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All right guys time to do an update on the lithium-ion, phosphate, uh headway battery bms board right. This is the bms board. These are the bus bar plates uh, those are for sale, you guys are buying a bunch of them, but we - i was developing this thing. So now i have a version of it that i could try it here for the first time.

So let's do that right now. What is this thing? Well, it's just a plate that fits right on top of this other uh battery pack that we've made right. You will need to solder the big old terminals here and the battery is capable of like more than 500 amps, but then the the boards, the pcb boards. Then then that brings down to 500 amps.

But then the bms brings it down even more to 200 amps because well, there's i haven't found a bms that can handle more than 200 amps. That is not bigger than this right. So if you have a preference, if you have a a a favorite bms unit that you use for a 4s lithium-ion, phosphate pack sort of like this one right, but as far as i was able to find um, i like using these dahle ones. We have a working relationship with them because we buy a lot of bms's from them, and so they have these ones here that are affordable and they're small, so they two of them fit right here on the on this form factor right.

So that's why it goes from two of these terminals that can handle 180 amps each, so that's 300, like 400 amps or something um or 360. Something then to a single one and then to a single one here. But this screws right on there should be really easy for you guys to build this right. I'll.

Give you the file, like every other project that we do, will give you first a file for you to print your own pcb right, printed circuit board and then um and then i'll. Give you the links to all the components, including the bms's and stuff, where to get them, and then you can build your own and then, if you wait a little bit longer until we are able to get the parts in and stock them or whatever, then you Can just order the kit uh or fully made like this? I don't know if i'm gon na sell the kit and food made or just fully made, have my guys, you know kind of build this and then ship it like this, so that you can just you know, put it on top of your battery there, but either Way this is we're going to test it today, because i haven't this, is i just put it together and then i haven't tested it. I still have to make a couple of little design changes on these bus bars uh. Just to make it a lot clearer on how to connect it uh it you, i will be able to connect it.

No problem like this is just uh: you'll have to pay attention to where i connect these three cables, there's only three cables. I have to connect down to uh. Well this bus bar and then the the one on the bottom one right there too, so uh yeah. Let's start with that project all right, so i guess you have to match the positive to the positive, the negative to the negative, and i guess, there's not a lot of risk here when you're putting this on that is going to spark or you can short anything You basically just have to align these four holes in here and use uh, three-eighths uh or the m8 uh bolts right here right.
So these go here. The positive just kind of goes transfers up, and then it goes to the fuses here. These fuses are kind of weird um, but if you have any ideas on how we can make this fusion better because they are too tall, so basically the only way that you can put the a terminal in here uh ring terminal. Is this way or like it's? This probably this way, because this this is too high - this is higher.

These three sides right here are higher than the actual terminal here, so maybe what we need to do is move these out of the way, so you can put this way or that way i don't know or end this way. Maybe that's what we'll do if you have any ideas posted in the comments? I need some inspiration, so this one's right here. What you'll have to do is the blue cable. That's the entrance right.

So that's the end to both of these. So you have to put the bolt right through that um ring terminal there. There we go and then another one here and you have to bend it a little bit like that. That's just kind of needed so that so that we can clear, because this is the in and then this is the out, and so this is where we're gon na put the the output right.

This is the output terminal right here and it kind of combines both of those this goes in here and then it combines them and then combines them before two. So now, we're just gon na need something to tighten these. These screws are uh, they have a hexagonal head, but also has this phillip thing and i just happen to have this big giant screwdriver that fits there and you're able to tighten that pretty. Well.

Remember, there's going to be 200 amps going through here, which uh is not that much comparing to the 500 amps that we were using right before, okay, so that that plate there, it's very easy, goes on there right, like that's it you're. You installed that bms plate on top of that. So now, there's uh the most positive and the most negative are already connected to the bms's here, because well, those are up here in this plate, but the uh second, you know the connection between the first and the second and then the third and the fourth or The second to the third uh cells. Those connections are not because these are over here only so this we're gon na have to connect them in here.

So i'm gon na have to get i'm gon na have to solder some cables in here and then solder them on the bottom over here, that's uh! The only way that i can think of doing that other than maybe having like a little connector. If you have any ideas by the way, i'm running out of ideas here, so the only way what we're going to do right now is connect the cable from here to there two cables from here to this. This board to that board and then one cable from this board to that board. So, if yeah other than the little connector, i guess right, maybe a little connector there i don't know yeah.
Let me know your ideas all right, so i soldered three cables in here to these three little pads that are labeled, c2, c3 and c4. So c2 should go between the first group and the second group, and the first group is the one that has the most negative. So those negatives here and it goes through the bms, and then it goes here so this this group right here is the most negative. So then c2 is the one between the most negatives positive and then the second group's negative.

So it's this one right here, um and i put a little pad in here - it's tiny, but you can see it in between here. So i think what i'm gon na do: uh i'm gon na modify this bus bar and put c2 right in between here, so that it's just easy for you to go down and then just put a little thing there right, um yeah! So for right! Now, what we're gon na have to do is go down and then go this way into that little thing there. So that's what we have to do: okay, no big deal, so we cut this here and then um. You know just solder it in there all right.

So we have to thin that let me get some solder all right, all right, so i flipped the thing over and this is the pin that we need to go to so i'm going to disconnect the bms's just in case. So i do things like that and i realize that's maybe the reason why i've never gotten a battery to catch fire, and i you know i mean, like i never electrocuted myself uh, because i always take some precautions like that, disconnect the thing plug it in and Then plug it, you know, but you should have all your attention when you're plugging in a device right that it's live uh, you shouldn't be worrying about soldering when you're plugging it in at the same time. So just these are just, i think, things that are common sense to me, but maybe not to everyone. So i do those things without even thinking about it, but when i'm making a video like this well, i attempt to you know, find a feel the need to explain why i'm doing those sort of things all right.

So there we go. Those are the three cables. So you see they're a bit messy, so i'm gon na have to change that in the in the next batch of these ones, so that they're a lot more elegant. So this one will go go and this cable right here will go down and connect directly here.

This one i'll go and connect directly here and then this one will go and connect directly here. Oh actually, no, this one will connect here. So there's not going to be any here uh right now. This one has to go this way that one has to go.

That way, and then that one has to go in here instead of just having one so once that is connected, the next thing to do is well to check if both vms's are going to work. Why is that? Well in a perfect world? Just because you connect two bms's parallel, they should both work right. But since we don't live in a perfect role, we should at least devise a simple procedure to check that both of them or at least verify that both of them are working right. So we're going to do that is we're going to use a multimeter right.
Let's see here, we'll set it to voltage, voltage voltage uh, you put it a dc voltage there you go so then here we go. Let me move it over here, so you can see it. Those stupid lights there we go so positive should be positive. There should be oh, there should be no voltage, but there is voltage.

No, so there isn't look 13.45 right. That's the voltage at the terminals of the battery, but at the output terminals of the bms it's only 12.08 or whatever. So people always often ask me hey what what's going on here. Why is the bms on it shouldn't be on because it's disconnected the balance leads right, and so it's like? Yes, that is correct.

That is what's happening here. That's there's a voltage drop in there because that's just a voltage leakage on the mosfets inside of the bms right, so there's some voltage that is leaking through, but it's as soon as you put it like an actual load here. This is, this is not pulling any any load whatsoever. This is just sensing wires right.

This circuitry here is just it has his own power a battery in there. So all he's doing is just measuring, and so that's why it detects the the leak voltage, but as if you were to put an actual load here, that would require any kind of amperage right, um or wattage. Then that would quickly go down to zero. It would just drain those little uh transistors right and so because they're off and so then that's what would happen.

So if you don't see a matching voltage here, then that means that the the transistors are off, and so what we do is we connect one of these bms's. Let's connect this one right here. Okay, so now that's connected it has the sensing uh voltages of all the cell groups and since they're all good. I hope since uh i charged this last.

I don't know it's been a week or so since i charged this, then the bms should be on, and so let's test again so 13.46 13.46. Now the voltage matches right so now we know this bms is working. So, let's disconnect it turn it off, so that we can check the other bms. So now, let's connect this bms and now this bms is connected, so the voltage needs to match again: 13.

145. 13.45. There we go so this one is on, and this one turns on when you connect these little cables here, which is exactly what they need to do. Um remember these are just switches, so the is when these when, when this doesn't sense, a healthy voltage, it just turns off the current path to here right.

So this is the output, and then this is the input it just disconnects these two, but when everything is within specs, then it just connects turns the mosfets in here turns them on and lets the power go through out of this black wire and then into this. So now we should be able to connect a load in here and then test it. Let's do that now and at least load it up with 200 amps to see that the bms's can put out their uh rated and right and they don't get too hot and the whatever any problems that we cannot foresee will come out there in a real test. All right so here are our tests.
Uh, here's our test setup battery 12, volts right to the bms 200 amp bms, then uh, six gauge wire going into this 3000 watt inverter, and this inverter is going to be powering just a little heater. We have the uh clamp here so that we can measure how many amps we're pulling, and this thing could pull more than 200 amps, so i'm just gon na use it as a gauge so that we don't blow our well. I mean this thing should turn off right if uh, if we pull more than 200 amps right. So let's see, let's start: oh there we go see here.

So that's 16 amps. Let me bring the thermal camera just in case, so there we go. 30. 40.

50.. Oh come on really. What do you mean overload? It's just overload. Okay, let's see here what the hell is going on with this, i might need to get the other one so dc, so they match at the very least they match.

Okay. So 70. 80. Okay, so that's 80 amps, okay, so i'm gon na put it somewhere around 40 again.

So i'm going to turn this turn the second. I don't know: okay, so 50, okay, so 100, amps. 120. 130.

160. Okay, look at that! So that's 200 amps right there and i mean i see a lot of heat. Okay, okay, so something happened. What happened here? I think the uh fuses blew yep, so the fuse is blue.

Oh, i guess so that's my problem. I have only 180 amps of fusing here instead of the 200. okay. Let's change those and redo this test all right, so i changed the fusing now to something above 200 like 240 or something like 230 amps, so they should be able to withstand 200 amps we're we're right now at 210 amps.

I see smoke turn this up. So i see smoke coming out of that battery. There uh, i think it's the fuses sure enough. The fuses are melting, so we're gon na have to change those fuses.

Those are not appropriate fuses for that all right. Well, i'd say this was a pretty that's a failure uh test here i mean it's successful test because we found the failure point and we realized that these are just not gon na cut it. Now i don't know what i am gon na end up doing, but we can't use these even even these right, eight of these little fuses uh at 30 amps. So three, six uh.

So what is that six? 120? So that's 240 amps! These fuses should be able to withstand 240 amps. We were at 200 amps and they're still melting. You could literally see that they're melting in there see that they're just and that's where the smoke was coming out of so uh. These are black in here.

They do make bigger ones in this on this form factor, but then the little base starts uh getting too hot. So that's the the reason why these fuses are just not gon na work. I could add more to right. Another two or three over here.
Just put a big old line, but now it just becomes a giant line of fuses in parallel, might as well just use two bigger fuses. So i do have uh other fuses that i have here that i have uh in quantity that we recycle from another thing. Right so maybe we can use those because those are cheap, but the thing is that once we run out it's going to be hard. I was trying to use these because they're easy to find and you can find these anywhere and so they're easy to place when you're buying them.

You can buy them from several sources. It's just a lot better right. So if you have any idea or any recommendations as to what fuses we should use here, to be able to do, the 200 amp continues by the way the bms's perform great. Yes, you can see in the thermal imaging and the video like these are not getting hot at all uh, it's just this stuff right, uh, the fuses and the cables that i had here were a bit too small, but it doesn't matter.

It was just a quick test. I wanted to see where the failure point on this, and it is these fuses here. So if you have any suggestions, put put them in the comments, i will look for another type of fuse. That is not too big.

It's not too expensive and then we'll use that instead, it's not yeah. Hopefully i can fit it in here and reconfigure it so that we can use that in here, right uh. The other thing is to add fusing outside of this box, but i'd rather keep it in here just so that it's a complete little system here, a battery that has fusing right um. Why not make it better than when you can just get there? Usually, batteries don't have internal fuses, but this well.

This is a custom battery that we're making here. So why not? Why not make it the best battery that we can make right so um yeah, if you have any recommendations, put them in the comments. Thank you for watching this video we'll keep developing this, and eventually we will get it right, and then we shall uh make some cool headway batteries for all of your uh high power applications out there right all right, guys, we'll see you on the next one, bye.

One thought on “Bms fail”
  1. Avataaar/Circle Created with python_avatars Paper Art says:

    Nice battery pack

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