Night Vision Power Adapter

Do you ever wonder if, some day, we’ll look back on COVID-19 and think of it as the golden era of weird pet project completion? Well this is one of those, something which otherwise might not merit the time, but now with time to spare evenings and weekends, it just started making sense.

The crux of hunting with night vision is always power supply. You can hunt for hours, but the batteries in your night vision typically can’t. Sure you can bring more batteries, and fumble around in the dark swapping them, but wouldn’t it be convenient if you could just run your night vision off a wall wart and not even think about it? Well that was my idea.

For reference, I’m using THIS UNIT. At STO this style of night vision is so popular, we actually have several kicking around of various generations. We actually prefer these to much more expensive night sights because of their simplicity, reliability, and the fact that they work great with your existing scope. They run on a pair of 18650s, which if you run the illuminator can be drained in a couple hours.

First step is to acquire the requisite wall wart. An 18650 outputs between 3.0 and 4.2 volts depending on charge. Some devices have low voltage cutoffs so you don’t damage cells by over-discharging them, so being somewhere above the minimum is probably good. 4v per cell across two cells means an 8v power supply should be just dandy. So THIS ONE seems like a cheap option. Other devices though may take other numbers of cells, or other chemistry cells for that matter, so SOMETHING LIKE THIS will give you a bit of versatility if you’re reading this blog post and liked the concept but wanted to power a different device.

Next step is to make an adapter. Because I want this to be 100% reversible, I figured just a battery analogue with power on one end would be an easy win. So I designed the “platonic” power adapter, with space for wires to run along the spine, an easy grip for removal, and a crowned face for good contact. This can be zipped out on an FDM printer quite quickly and easily.

Copper contacts are the next step. This can be done in a variety of different ways, but the easiest is with a little copper tape. The trick is that the adhesive can be cooked off if you aren’t fast and deft with the iron, so use a generous bead of flux, and solder quickly. Wash off the flux, then just peel the backer off the adhesive and stick. A file or a little sandpaper can be used to clean up the edges. Pro tip here, wipe the faces with your favorite contact cleaner/protector so that those pink and juicy fresh copper and lead faces don’t oxidize and start producing lousy connections.

Another pro tip, it doesn’t look pretty, but a little silastic on the wires will act as strain relief so the solder joints don’t just break off. It isn’t pretty, it never is, but we’re looking for function not beauty here. All this will be hidden in the battery box anyway. And one final pro tip before you throw this thing in your equipment and run it: hook it up to your multimeter and ensure the polarity and voltage are correct. Consider even going one step further and clearly marking them! Never assume the last monkey on the wrench knew what they were doing or gave a flying f*ck.

Success! You weren’t expecting a beauty shot were you? ;) It powers up, it works great, and that is good enough. This same principle can be applied to a huge number of different devices to provide wall power for whatever battery-operated device you want.

And I know what you’re thinking: what about an SoR? The answer is yes, however you’ll need a MUCH beefier power supply and to wet the copper contacts with more solder to fortify them against the amperage they’re about to have to carry or use heavier gauge copper plates. We actually have a bespoke SoR power adapter, one which runs off one of our big PSUs. If memory serves, it was built for our endurance testing of the light. But I digress.