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

"Jim Yanik" wrote in message
4...
"Robert Green" wrote in
:

"ransley" wrote in message
.
.. 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.

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.

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.

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. 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.

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

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.

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