Hello today I'm playing with the sodium ion battery. My first ever sodium ion battery. So I've got four cells in series here. so it's a nominal 12vt pack.

It's a little bit low at the moment 10.35 volts now. It's got this power supply on it, which is a buck boost. um, designed to put out 12 volts so it's actually going to be boosting currently. So I'll switch that on and you can probably see some lights came on I'll just zoom out a bit.

Yeah So here's the setup: Sodium Ion Cells for in series. Um, I'm just monitoring the voltage of that pack. Uh, buck Boost power supply a little two-way adapter thing and I've got two of these 12v strip lights. Uh, there can you see that this one's got a set of Lights missing? Yes! I think you can Now the voltage is getting a bit low.

We've dipped under 10 volts now and this can pack can go down to 8 volts because it can go down to 2 volts per cell. But of course I've no way of knowing at the moment. um, whether one of the cells has gone particularly lower than the others. it probably hasn't yet.

I Probably am all right to take this down to 8 Vols 2 volts per cell. One of them might be pushed a little bit lower, but what I don't want to do is take it so low that one of the cells actually gets pushed into reverse voltage. So I need some sort of individual cell monitoring now I Could make up four of my little uh voltmeters out of battery testers and put 4 volt meters on a little board over hanging this Uh pack. But I think um, one thing that would protect me against one cell dropping low would be a BMS s.

Now there are no purpose made, well, low cost like this sort of thing. uh, sodium ion Bms's this is a life Po 4 BMS and you can also get this kind of thing in lithium ion Nmc. So um, the only way I could get a BMS that had the actual correct voltages would be some sort of expensive smart BMS there's a JK BMS which I've ordered um which can actually is fully programmable and you can set it to two volts at the bottom, four volts at the top and that would work fine. But interestingly this life Po 4 BMS the cut off voltage at the bottom is actually 2 volts.

so I could use this for discharge and if any cell went below 2 volts, this would cut it off. Now what if I only used um half of this BMS the discharge part and then I got another of these Bms's the nickel mang Cobalt one and use the charge part of that. um, because that cuts off at 4225 I think it is Vols It's a little bit high for these cells, but if you remember I Looked at the data sheet for these things and it said that they'd been taken up to 6 volts with no fire or explosion. So I think they'd probably be safe to be taken up to 4.2 Vols which is a little bit above their spec of 4 Vols So what I'm thinking of doing is using two of these Bms's Now imagine one is Life po4 These are both life Po4 actually, but imagine one is Nmc.

so B minus on both of them, which is this left hand connection would be both connected to the most negative point on the battery and then B+ on the lithium ion phosphate, one would be used for discharge. so you put your load on there and then if this went below two volts, it would uh cut off and then on the Nmc one uh P minus here would be used uh for the charger. so you put the charger in there and then if any cell went above 4225 I think it is I looked up the data sheet for this chip. that's where I got these numbers.

Um, then this would cut off and prevent charging now. I'm only going to be using these Bms's as protection devices. more of a BPS Really a battery protection system? Um, the charging mechanism is not terribly good. Uh, so I won't be relying on that I'll have actually a separate Uh battery balancer now.

I'm thinking of using one of these uh, new battery balancers which have these Mlcc capacitors multi-layer ceramic capacitors. Um, this is an 8 cell BMS Um, sorry balancer. this is a balancer. I've ordered a four cell balancer so when that comes in I can attach that for doing balancing the thing I Like about this is it says if you go below the cut off voltage which I think is 2 and 1/2 Vols Um, it actually goes down to a standby state of 5 microamps so it's very tiny.

Uh, off. State current. Uh, so yes, the 4s1 of these is on its way. and even though this balancer is intended for Lithium Ion Phosphate or Nmc, uh, the cutof at 2 and A2 volts simply means that it will only balance in the midpoint of these cells and at the top and it won't balance at the bottom.

And in some ways that's an advantage because if you balance at the bottom and and then balance at the top, you're constantly changing the the balance arrangement of your pack. But uh, yeah. so I think that'll work perfectly fine on sodium ion and using one of each of two different Bms's uh also should work largely anyway. today.

What I want to do is uh, spot World these tabs on because actually at the moment they're just held on with magnets. Um, I've got 1.6 amps going out to those two strip lights. Now that's at 12. Vols at 9 and 1 half volts, we've probably got uh, in excess of 2 amps being pulled from this battery.

So these magnet. these are the steel nickel plated steel strips, but just held on with magnets. Yeah, it's good for 2 amps, but probably not much more than that. So let's switch off the lights.

Uh, I'll unhook all of this and I'll give you a Clos look at this battery pack right here it is then. So these are the 33 140s. They say 32 140 but they're actually 33 diameter. These are the 33 millim end caps.

Uh, you can see here that I've just got these magnets holding on these steel strips. couple of terminal posts here for my 12vt output. Uh, remember the fully charged voltage of this is 16 and the fully discharged voltage is just 8 volts. Uh, a couple of Steel strips on the other end.

Um, now I've got two cable ties I cut slots in the little recesses on these end caps. Uh, you can see the little triangles there. So I drilled and filed slots and I got two cable ties and they're slightly stretched. Not not one, uh, much, probably one of the little it clicks, pulled tight.

they're slightly stretched just to hold these uh, end caps on. and then if you see down there, I've got a threaded Rod it was just a piece of Rod I had that would happen to be exactly the right length to run through the battery pack, a couple of nuts and a couple of eye hooks which are screwed down into the wood. so I can hang this upside down and I've got 4 feet on the bottom so it's all held together, but the steel strips are just floating around on these magnets. They're not very good good.

So the first thing I want to do today is get the spot welder up and running and get those steel strips spot welded on so that I can draw a bit more current uh through this pack. So I'll just undo these uh terminal posts and get the uh steel strips off the end points. Uh, so all I've done is soldered the seal steel strip onto this uh ey hook this ring, terminal and uh, once that's welded on, that'll be a bit more permanent so get this one off. Uh, okay, so now what I want to do is I'll probably have to drill a hole in this piece of wood so I can stand this block of batteries up and then the little cable tie can sit in the hole while I spot weld uh, these things on and then I can get rid of all of the magnets.

So I'm unding this nut. uh so that I can pull out this through threaded. Rod Then that means I can lift the battery off the piece of wood. Uh, it's just two little tiny eye hooks on there which hold this down.

Uh, this is a bit of those um, threaded inserts aren't really necessary, but this is a piece of threaded Rod I Found from years ago. it's actually 2ba. It's not even metric. it's uh, ancient.

but it just happened to be the right length. So uh I thought right? I'll use that. Okay, so I need stand this thing up? So I want to drill a hole in here? Stand this up. Get the spot welder and get these spot welded on right? I've just been out to the shed and drilled that uh little hole in there that just lets that cable tie rather than cut this all off and then put it on again.

uh, that just lets that sit in. uh, there now. I can spot weld these on. So I'm going to need the uh spot welder.

I just haven't charged this for a while. So so I just wanted to check what it's got in it. it should. Oh, it's a bit low 4.6 volts, but that's held up really well.

That's been a couple of months I would have thought before since I last charged it. So these capacitors. these big 3,000 farad ones. They discharge pretty slowly, but I will put that on charge.

get it up to 5 volts. so I get some good spot welds uh and then get some welding done. Uh I got to try and remember the user interface for this thing. So I think press, hold down and yes, that seems to be setting the constant voltage parameter.

So I want 5.4 although I'll probably only charge the capacitors up to. oh, it's gone into super speed mode. That's annoying. Uh yeah, 5.4 but I'll probably charge them to 5 volts Perhaps I need to stop and then start again so it doesn't go into that super speed mode.

5.4 Okay, 5.4 Okay, so that's set to 5.4 Uh current? Don't suppose it matters really. Uh, so I've set this for 2 amps. Of course it's reading a much higher voltage here at the power supply uh than it is at the capacitor. but at least I can see the voltage on the capacitor.

So I'll wait till that gets to five. 5.1 volts. Maybe uh and then I can shut this off and start my welding. Uh okay, this has hit constant voltage at 5.4 volts at the power supply.

it's only 4.9 at the capacitor. It's because of this thin charging cable and as a result, it's winding the current down. which means it's charging slower I could raise the voltage on here, but yeah, I'm not too bothered. I think I'll wait till 5.1 and then I'll get on with my spot welding right? 5.1 volts there on the spot welder.

That's fine I can stop charging it and let's get spot welding. Okay, let's try a spot weld. So I'm using the magnet just to hold the strip in place. At that end, let's get the positive on.

Uh, does it matter which way? I do it? Suppose it does? Does it So let's get that on and then the negative and that's my first spot world. I think I'll do three pairs here and here. Okay, that's welded on. That looks pretty good.

Uh I'll slip the magnet out I can't do that on camera cuz I don't want it to touch the negative and get the positive welded on right Spot welding on the positive uh of this other cell. so let's hold that there. slipped a bit there but doesn't matter too much. These two weld themselves on.

Okay, that's my first strip spot welded on and if you like spot welding, well, I'll just do uh, this last one on this side on camera. oh, that drifted a bit, but it's all right and a third one. Okay, so that's the two strips. uh, on the back of the battery now.

I'll flip it over and do the one strip here and then I need to do these strips with the ring terminals on them. uh, on the two battery end points. Okay, so I've spot welded the Uh strips that come around onto these ring terminals. on to pause and next so that's all done.

I Just have to put the retaining threaded Rod through the battery and just to show you that the spot welder is now down to 4.9 volts after having done o what would it be? 12 *, 4 48 spot welds and let's put this threaded Rod back in so into one side into the other side and then I just span these out uh so that it wouldn't come off. That's all it wasn't for any other reason than that, really. Uh, okay, so now I need to drop that down onto the board and get the two nuts on. And of course these are 4ba nuts because the rod is 4ba right? I think I'm just going to mount this BMS uh there and then I'll Mount the other BMS when I receive it I have ordered an Nmc BMS which will do the Uh charging.

This will do the discharge charging as I say this one cuts out at 4 volts I'll have a look at the data sheet for this chip. It's quite interesting. It's a Byd chip. Build your dreams who are making the electric cars and bringing them over to the UK and um, they use lithium iron phosphate blade batteries in the car so they should know a thing or two about Lfp.

Um, and this is the Lfp version of the chip, but uh, let's just get that mounted on there first. Uh, so I'm just going to go in into these two holes. Oh, knock to the camera. That was inevitable.

Let's go in there and in there. I'll go quite deep cuz I'm not sure what length screws I'm going to use. Okay, that's good enough. So when I take things apart I just sort of keep all the screws and brackets and bits and pieces.

There's a couple of screws in there that I think might do the job. Uh, fairly long but not terribly thick diameter. and now I need to, uh, get these wires cut to length. So for example, this black one will go to the most negative point on the battery.

so I can cut that about uh, there. and um, this is this thing that I was saying in the last video about attaching the wires live. um, simply because it anchors that point there. But it's not a good idea because if something slips, it's all right with the very first wire.

Uh, but if something slips, then you are liable to blow things up. So I'll probably solder the first wire and then I'll bring this plug out and just blue attack it to the side of that cell or something while I cut all the other wires to length. But let's start getting these solder. I should be able to solder relatively easily to the steel strip, possibly not at the cell itself.

Perhaps I have to come come down away a little bit. but let's get all this soldered on. and then at least I've got a BMS for discharge so that I don't undercharge any one of these four cells, right? That's all cut and soldered. Uh, black to most negative Point that's the black wire there.

Uh, yellow goes off to the next most positive point. and yeah, these, Uh, steel strips are really easy to solder too. uh White to the next one. orange to the penultimate most positive point and red goes to the most positive point of the battery which also goes to the red external terminal.

Uh now I could plug that in Now in fact I think I might do that. but I also need to put a wire a higher current wire from the B minus Point Here that is B minus isn't it? Yeah, got this the right way around over to the most negative uh part of the battery. So I'll make up that little cable right I've made my uh thick wire from B minus to the battery negative I'm just going to try and shrink the heat shrink on that I can't use the little uh deflector there cuz I can't get it round so I just have to work this as much as I can and then um, perhaps take that off and use the deflector. Now where am I going to connect the P negative which will be the uh discharge point.

the point where I connect my load um I've made this a bit asymmetric. Actually, I was thinking of putting another terminal post there, but there isn't a lot of space. I might put one here offset from this one and then run a wire from P negative out to there and then that will be my point. where I connect the load I think I'll do that.

Uh, should we make this a blue one? I just have of a blue one here. So I'm just going to I've slightly opened that out I'm just going to try and screw this uh 3 mil thread down into the wood and then I'll use this ring terminal to connect a second black wire over to P negative which is there. There are some slight Flats on the threaded part of this uh, terminal block. so I'm trying to thread it in but it's getting very tight now and uh, I'm worried about it slipping and misshaping this.

I'm also being careful not to short black to Red there because of no fuse at the moment. Uh yeah, I just want to get that nice and tight. So when I bring that around, it's not going to slip and deform this thing. How close is that down? Another full turn? I Think right? so that's kind of finished.

Um, I'll just zoom in a bit actually. but of course this is a lithium ion phosphate. uh BMS So fine if I discharge through this. but if I charge through this, if I charge through the Blue terminal then this is going to terminate I think it was 3.85 volts.

it cuts out it's fairly high for lithium ion phosphate. um of course for sodium ion it's it's a bit low. um so what don't want to do is put the other BMS next to this and put a a second P minus wire to another terminal post which will be where I charge and then these will get charged up to 4225 volts I think it was I Was looking at the data sheet for this Byd chip and it's quite interesting. certainly.

Um, stuff about the balance the balancing circuits is really quite interesting. It's an interesting data sheet to read and uh now I've setled. saw this up again, switched on my two strip lights and it ran for 30 seconds or so and then cut off and it was 9 something volts 9.7 volts. So it didn't look like one of the cells had got down to 2 volts, but it obviously has because the BMS has now cut off and the voltage I'm getting on my Blue terminal here is only 240 M volts.

so nothing so the mosfets have all switched off. So obviously one of these cells has gone down to 2 volts and the BMS has now protected the pack. So good thing that it's on there. so I'm going to leave it there for this video.

Um, I'm waiting for the other BMS to come in. So that's the uh, Lithium turnery BMS which I'm going to use which I'm going to sit here and use for charging because it has the higher voltage parameters this will be used for discharging. Uh, waiting also for my four cell active balancer to come in and then of course I got to make a decision Am I going to put four voltmeters on here chopped up Uh Bt1 168 Uh Battery testers Am I going to go to all the trouble of putting that on this little battery. Um I don't know but for this video I think that's enough? So Cheerio.

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