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Activist Engineering: "Disposable" Vapes Take to the Skies

Air:Bit with LiPo Cell from Vape

There’s hardly a dog walk that passes in my remote mountainous North Wales village that doesn’t see me collecting a “disposable” vape. There’s a tiny part of me that used to feel slightly pleased, the sight of one of the little colourful tubes was essentially a free LiPo battery to add to my collection, but mostly it’s horrid to see this litter, little packets of lithium and other components nestled into the hedgerows.

To be clear this isn’t a tirade against smoking, I’m certainly no paragon of health and wouldn’t want to judge but the fact that these items exist and are so commonly dumped is appalling. It’s not just me either, it’s incensed so many of late that there have been numerous government petitions in the UK calling for the ban of single-use vapes. Rather though, let’s look at how we can collect these dumped vapes, salvage what we can from them safely and look at how we can reuse the precious LiPo cells that they contain.

First of all, we should perhaps consider safety a little. If you’ve ever seen even a small LiPo puncture you’ll appreciate the amount of energy that can be released causing burning and a host of noxious output. This is particularly a risk when these cells end up getting crushed under vehicles on the roads or when they get crushed by refuse collecting if they end up going in the landfill bins. It makes me wary of picking up a crushed or other visibly damaged vape which feels bad to leave them but is better than a small incendiary device sat in your coat pocket. We also need to consider hygiene a little as these have been in people's mouths and have been lying on the ground. As I mostly collect these whilst walking the dogs I tend to always have dog waste bags in my pockets and these make a decent impromptu glove into which I can pick up and turn inside out to get the vape in the bag without touching it. Once returned, with your newly found vape, the hygiene stuff becomes even more important when it comes to disassembling the device to salvage the internal cell and other components. The overriding need for this is not just that these are litter that has been in people's mouths but also because the internal components of the vape absolutely reek! The unvaporised "vape juice” or "E-Liquid" is sticky and usually incredibly pungent and anything that it into contact with tends to ends up smelling too. To mitigate this I tend to, having wiped the outer surfaces, dissemble the vape over a dedicated tray and I have a waste bag for the super smelliest parts to go straight into, I also tend to wear a pair of vinyl gloves.

Disassembling a VAPE

Whilst there is a great variety of single-use vapes by far the most common one I find and that is found anecdotally by others are the Elfbar 600’s. So we’ll look at the disassembly of one of those. It’s pretty straightforward, you grab a pair of wide pliers and with them, you can pull off either end cap. I tend to pull off the lower/non-mouthpiece end as this is the end nearest the LiPo cell. Embedded in this end is a small inlet hole and a pressure sensor, often with a small LED which lights when the unit is active with air being pulled into it by the user. With a gentle tug, you can continue to pull the wires that are connected to that end cap and you should pull out the LiPo cell. Indeed you can continue to tug and you can withdraw the small plastic and rubber chamber which contains some cotton wool wadding, the E-Liquids and a small length of fine nichrome wire which is the heating element that causes the vaporisation of the liquids when activated.

Removing the LiPo Battery

To reuse the LiPo cell you’ll need to remove it from the system. The main note here is obviously to try and avoid any potential shorting across the cell and so the golden rule is to certainly only ever snip one wire at any given time as if you snip both a positive and negative wire together you’ll create a short across the jaws of your snipping tool. Carefully consider what wires you need to cut and be aware that often these systems tend to defy convention: it’s common to see a black wire connected to a positive part of the circuitry. I tend to snip the wiring right back close to the cell terminals as if I discover that it’s a cell that’s worth keeping I’ll resolder entirely new cables and connectors to the device.

Measuring the battery voltage of a LiPo

With the LiPo cell removed check the voltage with a multimeter. I personally am reluctant to recharge a cell that has been taken beyond a safe discharge level of 3 volts as a cell discharged that low could potentially be damaged. If the voltage is over 3V then that usually would indicate a cell that is in good working order. I regularly find cells that are only discharged to perhaps 3.2 to 3.6V, again annoying that they have been disposed of when they haven’t even completed one discharge cycle!

Soldering on a different connector for a cell is straightforward enough and the cells usually have a small metal strip attached to either end to which the wires are soldered. I tend to run my soldering iron quite hot so that I can work quickly and minimise the amount of time and heat I impart to the battery. What type of connector you add is up to you, I’ve tended to use Molex 51005-0200 or simple JST type connectors as these fit in with numerous small electronics projects I’ve been working on or indeed they are compatible with some of the smaller quadcopters and RC planes in my collection. When I solder on the new connectors I’m always painfully aware that these cheap LiPo cells have the minimum amount of insulation on them and I always try to add a little more where I feel it’s needed. My go-to for this is the classic Kapton tape and I tend to add a little at each end of the cell and a strip along the side of the cell underneath where I run the longer connector wire so that if there was a fault in the wire insulation it would be unlikely to short onto the cell body.

LiPo Battery with Connector fitted

With the cell now re-wired, we need to charge it. There is an excellent Youtuber “BIGCLIVE” who has done extensive work on reusing these cells and they have some excellent videos on using the cheap and widely available TP4056-based charger modules to work with these cells. The TP4056 modules are useful in that they can be adapted to charge at different current values and the most common way is to charge at “1C” where the charge current is the same as the stated current capacity of the cell. Most of the cells I’ve recovered have the capacity printed on the side of them and I’ve discovered a range of capacities in different vapes. The most common cells from the Elfbar tend to be labelled as 550mA. The TP4056 modules need a compatible connector soldering onto them to connect to the cell and you can replace one resistor labelled as R3 or Rprog with resistors of other values which changes the charge current of the board.

Charge current vs Rprog

As the TP40456 modules are pretty cheap and often sold in multi-packs of 3 or 5 I’ve adapted a few of them so that I have a range of charge capacities. For these salvaged E-cig cells I tend to use the one I have set up with a 2.5K ohm resistor resulting in a charge current of roughly 480mAH, which means that a 550mA cell will charge in around an hour's time.

Air:Bit Package

To demonstrate just how excellent and useful these cells are I decided to see how well they worked to power a small interesting Quadcopter, (222-9372) the Air:Bit. The Air:Bit is a predominantly lasercut quadcopter kit that uses an onboard BBC Microbit coupled with a custom PCB as the flight controller with either an additional MicroBit set up as the controlling transmitter or indeed you can fly the Air:Bit using your phone.

Air:Bit being assembled

It’s a straightforward build to assemble the Air:Bit and there is an excellent build guide over at the OKDO website. The Air:Bit is a great drone to fly these recovered LiPo cells on as it has a simple elastic band battery bay underneath the airframe and as such it can accommodate a good range of sizes of cells without any adaption. The battery supplied with the Air:Bit is a larger 800mA cell which keeps it in flight for around 5-7 minutes however we’ve easily managed 5 minute flight times with our 550mA cells as they are a little lighter than the supplied cell and we’ve further reduced the weight of the Air:Bit by confidently flying it without the propeller guards! It's great fun and a good challenge to fly the Air:BIt using a second Microbit as an accellerometer-based controller and it's even better knowing that it's in the air powered by precious lithium that could have ended up in landfill!

General tinkerer! Freelancing writing about making things, rocketry, boats, electronics and a mahoosive pile of unfinished and unstarted! Author of "FreeCAD for Makers" book on Raspberry Pi Press and writes for Hackspace Magazine, Tindie, Kids Code Computer Science, Toms Hardware and more!