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This video is sponsored by pcb way where you can print all your pcb ideas, make them a reality all right: the 18 650 battery cell, it's the best battery on the planet. It is been in production the longest. It is the most abundant. It's been used in everything for about 30 35 years now, right, uh, it's in rockets for nasa.

You know, remember the spacesuit that uh nasa had where the astronaut was flying around in this little chair. Whatever 18650 is power that you know that little helicopter that it's in mars right now flying around powered by 18650. These batteries are everywhere. They are the best thing that has happened uh in modern times.

It's a modern marvel of engineering right here right, but what about its newer, bigger brother, the 21 700.? A lot of you guys have asked me: when am i gon na, make my little pcb project for this new version of the batteries right? If you don't know what i'm talking about, i made this pcb version of a battery module right, and this is super popular. I think i've lost track of how many of these i've being produced, but somewhere around a hundred thousand of these things have been produced. Half of those have been produced by me on my own website. We sell them uh jack 35.com right, but the other half is uh diy.

It's an open source project, so you can download it. You can print the things yourself uh. You can buy these from many sellers in many other platforms in china, including aliexpress and uh. All the other big platforms right.

So this is super popular people have been asking me. When am i gon na update the design to be able to accommodate the 21 700s, and i said: hey, you know what the 2017 new they're a thing they're too expensive. There are things that are hard to get the day, that i have a pallet or a couple pallets of these batteries in my warehouse, then i'll make into the guess what i have now for a little while for better part of the year. I think i've had pallets of these batteries on our website.

Uh brand new and uh. I haven't made the thing yet so i got ta do good on my promise of designing uh a pcb board for these, so that you can quickly and easily make battery modules using these cells uh without having to well know too much about batteries and not having To have specialized equipment to spot weld or other stuff right so today, i'm going to run you through the process of may design software right, and so i'm just going to do a time lapse because it takes quite a while to do this. A few hours, probably like four hours or something that's taking me, i've got the quickest one. I am a novice at making pcb boards these.

This is my first one that i ever did since then. I've made, i don't know a dozen others. Maybe i know at this point like 20 25 or something so, but i'm still not very proficient i'm making this stuff you're right, i'm self-taught! So i probably i'm doing things not the the way that the other people do them and stuff. So i am just going to speed right through this thing and then i'm going to do a voiceover and explain why you might want to do and why i'm doing the things the way i'm doing them and you know that sort of stuff.

So, let's start this video by showing you the pcb making process. Okay, so the first thing you will have to figure out how to do is the mechanical right. So this is the dimensional uh size of everything right, and so what i'm doing here is just drying up the holders. These are the little battery plastic battery holders that i bought on aliexpress that hold the cells right.

Those are the ones that are going to go and are going to populate this pcb right and for the purpose of holding the cells right. So i measure them. I use a caliper and then you know measuring and then i'll draw the footprint here. A lot of the times this sort of stuff - this is considered a component and so a lot of times.

You could just go into this program into a library of known components and you can sometimes find them there right, but on this time i just didn't bother even looking for that. I know like connectors stuff, like that, usually you're able to find it but stuff that it's a little bit weird or new uh it's hard to find it. So you might just be better off just starting and doing it like this, and there is a way to make that into a component right the footprint, and then you submit it up to this library so that others in the future that are designing a pcb board. Then they can use all this work that you're doing so you can choose in this case.

I didn't do it. I just went and started drawing it on the actual the well. This is a pcb a drawing right. It's a board drawing not a component uh one, and so that's what i'm doing here see those those uh.

Those green layers are basically i'm just using those as guidelines right, so i'm measuring and then i'm thinking like okay, so from here to the edge of the of the little holder to where the first pin it's x amount. You know 11.68 or you know 11 and a half or something like that right. So then i'll just make that in there and then i'll put it it just helps me guide it. Just you know gives me a visual aid.

This just what i do. I don't know that's the right way to do it, like i said, like i'm self-taught doing this, so you know i don't know, there's maybe other ways of doing this now. A thing that i kept coming up against here is that i kept seeing that the dimensions were not adding up and, as it turns out, the caliper that i have at home might not be very accurate, and so i had to that's why things weren't added up And it wasn't until the second part of this, drawing that i you know compared it with the caliper that i had in the office. I took the one from the officer home and then i was trying to do it and i'm like.

Oh okay, that's the problem. The problem is that these dimensions that i'm getting from the thing might not be very accurate, and so therefore that's why i kept just it just didn't - add up visually when i was doing this right. But you know here i'm measuring the second uh from the first pin to the second pin and then i put the little hole in there and then i'm going across and i'm trying to use. You know guidelines so that it's not crooked and you know it's like all the dimensions have the same.

You know the same well, the same numbers right, so it adds up so the red the purple outline there. That is the actual pcb outline right. That's the board outline and then this yellow ones are, those are called silk screen, and so it's basically just a paint uh layer right that you can. The pcbs have, and you have the yellow one - is the top silk screen layer and the bottom and the green one is the bottom one.

So here what i did is i realized that i have done this many times before, and so i'm like, why am i starting from scratch? I can just go and copy and paste from the other boards that i've already done right, and so that's gon na eliminate a lot of work right. Why reinvent the wheel when i already uh did it? I already dropped most of this. This this board is going to be very similar to the other 4s that i did for the 26650s. It's just the dimensions are going to be different because there's a different, you know so the board, the the cells dimensions are different, but everything else is the same.

I'm using that same connector, i'm using the xt90 connector or it's the it's a that's an xt60 connector, and so there we go now. I'm just adjusting the uh dimensions there on the other board right by just moving those things in there and then there we go. Okay, so that's what it looks like this is the 3d rendering and it kind of gives you an idea. So then i go into some of my other designs there, as you can see uh and i'm trying to bring some of those in here.

You know just to copy other stuff. Like you see, those pads are bigger on that on the 4s sport right and i have already gone through the whole process of you know, going back and forth to see what the the best size is for that right, and so sometimes when we're the only way To test this stuff right is to to actually draw the board and then get it in your hands and then try to populate it. And then you start thinking about things like. I should have more a bigger solar pad in here, so that the solar flows better.

You know or oh i need more distance between this connector and that connector, because it's really hard to populate you know to put the connector in there once it's in and a lot of these things. You can't see them until you have the physical board right in front of you, and so that's why i'm going and using a lot of this stuff from the other boards that i've designed before, because i already went through that process of like double checking and moving Things around so that everything works and everything works better right, and so now, when you're designing a thing, you might not have that right and you might have to just start from scratch and it's just going to be kind of trial and error. What you have to do is, you know, draw up your first iteration and then order it and then get a sample, get it in and then play with it and do the thing and then you're like ah yeah. This is a stupid mistake.

How come i didn't see it right like okay, so let's change it and then you, you know you change it, you revise it and then you order and that's why you have to order these sample batches of these boards, because it's going to take a few tries For you to try, especially if you have no experience or like me right, a lot of these markings will help you once you're populating these boards once you're using these boards, the more information you have there, then the less you have to think about right, um and Then not just on the front side, sometimes you're like i wish i would have put these markings on the bottom side because well, the top side gets covered by the components right, and so you can't see those marks once it's populated because you flip it around it's, Like all the marks on the wrong side, so then you want to get some of these marks also on the bottom, so you can see them okay, see now here what i'm doing after i got the dimensions, the the mechanical dimensions of the board right and all The placement of the connectors and the whole thing the next thing to do is to now start running the pads. These are the copper layers. These are the layers that are going to to transfer the power. You know the electrical energy from one you know pad to the other right or one component to another one, and so i guess uh.

This is all this is gon na, be seven cells in in series, and so it just makes sense, and i want all the cells to be oriented in the same way, right all the positives, to one side of the board, all the negatives to the other side, Because that makes it easier when you're populating the board, you know you don't have to flip back and forth, and so it eliminates the chance of people making a mistake. You know all the positives go one way and when you're, if you're populating 100 of these boards, you know with cells, then you just get into a rhythm you're like okay, just place all the cells facing the same way. You place all the boards facing the same way and then you, you populate them without much thinking about it right, and so it just kind of eliminates the chances of errors, and so that's why i'm doing it this way now i'm doing the pad here. This is that layer right, but you can't connect it.

That pad in specific, is just to hold that connector in there. So it doesn't it's it. It has to not be electrified right. I guess you can uh if you're running some kind of shieldy thing, but you definitely don't want electricity on that on that thing, because it's basically just to hold the board the connector onto the board right and so that's why i'm going around and cutting around there.

So it's not touching the actual, copper pad or the copper layer. So it's not electrified. Also, another thing that i'm doing here is i'm moving things around, because what you want to do is have the the biggest traces of copper, because these are gon na carry up to five amps right um. Once we build this board, we maybe will bump up a little bit, but it all really depends on the weakest uh component in this board, and that is going to be the cell holder, uh contacts spring context right so on the 18650 ones.

Anything above five amps starts heating up too much and starts melting those holders. So that's why we we put a five amp uh fuse in the border there, so that the fuse will blow before you start melting, your uh holders, your cell holders right and so we're gon na leave that here for now and then once we do run some Tests on these on these holders for the 21, 7 7 700s uh we'll see if they're the same, if they're the same, we'll just leave it like that, if they can handle a bit more current, then we'll change that in the board there and then we'll put Uh, you know the different: that's just the marking in there right um, but the actual sizes of the of the five amp or a six amp fuse is the same. So you it would be the end of the world if it's, if it's like that, so what i'm doing here is now changing. You know it's like it's gon na go from positive to negative.

So all these connector connections have to be diagonally right and that's because all the cells are facing the same direction. So now, though, you know the the cell, the terminal on the far left, has to connect to the far right on the next one, and so that's why we're doing this here and of course, here i made a couple mistakes that i ended up. Fixing on a later uh iteration of this uh in order to not have to make every single one of these, what you do is you make the first one and then you just copy it and paste it to the bottom. But that means you have to take in consideration certain dimensions so that the top line matches the bottom line right, and so you don't have to adjust every single one of that, and so here is that so i'm playing around with that in here, i kind of Did that backwards, because i started with the upper sections of that see now i'm changing it and that's you know, yeah you, you learn to do things quicker as you go, it's not okay.

I mean it's not kind of it's, not super counter-intuitive. You you have to just kind of have to get experience. You know see here how it doesn't match and i have to adjust it and then, but i adjust that and then like that, doesn't work right. It's just it's better if just the same shape works.

All the way down, and then you know just do it - i kind of got it right there, but not 100 percent, and there is the one side, the upper side. Now there was one day and then i came back. I think that was like on a friday and then over the weekend my computer froze or something so. I had to restart it when i didn't realize that i hadn't saved this file, and so i had to start all over uh and i had to redo it and so therefore uh.

The final version might have slight differences that when you're actually seen in the screen here, but i basically just had to redraw it right - and i didn't you know - i didn't record myself drawing it the second time, because i already had all this here and stuff right, But but it's the same concept, and this is what i'm doing, i'm just you know changing those pads because they're too small - and i figured that out. You know by experience on the first time that i did one of these boards and i realized that by putting a bigger one, it's just it just helps you a lot by when you're starting to um populate the things right. So then, what we're doing now is we're changing down to the back side right - and this is the bottom layer, copper layer and so because i'm going to connect that lower pad all the way to the upper pad right and then - and it's only going to be On the one side of this board, that's going to carry that. Then i want to make that pad kind of large, and but i also don't want to connect to those pads in there, because those are all the positives and negatives of the cell so has to be isolated from that.

And so that's why i'm drawing those little lines uh and those little circles that i put in there. It just makes it simple to make it nice and neat, and then you can just go back and just cut out like a rough like what i'm doing here. It's just little tricks that you learn to do so that uh it doesn't look. You know like uh, a five-year-old did it.

You know. I don't know this might be way too much work for a little board. You could just do it like more basic or more uh, you know everything doesn't have to be perfect and you know that's exactly aligned and you know, but you know the the the better you do this uh, the better it's gon na look, and maybe the better Is gon na work right? That's my whole philosophy there! So now, what i'm doing is i'm putting a second right, the the the back layer uh, i'm doubling it up on that one there, because that is the only pathway where that connector is going to be powered from, and so it's kind of you know it's there's Not a lot of surface area there to carry that, so i thought well, you got to do it on the opposite side and then it doesn't connect all the way through, but at the very least, if it's connected to the other side, uh, it's gon na help Dissipate some heat, if you ever use that connector there and stuff so and then that's what i'm doing here, i'm just basically just doubling up and following the same uh shape as the top layer on the bottom and then what we're gon na do is we're gon Na use some bias uh things on the later to connect the top and the bottom, so it could serve as a secondary. You know just to double up on the copper thickness at the very least on that section of the of that board.

This is the whole philosophy that we're you know just put as much copper to use right. This whole layer of copper is going to be on the board already right and whatever you don't end up using has to be uh with an acid has to be stripped away. It has to be you know whatever i don't know, what is it? Melted, not melted? It's got to be eaten away with acid, so so the the more copper are you end up using than the less copper that has to be removed from the board, and why not i mean it's. A copper is good.

It's a conductive material that we use here too, and so the more you have on there, the better it will be so there you go. It seems okay. Now i just got to add that little thing back in there, because why not again the more copper you have the better and here's where now i'm starting to add the biases. The bias is just a little a little uh, it's just a little hole with uh with solder right, and so it connects the one layer to from one side of the board to the other, so the top to the rear right and then basically that ties the Two layers together and it helps dissipate some heat and it helps connect the two layers together, uh to double up that current carrying capacity on those on those layers, right uh, and so that's what i'm doing here as anywhere where i can see that that it would Be beneficial to connect the top layer to the bottom layer, then i put some of those in there and so that's what i'm doing here now.

This might add a little bit of expanse to the board because it is another basically like every time. You add one of those: the the there needs to be little drill, a tiny drill with a tiny drill bit. These things are super tiny that has to go into that board and drill one of those, and then you know when they put solder, then it connects in there. But i think it's it's useful to do this, because then it makes your board a much capable of carrying the current that you're gon na ask of it, and so this this is the part here where i'm connecting the bottom layer to the top layer right and The bottom, the top layer, is the one that connects to the board to the terminal to the battery terminal.

But then the bottom layer is the one that's going to actually carry that current. All the way to the top of the board into the connector into the right to go into your load, and so that is those biases are basically those are the only things that are going to connect that thing, and so that's why i added so many of Them over here on the bottom, because that that's that's it right! That's what's connecting that layer! Everything goes through there. Now i'm just kind of carrying around all the you know again all the markings that are gon na help you when you're, when you're populating these and when you're troubleshooting you know i was like, did i put this board backwards? Well, i don't know what does it say it says top or should say bottom, oh, if it says bottom, oh man, i just you know this are sort of the things that we've learned throughout the history of doing these. That will make the uh assembly process a lot easier.

All right, so that's it after we finish that design, then all that is left to do is just to export it out as a gerver file and then i'm going to upload it to pcb way. This is a shop in china that makes some of the best pcbs and we've been using them for a while, and they are sponsoring this video right. So if you want to get this pcb, all you have to do is click on the link below go to their website, and then you can just purchase the pcbs there and you can print as many as you want now. Keep in mind that this is the preliminary you know just the first try at this, so the dimensions might be off a little bit and i will update it once i get it and i try and i make sure that all the things are done correctly and We didn't make no mistakes and stuff, then i'll update the the file up on on their website and stuff, and so now from then you'll be able so you're watching this.

Like later, you know a month, two months, three months a year down the line from where this video uh is uploaded, then you know the the file is going to be checked out and you know will it it won't be. It won't have any mistakes right because we'll work out all those mistakes, but if you're watching this today, you know the same week or the same day that i'm uploading this and you want to order. You know just keep in mind that you might get uh a few little things here and there i don't think, there's going to be anything critical, it's just going to be a slight dimensions or something like that right. So all right! Thank you for watching this video we'll see you guys on the next one bye you.


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