" wrote in
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On Sat, 3 Apr 2010 16:51:08 -0400, "Robert Green"
wrote:

"Jim Yanik" wrote in message
. 44...
"Robert Green" wrote in
:

"ransley" wrote in message
.
com. .. 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.

then do your homework before buying.
The Internet is a powerful tool for researching a potential purchase.


LiOn powered tools HAVE to use a limiting charger or
they will explode. That's one reason why LiOn is the better choice.

Jim is right. There is no significant "memory effect" in NiCds, at
least there hasn't been for 30 years or so. There are all sorts of
ways to kill NiCds, but the "memory effect" isn't one of them. If
you're worried about chargers killing batteries (not anything to do
with the mythical "memory effect"), buy only tools that have a quick
charger. If you're really squeamish buy only tools with chargers that
shut themselves off after charge.

I wonder if Mr.Green knows what "memory effect" actually is.
It has to do with charge capacity.

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.

NOT relevant,as the OP already HAS a NiCD tool.
At best,a lesson for the NEXT purchase.

If you allow NiCds to reverse charge, yes, you are asking for trouble.
However, LiIons aren't without problems. They're expensive and have a
finite life. NiCds are a better choice for many tools. No battery
likes to be overheated. LiIon is no better.

I've had NiCads die (go to 0 volts) and become unchargeable just
sitting in a drawer.

Well,Yeah,that's the "self-discharge" thingy...

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.

Except the original poster SAID he HAS an item with NiCD,and also SAID he
wanted to know how to maintain them.
Sure,he didn't read the package to find out what he was buying,but that's
not the NiCD's fault.
Sure,he can probably return the item.But that's not "maintaining" them.

Those are probably all salvageable. NiCds tend to grow dendrites,
which are repairable (burn 'em out).

Not really "repairable". Sure,you can burn out the dendrites,but the
separator still has that puncture in it,and new dendrites will grow.

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?

READ the box? or research BEFORE buying.
Or ASK a knowledgeable clerk,if you can find one.

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.

What is there about "fast chargers" is difficult to figure out?



It requires READING and UNDERSTANDING.

--
Jim Yanik
jyanik
at
localnet
dot com