Ryobi Li-Ion Battery Pack

thingiverse

While working on my Lack project, my 10-year-old Ryobi batteries, which had been rebuilt several times, weren't holding up anymore... So I started looking for a better option. 3D printer - Check! Ton of 18650 cells - Check! I found a few reference models on Thingiverse that I've used before (like Enif's battery case design ideas and leaning on Simhopp's modeling work on the case). I redrew it, modified it, and built a couple extra parts to suit my needs. In the end, this pack is roughly 50% the weight of a Ryobi NiCad case (600g vs 1kg) and has almost four times the capacity (~1200mah NiCad vs ~5000mah (2x2500mah) LiIon). Images of the scale are included; I didn't know it was going to be this light... On the downside, my large drill can now tip it over, lol. Might have to add some weight. Let me state this right off the bat: Lithium Ion batteries can be extremely hazardous! Improper charging, accidental shorting of cables, and so on can cause them to catch fire and/or explode. If you're not confident in what you're doing, I'd go with another battery pack - it's much safer. I'm not going into too much detail on the wiring for that reason; if you understand it, it'll be straightforward. DO NOT charge this pack on the factory charger! Why? It's designed for NiCad or NiMH packs, and this one also lacks temperature sensing. Remove the cells and charge them separately in a proper charger OR build an adapter to connect it to a proper LiIon charger like I did. What happens if you do? See above! Comments are greatly appreciated - let me know what you think!