How to Rebuild a Dewalt 14.4v Battery Pack

$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

wait

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!!

Comments

[andrea biffi]

I fear that soldering will heat batteries too much, it's surely harmful to li-ion cells, I'm not sure about other chemistry...

[35szabo]

Whats the best Flux and solder to use for this project

[auto13142828]

I have some Li-Ion Cells - Eve ICR18650 . Is there any way to use these?

[MartinV159]

Hi, I have a DW952 Drill/Driver, and his battery is DW9062 9.6V Ni-Cd and I open the battery for buy the replacement pack are 8 batteries but I don´t know what kind of battery cells pack replacement use it, Could you help me Where can I get the bateries pack remplacement and what kind to use please? my email is [e-mail] thank you for your great help

[digimancer]

Just a heads up, you can now get a 2 pack of NiMH knock offs on Amazon for around $30 which comes in way cheaper. Great instructable though!

[LegoSurvivor]

for step six just use a old 9v battery.

[jdawe2]

Just found this - THANK YOU! great idea. These darn batteries are hideously expensive. Also - found a decent price on replacement nicd's with tabs here at amazon:

https://www.amazon.com/dp/B01B182KQG?tag=amz-mkt-chr-us-20&ascsubtag=1ba00-01000-org00-def00-other-nomod-us000-pcomp-feature-scomp-wm-4

[Creamaster]

I haven't read through all these comments so apologies if I'm repeating someone.

I'm pretty sure you just destroyed every one of those new cells when you soldered them. You should always buy your batteries with the tabs soldered on - the extra expense is worth it. If you look closely you'll see the tabs get attached with a very small spot-weld or two to the battery cel. That's done with a machine that's very fast and doesn't heat the battery up. Your solder iron heats up the battery - even just as the solder and flux cool - that extra heat hurts the chemical makeup of the batteries and that shortens their life, if not destroying the battery right there and then.

Probably you took about half the life span off these batteries.

This would all be fine if you're stuck and had to have a battery pack work right now, but if you're trying to save money, do it right.

[Ch34pskate]

Where do you pick up the batteries with the tabs on them already. I have wasted ~$40 trying to solder directly to the battery. One started smoking. Had a bucket of water to drop it in but it bubbled for about five more minutes. And I only hade the soldering iron on the battery for no more that five seconds.

[Creamaster]

Any reputable battery shop should be able to make them for you. Yellow Pages? Is that still a thing?

At any rate, spot-welding is almost instant.

If you're game, here's a video on how to make a spot-welder from an old microwave: https://youtu.be/vrlvqib94xQ

[ksickafus]

i don't have a welder

and, this site is for the DIY peeps who have duct tape and a paper clip

so, you gotta go with what you have

but, I am sure you are right about the battery life

the batteries I found did not have tabs

plus the tabs need to be in specific angle for this thing to fold back into the holder

but, if you have tabs and a welder . . . go for it!

[geconi2o4]

Total novice here, if you just connected copper mesh between the battery tabs, could that work?....without adding too much resistance?

[garver brown]

Based on everything that was explained and then all the comments, If you figure $20.00 an hour for labor its then cheaper to buy a new battery pack. Also test the batteries usually there is only one bad one in the bunch of old batteries.

[Stonewall Craftworks]

How much do you get paid when you aren't working? I don't get paid anything, so doing things like this not only expand my mind and give me a sense of accomplishment, but also save money in the process. Also, this site is called Instructables, not buyables.

[shootermatic]

If i was to do this instructable i would'nt charge myself anything.

[SueD32]

I would rather pay myself $20 an hour than pay someone else to do something.

[DaveP80]

Would it work with 2200 mAH batteries instead of 1800?

[Ion-ChristopherD]

MY BAD - that should be 300 WATT not 30. 150 on low, 300 on high. Two stage trigger.

BY ALL MEANS BUY TABBED BATTERIES. And yes, soldering can shorten the life of one or more of those batteries.

[Ion-ChristopherD]

PROPER SOLDERING TECHNIQUE for batteries, 30 watt iron, flux paste, practice how to "tin" your parts before assembly - including the iron tip. Use a wet sponge to wipe the tip every time you solder, and fine garnet wet-dry sand paper to clean the tip every hour or so, and to prep the surface of things you want to solder. To tin, apply a spot of flux and make it boil, quickly feed some solder right at the junction (tip/part). The solder will spread into a thin, shiny film. Great! Lift the iron as soon as this occurs.

TIP for experts - cut about an inch of solder wire and use a needle nose pliar to roll it into a circle. Put that on top of the area you just tinned. Put your tinned wire braid on top of that. Now you won't need three hands. Proceed....

Now you put your tinned pieces together and hit them with the full 30 watts - they will melt the solder quickly. You SHOULD add a bit more solder from the roll (or see above(. Use a cheap holder - and you will be able to use two hands!

[ilz19]

great writeup. will give this a go.