As with most Battery pack tools, they are great when they are new, then the battery goes to crap and you have to buy a new one. And these battery packs are expensive and generally proprietary so each tool manufacturer needs a different battery type. The batteries also have a short life span and end up in the land fill. I have a couple ways to service these tools making your battery costs very low and the battery tools much more versatile. Not only is this a GREEN project, but it also keeps GREEN in your wallet.
The best parts of this are,
-The dead packs are modified, not the tool, so I can pop out My Modified pack and put in a regular battery if I need to get to a tight area where the cabled battery would be tough to work with.
-This battery has a much higher amperage than the standard battery packs. I find it lasts more than 5 times longer than the standard packs on a single charge.
- The actual life of this battery is longer than the regular battery packs.
-Cheaper and universal. One battery, several tools.
Step 1: SAFETY NOTE!
Always work safely with safety eyeglasses and gloves when working with these packs. A slip of a tool while prying could hurt you.
I took an old battery pack and opened it up. This one happened to be a 12Volt and it had screws holding it together. It was easy to open. Some packs are glued together and are much trickier to open, but it is still doable. There is some 2 sided tape usually holding the batteries into the bottom of the tray. Just pry them out. Basically we are removing the old dead batteries from the pack and replacing it with a cable that runs to an external standard GelCell Battery.
Now remove the wires connecting the batteries to the connector prongs. This prong assembly will be reused as well as the battery case. Becareful to not break or bend these connectors. They should slide out so you can resolder the new cable to it.
Step 4: Check Polarity
The polarity is usually marked on the top, but if not then it can be resolved later. The Connector you removed from inside will line up with these markings showing you where to connect your wires. Most of the tools will only use "+" and "-" for connections. The other connections are used for recarging of the old pack, which we will not use.
Step 5: Soldering the Wire
I found some old heavy gauge stranded lamp cord. I cut mine about 4 feet to have some extra room to move. But you can make yours as long or short as you wish.
The batteries will sometimes have 3 or 4 connectors on them, Try to find which pair work as the "+" & "-" terminals. There can be markings, or you may have to use electronic fundamental reasoning to figure it out. You can try to use temporary jumper clips to figure it out by hooking to a battery and to the tool terminals, trying different configurations until you get it right. Solder the cord to the two connectors that you determine are correct. Then I hot glue the cord to work as a stress relief if pulled.
Step 6: Insert the Connectors Back Into the Case
Once you are sure you connected to the proper terminals, put the connector in the case. I secure the connector in place with hot glue. Fill the end up good with glue. This will stop any movement of the connector inside the case. So you shoould end up with the connectors back in their original location with your new cable soldered to them.
I drilled a hole in the bottom to pass the cord through. I also tied a knot in the cable so it works as a stress relief in the bottom of the case, so that if the cable gets pulled hard, it wont tear at the connector you just soldered. You can put the hole in the bottom back end, for the cable to exit out of, as some tools stand up on the battery pack and my positioning will prevent this. I personally don't stand my tools up because they easily fall and break.
Step 8: Finished
Here I have two tools running off the same battery. Here is my 12 Volt Drill Adapter, and my Makita impact driver running off the same 12Volt battery.
For any tool guru, you may say "Hey that Makita impact tool is a 9.6Volt". I say, yes it is, and I use it with direct 12 volts and it works better than when new, and I have driven MANY MANY MANY screws with it, so I haven't found it to burn out. But if you are concerned, you can add in a High Wattage resistor in-line to lower the voltage. Or get fancy and build a regulator circuit that plugs onto the battery giving you several voltages to power different voltage tools.
The battery can be purchased from surplus stores for less than $10. And it gets charged with a standard car charger. These are regular no spill gel cells used in many different applications.
Step 9: Battery Belt
I also made a Belt strap harness that holds the battery so I can walk around with the tool in hand. This was a holster that holds those "Barcode Guns" you see people doing inventory with. It lets the battery slip right in and clips closed so it wont fall out. The battery wont leak so there is no possibility of spillage. It is not back holding it on your hip, but seems to be best located at the back like a fanny pack. Hope this is clear enough. Once you perform one, you will see how easy it really is, and if you are working with a dead pack, it will cost you nothing to try to save yourself lots of green.