"Jim Yanik" wrote in message
...
"Robert Green" wrote in
:
"ransley" wrote in message
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.. On Mar 31, 6:22 pm, Anthona wrote:
I just purchased online from home depot an edger/trimmer...In the
specifications it said electric, nothing mentioned about batteries.
and i thought that was what i getting. It turned out it was cordless
with 18v ni-cad battery. Now from past experience, i have had bad
luck with those batteries...mostly through my ignorance of different
type of batteries..Recently i learned that Lithium batteries were the
better choice, if i was going for cordless. I went back to the site
and sure enough, the heading of the sale did say cordless. Now can
someone tell me how to maintain these batteries when not in use?
Obviously here in the new england area i won't be using it all year.
The manual says nothing about that.
Who made the trimmer, HD Ridgid brand has a lifetime warranty on even
batteries, but if its maybe B&D dont count on much the second year,
with HD I think you have 30 day return, for an edge trimmer I would
only use gas or 120v corded. Nicads are considered discharged just
when the unit slows, running a battery dead can ruin it, they also
need to be charged to their peak then charging must stop or you cook
the battery to a shorter life, so you need to know how to determine
your charger does it right.
Agree. B&D cordless tools have had the worst performing batteries
I've ever run into. The only exception was their cordless lawn mower
and those batteries lasted only because I completely disregarded their
instructions and did NOT leave it plugged in all the time.
The mower uses lead acid cells, which may be why it lasted, but the
trimmers, edgers, drills, vacuums and every other B&D nicad based
cordless device I have ever owned did not survive longer than one
season.
The drill packs always suffered the same failure mode. The centermost
battery in the back failed first because it overheated when charging
because it was in the center of a ring of other ni-cads and could not
dissipate the heat from charging as well as the outer batteries.
Any tool you buy today should either be NiMH or LiOn.
NiCad is old,
bad technology, subject to memory issues and premature death.
IF misused. Otherwise,they are fine."memory issues" has been debunked.
you can screw up NiMH just as easily as NiCd,if you don't charge them
right.
My drawer full of dead NiCad packs takes issues with your statement that
"memory issues" have been been debunked. They are just too sensitive to
charging issues and UNLIKE LiOn cells, often don't have limiting circuits in
their chargers. It's hard to know whether a NiCad tool comes with a
limiting charger from reading the box information. LiOn powered tools HAVE
to use a limiting charger or they will explode. That's one reason why LiOn
is the better choice.
Two more are that they completely surpass NiCad in power delivered per pound
of battery, imporant in a hand tool that you carry around, and secondly the
individual cells are much less likely to reverse polarity or go completely
dead and take other cells down with them. That may be entirely because LiOn
chargers detect overvoltage and overheating conditions, but whatever the
reason, they are far superior in terms of longevity.
I've had NiCads die (go to 0 volts) and become unchargeable just sitting in
a drawer. To be candid, I still have some NiCads bought at Lafayette
electronics (a clue to how old they are!) that will still take and hold a
charge, but far more of them just died in their sleep. Not the kind of
battery the OP wants, IMHO.
Also,
with LiOn cells, manufacturers HAVE to build in overcharging
protection. In the B&D devices I took apart, they charged as long as
they were kept plugged in and overcharged very easily. There was no
autoshutoff when charged circuitry.
probably due to cheapo slow chargers,that aren't regulated in any way.
Fast charger systems have sensors or smart ICs to monitor charge and shut
down when the pack is fully chargerd.
Great. How does the OP know which one he's gotten? It's a guessing game,
and the final determinant is monitoring the pack while charging or taking
the charger apart. Who wants to take the chance you've bought a unit with a
charger that has the capacity to kill you batteries if you forget to remove
them from the charger promptly.
With LiOn, you can be *almost* certain you're getting the charger you
describe. With NiCad, almost the reverse is true because you know the
manufacturer of the tool chose a cheaper power source to save money. It's
just as likely they chose a cheap charger to lower prices as well.
LiOn packs will explode if overcharged, so manufacturers put
temperature and other sensors in their charging circuits to prevent
overcharging. Sometimes, other things go wrong, though:
http://en.wikipedia.org/wiki/Lithium-ion_battery says:
"For example, approximately 10 million Sony batteries used in Dell,
Sony, Apple, Lenovo/IBM, Panasonic, Toshiba, Hitachi, Fujitsu and
Sharp laptops were recalled in 2006. The batteries were found to be
susceptible to internal contamination by metal particles. Under some
circumstances, these particles can pierce the separator, causing the
cell to short. The cell will begin to rapidly convert all of its
energy into heat. This creates an exothermic oxidizing reaction,
causing the temperature to a few hundred degrees Celsius in a fraction
of a second.[81] A chain reaction occurs when neighboring cells heat
up, and in some cases, causes the battery to ignite."
So, not ALL the kinks have been worked out with LiOn batteries, but
I'd still prefer them for the power-to-weight ration in any hand
powered tool with one exception.
All that said, I often still prefer to use devices that accept
standard battery sizes so I can buy and charge my own NiMH cells. Not
as convenient as built-in lithium ion batteries, but a certain class
of items, like cameras, MP3 players, etc. it's nice to be able to buy
batteries when away from a charger or carry ready spares.
Ok,the guy wanted to know how to maintain the NiCd pack he ALREADY HAS.
Are you SURE? That's not what I got from the post. I read that he expected
to get a corded unit and got a cordless NiCad instead. I also read that he
just bought the unit from HD, and they certainly allow refunds within a
reasonable time period. I further read that even the OP knows that LiOn
batteries are better.
Taking all those facts into consideration, I am advising him to run, not
walk, to HD and take the damn thing back because my experience is that NiCad
will not last long, especially with a crappy charger, and that within a year
or two, he will face the expense of replacing them, which for some (most?)
tools is a factory job costing more than a new tool.
It's best if you recharge before putting the item away;don't store NiCds
if
they are depleted.
Also,chargers that fast charge (1 hr or less)give better NiCd life.
IF you happen to have a slow (trickle) charger,use a timer to charge to
the
recommended full charge time and no more.it's probably best to remove the
pack from the charger when it's finished charging;some chargers will
discharge a pack left in it.
Great advice if someone wants a battery pack they have to shave in the
morning. (That's what some soldiers said about our rifles in 'Nam compared
to the lowly but much more reliable AK-47 used by our enemy.) If they want a
tool that's light and performs rings around NiCad powered ones, LiOn's the
only choice, far superior to even the best NiMH cells. I have a lot of
power hungry devices that use AA's but for the ones that use 12V's worth of
double AA's I've been switching over to LiOn cell packs and chargers because
they last twice as long as even the best NiMH but weigh far less.
One nice thing about Lithiums is that they keep a charge much longer in
storage. (but they cost more)
both NiCds and NiMH self-discharge in storage.
True, dat. But new NiMH's like the Sanyo Enerloop appear to maintain much
of their charge for a year. I haven't personally tested that claim - but I
just might to see if it's really true. A year long charge would make them
good enough for seasonal work. There's no NiCad battery I know of that will
hold a charge for much more than a few months.
NiMH's also don't have to be completely discharged to be recharged. Unless
you point me to a reputable site that says the NiCad memory issue is solved
and no one sells a memory-effect troubled NiCad, I am sticking with over 25
years of experience and research that says NiCads can't touch LiOn cells for
reliability, charge holding, immunity to charging errors and power to weight
ratio. Whenever a NiCad pack fails, I replace it with some other
technology. Sometimes, like on power drills, I cut apart the old pack and
attach a 12V gel cell. Not a convenient as a replacement, but far more
reliable and powerful than the NiCad based original.
There are a couple of brands of loose NiMH cells that have very low self-
discharge,like Kodak,but you don't find them built into packs.
Anyone with a little ingenuity can deal with that. The 100 LED superbright
flashlights I use have holders with two buttons on the end. I made a
charger out of some scrap plastic and a 4 NiMH wall-wart charger I got from
Allelectronics. I just slide the pack out and into the charging jig. I
prefer this system because I can replace problem cells easily. I've been
using 2500MAh Maha and Ultralast AA cells in those units, but I am thinking
of switching over to the Sanyo Enerloops if they hold a charge as long as
they claim.
My theory on flashlights is that they should light up every time you need
them. Used to use AA Alkalines, but there's a design flaw in the flashlight
that in its normal head down position, you can't tell whether the light is
on or off. I say "normal" because this a showerhead flashlight with a huge
head studded with 100 white LEDs. It's absolutely unmatched as a light
source for microphotography because it's virtually shadowless. I somewhat
solve the problem by putting little rubber bumpers on the face to hold the
light up a few mm's off the table top. That way enough light leaks out that
you can almost always see that you've left it on.
They're called "precharged NiMH". I don't know if they are offered in
other
than AA,AAA sizes yet.
The chemistry for NiMH is slowly improving because each year, new and better
batteries appear. Some manufacturers allege that their NiMH double AA cells
deliver 3000MAh , but I am skeptical. I'll be able to report more precisely
when my new LaCrosse LCD charger arrives that gives a readout on how many
milliamps a discharged battery absorbed, among other things.
http://www.thinkgeek.com/gadgets/travelpower/b7fd/
Oddly enough, this multiple featured charger comes with a NiCad
reconditioning mode to completely drain and recharge NiCads over multiple
cycles. That's a curious thing to add to a battery charger if NiCads don't
suffer from memory issues, but both their engineers and I could be wrong and
you right.
Just show me the $/URL. (-: It wouldn't be the first time that 25 years of
experience goes out the window with some new breathrough, but memory free
NiCads I think I would have heard of. Still, to be safe, I'll Topeka it .
.. . .
http://www.facilitiesnet.com/equipme...-Battery--3001
"The professional grade tools that use NiCad batteries make up a small
portion of the cordless power tool market, Fairchild says. "About 15 percent
of the market is upper-end tools and about half of those tools that use
NiCad batteries don't suffer from memory effect," he says."
So, I still stand by my belief that the batteries you find in specially
manufactured items for HD or WallyMart (translation: lowest bid) are not
going to be China's best and they are likely to perform badly if subject to
the typical (mis)use/charge cycle of a seasonal tool.
There are a lot of things to consider, but if the OP wanted corded
originally, I think he should return the unit and get a corded one. Edger
trimmers are easier to handle on a long cord than some other tools, like
hedge clippers or snow blowers. And a line power trimmer will run for a
long time after a NiCad powered unit is only good for one side of a short
walkway or less per charge.
--
Bobby G.