In this second installment in the series, I want to discuss choosing an enclosure for your project. The enclosure is the case and final form factor your mod will take. There are many factors to take into consideration when choosing an enclosure. I will attempt to discuss some of the major ones here. This list is by no means exhaustive, but hopefully it should get you pointed in the right direction as to what you should look for when planning your build.
Probably the biggest consideration is size. How big do you want your mod to be. Factors to be considered in choosing the size of your enclosure are battery capacity (the bigger the mAh the bigger the battery, the bigger the enclosure), making sure there is room for all components (main board, buttons, switches, LEDs, atomizer connection, wiring, USB charging board, etc.), layout of the controls, and ergonomics (how the finished product feels in the hand).
Components take up space; batteries, the chip, screen, buttons, atomizer connection, MicroUSB charging boards and wiring can be laid out to maximize efficient use of space in an attempt to get the best performance and battery life, in a package as small as possible. The DNA20D AND Nivel Chip both require high drain batteries. You can use IMR batteries, or LiPo (Lithium Polymer). An Advantage of the LiPo battery is that many of them come as flat packs which can be soldered together to increase capacity (mAh) without taking up a lot of valuable space inside your mod.
The downside to using LiPo batteries is that not many places sell them in the US. The types of LiPo batteries with a C rating appropriate for modding are usually designed for model airplane/helicopter use. Thus the best place to find them is a hobby shop that specializes in model aircraft. I managed to find a few at my local hobby store, but they were quite expensive ($30.00 USD for 2). Online hobby retailers (like HobbyKing) carry them at a reasonable price, but pay attention to where they ship from. Many come from overseas which greatly increases shipping cost, and can complicate things since many carriers won’t ship LiPo batteries.
Pictured below are some size references of different components.
Below are some common off the shelf enclosures that many people have used for modding. Again, not exhaustive by any means. The first picture features two small enclosures purchased at Radio Shack very inexpensively. They are plastic, easy to work with, and cheap, but may or may not be the most aesthetically pleasing (beauty is in the eye of the beholder). The third enclosure I ordered online from Hammond Manufacturing (part #1455C801) and is made of extruded aluminum. Personally, I like the durability and look of a metal enclosure, but it is more expensive and harder to work with (especially the screen cutouts).
Other enclosures can be found easy enough if you don’t mind buying online, often directly from China. eBay in another good source for finding enclosures. A quick search for 18650 battery case found several including this one, which looks like it would be very easy to mod.
For aluminum enclosures, this Chinese eBay seller has several that will work.
Another option to consider is modding an existing product. A common item that lends itself to modding, due to its size and original purpose, is the portable USB cellphone/tablet charger. These can be purchased several places from domestic retailers, Amazon, or direct from China via alibaba.com. To mod an existing device, you will first need to gut the original components (the batteries and various other components) and toss them aside. Many of these devices come with 18650 batteries already in them. Do not use these Li-Ion 18650’s, as they are not rated to handle the amp draw necessary for use in an APV. A nice feature about modding an existing portable power supply, is that it will most likely already have a MicroUSB charging board installed in it that you can use for your device.
Once you decide on the type of enclosure you want, ordered all of the other parts to complete your project (controller, batteries, switches, etc.), it’s time to start putting it all together. In the next entry in this series, we will discuss just that. We will take a look at soldering, dremeling/routing, routing wire, using epoxy, and lots more. Stay tuned!