Transcription

After the insane response to my first video where we turned all of these wasteful single-use vapes into a fully rechargeable power bank, I decided to make a version 2 which is smaller, lighter, safer and easier to assemble. And the best part is I'm open sourcing the entire design so everyone can make their own and also improve upon the design. I'm also going to show you a much more detailed build process so hopefully everyone can follow along, learn a bit extra and I'll also include as much safety information as I can. Also I'll be showing you things that you should absolutely not do but in a controlled way. It's pretty clear a lot of you really disliked the previous design and I totally agree with you. It's bulky, not very space efficient, weighs a ton and has more bolts holding it together than the Golden Gate Bridge. So hopefully this second iteration clears a lot of that up. Also a massive shout out to every single one of you that watched and engaged with the previous videos. We've done such a good job of making some noise and raising awareness of this insane source of e-waste. Even the news have got involved. I've got a big disclaimer for this one. I'm going to be handling lithium-ion cells in this video along with other potentially dangerous tasks so please take a moment to read all of this very carefully. Everything is for educational purposes only and you assume all risks if you decide to replicate anything I show here. Let's have a quick look at the parts that we need to build this thing. We've got the 3D printed cell holder which is way more compact this time and will hold all of the 35 vape cells. There's these lovely new PCBs with way better spring tabs, fuses, soldless connections and much more. And these PCBs will screw down onto all of the vape cells in order to wire them all together and form a big battery pack. This is going to make the construction, servicing and cell replacement much easier. We also have the 100 watt fast charge USB board that we can buy from AliExpress and finally the 3D printed enclosure which is resizable so we can use it for longer or shorter vape cells. All of these parts stack nicely together to build up the complete power bank. All the design files and the links will be available in the description. And speaking of the PCBs, this video is sponsored and made possible by JLCPCB. I've been using their PCB assembly to create all of the prototype PCBs for each iteration of my vape power banks. And this has been without breaking the bank because their prices for manufacturing and assembly are pretty much the cheapest that I can find around. As a hobbyist there's absolutely no way I'll be making the things I am today without accessible and low-cost PCB manufacturing. Especially as ordering five four-layer PCBs can be as little as two dollars. So I don't bother with prototyping with sketchy breadboards anymore. I'll order some low-cost PCBs and get my project working in no time without the headaches of debugging jumper cables. They also provide other services such as 3D printing which I use to create the disposable vape ebuy battery. Later in the video I'll be showing you how to order the exact PCBs that I use to create this power bank. So check out JLCPCB using my links in the description. Okay first I'm going to go into a bit more detail as to how we can remove the batteries safely from vapes and also how we can identify the types of batteries that we want. These cylindrical style vapes seem to be the most popular and I've collected around 500 of these from the street and from nearby vape shops. They come in all sorts of weird knockoffs but they all seem to be identical on the inside. The batteries in pretty much every different type of vape are typically stored at the bottom and that's because the liquid sponge would always be located at the top near the mouthpiece. So I use something such as these cutters to pry at the bottom and pull the insides out. But I've got to be really careful because they absolutely do not want to cut too far up and puncture the cells. Even the smallest cut in these things can cause them to go up. Let me demonstrate. Remember this applies to any lithium battery not just vape cells. Now I'm not showing this to scare people from using lithium cells but to make sure everyone takes the safety very seriously. Also no wonder there's a lot of waste disposal fires when the majority of people are throwing these straight in the bin and it'll later be compacted down. Basically just don't do anything stupid. I take a bit of time to figure out a solid process for taking a particular style of vape apart and then I'm able to gut tons of these in no time. I also make sure that I have a clear route to the outside and I have a tray with some sand in it available. Therefore if any of the cells start to get hot or start releasing any fumes I can chuck it straight in the sand and get it outside ASAP. Here's a little clip of me cracking open some other common types of vapes. Easy peasy. Now the cells in these things come in all sorts of shapes and sizes. Pretty much all of them can be identified with a six digit number such as 13400 as we have here. This number actually refers to the cell's dimensions which in this case is 13 millimetres diameter and 40 millimetres long. My design fits any 13 millimetre cell which is fortunately used in the vast majority of disposables. I then remove any foam or tape covering the battery terminals before desoldering the vape components from the battery making sure that most of the solder is removed. There we go nice and clean. Or sometimes I just use flush cutters to cleanly cut off the solder joint but I've got to make sure that the tab stays fully intact though. There's also usually a number on the cell that indicates its capacity in milliamp hours and in this case the cell is 550 milliamp hours. The bigger the capacity is the longer the power bank is going to last. This design needs 35 identical cells so I'll aim to collect together about 40 of these because some of the cells might not be healthy. Let's have a look at how we could determine whether they are actually good or not. Lithium batteries are actually really sensitive to voltage. If they're discharged below 3 volts then they'll permanently degrade and if they're charged above 4.2 volts then they'll actually explode and that is why pretty much every device with lithium-ion cells in it has a battery management system which monitors the cells and makes sure they're always within this particular range and vapes are no exception. They actually have a little battery management system in the bottom which stops you from being able to use the vape once the battery discharges below around 3.2 volts. However I've found that if the vape has been sat unused for a really long time or if the cell is particularly low quality then they'll actually self-discharge a bit bringing it below 3 volts. So what we're going to do is use a multimeter to double check that it is actually above 3 volts and we can also give the cell a good inspect to make sure it's not corroded or swelling at all. To be extra safe I can use a cell tester to fully discharge and recharge the cells which will then reveal their true capacities. This allows me to match the cells by their capacity therefore extending the power bank's lifespan. While it's not essential it is best practice and it can let us skip some steps later as all the cells will be charged the exact same voltage. By the way I've noticed some videos where some people strip apart a USB cable and use this to manually recharge their disposable vape batteries but this is a terrible idea though because a USB cable puts out 5 volts and if we charge a lithium cell above 4.2 volts this happens. So yeah definitely don't do that and it's also a really good thing that we're using parts that do charge the cells properly. As I discovered in the last video when we connect the cells together via the PCB the odds of every cell making a solid connection with the PCB springs is pretty small seen as the cell terminals are so tiny. Here we can see that four of the cells are actually unconnected and that is why I've applied some conductive copper tape to both ends of the cells to make my own big terminals and there we go we have a nice solid connection across all of the batteries now. This time I'll show you a bit more of the preparation that I do to make sure that the copper tape actually adheres nicely to the cells which I kind of skipped over last time but is really important. I unfold the battery tab so that it's as long as possible and I also remove any tape that is covering it. I'm basically aiming to maximise the surface area for the cell then using some sandpaper I give it a light sanding which removes any crud or debris which removes any crud or oxidisation that has built up on the surface. Then I cut off a section of copper tape that is about two centimetres long and place it over the end of the cell pushing it down firmly. Then I use a small plastic thing such as a guitar pick to apply some pressure just around the tab. This makes sure that the conductive adhesive has a really solid connection to the metal tab on the battery. I do this for both sides and then I use a multimeter to make sure that I can read a nice solid voltage. If the reading is erratic or lower than I expect then it means I've got to remove the tape and repeat the process again. Next I make a mark on the edge of the negative side of the cell using a marker pen which is really important for the later steps as I'll definitely need to know the orientation of the cell when it's been inserted into the cell holder. Also now that the cell terminals are huge it's really easy to accidentally short them out on some nearby metal or with cells nearby so I'm going to make sure that they're stored apart from each other. The new cell holder is much better than the last one. It is so much more space efficient and uses way less filament. The tabs to hold the cells in have also been optimized a bunch so it provides the perfect amount of clamping force for these 13 millimeter cells. However it is a pretty complex shape so it does take a good while to print. I'll get one printed off now. Now that the cells are all prepared we are ready to insert them into the cell holder but the cells need to be inserted in a very particular way in order to match the PCB wiring. If we insert even a single cell the wrong way around then we can either damage the PCB or the cell itself so it's pretty important. The cells have to be inserted in rows of seven in which each row is alternating in its orientation. To understand why let's take a look at the wiring inside the PCB. We can see that we have long copper traces that connect all of the cell rows in parallel. This basically combines them all to form five separate big batteries which have an individual average voltage of 3.6 volts. Then we have some extra PCB traces which connect the positive end of one row to the negative end of the next row. This is connecting all of these five batteries together in series therefore adding up all of their voltages to form a big battery pack with an average voltage of 18 volts. It's this higher voltage that lets us do fast charging and also charge laptops. We also have these six connection points from both of the PCBs and these are connected to all of the rows terminals so that we can measure all of their individual voltages. This is then used by a battery management system to make sure that all of the cells are operating safely. So you see the layout of the cells is really important so that they all get connected together in the correct way. That's why I made a marking on the negative side of all the cells so that I definitely know that they're inserted the correct way around. Finally I just need to check that the cells are perfectly centered in the 3d print and that there is a spacing of about 2.5 millimeters or less between the cell and the top of the 3d print. If the spacing is bigger than this then the springs won't make a good contact because they're not long enough. I've also got to make sure that no cells are too long and are poking out the top of the 3d print otherwise we can't screw down the PCB correctly. Time to get our hands on the PCBs. Just download the PCB files from the description then drag and drop the Gerber file on the order page that I've linked below. The default settings should be okay and the color can also be customized. Scroll down to the bottom and check assembly. You can then choose between two PCBs and five PCBs to be assembled. Hit next and upload the CPO and BOM files. When it shows you the preview of the board you'll want to rotate the three connectors to make sure that they're all pointing in this exact direction and then send off the order. When I built the first power bank I explained that we can't just immediately connect up the PCBs because the cells in each row might have different voltages and if we connected them directly to each other in parallel they would charge each other really fast and maybe explode. So I made a separate PCB which has some resistors between the parallel cells so they can charge each other to the same voltage nice and slowly and then the PCB without the resistors could be fitted afterwards. However this new PCB comes with the resistors pre-installed and we can easily bypass the resistors later on once all the cells have charged each other so we don't need any additional PCBs for this. We can see that the cells are indeed different voltages so the resistors between the cells are certainly going to be needed. If we measure the resistance between two spring taps on the same row then we can see there's a few ohms of resistance which is going to balance charge them nice and slowly. I used some 50mm M3 bolts to screw down two of the PCBs which then sandwiched the cell holder and then I'll leave it for a few hours so that all of the rows of the cells can equalize each other's voltages. I'm also going to supervise it and just make sure it doesn't get hot at all. The design still uses quite a few bolts but I definitely want to make sure there's even pressure all over the PCB and that all of the spring tabs are definitely pushed down. I went a bit overkill and left it for about four or five hours and let's have a look if the rows now have equal voltages. Yep, looking pretty good. They can differ by about 0.1 volts but here this is pretty spot on. It doesn't matter that the rows have different voltages from each other because the USB board will sort this out later. If any of the cells still have a big difference compared to the others in its row then it likely means that the spring did not make a good connection to the cell so I'd have to reposition the cell again, stretch out the springs and install the PCBs. Quick side note, these PCBs are so much better than the last ones. We have fuses on all of the connectors to the USB board in case anything goes wrong and all of the cells are connected together via these thin fusible traces. This means that if any of the cells fail in a way that they short-circuit the other parallel cells, these fusible traces will burn out and disconnect the faulty cell from the rest of the battery pack. I've got much bigger spring tabs compared to last time and I wanted proper big springs on here but I couldn't find any that were suitable for assembly and were also cheap so I've had to stick with these for now. Okay, finally all of our cells are fully ready to be properly connected together and to make up the big battery pack. I'm going to bend all of the springs back in preparation for the board to be installed again. Ideally they're bent back as high as they can physically go. I also need to modify the board so that we bypass all of them resistors between the cells. You see these little silver pads next to the resistors? They're called solder jumpers. All I need to do is join the two pads together with a thin blob of solder and this will bypass the resistors allowing all of the cells to be directly connected to each other so I've just got to do this for all the solder jumpers on both PCBs. In preparation for the final assembly I'm going to print off both sides of the enclosure. Time to get the USB board prepared. There are about six wires that need to be added to the board. I've just got to cut a five centimetre black wire for the negative and five centimetre wire for the positive and get these soldered onto the positive and negative pads of the board. These are going to be the main power wires. I use at least 18 gauge wire for these because I know the USB board can draw around five amps. Then we also need to add four extra wires to the board which will allow the board's built-in battery management system to monitor the voltages of each row. I'm using a JST connector to make wiring it all up easier but directly soldering up the wires is fine too. It's important that no solder is bridging any of the pins because this will cause a short circuit and will blow the PCB fuses. Another step that isn't entirely essential is to tell the USB board the capacity of all the cells by replacing a little resistor on the back of the board. I can get away without doing this but the battery pack percentage reading will be wrong. I'll leave some details on how you can select the correct resistor in the description. Let's get the board clipped into the enclosure. I just need to slide it along these little rails and use something to push the screen to make sure it pops off in this little gap. Once everything is aligned the two tabs at the back should hold it all in place. Now I'm going to find an edge of the board that has a row of negative terminals. These will be the ground of the battery pack so I'll put a little mark here. Then I'll mark the four connectors which are used by the battery management system. These alternate on the sides of the pack because of how we've laid out the cells and finally I'll mark the positive edge. Now I'm going to slightly tin the wires from the USB board which just makes them easier to push into the PCB connectors and working from left to right I'll plug in the negative wire, the four BMS wires and the positive wire. This little red thing here is a temperature sensor and we can just fit it in this little hole so that it touches one of the cells. So I'll slot it all together and make sure I don't trap any wires and then I'll screw the whole unit together. The unit doesn't work straight away because it only activates after the first charge so I'll whack in a USB-C cable and there we go. Now it'll likely take a few charge cycles for the full capacity of the battery to be available. Now I'm going to run some tests on this thing. I've got this cool programmable load that we can use to measure the final capacity of it. I'm able to draw about 92 watts from it which is pretty cutting edge in terms of what other power banks can do and after discharging it for a while it looks like we have a capacity of 62 watt hours which I'm actually really impressed with. If all the cells were brand new and at 100% of their stated capacity then it should be about 70 watt hours so not bad seeing as most of these cells have been sat in my cold garage for a year or so and in nonsense power bank marketing terms this capacity equates to around 14,500 milliamp hours and the best thing is this thing will pretty much last forever as long as I'm able to keep collecting vape cells and swapping them out when they go bad and I've been using the original one for about six months or so and it's been working great so far. It's sad to think that hundreds of millions maybe even billions of these things are being thrown away each year and they're marketed as disposable just to get people to buy another one so I guess in the meantime it's up to us to find ways to give these cells a second life and to also spread some awareness of how much damage this industry is doing. Subscribe if you want to see other interesting stuff like this. I'm working on a vape battery power wall but it's going to take a long while to make so I've got some other videos lined up in the meantime.