I have a Milwaukee power tool with 3 18v Power Plus Batteries (NiCad) that
are 4 years old. The batteries were working just fine and then all three
went bad at the same time. I did not know if it was my charger until I took
it into the dealer's shop. Apparently the charger will not charge the
batteries unless there is a small charge already in them for the charger to
kick on. Even the dealers special charger works this way and would not
charge the batteries. The shop technichian thought that if I could connect
one of my batteries to a good one with jumpers for a short period of time
that I could bring it up enough that the charger would detect it. I do not
have a good battery. The batteries have three connecters. Does anyone know
which connector is what? My thought was to hook up a bunch of 1.5 v
batteries in series to produce 18 v. and then connect it to one of my
batteries as a substitute to the techs suggestion of hooking it up to a good
Thanks for your assistance.
I've got some OLD 14.4 batteries that died but I still charge & use
them. Mt technique; put two 12 volt car batteries in series to get 24
volts, and put the 24vdc across the battery terminals +to+ & - to- for a
short time, maybe 10 seconds. Check battery voltage and if it isn't
over 14.4 (in my case) do it again for a longer time. When the battery
gets to FULL voltage put it on the charger and charge normally.
What I'm doing is zapping the batteries with a heavy current surge to
melt the dendrill crystals that are shorting some of the cells; with the
shorting crystals gone and a small charge on every cell it will charge
normally and hold a charge for a few days. It will eventually short out
again since there is a hole in the electrolite where the crystals were
and new crystals will form there as the charge disappears. Works well
for occasional use if you have an hour or 2 to prep the battery for use.
Just go get one or two replacement battery packs, and toss the old
ones in the "Ni-Cad Recycling" bin at the home store - they go bad
just from old age, and it isn't worth the hassle to constantly be
Get one pack for now, and keep your eyes open - around Christmas
they often sell two-packs of power tool batteries at deep discounted
prices. The DeWalt 18V XRP battery packs go from $75 each to "Two for
$99" for the big sales periods.
And it isn't worth the effort to build new cell packs from loose
cells unless the drill is obsolete and the battery packs are not
available new at a reasonable price - your time is money.
If they sell pre-clustered and welded replacement cell packs for
that particular drill battery pack, then it may be worth the effort to
open the pack case and solder the lead wires on.
And from now on don't let the battery packs set for long periods
between uses and NEVER let them set totally dead for very long - get
them into a battery charger the minute you get a chance.
Ni-Cad's will self discharge just from sitting around, and even
unused you have to charge them every month or two or they go bad.
As Nick says, once they sit dead they develop internal shorts, and
the end is inevitable. You can blow that short clear and get a few
more cycles out of the battery, but it won't last long.
The problen is that the chargers are built to recharge fast and if you
leave the batteries on them it will overcharge them and cook them.
Especially if you have a power glitch that restarts the charge cycle all
Only if the charger is defective or designed by the brain-dead. That
third terminal on the pack goes to a temperature sensor inside the
pack, it's supposed to signal the charger to cut the current if the
pack gets hot. Most multi-cell packs(and chargers) that cost more than
$20 are designed this way these days. If the sensor goes bad, the pack
can be cooked, I suppose, or just not activate the charger.
With any of these rechargeables, you're lucky to get 5 years use out of
them. If you use them heavily, you run up against the max number of
charges they can take, if you don't use them at all, they
self-discharge. The various technologies have different limits, but
they're all chemical systems and slowly turn to toxic junk over time,
used or not.
A problem arises when the battery is completely charged and there is a
power glitch. Cheap chargers will restart the charge cycle until the
battery gets hot again. This is not good.
Most multi-cell packs(and chargers) that cost more than
My problem is I seldom use the rechargable, but occasionally really need
it (on a farm). 5 years is too short a life for what they cost. I need
something that lasts longer to keep my cost per use down. Maybe someone
will come out with a supercap 'battery' that I can recharge quickly in
the field off my tractor battery so it's shorter in-use cycle is no
Why not turn an old drill motor battery into a conector with a wire
coming out of it a couple alligator clips on the end and you have a 12
volt corded drill that will last a long time betwen charges. Thinking
about it I'd use pigtails with a plug on the drill battery pigtail and
a receptical on the tractor battery pigtail. Then I could use extension
cords to get the length I need.
Nick Hull wrote:
I'm waiting with bated breath for the new Lithium-Iron Phosphate
batteries to hit the general-use market. Shoprider uses them on their
Scootie(TM) power chair right now. The batteries' producers are starting
to make noises about entering other markets.
These batteries seem to be outperforming most other technologies in
Amp-hour capacity for unit size, durability, and recharge time and
cycles. The last I read on them claims 1/3 to 1/4 size for a given
Amp-hour capacity, up to five years service life, and up to 5000 charge
cycles at only 2 hours per charge.
The typical sealed lead acid or gel electrolyte wheelchair batteries
last anywhere from 1-3 years, with some exceptions, usually last through
about 500 charge cycles, and take up to 12 hours to recharge.
Apparently the iron phosphate formula allows this type of Li batteries
to tolerate far higher current draw than other Li-ion technologies, most
of which don't allow discharge at much more than fractional Amp draws.
The chemistry allowed them to choose a great marketing name for them
too: LiFe Batteries.
Of course, they cost 4 times as much as lead-acid right now, but that
will change with widespread use, if there ever is widespread use.
I notice my rechargable shaver does not have these problems. IT stays
on the charger forever and does not get cooked and lasts a lot longer
than 5 years. I need to find a drill with this technology; I don't need
fast recharge and I don't need extreme endurance, but it sure would be
nice to have a cordless availiable when I need it for small jobs.
Mm, - Gunner (who posted on this) is Basically Correct. And I will
offer the following comment based on working with the things (ie, Ni
1. You need a multimeter to check the polarity - even a $5 el cheapo
digital one will do. Useful thing to have in your toolbox, anyway.
2. Once youve worked out the pos and neg on the packs, use jumper
leads to connect to your 12 car battery - BUT put a tail light globe
in series with it - this will limit any peak current and not destroy
things. A few minutes is all it needs - the globe should intitially
glow brightly, then dim. It does not matter that the car battery is
12v and your packs are 14v, you only want to kick enough charge into
the things to get your pack charger to recognise them.....
3. Once you can get a charge into them, then see how long they last
under load - yes, NICADS do die with useage as described in others
posts, BUT you get what you pay for - the reason (one of em) that
Dewalt tools are expensive is they use GOOD QUALITY Nicads in their
packs. The elcheapo Chines ones dont, and consequently have a short
life. Add to this, the Dewalt chargers are more sophisticated (again,
you get what you pay for) and so get the most life out of the barttery
4. If the battery packs are stuffed, get them rebuilt. Cheaper than
buying new ones, and the Dewalt drills etc are worth keeping on the
road. Would like to have them here, but cant justify the cost to the
Ministry of Domestic Affairs.....
Have fixed a few Dewalt "Builders Boom Boxes" now (the building site
radios with the chargers in them) - a nice unit, designed by someone
who realised that it would, someday, need to be fixed and so made them
fixable by human hands. Wish more things were built like that.....
And even buying premium Japanes NICADS, the packs were worth rebuilding
- a mechanical process more than an electrical one....
Bugger. Brain wasnt working on the last post - somehow, thought it was
a Dewalt. My comments stand re testing etc, but rebuilding battery
packs MIGHT be dubious if its a cheap import drill. (Remember when
brand names meant something, and were a guide to quality...)
You should be able to locate a battery supplier that will spot weld new
cells together, in the correct configuration that fits into your
Some battery suppliers will offer a choice of battery grades and
There are several sources of high quality cells for use in power tools
(and other specific uses), although high quality cells are fairly
expensive. The best cells, as far as I know, are produced by
manufacturers in Japan.. Panasonic and Sanyo, for example.
Higher quality tools generally include good chargers and
appropriately-rated cells in the original battery packs. Replacement
packs from other sources might be filled with cheap under-rated cells.
If you examine the Panasonic cell's specifications, you'll discover
that there are cells that are specifically designed/rated to be capable
of being left on charge continuously, fast charging, ultra-fast
charging, rapid discharge, and other types of uses/parameters.
The shop tech should've suggested that your cells were probably dead
from non-use or end-of-life. If he was offering opinions, he should've
been able to analyze the battery packs to confirm if they were dead or
Neglected cells will die from internal shorts. Neglect is probably the
greatest contributor to early battery death. Since they self-discharge,
it is neccessary to remember to apply refresh charges periodically.
Packs that are used until they're near-dead, then not charged, will
most likely not charge.
Chargers vary a lot in design, and cheap chargers will often contribute
to short battery life. Using a simple lamp/appliance timer with
chargers (cheap or well-designed types), will prevent overcharging and
unwanted restarts of charging cycles.
Many power tool packs can be opened by removing screws, or glued cases
can be cracked along the glue line by exerting pressure at the seams
(at a certain point, the glue snaps free).
The separate cells can be checked with a voltmeter and ohm meter. Cells
that show 0.0V will likely measure 0 ohms, indicating shorted cells.
The practicality of zapping shorted cells will vary, but if the user's
livelyhood depends on his power tools, it would be a good decision to
replace the batteries completely with fresh new cells, or fresh new
The practice of zapping new or used cells, includes discharging a
voltage surge from a large capacitor.
I would not recommend connecting any batteries to a high current source
such as car batteries, if the condition of the cells is unknown. Cells
can explode, and used cells can have faults that would increase the
likelyhood of injury.
A friend experienced a new nimh cell expolsion a few weeks ago (using
the correct charger). Charger parts and one cell were scattered
throughout the room, although no one was in the room at the time.
Battery packs often include several other components besides battery
cells. It's common to include a self-resetting thermal limit switch,
but some packs include circuits for other purposes.
If rebuilding battery packs is favorable, it would be best to choose
quality cells, with fresh date codes to insure that you're not getting
old stock. I've seen some online suppliers that will assure that their
stock is fresh. Some suppliers offer free welding of custom
configurations to fit battery packs.
Tom Haught> I have a Milwaukee power tool with 3 18v Power Plus Batteries (NiCad) that
All the suggestions about re-building the batteries?
Check out eBay. You should be able to pick up a Pair of those
batteries, for under $100. Including shipping. That is the 18V
Milwaukee battery packs.
They are buying them for about $40 each, and re-selling them on eBay.
Oh, in bulk from Amazon.com
Now The secret is out.
What's that Lassie? You say that Tom Haughton fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Sun, 24 Sep 2006 23:33:01 -0700:
you can get the packs 're-celled' at