Hello New printed circuit boards from Jlc PCB So let's take a look in the box and here they are. So these are my new battery interconnector boards or cell interconnects I suppose. Um, to replace a smaller one that I made some time ago which is this one. Let's get them out of the packaging and take a look.

I have made quite a lot of these 25 I Know that for my latest battery I do need 18 of these I'll just, uh, unpack them. This is my new interconnector board. This is the old one. The most obvious difference I suppose is that uh, this is two by three whereas this was just two by two and there are a couple of extra holes up here which I'll explain in a moment.

let's bring in one of my batteries. So this is for these six amp hour lithium-ion phosphate cells which have the threaded studs on each end. Um, oh, that's interesting I just had a thought about that. but I'll come back to that in a moment.

I'll just take off these two end ones actually. I'll take off these three and then we'll try one of the new ones. All right, let's undo these nuts and get one of these boards off and see if my new board fits. So I have made a change to the pitch.

Uh, the distance between these holes on the original board? it's that way around. Really? isn't it on the original board? I did 34 millimeters. But the distance between these two threaded studs is something ridiculous. Like 34.4285 174285147 Something like that, it's the one over seven fraction or decimal and so that was, um, quite irritating.

So I thought no I can't do 34.42 I did 34 which was a little undersized. so I made the holes five millimeters even though these are M4 threads. uh, just to compensate for that. but on these I have actually made this distance 34.4 so let's see if it's a drop in fit.

And yes, that looks really quite good. I Also slightly reduced the size the diameter of these holes to 4.5 millimeters, so they're just a little bit of a better fit. And actually, it makes sense because there's a little flat on these studs. It's a thread with a flat I'll get in a bit closer actually.

Yeah, the stud is a copper I think or possibly brass stud. It's clearly welded on to the metal and it's got this uh, flat well top if it were the other way up. um, which is I don't know. vaguely hexagonal it looks like, although quite why you need that I don't know.

but yeah, that's an M4 So it's um, four millimeters diameter hole clearance. but uh, yeah, that fits really quite well on there. now. another difference you'll notice is that I have spoked these holes into the copper area and the idea of that was to act as fuses.

A lot of people think that cells should be individually fused into the bus bars. So yes, I thought I'd incorporate fuses now I've no idea I'll get in a bit closer again. Actually, Yes. I have no idea what the current rating of these four spokes would be.

And of course, it's not four, it's eight because there are also four spokes on the other size, you can also see um I've peppered this thing with wires I did that on the old board as well. just to link the two sides together. they are linked through these large holes. but I thought I'd go for the wires as well.

Um, yeah, so that's another. Innovation fuses um on the end of on both ends of each cell. Now one thing I've noticed about these cells is is that they do vary ever so slightly in length. so some of them are a little bit shorter end to end than others and it kind of gets absorbed by the flexibility in the PCB.

So if one cell is a little bit shorter, then the PCB will just dip down in that area having put more holes on one board. Um, I've yet to see whether that the board's flexibility can still accommodate this slight difference in cell length. I've made these pads large enough diameter that it will take a washer without the washer bridging across my new fuse spoke. So let's put the four washers on, get the nuts on, and then I'll explain what these two holes are up at the top.

So yeah, these two holes up here on the top. they are for angle brackets and I've gone for 18 millimeters between these two holes, which seems to be a standard size for small angle brackets. I Don't want to drop this because I don't want it shorting across somewhere like that. So the idea is that this angle bracket fits on there now.

I Was rather hoping it would fit on the inside, but I don't think it will. It's not a problem because it can still sit on the outside. so I've got some bolts here I'm completely run out of M4 nuts, so I've got to order some more of those. but I'll just pinch these two for the moment.

so let's take. Oh gosh, they're a bit tight, so let's resort to the seven mil spanner for those. Take these nuts off and then I can fit my bracket onto there. and I've gone for a slotted hole here because these seem to be sort of a slightly very varied in their manufacturing tolerances, so that may not be always a consistent 18 mil.

Okay, let's bolt that on there. and then with these, uh, metal brackets these plates on the top. The idea is to use terminal posts. so I'll just open this brand new packet of terminal posts which I got in various colors because I thought I could go black to blue to green to Yellow to Red to kind of hint at the different Uh potentials across a 4S battery doesn't quite work on an 8s, but whatever.

Actually, these have more nuts than they really need. So I've got a temporary spare set of M4 nuts so I don't need the tag I probably do need the washer and one or more nuts. Ah, Now the other thing I wanted to know is does that little shelf thing there fit in the new 4.5 millimeter holes? And no, it doesn't But it doesn't really matter. it fitted in the old five millimeter holes.

but it doesn't matter because I can include the plastic on there. But anyway, let's get this mounted on the bracket on the top and I'll just tighten that with my seven mil spanner. And then the idea of this is that all of the connection points for the BMS the balance. uh, the volt meters.

They all go in to these banana plugs. or they could use Spade terminals around that post bit there. Or they could even use these original four M4 lugs to sit on that underneath bit. That might actually be better for the Voltmeters.

I've been putting these little lugs on my Voltmeter Jst cables, so I'll just replace these two boards with two of the newer boards and put the angle brackets on. and I think you'll get an idea of what this is going to look like. might as well film this actually and then I can speed it up in post. Oh, because I've done the whole thing upside down, haven't I but never mind more footage which I can speed up hahaha.

Actually, although that little shelf there no longer fits through these holes, um, it does fit through these bracket holes. so I can sit those right down and have them quite low profile there. Um, right. So this point here is slightly more positive than this midpoint here.

I know that because that's the most positive end of the battery. So I'll put a yellow one here and then a red one on the board that I fit on that end. That's the uh, yellow, green, and blue done now. I need to put on the most positive connection which is red I've prepared this board now.

this board does of course stick out the side, but it's not a bad thing really because you do get these extra holes where you could connect um I don't know power connections or other devices to the most positive end and the most negative end I'm just thinking about. is this right to put this on here? I think it is. yeah and finally, the most negative terminal which is black so that goes on there. couple of M4 washers and M for nuts and that's it that's complete.

I'll just tighten those up with my seven mil nut spinner and then just to be sure, I'll use the seven mil spanner. Okay, that's complete. Let's get all the metal bits out of the way. We don't want metal lying around while I'm playing with this.

Um, so that's it. That's complete. Now these brackets I can put additional terminal posts in these other holes. they're really for the BMS the balance and the volt meters and I have a balancer and it has plugs on it so I can plug it in immediately.

Yeah, so the whole idea of this system was that it's very Plug and Play So now I can just grab the wires of this balancer. that's the black that goes in there. The balancer actually has a white lead for the next one. The terminal posts come in blue.

for whatever reason, then it's green I'm tangling all these wires up. but never mind. you can see the little green LED coming on there. then it's yellow that's on.

pretty bright now and then it's red. So I Now know that this balancer which you saw in a previous video is now balancing these cells I Have no idea what the voltages are but I just know that they're being balanced. Oh a big thanks to Jlc PCB for sponsoring this video and letting me have these 25 Cell Connect Pcbs which I think are going to be awesome for building these batteries. I can extend this out now to 8s and in order to build it five cells high so that'll be 5p.

I'll put three on the first boards and then higher up I'll have another set of boards where I'll have two cells and then of course I've got this overhang where I can put on the brackets so that I can attach BMS Balancer and my voltmeters. but I think that's it for this video. I'll put a link to Jlc PCB in the description below, but for the moment, Cheerio.