DIY Dewalt Battery

by jayliu

--- **Important Note:** *This model is not designed for repair or modification of original Dewalt batteries. Parts are incompatible and will not fit.* --- This design supports **21700** and **18650 cells**, with options for 5 or 10 cells. There are **four types of batteries** you can build with this model: - 5-cell 21700 - 5-cell 18650 - 10-cell 21700 - 10-cell 18650 Regardless of the cell type, the overall size of the battery will remain the same. --- **Recommendation:** For the best results, I recommend building a **5-cell 21700 battery**. I’ve made two myself and have been impressed with their performance, even after heavy use, drops, and impacts. By sourcing high-quality 21700 cells, you can achieve **double the energy storage and power output** compared to typical Chinese 18650 batteries found in new Dewalt tools, with minimal size and weight difference. **Why DIY is Better:** Building your own battery offers superior performance to knockoff options sold on Amazon or eBay. By choosing quality cells, you reduce the risk of dangerous malfunctions, and assembling this design with plenty of glue makes it **more durable** than many commercial alternatives, which often skip adhesives altogether. **A Word of Caution:** While the **10-cell 21700 battery** is possible, it has a higher risk of breaking if dropped, and it may not be compatible with Dewalt’s fast chargers. This is because Dewalt uses a [different BMS board](https://www.aliexpress.us/item/3256805075613649.html) for their larger batteries. If you choose to build a 10-cell version, please share your experience with fast charging, and I will update this guide. --- **Materials Required:** - Four M4 screws (20mm for 5-cell, 40mm for 10-cell) - One small spring (9mm diameter or smaller, about 15mm long) - Tube of silicone (caulking or RTV) - Five or ten 21700 or 18650 cells - Dewalt BMS board You can build this for under **$30**, especially if you find a deal on cells or have some available. For 21700 cells, I re