Rebuild DeWalt battery pack?

[KenTaylor]

Has anyone rebuilt, that is installed new cells in, a DeWalt or other power tool battery pack? Specifically I have a couple of 9.6v DW9062 packs for my drill which have seen better days.

TIA,

Ken

 

[bhds]

Take a look at this old thread of mine.

http://www.candlepowerforums.com/vb/showthread.php?t=93053

About half way down you'll see my comments relating to the dewalt batt pack

 

[Robstorch]

I had one of my 12 volt Dewalt Xr packs rebuilt by Batteries Plus for about $30 something dollars. check to see if your charger is one of the recalled ones. If so
you can get a new charger free that is better.

 

[MrAl]

Hello,

I rebuilt mine. It was a Ryobi drill pack. The original batteries went dead
really fast, with almost no use at all.

One problem is that when you solder the cells together the solder blob can
not be too large or the cells dont fit back into the batt pack case.
Since they use thin flat strips to connect when new, it's better to use two
or three strands of thinner wire than to use one heavy wire to connect cells,
because again the heavy wire will interfere with the length of the cell and might
not fit back into the case when all are soldered together.

 

[Eugene]

Don't solder the cells, the heat from soldering shortens their life. Order cells from somewhere like digikey or mouser who can spotweld the tabs on properly.
I've found that my old 9.6v batteries are not real cost effective to rebuild since I can buy the cells for about $25 and a new battery is about $30 so I'm just holding on to my old ones until they are not longer available in stores or I can bulk order the cells to get a price discount.

 

[MrAl]

Hi there,

Yes i forgot to mention to get the cells with tabs, not the plain cells, because
it's not good to solder directly to the ends of the batteries. Even though it can
be done, it's better to get the cells with the tabs as soldering the tabs is still
safer for the cells.
Another thing to do is put a piece of thick electrical tape under the lead on the
positive end of the cell to prevent it from being jammed into the metal case
through the normal case covering in case the pack is dropped. I did this with
all of my cells too as an extra measure.

 

[paulr]

Replacement 9.6V pack for my old Bosch drill is $75, bah. That's a 1300 mAH nicad pack, too. I will probably attempt a rebuild when the pack craps out but it's holding up so far, after 5+ years (but not that many charge cycles, I only use it occasionally).

 

[MrAl]

Hi there,

Yeah, 1300mAh is too low when you can get 2Ah or better sub C cells with tabs
these days.
The charger that came with my Ryobi was a piece of junk too, so i ended up
designing my own charger with built in daily self-discharge replenisher using
a PIC.

 

[vmv55]

I purchased 2400 mah NiCd sub c with tabs to do a little battery rebuild. I broke the tabs off the negative side and soldered the pos tab to the battery itself. I check and rechecked that my polarities were in order...A work of art, it tested fine, charged fine and again tested fine with a vom. I put it in my drill and tested, it was very peppy. I went to use a saw and smelled burning behind me. The battery was smoking while in the drill but at rest. I removed the battery from the drill which stopped the melting and when it cooled I opened the pack to inspect. The tabs were the source of the heat... can anyone shed some light on this? Is perhaps the batteries' factory tab 'too small a pipe' to carry the power? I am truly puzzled and would love to understand the error of my ways. Thanks in advance.

 

[MrAl]

Hi there vmv,

Well, there are a number of things that can cause this, the most common
would be that once the cells are inserted into the case some of the terminals
short out. Sometimes some insulation paper has to be inserted between cells.
Watch for a problem when the trigger is pulled in too, as it may push
against some cells (some models only).

See if you can take the cells out and connect with wires to see if the
problem still exists. If it goes away, then look for a short once the cells
are put into their final place in the drill body.

Another problem that comes uip some times is the negative of one cell
shorts to the negative of a previous cell in the series string of cells,
causing that previous cell to short out completely and that would get
very hot.

Just a thought, but does the problem stop when you stop running
the drill too?

Just to note, the tabs are usually fine for these apps.

 

[Darkpower]

I had considered rebuilding a Ryobi 18 volt pack. After pricing out sub-C cells it was cheaper to buy a new one. Home Depot sells the battery packs for $39.99 for two. The unfortune thing is that the NiCds just don't do well in power tool battery pack because of voltage depression or memory as many people call it. If the chargers had a discharge button it would help, but most of the time when I go to do a project I will top off the batteries and I never discharge them all the way. The result is they go bad after a year of two from being topped off and never fully discharged.

They just came out with the Lithium version which is backward compatible with the tools. It needs its own charger and the new charger also charges the NiCds packs. The Lithium batteries cost about $80 for a new pack which is 2400 mA 18 volts and they are hard to find, supposedly has half of the self-discharge and twice the capacity of the NiCds.

 

[SafetyBob]

I just checked prices and it looks like I save around 30 dollars for me to solder tabbed sub-c's from batteryjunction together for my Porter-Cable 19.2 battery pack.

The tennergy sub-c's seem to have long tabs that should be easier to solder together (I hope!!).

Bob E.

 

[izzy0855]

There's a great company called; Cordless Renovations that manufactures DeWalt battery-packs inserts that you can insert right into your existing DeWalt battery-pack case for about 1/3rd less then what you can buy it for new. Check them out: www.cordlessrenovations.com

 

[Eugene]

I had considered rebuilding a Ryobi 18 volt pack. After pricing out sub-C cells it was cheaper to buy a new one. Home Depot sells the battery packs for $39.99 for two. The unfortune thing is that the NiCds just don't do well in power tool battery pack because of voltage depression or memory as many people call it. If the chargers had a discharge button it would help, but most of the time when I go to do a project I will top off the batteries and I never discharge them all the way. The result is they go bad after a year of two from being topped off and never fully discharged.

They just came out with the Lithium version which is backward compatible with the tools. It needs its own charger and the new charger also charges the NiCds packs. The Lithium batteries cost about $80 for a new pack which is 2400 mA 18 volts and they are hard to find, supposedly has half of the self-discharge and twice the capacity of the NiCds.

Your short lifespan is due to them being from ryobi, if you put in the lowest quality cells then the packs are not going to last long. I got nine years use out of abusing Makita Nicads.

 

[Stevo#1]

My old DeWALT's lasted over 10 years and my newly rebuild packs cost less then 1/3rd the retail price and are stronger batteries. I got tabbed batteries but I pull the negative tab off and chain them all together soldering the positive tabs to the negative adjoining batteries. Yes I heat up the negative side of the battery so I may loose a couple of days of use, o'well I'll live. If someone will buy me a press Ill be glad to press the tabs instead.

I just rebuilt two of my DeWALT 14.4v batteries for $42 total instead of paying around $130 for new ones from a local retailer. In doing so I have made a guide and battery build template to help those that would like to do the same. Even though this is setup for a DeWALT 14.4 it could be used and modified for 18v & 12v batteries even from other manufactures. You might want to tweak the template for any other types of cordless batteries though. The masters are in Visio 2003 format which I've made PDF's from for those that don't have Visio. If your thinking of replacing or rebuilding your cordless battery(s) I think you'll find this of value.

Download Guide & Templates
http://rapidshare.de/files/46017771/DeWalt_14.4v_XR_BATTERY_REBUILD.rar.html

 

[LuxLuthor]

I've done it but used my battery pack welder to put back strips, no soldering.

 

[kitelights]

I've done it but used my battery pack welder to put back strips, no soldering.

I know you don't want to be self serving, but I wish you'd post more about the dangers of soldering. I cringe when I hear about soldering cells. You can't see inside and know if you've melted that membrane or not.

 

[65535]

Direct cell soldering has been done for many years, and there are a few simple common sense guide lines. In can be done 100% reliably and safely.

Common sense.

Get the area to be soldered to soldering temp as fast as possible to prevent heat damage to the cell.

Use an appropriately sized iron (read: wattage) with the largest available tip that doesn't interfere with your work area.

Use solder to transfer heat, the small amount of contact the tip makes doesn't transfer much heat, a small puddle of solder between the tip and part will transfer heat better and flow into the joint.

A 50watt iron with a large tip ~1/4" minimum is recommend up to sub-C cells. Large cells I would probably recommend a larger iron.


RC hobbieists have been doing this for many years, and with a little planning and know how there is nothing dangerous about it. I have personal experience as an RC car racer myself.

ETA: LuxLuthor (who I would like to consider a friend) is an excellent source of information and maintains an excellent personal stance on electronics. I do not believe he has anything against soldering cells but finds his small spot welder to produce excellent results in a fraction of the time and easier.

 

[LuxLuthor]

Direct sell soldering has been done for many years, and there are a few simple common sense guide lines. In can be done 100% reliably and safely.

Common sense.

Get the area to be soldered to soldering temp as fast as possible to prevent heat damage to the cell.

Use an appropriately sized iron (read: wattage) with the largest available tip that doesn't interfere with your work area.

Use solder to transfer heat, the small amount of contact the tip makes doesn't transfer much heat, a small puddle of solder between the tip and part will transfer heat better and flow into the joint.

A 50watt iron with a large tip ~1/4" minimum is recommend up to sub-C cells. Large cells I would probably recommend a larger iron.


RC hobbieists have been doing this for many years, and with a little planning and know how there is nothing dangerous about it. I have personal experience as an RC car racer myself.

ETA: LuxLuthor (who I would like to consider a friend) is an excellent source of information and maintains an excellent personal stance on electronics. I do not believe he has anything against soldering cells but finds his small spot welder to produce excellent results in a fraction of the time and easier.

Pretty much agree if you follow above guidelines, and because these are safe chemistry Lithium cells. One advantage with the spot welder besides being faster/easier is you can keep the (-) vent port free on these cells which solder easily flows into if you are not careful.

 

[coolhand]

I am in the process of an 18V rebuild. I noticed that there is what I believe to be a thermal switch on the battery, it is soldered onto the side of the center battery.

Has anyone hooked this up when rebuilding their pack? If so how do you solder to the side of the battery or could you also just connect it to the negative terminal and get the same result?