If you download and print this thing, please consider giving me a tip; I am a college student and do independent 3D modeling and design work to support myself. Believe me, every little bit makes a huge impact.
This is an air-cooler I designed for use with Lynxx harbor freight batteries. It works by circulating air through the battery's existing vent holes. The blower is powered via usb cable, so you can plug it into your car's phone charger, a portable usb battery pack, or even a little solar usb power source.
Why cool your batteries you ask? First and foremost, it'll allow you to get the most out of your batteries in the field: every time I go out to cut firewood with my Lynxx chainsaw, I find that I overheat the batteries before I can use all of the battery charge, and have to sit around and wait for the batteries to cool down before I can continue. With this cooler, I no longer have this problem. If you have two batteries, you can use one and have the other snapped into the cooler, and swap them out so neither over-heats. Or if you have just one battery, simply pop it into the cooler every time it gets warm and it'll cool it down in a jiffy.
Secondly, keeping your batteries cool can improve long-term performance and battery life, helping you squeeze the most value out of your hard-working batteries.
Thirdly, and perhaps most importantly, an over-heated battery poses a very real threat to your safety and the safety of those around you. Play it safe, and keep it cool folks.
When you print it, make it so that only completely horizontal surfaces are supported. There are a couple of surfaces in the locking interface that need support, but the ductway was designed so it does not need to be supported (note the onion arch). 0.1 mm layer height or 0.2 mm layer height should work fine.
The blower I used can be purchased via ebay here: link to blower on ebay.
You will also need 2 pcs. 1/8" diameter by 1.5" length machine screws and a nut for each. These can be found at any hardware store, and the screws and nuts are often sold together. Double-check the length before you buy! Random screws have a way of getting into the wrong drawers at hardware stores.
Assembly and demo video