Most of my tools are cordless Black and Deckers, using 20v lithium batteries.
But there was one drill that wasn't a part of the lithium family.
It is a pain to charge different batteries using different chargers...
So I've decided to make ALL of my tools universal.
Here's a tutorial on how to convert an old 18v battery to accept a new 20v lithium one...
And a Link to a Video File...
Step 1: Mark (+) and (-) Terminals and Gut Out an 18v Battery Pack
Old 18v battery has only 2 terminals, (+) and (-). Use a multi-meter to find out which one is which.Set it to measure Voltage and touch contacts with the alligator clips. If the number on the screen is Negative (-), reverse the clips. If the number is Positive (+), you've got correct terminals. Red one will be (+) and the black one (-). Mark THEM.
Disassemble battery by removing 6 screws (used my favorite Winchester multi-tool) and gut it out by removing everything that's inside (mainly a bunch of ni-cd batteries). Leave only an 18ga wire that is connected to a + terminal and a metal plate that is connected to a - terminal. Keep plastic divider, you will need it later as well.
Step 2: Cutting, Chiseling and Filing (most Time Consuming Step)...
In this step, we're working with the bottom part of the old battery pack. I took dimensions off of 20v tools and 20v battery itself and marked areas to be cut onto the old 18v battery case(new 20v lithium battery will be inserted here).
Using a junior hacksaw blade and a chisel, I was able to make rough cuts. File was used to make cuts smoother. Pliers were used (and some cuss words as well) to twist and break some plastic parts.
Finally, new 20v battery securely clicked into the custom made opening. Onto the next step...
Step 3: Soldering, Gluing and Testing...
To secure old battery's terminals in place, I've cut a hole for (+) terminal 18ga wire and a slot for a (-) terminals using a push drill into a plastic divider you've kept from Step 1. Pull both terminals thru their designated slots and using JB Weld epoxy glue, attach the above mentioned divider into the Top battery part, sanding it beforehand (and the divider for better adhesion). While it dries, cut a wooden block using a handsaw to fit flush with the 20v battery (as seen in the first picture). Secure wooden block with 2 construction screws (1in is fine) thru the sides. Also, as seen in the picture, mark the terminal locations on the wooden block. As for terminals themselves, I've cut them from a curtain rod brackets - perfect 90 degree angle and it already had a hole!!! Chiseled down a bed for those terminals on the wooden block and secured them with a single screw.
Then i needed to extend the wires and solder them to corresponding terminals. I've used a 18ga wire extender to add extra length to a positive (+) terminal and soldered it to the other end of the (+) terminal on the wooden block. Same thing for (-) terminal. Soldered 16ga yellow wire to a metal bracket on the battery and the other end to a (-) terminal on the wooden block.
At this point, it will be a good idea to use your multi-meter to check for continuity of your wires. Meaning you need to make sure that + is + and - is -. Mine was good!
After chiseling down terminal beds, I broke my wooden block in half and was too lazy to cut out a new one, so I've used some EXTRA epoxy glue to secure it to the plastic casing. It wouldn't move a millimeter!!!
Assemble old battery casing back, insert a 20v lithium battery into it and TEST it!!! It worked like a charm!!! You can tell how excited i was from watching the video!!!
P.S. I hope you've enjoyed my tutorial. It took me about 2 weeks to complete it, mostly because I work full time and am quite busy. I worked on it mostly after hours. If you do have any questions, do not hesitate to message me!