the chemical equation whether charging or discharging.
This is why you do not need to add more water to a nicad battery
which operates as a sealed reaction container. It regenerates
its electrolyte in both the charge and discharge cycles.
All of this is an ideal nicad cell. The real world of computers
and rechargeable batteries is not quite that simple. The first
SERIOUS item to consider is that all nicad cells and batteries
generate gas during both the charging, and to a lesser extent,
discharging cycle.
During recharging, oxygen gas is generated at the positive
electrode while hydrogen gas is produced at the negative
electrode. In other types of rechargeable cells, a standard lead
acid car battery for example, these gasses are usually released
into the atmosphere. The nicad cell does not have this luxury
since it must operate cleanly and with minimum release of gasses
or liquids. To minimize hydrogen gas release, nicad cells
usually have an oversized negative electrode which tends to
reabsorb hydrogen gas. In addition oxygen is recycled by
combining with metallic cadmium to produce cadmium oxide. So
called "fast-charging" nicad cells prevent gas buildup and
dissipate some of the heat generated during the quick charge
cycle by further enlarging the electrodes. Heat and gas buildup
is thus controlled and kept to tolerable limits in quick charge
nicads.
The first of several lessons which can be derived from this
technical discussion is that the buildup of hydrogen and oxygen
gas during the charging cycle is normally dissipated unless HIGH
recharging rates are attempted or unusually high temperatures
are produced. If the nicad cell is charged at abnormally high
rates the oxygen gas cannot dissipate and will EXPLOSIVELY
rupture the cell.
A safety system of sorts exists within the design structure of
most nicad cells via a pressure venting system - a plastic
diaphragm membrane at the top of the cell and small external
hole or "exhaust vent." In theory the system safely vents excess
pressure and then reseals. In practice the resealing is never
complete and the cell may continue to ooze caustic electrolyte
or worse the vent may not open soon enough and the cell may
simply explode. The vent is really designed for SEVERE charging
or discharging rates. In normal use it should NEVER activate; if
it does, the battery should be discarded. In cases of massive
overcharge or discharge the safety vent is usually too little
too late and a dangerous battery explosion takes place anyway.
During rapid discharge - short circuiting the nicad cell or
battery with a piece of wire, for example - gas buildup and heat
can be generated and a violent explosion can occur. Another
reason why nicads can explosively burst when short circuited and
forced to discharge quickly is that they have relatively low
"internal resistance" which allows them to dump their electrical
capacity quickly and with explosive force.
Common zinc carbon batteries have a much higher internal
resistance and when shorted may produce serious burns to your
fingers from melting wire but usually will not explode due to
sudden gas buildup. On the point of sudden nicad discharge by
short circuit you might be tempted to say that it would be highly
unlikely with a portable computer battery. Not so. Tales are
told of laptop computer batteries which have exploded when a
careless owner shoved several fully charged nicad batteries in a
travel case with a set of spare keys. If the keys accidentally
contact both the positive and negative poles of the nicad
simultaneously, a violent explosion reaction can occur!
Clearly nicads have some unusual features to be respected and
understood. Be careful with charged nicads and treat them as the
small "hand grenades" which they can become. Heat, sudden short
circuits and high rates of charging are the problem in this
area.
The correct operating temperature for discharging and recharging
nicads is from 65F to 85F, according to most manufacturers. High
and low ranges of from +32F to 115F are possible as upper and
lower limits if nicads MUST be used in extreme environments
although discharge and recharge efficiency may be adversely
affected - it may require more power to fully charge the battery,
charge may not be held for as long on the shelf after charging
and finally discharge may not produce a full three or four hour
computing session at these severe temperature ranges.
Electrically, individual nicad cells - the units which are
hooked together to produce the final battery - have a charged
voltage of 1.25 volts. Nominally this drops to 1.2 volts under
actual discharge use or "load" in the electrical device.
Individual cells are strung together in "series" with the
positive terminal of one cell touching the negative terminal of
the next cell in sequence to raise the voltage to that suitable
for the electrical device. Thus two cells hooked in "series" as
a battery produce 2 X 1.2 volts = 2.4 volts. Likewise, three
cells connected as a battery produce 3.6 volts. By the way,
ordinary flashlight batteries of the carbon zinc type have a
nominal voltage of 1.5 volts compared to the 1.2 volts of the
nicad cell.
Nicad batteries have an unusual and highly characteristic
discharge behavior which is best described as "a stable
discharge plateau then sudden voltage drop." Essentially a fully
charged nicad battery provides constant voltage and current
until near its exhaustion at which point the voltage SUDDENLY
DROPS and the cell is, for practical purposes, completely
discharged.
Compare this to standard carbon zinc and alkaline batteries
which gradually drop in voltage and amperage through the
discharge cycle of the battery. In use nicads tend to be stable,
then die suddenly at the end while conventional non-rechargeable
batteries slowly decay in voltage as their power is consumed.
One conclusion you might draw from this is that when your
portable computer beeps that the nicad battery voltage is
nearing exhaustion you literally have only moments of use left!
The good news is that nicads produce dependable power through
their discharge cycle which is highly desirable with digital
data and computer memory devices.
The "memory effect" of nicads is perhaps the most discussed and
misunderstood phenomenon associated with nicad cells and
batteries. An undesirable and somewhat unique characteristic of
nicad batteries that they can develop a "memory" which can
decrease either the capacity or voltage of the battery.
The first type of memory problem in nicads - voltage memory - is
caused by sustained charging over many days or months. This
memory effect can be accelerated by high ambient temperature
extreme duration of charge and high rate of charge. In effect
the battery is charged for such a long period of time or at such
a high rate or high temperature that the efficiency of the
chemical reaction is impaired and proper terminal voltage
readings are not achieved.
In the second, more common "memory capacity" problem, the nicad
loses the capability to deliver its full power capacity. One
cause of this peculiar memory problem is the FREQUENT PARTIAL
DISCHARGE of the battery - use for perhaps 30 minutes - and then
full recharge again. In effect the nicad battery "learns" that
only part of its capacity is used and over several cycles of
"partial depletion and then full recharge" that less then full
capacity is needed. It will then be unable to deliver a full
two or three hour standard discharge in normal use. Fortunately
memory effects are usually temporary and can be reversed.
The chemical basis for these two memory effects is not fully
understood, but may have to do with obscure oxidation reactions
which temporarily coat the internal electrodes of the battery
with thin layers of complex non-reactive chemical compounds
which can be removed by more fully "exercising" a nicad through a
complete charge/discharge cycle.
It is claimed by many manufacturers that this odd memory effect
of nicads has been largely eliminated due to modern
manufacturing methods. However to some degree this may in fact
be a result of newer charging systems and the relatively
complete discharge of nicad power by modern laptops. In effect
the batteries are charged and discharged in a more appropriate
manner by most laptop users so memory effects "appear" to be no
longer a problem.
Both memory problems - voltage memory and capacity memory - are
usually temporary and can be corrected by discharging the
battery to or very near its exhaustion point (optimum drawdown
voltage is about 1.0 to .9 volts for a standard 1.2 volt nicad)
and then recharging it to full capacity. Repeat this discharge-
recharge cycle from 2 to five times and frequently the nicad
will lose its memory for the "partial capacity" and again
provide a full 3 or 4 hours of use in most laptops. Actually,
frequent FULL discharge and recharge prolongs the life of a
nicad. The more you use them the longer they last!
Most folks who want to completely discharge laptop nicads simply
leave the computer on until it runs down. A much faster method is
to use the following batch file which continuously reads the
directory of a disk and writes the contents to a disk file.
The continuous disk access drains nicad power much faster. If
you are not familiar with batch files, read the batch file
tutorial elsewhere in this program. Here's the three line batch
file. To stop the batch file at any time press the control and
break keys simultaneously. When finished you may wish to erase
both the batch file and the small file named "test" which it
creates.
:start
dir>test
goto start
As an aside, the newer nickel-hydride batteries used in some
laptop and notebook computers do not seem to suffer from memory
effects. But these batteries are more expensive and not in
common use by most laptop manufacturers.
Nicads do eventually fail. And for various reasons. Temporary or
partial failure due to memory effects was discussed in the
previous paragraphs.
Permanent failure - usually between 3 to 5 years into the life
of a typical nicad can happen due to the growth of
characteristic "whiskers" of conducting chemical compounds which
effectively bridge the internal gap between the positive and
negative electrodes inside the battery. Effectively these small
contamination deposits gradually short circuit the battery
internally which leads to inability to charge or discharge. Some
clever electronic hobbyists build high current "surge" power
supplies which can burn open these internal deposits and reopen
the gap between positive and negative electrodes. A risky
practice at best - given the explosive reputation of nicads - but
"zapping" nicads in this manner has been documented as one way
to add life to an otherwise dying battery. A risky an usually
ill-advised attempt to salvage an otherwise dying battery.
A different permanent failure can result from premature loss of the
liquid electrolyte from the battery. High temperature and/or
high charging rates are usually the cause here. Quick-charge
batteries frequently fail due to this problem if their charging
circuits are not properly designed. If the top edge of the cell
which contains the fail safe pressure release valve has a
buildup of white corrosion powder this is probably the residue
ot the expelled electrolyte and the cell may be on its way to
failure and should be replaced. Note that you can only see this
corrosion buildup on the top of the SINGLE nicad cells which are
usually encased within a surrounding plastic battery housing.
The plastic housing may show little problem externally.
Generally, however, the average computer user should not attempt
to open the protective plastic case of the battery to examine
each cell. If the manufacturer seals several individual nicad
cells in a plastic battery container it is for GOOD reason and
your own personal safety. As a rule quick charge nicads do not
last as long a regular nicads due to heat build up during the
charging cycle.
So how long will a nicad battery last before complete failure
occurs? Manufacturers estimate LOW figures between 500 and 1,000
full charge and discharge cycles or about 3 to 5 five years, as
noted above. Some nicads have been known to approach 5,000 to
10,000 charge and discharge cycles before permanent failure.
Excessive quick charging, heat buildup, infrequent use and lack
of full charge all contribute to shortened nicad lifespan.
Charging and discharging mathematics...
Charging nicads is generally done automatically by a charging
circuit. Two practical pieces of advice: 1) if the battery
becomes VERY hot something could be wrong 2) if the manufacturer
tells you that the battery will be fully charged after a certain
length of time although it can be left charging longer you will
probably do the nicad a favor by removing it after full charge
is reached. Some clever nicad users simply attach an inexpensive
electrical timer - similar to those used to turn lights on and
off in the evening - directly to the nicad charger to prevent
overcharging.
Generally nicads have a proper charging rate which depends on
each manufacturers recommendation. For standard nicads which are
NOT quick charge types the proper slow or "trickle" charge rate
is determined by dividing the ampere hour capacity of the
battery by 10. For example if a nicad has a total capacity of 1
ampere hour, dividing this by ten (1/10) produces a correct
trickle charging rate of .1 amps or 100 milliamps. Quick-charge
nicads can accept a charge rapidly and the suggested charging
rate is determined by dividing the ampere hour capacity of the
battery by 3 rather than by 10. These figures represent the
trickle charge rate which theoretically means the nicad "could"
be safely left charging indefinitely without harm.
Higher efficiency chargers are designed not to simply trickle
charge nicads but start a discharged battery at a HIGH rate of
charge and then taper the charging current back quickly to the
safer "trickle" charge rate once full charge is reached. Usually
for regular nicads this "initial surge charge" can be as high as
the ampere hour capacity divided by 3. For quick charge nicads
this "initial surge charge" can be as high as the ampere hour
capacity divided by 1. Obviously these are very high charge
rates and are provided to discharged batteries and then
quickly discontinued once full charge is approached. Clearly a
charging circuit of this sophistication is expensive and may
even contain its own microprocessor to sense the discharge level
of the nicad and calculate the optimum charge rate, time and
trickle charge transition. Since we have previously discussed
the adverse affect of heat on nicads it is essential to note
that NICADS SHOULD BE CHARGED IN A COOL OR ROOM TEMPERATURE
location since they normally generate heat when charged. If you
minimize heat buildup - especially during the charging cycle -
you will prolong the useful life of your nicad battery.
Discharging a nicad - especially if you are trying to remove a
"memory" problem such as that discussed earlier does NOT mean
discharging a cell to zero volts. Usually the correct discharge
voltage is about 1.0 volts. This may seem odd when you consider
that the fully charged cell has a 1.2 volt reading, but in fact
at 1.0 volts a typical nicad cell has released about 90% to 95%
of its energy - another eccentric, but predictable behavior of
nicads given the rapid "voltage drop off" as they near the end
of their three or four hour life in a laptop computer.
Shelf life. While carbon zinc and alkaline batteries can hold
their charge for years, nicads lose their charge relatively
quickly. Although it varies, one quick rule of thumb is that a
typical fully charged nicad will lose roughly 25% to 35% of full
charge in one month. Then another 25% to 35% of THE CHARGE
REMAINING in the next month. And so on and so on. Thus if you
have several nicad batteries you want to charge for a trip you
will be taking in a month, it is probably better to charge ALL
OF THEM the final week just before the trip rather than the
month before. For want of a better phrase, this might be called
"shelf discharge" and is normal with all nicads and has to do
with slight electrical leakage and chemical compound decay
internally within a charged nicad which sits on a shelf. Cooling
or refrigerating the nicad (but NOT freezing) will slow this
"shelf discharge" since you are cooling and slowing the
breakdown reaction. In fact ALL batteries will last longer when
refrigerated until they are used. Simply store them in
individual sealed plastic bags (to minimize moisture
condensation) and place them in the refrigerator.
And so we conclude with a little summary....
1) Do exactly what the manufacturer suggests for both
discharging and recharging a nicad.
2) Keep temperatures - especially during charging - cool or at
normal room temperature.
3) Never short circuit a nicad intentionally or accidentally.
4) Try cycling a nicad through several COMPLETE discharge and
recharge cycles if it "appears" to be faulty an incapable of
operating your equipment for a normal three or four hour
operating period.
5) Remove nicads from charging circuits or discontinue charging
when full charge has been reached.
6) Watch for white flaky corrosion deposits on the upper edge of
the cell near the pressure vent this can mean impending cell
failure and electrolyte loss.
7) Dispose of permanently defective nicads properly - contact
the manufacturer for instructions since cadmium is a dangerous
toxic metal and has been banned from many dump sites. Try
calling your local city hall and ask who can answer a question
about cadmium metal waste disposal.
8) When the nicad battery power begins to drop near the end of a
discharge cycle it will drop VERY QUICKLY due to the rapid
characteristic dropoff of nicads. Prepare for laptop shutdown
quickly.
9) Cycle your nicads through a FULL DEEP discharge and FULL
COMPLETE recharge frequently - they will last LONGER before you
must dispose of them and deliver MORE power when used.
10) Infrequently used nicads should be charged and discharged at
least once or twice every two or three months to prolong their
usable lifetime before permanent failure.
11) If your nicads are stated by the manufacturer to be quick
charge type, you can probably prolong their life by slow or
trickle charging them (if your charger provides that option)
since you will minimize heat and gas buildup within the cell.
Just because they can be quick charged does not mean they MUST
be quick charged. Nicads last longer and deliver more power when
not driven to extremes of temperature or overcharging.
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LAPTOP RESOURCES VIA COMPUSERVE
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After a while you begin to wonder. Is there a single centralized
source for laptop and notebook computer information? Somewhere
you can ask questions, comparison shop among various portable
computer models, locate specialized laptop software and obtain
tips on travelling with portable computers? No problem. Try
CompuServe - a vast computer network accessible by computer,
telephone line and a modem. Before we highlight some selected
resources for portable computer users a little background
concerning the CompuServe service....
CompuServe. Telephone: 800/848-8199 or 800/8488990. 5000
Arlington Centre Blvd, Columbus, OH 43220. Claiming that more
than 800,000 members can use the service at any one time,
Compuserve is without doubt the most extensive online service in
existence. The vastness can be overwhelming with literally
hundreds of conferences including gardening, coin and stamp
collecting, legal research, music, games, foreign language
training, desktop publishing, travel planning, banking, ecology,
portable computers and more. Over 1,400 databases are contained
online and users can send and receive messages and software from
anywhere in the world.
Compuserve users can use an attractive basic monthly service
plan, costing $7.95 per month, which includes messaging, limited
but useful services such as Consumer Reports, News, Weather,
Encyclopedia, Peterson's College search and others. Additional
forums and advanced services are charged on a per minute connect
time basis with additional surcharges for advanced services.
Connect time rates for forum access and advanced services cost
about $6.30/hour at 300 baud, $12.80/hour at 1200 or 2400 baud
and $22.80/hour at 9600 baud. Depending on services accessed,
Online databases, such as the IQuest service of Compuserve
provide access to corporate financial data, full text magazine
articles, legal data, medical topics and more - although a
surcharge of between $2 to $100 per search on advanced database
searches can make Compuserve expensive but cost effective if
vital data is needed quickly. An online member directory and
national telephone and address database is also available.
A Compuserve starter kit is available from most retail software
stores ($39.95) or can be ordered from Compuserve via their toll
free telephone number. The starter kit includes a $25 credit for
online time which more than pays for the included software and
reference materials. Compuserve also publishes a richly detailed
monthly magazine for members which includes articles on travel,
research, shareware, forums of interest, shortcuts and news for
members which is well worth the price of basic subscription
services described above. Compuserve is owned by H&R Block
Company.
What is available on CompuServe for laptop and portable computer
owners? There is so much information it almost becomes a
necessity to organize the topic into three areas: forums, files
and services.
Let's start with forums. Containing both message areas and
specialized library areas where software files are located,
forums are the primary conduits of specialized information. All
can be quickly accessed using a GO command. For example GO
PALMTOP would quickly transport you to the palmtop computer
forum which contains information on devices such as the Sharp
Wizard, Casio BOSS, Psion and Poquet computers. Here is a brief
list of applicable CompuServe forums and their specialty areas
which laptop and portable computer owners should investigate.
The IBMHW forum, library 6, is an especially rich treasure
trove.
Laptop, portable and notebook computer interest areas
Forum name Focus/specialization
IMBHW IBM hardware forum, see library 6, small computers
PALMTOP Palmtop computers and personal organizers
TRAVSIG Travel special interest group
CEFORUM Consumer electronics and the mobile office
IBMNET Vendor forums for IBM related hardware/software
CLUB Computer club forums, small computers
IBMCOMM IBM communications forum
EUROPHONES Telephone access numbers (CompuServe) in Europe
IBMEURO IBM European users, travelling with laptops info
IBMFF IBM file finder, locate files you need
Specialized vendor and manufacturer forums...
APORTFOLIO Atari Portfolio forum
TOSHIBA All toshiba portable and laptop computers
ZENITH Zenith laptop and desktop computers
EPSON Epson printers and portable computers
HP Hewlitt Packard computers, printers
HAYFORUM Hayes modem forum
M100SIG Tandy model 100 notebook computer
CANON Canon portable computers and printers
PPIFORUM Practical Peripherals - miniature modems
PCVENA Vendor A forum, section 10, Northgate computer
PCVEND Vendors such as Dell computer
MALL Electronic shopping mall - merchants/vendors
Routine commands/helpful GO words and commands
BILLING Review your current charges
COMMAND List of commands for efficient use
RATES Fees and charges for various services
FEEDBACK Ask questions on ANY CompuServe topic
INDEX Locate a forum, service or topic
DIRECTORY Locate a person and his/her ID number
MAIL Check your mail, send messages, FAX, postal
QUICK Master list of GO words
LOGON Telephone access info and numbers
TOUR An informative guided tour of the service
QALOGON Commonly asked logon/logoff questions
NEW What's new this week on CompuServe
BYE Command to logoff, exit the service
The treasure trove of CompuServe software files of interest to
portable computer owners in almost overwhelming; one service
which helps you navigate through files bears mention: the IBM
File Finder (GO IBMFF). Using this speedy "search engine" you
can quickly locate selected software files by keyword, filename,
uploading author and other criteria.
CompuServe software files are associated with "keywords" which
help index them. For example a file on using laptops might
contain keywords such as "beginner, laptop, notebook, travel,
portable". Using the IBM File Finder you can ask for a listing
of all files containing the single word "laptop" or, for a more
precise search, BOTH the words "beginner" and "laptop".
The File Finder report will tell you the forum (e.g., IBMHW,)
library (e.g., Library 6, small computers) in which the selected
file resides as well as the filename. Now that you know the
details, simply jump to that forum (e.g., GO IBMHW), switch to
the library (e.g., DL command, then select library 6). Finally,
read a full description using the BROWSE command (e.g., BRO
filename). Quick and painless.
What types of files are available to laptop and portable
computer owners? A sampling....
AIRPRT.ARC (GO IBMHW, library 6) discusses airline travel
concerns and issues of laptop computing such as use of laptops
while airborne, airport security and X ray inspections.
PORTCS.TXT (GO IBMHW, library 6) discusses business situations,
mostly oil drilling and prospecting, where laptop computers
processed crucial business information and assisted in
investment decisions.
TRAVEL.INF (GO IBMHW, library 6) contains a clever assortment of
tips and accessories for the well-equipped laptop traveler.
BC3.COM (GO TOSHIBA, library 5) cursor utility which changes
shape from thin underscore line to large block shape for better
visibility.
3PARTY.ZIP (GO TOSHIBA, library 4) retailers who can supply
specialized memory, modems, cables and accessories for Toshiba
laptop computers.
LAPKEY.ZIP (GO ZENITH, library 5) a clever utility which lets
you redefine the cursor control keys (right/left/up/down arrows)
on your laptop.
PKL105.EXE (GO ZENITH, library 5) PKLITE allows laptop users
with limited disk drive space to compress COM and EXE files to
save space - yet files still uncompress and run programs
quickly.
LAPTOP.ARC (GO TOSHIBA, library 4) discussion of common laptop
questions and issues concerning mobile and cellular computing.
CLAP.ARC (GO IBMHW, library 6) cursor pulsing speed can be
altered for better visibility.
TOSHUT.ZIP (GO TOSHIBA, library 2) an assortment of utilities
for Toshiba laptops, many of which also work on other portable
computer models, which toggle displays, cursor size, report
system setup information and more.
GAS50.ZIP (GO TOSHIBA, library 2) clever "gas gauge" utility to
report nicad battery level for older laptops lacking this
feature.
BF171A.ZIP and BF171B.ZIP (GO ZENITH, library 4) Back and Forth
allows you to rapidly switch between several applications for
increased laptop productivity. Switch quickly from word
processor to notepad when the phone rings. Jump from spreadsheet
to database or other program when you need real productivity.
VIDTOG.EXE (GO IBMHW, library 6) switch between internal LCD
display and external monitor on Compaq SLT computers.
Beyond files, other services await you on CompuServe. If
computer research and cost comparisons are what you need, try
the following services. Most of these services have surcharges
and special connect time charges in addition to normal rates, so
check rates before you begin an extensive search....
The Computer Directory (GO COMPDIR) contains almost 10,000
manufacturers and 60,000 product listings. You can search by any
word or phrase such as product name or manufacturer name.
Likewise, the Computer Database Plus (GO COMPDB) contains
reviews of products from almost 150 computer magazines and
periodicals. You can search articles individually or in linked
groups.
InfoWorld Online (GO INFOWORLD) provides further research by
way of product reviews on selected hardware, manufacturers and
software.
Finally Consumer Reports provides general information and
ratings for many consumer items such as computers, cars, toys
and food (GO CONSUMER).
Tutorial finished. Have you registered PC-Learn to receive your
bonus disks? Registration is encouraged. Shareware works on the
honor system! Send $25 to Seattle Scientific Photography,
Department PCL6, PO Box 1506, Mercer Island, WA 98040. Latest
version of PC-Learn and two bonus disks shipped promptly!