Description
Overview
Trailhead 40 is a battery boombox built to be carried and abused. The enclosure is printed in ASA so it survives a hot car, and every seam uses brass inserts so it can be opened and serviced without stripping plastic.
This is a live build log — the power system is wired and the amp integration is next.
Status
- Enclosure: printed and sealed
- Power system: pack and BMS done, charge port pending
- Audio: amp mounted, crossover not yet tuned
Specifications
| Amplifier | 2.1 Class-D 2×30 W + 60 W |
|---|---|
| Battery | 4S2P 18650 ~60 Wh |
| Runtime | 8–10 hours at medium volume |
|---|---|
| Drivers | 2× 3" + 1× 5.25" passive radiator loaded |
Bill of Materials
| Component | Qty | Unit | Unit Price | Total | Notes | Buy |
|---|---|---|---|---|---|---|
| 2.1 Class-D amplifier board | 1 | €24.00 | €24.00 | |||
| 18650 cells | 8 | €32.00 | €256.00 | Reclaimed cells tested for capacity | ||
| 4S BMS + buck converter | 1 | €12.00 | €12.00 | |||
| 3" full-range drivers | 2 | €18.00 | €36.00 | |||
| 5.25" woofer + passive radiator | 1 | €26.00 | €26.00 | |||
| ASA filament | 1 | €22.00 | €22.00 | ~600 g for the full shell |
Build Guide
Model the enclosure
6 h- Design the battery bay as a removable sled — you will reprint everything else before you reprint the pack holder.
Print and post-process
2 days printWire the power system
4 h- Fuse the battery directly at the pack — not after the switch.
Integrate amp and tune
Discussion
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