3D Printed Parts for Solar & Battery Projects
One of the best things about building your own solar and battery systems is that you can fabricate custom parts that the commercial market doesn't sell. A 3D printer lets you make brackets, enclosures, covers, and adaptors that fit your exact hardware, in exactly the colour you want, for pennies in filament.
Below are the projects I've actually printed and installed in my own systems. Each one solves a real problem, includes links to the STL files, and tells you exactly what filament, infill, and hardware you need. No theoretical designs that look good on a screen but warp in the sun: these are battle-tested.
Projects
MultiPlus Fan Silencer Duct
The Victron MultiPlus-II 48/5000 has a noisy 80mm fan that ramps up under load. This duct replaces the stock finger guard with a tuned chamber that drops perceived noise by 8-12dB without restricting airflow. The secret is the internal S-bend that breaks up the fan blade frequency without creating back pressure.
Bed size: 220x220mm minimum (prints in two halves that clip together)
Hardware: 4 x M4x16mm bolts + M4 nuts
STL: Printables (search "Victron MultiPlus fan silencer")
Venus OS Raspberry Pi DIN Rail Case
A compact DIN-rail mountable case for a Raspberry Pi 4 running Venus OS. Replaces the £200+ Victron Cerbo GX with a £45 Pi and a £25 VE.Direct to USB cable. The case has cutouts for all ports, a slot for the microSD card, and ventilation that actually works (unlike some sealed cases that cook the Pi). Snaps onto standard 35mm DIN rail.
Bed size: 180x180mm
Hardware: None (snap-fit design)
STL: Printables (search "Venus OS Raspberry Pi DIN case")
MPPT Wall Mounting Brackets
Clean wall-mount brackets for any Victron SmartSolar MPPT from 75/15 to 150/100. Much better than the janky screw-through-the-heatsink method that blocks airflow and looks terrible. The bracket snaps onto the MPPT's heatsink fins and provides a flat mounting surface with 5mm screw holes. Designed with an air gap behind the MPPT for proper convection cooling.
Bed size: 200x200mm
Hardware: 4 x 5mm wood screws + wall plugs
STL: Thingiverse (search "Victron MPPT wall bracket")
Busbar Covers & Terminal Guards
Snap-on insulating covers for common busbar sizes and battery terminal posts. Prevents accidental shorts from dropped tools or wandering fingers. The busbar cover fits 4-post and 8-post bars up to 250A. Terminal guards fit M8 battery posts. Both designs use a living hinge and snap-latch so they're secure but removable without tools.
Bed size: 150x150mm
Hardware: None (snap-fit)
STL: Printables (search "busbar terminal cover guard")
18650 Cell Holders (Modular)
Interlocking cell holders for building custom 18650 battery packs. Each block holds 4 cells (2x2) and snaps together with dovetail joints so you can build any pack configuration. Includes slots for nickel strip and recessed channels for balance leads. Much more rigid than the flimsy eBay holders and designed so cells can be removed without destroying the holder.
Bed size: 150x150mm (each block is 75x40mm, print multiple at once)
Hardware: 0.15mm pure nickel strip
STL: Thingiverse (search "18650 modular cell holder dovetail")
MC4 Tool Holder & Wrench
An MC4 connector wrench that actually works. The plastic wrenches that come with MC4 connectors are universally terrible and break on the second use. This one uses a 4mm thick body with reinforced jaws that grip the MC4 collar properly. Also includes a wall-mount holder that keeps your MC4 wrench, spares, and a cable stripping gauge in one place.
Bed size: 100x100mm
Hardware: None
STL: Printables (search "MC4 wrench tool reinforced")
Material guide: which filament for which job
| Filament | Heat resistance | UV resistance | Ease of printing | Best for | Buy |
|---|---|---|---|---|---|
| PETG Go-to | 80°C | Good | Easy (similar to PLA) | Indoor brackets, covers, enclosures, cell holders | Amazon |
| ASA | 100°C | Excellent | Moderate (needs enclosure) | Outdoor brackets, roof-mounted parts, full sun exposure | Amazon |
| ABS | 100°C | Moderate (degrades without paint) | Moderate (needs enclosure, warps) | Hot equipment enclosures, fan ducts near exhaust | Amazon |
| PLA+ | 55°C | Poor (becomes brittle) | Very easy | Prototypes, temporary jigs, indoor tools only | Amazon |
| TPU (95A) | 70°C | Good | Hard (slow, stringy) | Cable grommets, vibration pads, flexible covers | Amazon |
My default: eSUN PETG in black. It's £16/kg, prints cleanly at 240°C/80°C bed, and has never let me down. For outdoor parts, Polymaker ASA (£25/kg) is worth the extra for UV stability.
Recommended 3D printers for solar DIY
You don't need anything exotic. All these parts were designed for standard FDM printers. Here are the three worth buying at different price points:
Bambu Lab P1S Best overall
Enclosed CoreXY printer. Prints PETG, ABS, ASA out of the box. 256x256x256mm. The AMS (automatic material system) lets you use dissolvable support material for complex parts. This is what I use. It's fast, reliable, and the enclosure means ABS/ASA prints don't warp.
Creality Ender 3 V3 SE
The updated Ender 3 with direct drive extruder, auto bed levelling, and a PC-coated spring steel bed. 220x220x250mm. Prints PETG easily. ABS needs a DIY enclosure (cardboard box works). The classic beginner printer, now actually good out of the box.
Prusa MK4
The reliability king. 250x210x220mm. Input shaping for fast prints without ringing. The quick-swap nozzle system makes changing between 0.4mm and 0.6mm trivial. Open-frame so ABS needs an enclosure, but PETG prints flawlessly. Support and community are best in class.
Essential accessories
- Brass heat-set inserts (M3/M4 kit) (£10) - For adding threaded holes to PETG/ABS parts. Much stronger than tapping threads into plastic. Use a soldering iron at 240°C to press them in.
- Stainless bolt assortment (M3-M5) (£15) - Every project uses these. Get a kit with 200+ pieces.
- Deburring tool (£6) - For cleaning up brim edges and support marks.
- Digital calipers (£12) - If you're designing your own parts, measure twice, print once.
Want to submit your own STL?
We're building a library of community-tested 3D printable parts for solar and battery projects. If you've designed something useful, send us the STL with print settings and we'll add it to the collection.
Check the 3D prints directory for downloadable STL files.
Common questions
What filament should I use for solar parts?
PETG for almost everything. PLA will soften in direct sunlight (glass transition is only 55-60°C) and becomes brittle over time outdoors. PETG handles 80°C, is UV-resistant, and prints nearly as easily as PLA. For parts in enclosed spaces with electronics (like a MultiPlus fan duct near warm air exhaust), use ABS or ASA which handle 100°C+. For outdoor brackets in full sun, ASA is the best choice; it's basically UV-stabilised ABS.
Is it safe to 3D print electrical enclosures?
For low-voltage DC applications (12V-48V) and non-critical parts like brackets, covers, and cable guides: yes. For mains AC enclosures (230V): no. 3D printed parts are not fire-rated and should not be used as primary electrical enclosures for mains voltage. For battery terminal covers and busbar guards, PETG or ABS are fine since these are at extra-low voltage.
What 3D printer do I need for solar parts?
Any modern printer with a heated bed and a 0.4mm nozzle can print these parts. Most designs fit on a 220x220mm bed (Ender 3, Prusa MK4, Bambu A1). For larger parts like the MultiPlus fan duct, a 256x256mm bed (Bambu P1S/X1C) or Prusa XL is helpful but the duct is designed to print in sections on smaller beds. An enclosure helps with ABS/ASA but is not essential for PETG.
Can you sell 3D printed parts on Etsy/eBay?
Check the licence on each STL file. Most of the designs we link to use Creative Commons Non-Commercial licences, which means you can print them for yourself but not sell them. Some designers offer commercial licences for a small fee. If you're printing to sell, verify the licence first and credit the designer.
Why not just buy these parts?
Some of them you can't buy. A Victron MPPT wall bracket that fits your specific model with the right air gap doesn't exist commercially. The MultiPlus fan silencer is a niche mod that no company sells. And even for parts that do exist commercially (like busbar covers), printing them costs 20p in filament vs £8-15 to buy. If you already own a printer, it's a no-brainer. If you don't, buy a printer. It'll pay for itself within a year on brackets and adaptors alone.