Bosch to Porter Cable 18V Battery Adapter





Introduction: Bosch to Porter Cable 18V Battery Adapter

This Instructable will show you how to assemble an adapter to use a Bosch 18V Lithium Ion battery on a Porter Cable power tool.

I have two Porter Cable power tools, a drill and an impact driver. When the original 18 volt NiCad battery packs fizzled out, I decided to look for Lithium batteries to replace them. The Porter Cable batteries are ridiculously expensive compared to the Bosch batteries. I could get two Bosch 18V Lithium 1.5 amp hour batteries for less ($60 delivered) than the cost of just one Porter Cable ($80). I ordered up two Bosch batteries, thinking I would simply adapt the cells into the original PC battery pack housing. When I looked at the interface differences between the two battery types, it seemed like a good little design/build project for CAD and 3D printing. The adapter was designed in Autodesk 123D Design. I'm going to work on redesigning in Fusion 360 when I have time. STL files area available for download.

Step 1: Start With the Original Battery Pack

You'll need to start by opening up the original battery pack to retrieve the plug interface (assembly) from the pack.

Step 2: This Is What You'll Need From the Original Pack

Once you have opened up the housing, clip the wires from the plug interface for use later on.

Step 3: The 3D Printed Parts

The parts must be printed out of ABS because they will be glued together later on. The lower section fits the Bosch battery. It has a 1mm recessed section that outlines where the upper section will be glued in place after soldering in the plug interface and electrical contacts for the Bosch battery. The latch is designed to be actuated by the spring loaded Bosch latch, through the upper section with the assistance of a light weight ball point pen spring to release the latch on the upper section where it interfaces with the Porter Cable tool.

Step 4: Preparing the Plug Assembly

The plug assembly is fitted in place as shown. Relieve the areas where the wires will need to be connected with a Dremel tool. View additional steps if this doesn't make sense.

Step 5: Battery Contacts - Solder and Assembly

Use standard spade connectors (14ga) and solder wire leads to the connectors. Thread the wires through the hols and use needle nose pliers to install the spade connectors as shown. The printed part should hole them securely enough to interface with the Bosch battery easily.

Step 6: Soldering the Plug Assembly in Place

Place the plug assembly in position to measure where to trim the wires to be soldered in the following steps. Remove the casing from the wires and bend them down so they are just above the lower section as shown in the second image. Tin/solder both the wires and the plug in the areas where the wires will be soldered.

The solder connections should allow the plug assembly to sit down flush on the lower section, once complete.

Step 7: Installing the Latch and Preparing for ABS Glue

Find a cheap ball point pen to steal the spring from it for use in the latch release mechanism. You may need to chase the hole first before installing the spring.

Step 8: Glue and Clamp

Use a small brush to wet the areas that will be fused together between the upper and lower sections. Use caution around the area of the latch to make sure you don't slop any glue into the channel where the latch will need to be free to move.

Drying time for ABS glue is pretty quick. You should be able to use the adapter as soon as an hour after gluing if kept at room temperature to dry. The glue is acetone based so keep in a well ventilated area for drying.

Enjoy your new adapter and inexpensive lithium battery pack!



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wow! this is incredible! great Job!


do you or anyone sells this adapter? if yes, how can i order it?


2 replies

No the adapter is a "you build it" instructable and is not available on the market. I'm sure if I tried to sell something like this, someone from either Bosch or Porter Cable would try to sue me.

:-), probably you are right. Thanks

What do I do with the small wires coming out of the cells? I also printed mine with PLA. Is there any other glue I can use besides crazy glue?

3 replies

Sorry I missed this and didn't reply in a timely manner. It looks like you got it worked out.

That's ok, it all worked out. Much lighter than the PC batteries. I was dreading having to buy replacement batteries or even worse, a whole new cordless tool kit.

Glad it's working for you. I just cranked through some 7/8 holes in steel with my drill and it powered through it no problem. It's nice to have the power of the lithium packs.

Good idea but I am not 100% sure but these Bosch batteries do no have
temperature or deep-discharge protection in them, you could damage these
batteries especially if you use then for "always on" application tools
or lights. Temperature should not be an issue with normal load. Deep
discharge should be done at 2.7 volt/cell, in this case 13.5V.

2 replies

I can say that I have had no issues since using the adapter with my circular saw.

I've had no issues with this set up. I believe you are correct about the temperature protection but I figure if the Bosch tools don't have any issues with it then neither will the PC tools. This has proven to be true over the past year as I have used the crap out of these tools since building these adapters.

I think it would be strong enough but the design was made to glue together using PVC glue so you would need to use something like super glue to bond the two pieces together.

Thanks Russ. Some of those are a little humorous but I have to give everyone credit for their ingenuity!

Congrats, replacement batteries are an overpriced revenue stream for manufacturers.

Thank Jason. That's a nice compliment coming from you. You're quite the hacker! I enjoyed looking through your work.