Fused Poleshoes: Insulated Terminals For 12V Lead Acid Batteries

thingiverse

My first attempt at a protected auto battery post assembly featured a direct power cord connection to the terminal posts, requiring an external safety switch to prevent accidental overheating from electrical short circuits. This new design incorporates the safeguard directly into the post unit itself, using a conventional car fuse (typically rated for 5-20 amperes) that is readily available and affordable. The fuse attaches to one terminal via stripped 1.5mm² copper wire while the other end connects outside of the post as a standard spade connector, securing the power cord. Although just one terminal needs protection in principle, combining this new version with an unsecured post from the previous iteration is possible. I opt for uniformity by installing this fused assembly on both posts, using higher amperage fuses (30 amps) where needed. For clarity and safety's sake, terminals should be colored according to industry norms – red indicating the positive polarity, black or green the negative counterpart – to avoid mix-ups that could damage the system. Note that minus terminal conical shapes are slightly narrower than those of plus counterparts. For effective manufacturing, these protective post sleeves can be printed with an FFF/FDM 0.4mm nozzle, maintaining an extrusion width of 0.56mm and a layer height of 0.25mm. When it comes to attaching the assemblies for proper function, flexibility in connection points is vital – which often renders ABS the most suitable material. As an addition to printed parts per assembly: * You will need screws, washers and nuts measuring M3x12 mm * About 6 centimeters of copper wire measuring 1.5mm² that has been stripped * Conventional car fuse measured in desired amp rating * Electrical cord terminating with a spade connector in the six millimeter variety