On Fri, 11 Dec 2015 00:09:14 -0500, "Percival P. Cassidy"
wrote:
have an 18V 2.4AH battery pack for Ryobi power tools that will no
longer take a charge and that the charger indicates is defective.
I totally agree with Clifford Heath. However, let me add a few
additional comments.
I don't have a spot-welder. If I use a Dremel cutting wheel to cut the
tabs on the defective pair, would it be OK to solder new ones in place
using copper flashing?
The cases on most 18650 cells are stainless steel. You won't be able
to solder to those. Copper flashing might make a connection, but at
the high currents involved, will probably give you intermittent
connections, corrosion, or heating problems. Spot weld or forget it.
You can buy 18650 cells with tabs that can be soldered:
https://www.google.com/#q=18650+with+tabs
I do something different, which might be of interest. Instead of
using 18650 cells, I use flat cells usually used in model airplanes,
cars, quadcopters, etc. Something like this:
http://www.hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?cwhl=US&idCategor y=86&v=&sortlist=P&LiPoConfig=5&CatSortOrder=asc
The listing are for 5 cell batteries (5S), west coast warehouse, and
sorted by ascending prices. If you're lucky, you can find a 5S
battery pile that will fit in your Ryobi battery box. If not, you can
bash a big hole in the battery pack and improvise.
Note that all the batteries have a "balance charger" connector. I
won't go into detail now, but basically this is the way you avoid
killing a battery pack. Each cell is monitored individually with no
risk of overcharging any of them if another cell is low voltage.
https://www.google.com/search?q=balance+charger
The technique is SLOOOOOWLY creeping into the power tool biz.
https://en.wikipedia.org/wiki/Battery_balancing
If you decide to go this route, bug me as there are a few other things
that you'll need (power connector/adapter, balance charger, etc).
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558