This is a battery pack for those cheap drills that were produced around 2003 - 2015. Einhell, Defort, Ferm, Challenge, Amtech, ProUser, Speedway, Workzone, Power-G, Boston, Draper, XU1, Trades Pro and Top Craft (maybe Mastercraft) made (or relabeled) them. You can find pictures of those drills on the page of the original design.
This is a rework of my first cheap drill battery.
After printing and testing my first battery, I found it was a bit heavy and the parallel setup was too much for my drills. It can run forever without needing a recharge. I decided more voltage (4.2 x 5 = ~20)) from five 18650 cells and no cells in parallel would be better.
So this new thing is just that. Room for 5 cells and the same fitting on top. It uses the space more efficiently, is a lot smaller and provides more angry pixies to the drill.
I noticed my design will support 6 cells as well. (that was not intentional). I already tried it and my drills seem to be ok with 6 cells, but still, better safe than sorry. 25,2V is a lot of juice for chintzy drills like these.
My software reports a print time of 3h35m. I do print with optimized settings for speed and strength. Quality is less of an issue with this sort of thing.
This pack is a bit different from the previous one. You will have to solder the 18650 in series. My previous pack was made with contacts and stuff, mainly because I didn't want to solder my good 18650's without knowing if it would actually work. Now, a year later, I know it works very well, so soldering up a pack isn't a concern any more.
Make sure you use 18650 cells that have enough power. They should be able to deliver the amps your drill needs without overheating.
Solder five 18650 up in series. Use at least 16 Amp gauge wire. Tape the cells or glue them, do whatever you want to keep them together and put them in the thing. Run the wires up to the top, make some contacts and attach your wires.
Use superglue to get the lid to stay on the pack.
Note that the clicky mechanism I included in the previous version is gone. I removed them from the design and I also removed the clips from my drills. They just don't provide a secure connection of the battery. I use an industrial rubber band to keep the battery on the drill. Works way better.
Custom choocher done.
To charge these batteries I use my adjustable power supply. I disassembled the old charger, threw it's guts out and ran wires to the contacts. I made wires that can plug in to my power supply.
Make sure to check your charging voltages. Li-Ion batteries are dangerous!
Do not, i repeat, do not charge in a Ni-Cd charger. The cells will overheat, explode or even burn your house down.
You have been warned.
5 x LG 2400Mah = 18,5V - 2,4Ah (charge at 21V - 500Mah)
5 x Samsung ICR18650 28A = 18,5V - 2,8Ah (higher charge voltage 4,3V/cell so 21,5V - 500Mah)
5 x Samsung ICR18650 13P = 18,5V - 1,3Ah (charge at 21V - 500Mah)
Experimental & at your own risk :
6 x LG 2400Mah = 22,2V - 2,4Ah (charge at 25,2V - 500Mah)
6 x Samsung ICR18650 28A = 22,2V - 2,8Ah (higher charge voltage 4,3V/cell so 25,8V - 500Mah)
6 x Samsung ICR18650 13P = 22,2V - 1,3Ah (charge at 25,2V - 500Mah)
Don't use the cheap chineseum cells. They will give you a bad time. One exception. Efest 3000Mah. Those actually work.
Always check datasheets for allowed discharge rate. You should at the very least be able to discharge them at 5A. Otherwise you are creating a custom flame thrower.
Li-Ion cells don't lose their charge as fast as Ni-Cd or Ni-Mh
Recycling / Upcycling
New drills / battery packs are expensive
I have a lot of these drills.
I have a lot of 18650 cells available (from old notebooks / power tools / bikes)
I like messing around with this stuff.