Spring-loaded 18650 battery jig with banana jacks

youmagine

Printed without support at 0.65mm extrusion width and 0.4mm layer height, sliders were printed with 2 perimeters while the box had just 1. Users can dial their preferred number of slots directly into the OpenSCAD source. The banana jacks are experimental; my specimens remain strong after approximately 50 insertions using 0.6mm wire. These jacks function best when paired with plugs that boast a "cage spring". Classic plugs equipped with a "banana spring" also work, but require precise orientation so the spring opposes the wire for reliable contact. Unfortunately, "bunch of springy wires" style plugs prove unreliable because the contact wire sets itself between the spring wires instead of compressing any of them. To create effective spring guides, I utilize 5cm pieces of 3mm diameter PLA filament (ballpoint pen springs tend to buckle when unsupported). These pieces are straightened by heating them with hot air until gravity begins to bend them; they're then allowed to cool while being rolled between two flat surfaces. When friction-welding the spring guide to the slider, I place the slider on the rail and spin it through the hole in the box to achieve a perfectly angled alignment. The slider is moved slightly during welding to prevent the filament from bonding with the box.