How To Fix Your Ni-Cad Makita,Dewalt and other Batteries for free including step by step video

Cordless Power Tool Batteries and other batteries that contain Nickel Cadmium (NiCd) Cells can be
Re-Conditioned to perform as well as new or even better than new.   Proper maintenance after the
procedure will insure years of usable life.

The First and most common procedure for Re-Conditioning a NiCd cell is by using a Technique
called “VOLTAGE SURGING”.  Over time the crystals within a NiCd cell begin to combine and get
larger.  This causes them to loose capacitance and also break through the inner seals of the cell.
Surging the NiCd cell using a higher voltage causes the crystals within the NiCd cell to shatter and
become smaller.  These smaller crystals have a greater surface area and therefore contain a greater
capacitance for energy.  Crystals primarily grow larger during “OVER CHARGING”.  Over Charging
is the enemy of a NiCd Cells so Remember to leave your batteries on the charger for only the
minimum charging time OR LESS!  This is usually an hour or less for Rapid Chargers or 2 to 4 hrs
for standard chargers.  It is also best to only charge your batteries immediately before you use them.
Storing your batteries with a full charge encourages crystal growth.  Storing your batteries on a low
charge , but not dead, is best.  To keep crystal growth under control, you must also perform the
surge process below once every 3 months to keep you NiCd battery at its peak.  Follow these
maintenance techniques to insure years of dependable use.

The “VOLTAGE SURGING” Technique below may be repeated until the battery holds a dependable
charge but wait at least 15 minutes between “SURGING” to allow for the vapors within the cell to
cool.  Surging the battery without waiting will result in the cell EXPLODING! Most batteries will only
require one or two “VOLTAGE SURGES” but extremely damaged cells may take up to 20 surges. For batteries up to 9.6 volts you will want to run two wires from a good 12 volt battery, such as a car
battery or two 6 volt lantern batteries run in series. use like size cells and not a combination. Clamp
the ground wire from the car battery to the negative side of the tool battery.  Small alligator clamps
work good for this application.  The positive terminal on the tool battery is usually golden in color
and the negative is usually silver in color.  Use a voltage meter to be sure.  One end of the positive
wire should be rigidly attached to the car battery and the other end of the positive wire should be
stripped at the end.  Then simply tap the stripped end of the positive wire against the positive
terminal on the tool battery for about 10 seconds tapping rapidly at a rate of 2 to 3 times per second.
See charts below for exact recommended “SURGE TIME” for your battery pack size and your
specific power source voltage. Check the voltage of the tool battery with a voltage tester and if it
does not give a voltage equal to or slightly higher than the tool batteries rated voltage, then repeat
these steps for a few more seconds until it does (waiting 15 minutes between surges).  See Fig. A.
For batteries of 9.7 volts to 19.9 volts you will need at least 24 volts.  Four 6 volt lantern batteries
run in series also works.  It is also possible to use other tool batteries wired together in series as a
power source, but if you are using two 18 volt tool batteries in series you will generate 36 volts and
10 seconds will be to long.  Shorten re-conditioning process to 6 or 7 seconds.  You can also use
2-18 volt tool batteries in series for re-conditioning 24 volt tool batteries.  Using other DC power
sources such as welders and battery chargers can also be used for the “VOLTAGE SURGING” but
small transformers won’t work because they don’t deliver enough amps.  Use lamp cord thickness
wire or larger and always use safety goggles!

STEP BY STEP INSTRUCTIONS1.)  Using a voltage tester, determine the polarity
of your battery (pos. & neg.)

2.)  Use Tables E, F & G  to determine the “Surge
Time” for your particular battery size and power

3.)  ’TapZap’ your battery for the suggested time
and allow to cool for 15 minutes.  Then place on
charger for 15 minutes.  It may work again.

4.)  After a short charging let the battery sit.
After sitting 1hour check the voltage to see if it
is slowly draining.  A slow drain will indicate a

5.)   If battery fails to charge, or hold a charge
then repeat steps 3 & 4.  This process can be
repeated up to 25 times.

NOTE:  Wiring batteries together in
series sounds dangerous because
directly  connecting a positive to a
negative usually is.  In the case of
DC batteries, this is not true.
Connecting the positive of one
battery to the negative actually
increases voltage (see fig.B).There is no risk of explosion when
properly connected.  This principle
can be seen in flashlights where
the batteries are also ran in series
where the positive of one battery is
butted to the negative of the next

The previous Re-Conditioning method
will work 90% of the time but
occasionally a battery will still not retain
its rated voltage.  For those of you who
are mechanically inclined, there is
another option.  Remove the battery cell
cluster as shown in Fig. C.  Test each
individual cell for voltage with a voltage
tester.  If an individual cell fails to
register at least one volt, that particular
cell will need to be Re-Conditioned.
There may be a fibrous insulator on top
and/or bottom of the cells that will need
to be drilled to reach the individual
cells, but do not drill into the battery
cells themselves!  NOTE:  Each cell will
have to be tested for Polarity (+ or -), the
cells are rotated so the positive end of
the cell on some will be facing up and
others will be facing down.  Once you
locate the bad cell(s) use a 12 volt car
battery to Re-Condition the individual
cell by holding the Negative wire to the
Negative side of the cell and then hold
the Positive wire to the Positive side of
the cell for 2 to 3 seconds, but no
longer.  Repeat this process for each
cell that doesn’t register at least on volt.
This process will work on 18v and 24v
batteries as well as lower voltages
because the individual cells are the
VersaPak BatteriesVersaPak batteries have three 1.2 volt cells
inside of them so they should register 3.6
volts.  If they are bad they will typically
register 0, 1.2 or 2.4 volts.  The VersaPak
batteries are very simple to Re-Condition.
Simply hold the negative wire from the
battery to the outside housing of the
battery which is its ground.  Then Rapidly
Tap the Positive wire to the inside of the
battery for 3 seconds but no more.   Repeat
after 15 minutes in necessary.   Its that

Note;  If your battery has more than two
terminals you only need to surge ANY two that
register voltage.  Manufactures put an extra
set of terminals on to improve connection but
they go to the same cells.  Be sure to
determine polarity (+& – ) because the surge
process will not work if performed backwards!
Another Method for Re-conditioning NiCd cells that is still in development is the Freeze Technique.
We are finding that some batteries that do not respond to the surging technique respond to the Freeze
Technique.  This is a simple procedure.  All you have to do is freeze your battery pack in the freezer for
1 hour and then rapidly tap the bottom of the battery pack with something like the but end of a
screwdriver for about a minute.  The freezing of the internal crystals makes them more fragile and the
vibration physically breaks them apart.  This is hard on the cells and should only be performed after
the surge process has failed.  After you have tapped on the battery pack immediately place the battery
back in your tool and turn it on.  It won’t work much because the pack is still frozen but putting a load
on the battery in this condition will encourage the internal crystal structure to break apart, which is
good!  Single cell batteries like A,AA,B,C and D batteries have been shown to respond well to this
technique using a hammer and giving the butt end of the battery a good solid hit, but not too hard as
to break the battery housing.
If you attempt to surge your batteries 20 times and then freeze your battery 5 times and you are still not
getting your battery to charge then you are either performing the process improperly or your batteries
are just too far gone.  One of the most common reasons for failure is improper polarity surging.  If you
surge the battery backwards this process will not work.
explode if over surged

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