I purchased this Ryobi drill about 18 months ago, it has been a real workhorse over all.
The batteries are Ni-Cad and do not last as long as I would have hoped.
I started searching Home supply stores and online only to find that replacements are rare to find and
expensive if you do find them. The following Instructable is how I chose to solve part of the issue.
Step 1: The Batteries and What They Contain.
So before I go into detail on the batteries themselves I want to talk briefly about why I decided on this project.
The Drill came with a set of 2 batteries and I figured if I could open one and rewire it I would be able to use it in a 12vdc outlet. The second one I plan to do a lithium re-pack and charge controller for it but that will be a different Instructable.
The batteries have 4 screws in the bottom. You will need a medium phillips head screw driver. BECAREFUL the screws have small heads and tend to be in tight. Use plenty of pressure into the head of the screw and turn slowly to break them free. With screws this deeply recessed if you were to strip a screw head you would be pretty much out of luck at getting the case open gracefully.
After you remove the screws the top and battery pack (attached) will come out with some care as to the depressable side locks that latch the drill head to the battery.
Upon removing the top and batteries clip the red and black wires as close to the battery connections as possible.
Every little bit of wire counts especially on the red (+) wire.
I took the circuit board out and found the drill head connector is permanently attached to the circuit board so do not bother with any of that as wiring direct to the red and black wires will put power straight to the drill. The circuit board contains a Ni-Cad charging circuit and a port to plug in a wall wart charger. Put a good drop of glue in the wall wart port so as to keep someone from plugging it in the wall :)
Step 2: How I Did the Re-wire
Not actually planning to do the project today, I had stopped at Harbor Freight and picked up a cigarette lighter plug adapter. (The type the make 2 sockets out of one).
I was going to cut the 2 outlets off for another project so this worked out good. I had a male plug in with no purpose until now. Since the plug has an internal removeable fuse I chose not to insert another one.
You will see I used #14 wire, its a bit overkill for this project but it was what was on hand at the time.
I drilled a hole the size of the wire I was going to use. BE CAREFUL NOT TO DRILL THROUGH THE SCREW HOLE CHANNELS!
I tied a knot in the cord and inserted it into the case. I then tied a knot on the other side. I'm sure that there are more tasteful ways to insert the wire but I'm about doing it safely on the cheap.
I stripped and tinned the wires. You could use twist wire nuts if you choose, your choice. The positive (+) red wire goes the other red wire and the Negative (-) black wire attaches to the other black wire.
I used shrink tubing that you can heat with a hair dryer or very carefully with a lighter from a distance. Heating will allow the tubing to shrink over the joint both for electrical insulation as well as some solder joint strength.
*** Black electrical tape will also work if wrapped around the joint.
You will see the pink lithium batteries in the picture. The batteries are a set of cells from my 5 hour Dell laptop battery that was getting older. It was down to 1.5 hours of storage so as a laptop battery it was dying fast, but for a drill battery it will work just fine. The lithium batteries when charged are about 12.65v dc so they will connect real well volt for volt. I will be building a 12v dc rechargeable power pack useable for several applications this will allow me to have a drill I can use most anywhere.
Step 3: Adding Ballast
The previous batteries added weight to the pack to keep the drill standing upright when it was set down.
With out the old batteries I had to find a ballast weight to help balance things out.
I wanted something environmentally safe, non conductive, heavy to some degree, and cheap.
After some thought I realized a baggie with some sugar and a zip tie would work well.
***** Salt, sand, and other substances might work as well, steer clear of metal as it is conductive and could short out the project if it gets wet. *****
I put some sugar in the bag and inserted the bag into the casing. I worked the sugar and bag into the openings then topped off the sugar so it just fits with the top on.
I zip stripped the bag and trimmed the extra bag portion. You could use a grocery bag, I chose to use a zip lock bag so you could see the contents better.
Use care in keeping the screw channels and cord knot out of the way of the sugar bag as you re-insert the top on to the bottom.
Screw it back together and you are done.
Questions? please post them in the comment section.