Salvaging 18 v. battery

[Pintlar]

I have two DeWalt 18 volt XRP batteries that are shot. They will charge but
only run for a minute or two.
Is there some way I can identify the best batteries from those two units and
make a single unit from those.? Should I charge first and then refrigerate
or some type of regime like that? After a charge should I monitor the
voltage (1.2 v. I imagine) and see which ones voltage drop first? Should I
put a load (how much?) accross each one and then find the weak sisters?
Sure would appreciate some insight on this as they are expensive as heck and
I have 3 tools that use the 18 v. XRP.

 

[Charles]

"Pintlar" wrote in message
news:19338$4d6d7f51$459201aa$2304@news.sonic-news.com...

I have two DeWalt 18 volt XRP batteries that are shot. They will charge but
only run for a minute or two.
Is there some way I can identify the best batteries from those two units and
make a single unit from those.? Should I charge first and then refrigerate
or some type of regime like that? After a charge should I monitor the
voltage (1.2 v. I imagine) and see which ones voltage drop first? Should I
put a load (how much?) accross each one and then find the weak sisters?
Sure would appreciate some insight on this as they are expensive as heck and
I have 3 tools that use the 18 v. XRP.

Ni-Cads are terrible batteries. I feel for you as I have faced similar
issues. You can sometimes de-construct them and re-build them with fresh
cells, but mostly not. There are some safety issues as well. Bite the
bullet and replace them.

 

[krw@att.bizzzzzzzzzzzz]

On Tue, 1 Mar 2011 18:30:07 -0500, "Charles" <charlesschuler@comcast.net>
wrote:

"Pintlar" wrote in message
news:19338$4d6d7f51$459201aa$2304@news.sonic-news.com...

I have two DeWalt 18 volt XRP batteries that are shot. They will charge but
only run for a minute or two.
Is there some way I can identify the best batteries from those two units and
make a single unit from those.? Should I charge first and then refrigerate
or some type of regime like that? After a charge should I monitor the
voltage (1.2 v. I imagine) and see which ones voltage drop first? Should I
put a load (how much?) accross each one and then find the weak sisters?
Sure would appreciate some insight on this as they are expensive as heck and
I have 3 tools that use the 18 v. XRP.

Ni-Cads are terrible batteries. I feel for you as I have faced similar
issues. You can sometimes de-construct them and re-build them with fresh
cells, but mostly not. There are some safety issues as well. Bite the
bullet and replace them.

Utter nonsense.

 

[Jeff Johnson]

"Pintlar" <footboarder@bresnan.net> wrote in message
news:19338$4d6d7f51$459201aa$2304@news.sonic-news.com...

I have two DeWalt 18 volt XRP batteries that are shot. They will charge
but only run for a minute or two.
Is there some way I can identify the best batteries from those two units
and make a single unit from those.? Should I charge first and then
refrigerate or some type of regime like that? After a charge should I
monitor the voltage (1.2 v. I imagine) and see which ones voltage drop
first? Should I put a load (how much?) accross each one and then find the
weak sisters?
Sure would appreciate some insight on this as they are expensive as heck
and I have 3 tools that use the 18 v. XRP.

http://www.instructables.com/id/Revive-Nicad-Batteries-by-Zapping-with-a-Welder/

 

[George Herold]

On Mar 1, 6:20 pm, "Pintlar" <footboar...@bresnan.net> wrote:

I have two DeWalt 18 volt XRP batteries that are shot. They will charge but
only run for a minute or two.
Is there some way I can identify the best batteries from those two units and
make a single unit from those.? Should I charge first and then refrigerate
or some type of regime like that? After a charge should I monitor the
voltage (1.2 v. I imagine) and see which ones voltage drop first? Should I
put a load (how much?) accross each one and then find the weak sisters?
Sure would appreciate some insight on this as they are expensive as heck and
I have 3 tools that use the 18 v. XRP.

Pull 'em apart and test each cell. You've then got to re-connect the
good ones.. get out the Weller soldering gun. But be careful, you can
short them out, (the negative tab folds all the way round to the
top.) And it might be hard to get them into the original
package....

Before there were LED head lamps, I had this stack of NiCad's I'd
rescued from a few lawn mower 'starter packs' made in the early 60's
perhaps. While a grad student I'd charge 'em up and take them to the
lab with me. Then on the bus ride home in the dark, I'd switch on a
little incandesent bulb and read. (I seemed to always be on the last
bus of the night, else I'd just sleep in the lab.... Ahh those were
the days... :^)

George H.

 

[Michael A. Terrell]

"krw@att.bizzzzzzzzzzzz" wrote:

On Tue, 1 Mar 2011 18:30:07 -0500, "Charles" ?charlesschuler@comcast.net?
wrote:

?
?
?"Pintlar" wrote in message
?news:19338$4d6d7f51$459201aa$2304@news.sonic-news.com...
?
?I have two DeWalt 18 volt XRP batteries that are shot. They will charge but
?only run for a minute or two.
?Is there some way I can identify the best batteries from those two units and
?make a single unit from those.? Should I charge first and then refrigerate
?or some type of regime like that? After a charge should I monitor the
?voltage (1.2 v. I imagine) and see which ones voltage drop first? Should I
?put a load (how much?) accross each one and then find the weak sisters?
?Sure would appreciate some insight on this as they are expensive as heck and
?I have 3 tools that use the 18 v. XRP.
?
?Ni-Cads are terrible batteries. I feel for you as I have faced similar
?issues. You can sometimes de-construct them and re-build them with fresh
?cells, but mostly not. There are some safety issues as well. Bite the
?bullet and replace them.

Utter nonsense.

No kidding. The DeWalt 18 volt XRP battery comes in four models in
either Nickel Cadmium or Lithium Ion and 'Charles' has no way of knowing
which of the four the OP has.

"The 18-volt models of Dewalt rechargeable batteries are designed to
different weights. Their 18-volt nickel cadmium batteries are generally
heavier than their 18-volt lithium ion counterparts. The lithium ion XRP
battery weighs 1.5 lbs., while the Compact lithium ion battery weighs 1
pound. The nickel cadmium XRP battery weighs 2.4 lbs., and the nickel
cadmium Compact battery weighs 1.7 lbs."

http://www.dewalt.com/tool-categories/cordless-batteries.aspx is
Dewalt's replacement batteries. There are five 18 volt, and four of
those are listed for the XRP series.

If the OP has one of the Nickel Cadmium versions, there are sets of
replacement cells on Ebay for about $40. They are probably higher AH
rating than the original, as well.


<http://cgi.ebay.com/REBUILD-DEWALT18-V-DW9096-DC9096-XRP-XR-BATTERY-/200576493831?pt=US_Batteries&hash=item2eb34a6907>


--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.

 

[Tim Wescott]

On 03/01/2011 03:20 PM, Pintlar wrote:

I have two DeWalt 18 volt XRP batteries that are shot. They will charge but
only run for a minute or two.
Is there some way I can identify the best batteries from those two units and
make a single unit from those.? Should I charge first and then refrigerate
or some type of regime like that? After a charge should I monitor the
voltage (1.2 v. I imagine) and see which ones voltage drop first? Should I
put a load (how much?) accross each one and then find the weak sisters?
Sure would appreciate some insight on this as they are expensive as heck and
I have 3 tools that use the 18 v. XRP.


Do you have an idea of how much current the tools draw? You probably

want to draw at least 10% of that, and poke around with a voltmeter
looking for your 'weak sisters' (I like that phrase).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

On Mar 1, 3:20 pm, "Pintlar" <footboar...@bresnan.net> wrote:

I have two DeWalt 18 volt XRP batteries that are shot. They will charge but
only run for a minute or two.
Is there some way I can identify the best batteries from those two units and
make a single unit from those.? Should I charge first and then refrigerate
or some type of regime like that? After a charge should I monitor the
voltage (1.2 v. I imagine) and see which ones voltage drop first? Should I
put a load (how much?) accross each one and then find the weak sisters?
Sure would appreciate some insight on this as they are expensive as heck and
I have 3 tools that use the 18 v. XRP.

The ultimate bad thing for nicads is to reverse polarize them. You
probably do what most folks do and use the pack until it totally dead.
One of the 14 cells was dead before the others and it reversed as the
other cells supplied current. When it starts to slow down stop and
change the pack and leave it discharged until you really need it. When
you notice it running a little slower, pop the other dead pack in the
changer. It's _good_ to run them down but the only way to do it
reliably is to let them self discharge. I learned this 'trick' from
the RC modeling guys as they used to do lots of nicads. I had to toss
my 12 year old Bosch because the chuck broke. The original nicad packs
were still going strong.

G˛