Introduction: How to Rebuild a Dewalt 14.4v Battery Pack

About: Karl Sickafus @ FB

$80 for a new battery pack.

$25 to build your own.

Plus bragging rights!!!

Step 1: Take Apart Battery Pack

remove the six screws that hold the pack together

carefully pull apart the two halves

take notes as to where things are and how they go back together

have a digital camera on hand for documenting dis-assembly

Step 2: Remove Battery "pack"

carefully pull the battery pack out of the holder

Step 3: Document Everything

as you pull the battery "pack" apart

take pictures and draw pictures of how the 12 batteries are packed and connected so tightly

Step 4: Buy Replacement Batteries

Google 1.2v subC batteries

(1.2 * 12 = 14.4)

find your best price for 12 batteries

when you place your order make sure you have measured your battery cells and are getting the correct "physical" size

buy with or without tabs

without tabs is less expensive and the following steps will show you how to make your own tabs

Step 5: Diagram the Connections

you will notice after folding and unfolding the string of batters

that the 12 batteries are wired in series pos-to-neg, neg-to-pos and so on

use the gummy insulator that you pried away from the top and bottom of the batteries to draw a template

then use a coin to complete the circles representing the batteries

draw a diagram looking at the batteries from the bottom

then draw a diagram of the batteries from the top

note each connection and how the battery tab is oriented

number the batteries on your diagram

while you are waiting on your new batteries to arrive in the mail

practice refolding the old battery string and placing it back into the holder

Step 6: Making Battery Tabs

the battery tabs, as you can see, need to be flexible

one very good source of material for making battery tabs is an old computer cable with an outer mesh

this is an old Firewire cable cut into small strips with the innards removed

the mesh can be squashed flat and take on solder very well

you will need eleven strips

cut extra just in case

put some flux on both ends and tin the ends with solder in preparation for soldering to your new batteries

Step 7: Preparing the New Batteries

when your new batteries arrive, flux and tin both ends with solder

use a small iron with a nice large flat head

do not hold the iron on the battery for more than a second or two


try it again until the solder melts and adheres to the battery

wear eye protection and use common sense

common sense says "overheat . . . and BOOM!"

take your time tinning the ends

one or two seconds at a time

flux is a must!!

Step 8: Build Your New Battery Pack

arrange your new batteries on one of your template drawings

solder your homemade battery tabs to the batteries following your diagram for the bottom view

slowly, not overheating the batteries

sice you have tinned both the battery and the tab, soldering will go quickly

once you have the tabs on by following your "bottom view" drawing

flip the batteries over

set them on the gummy insulator you saved

and put the whole bundle in the battery holder

now solder the remainder of your tabs following your "top view" drawing

the first battery in the string of batteries has a special connector that is spot welded in place

use an old wood chisel to pry it away from the old battery, it pops off easily

tin that connector with flux and solder and solder it to you last new battery

the bottom of this battery may need a longer battery tab to get to the next battery in series

and the wire coming from this special connector goes to the last battery in your series of batteries

if you saved the gummy insulator from your earlier steps, place it on top of the batteries

otherwise cut a new template from some sort of nonconducting material and put it in place

now reassemble the two halves of your battery housing and screw them together

having total confidence in yourself drop your new battery pack into the charger

a steady red light means everything is good and the battery is charging

wait 5 minutes and try your drill

if all is good give it a full charge

but just to be safe . . . keep an eye out for smoke

Step 9: Charge Your New Battery Pack

steady read light means all is good and the battery pack is charging

if you end up not calling the fire department

take yourself out for a beer

and brag about your experience!!