Hello today I'm playing with my 768 W battery. um I need to fit the BMS Now I've not powered the BMS up yet but here it is. This is the Uh Yunu BMS I think it says no it says that there yunu um 80 amp says it there. uh 3.2 volt so it's life po 488 s now that's going to fit on the side here.

So I just need to bolt on these link pieces onto these two points and then fit this connector now I've not uh done this yet but I have wired the connector on uh, it was back to front as was the balancer actually so all the wires head off in the wrong direction. um so yeah. black to this first point and then the first red to blue and so on all the way up the line. and I've double treble checked that so we should be fine and then I'm going to plug in the balancer.

Now you can see that the balancer is not connected and all these wires dangling down here have been uh, insulated so they don't touch something they're not meant to. Um, the problem with the balancer is that I destroyed it I blew it up and uh, you can might be a to just see one of the cap ends is popped there. um I was what I was doing was cutting these wires to length and then plugging them in and then working on the next wire plugging that in. And of course that's a really stupid thing to do because inevitably what happened I think it was this white one slipped out of my hand, touched all the bits of metal.

There was a pop and a Pluff of smoke. Um, I'll put the camera on to times one actually and I lost three of the mosfets. Yeah, you can see the first three mosfets there. um, have heat blisters on them so they all popped.

These ones might be okay and the Caps I'll just repos position the camera. Yeah, I think it's the first three again. Uh, that one seems all right. Actually, that hasn't popped.

this one's popped and some goo has come out. This one's bulged. So yeah, there's a problem with that. but I did order, then immediately another one and I do have that in a bag somewhere.

So uh, I think I'll try and find that. Now you can probably see I've got my electronic DC load here. So what I'm going to do is hook this up to the battery once the BMS is on and then do a discharge because I want to check that the BMS cuts out when any one of these voltages gets down now. I think the BMS was quite low I think it was set to 2.1 volts which is a bit low for life po 4.

but whatever, we'll take it down there and just see if the BMS is working. Um and then I want to charge this up. Actually, maybe I'll charge it up first and then discharge it cuz I want to then do a full uh discharge test with this thing. make sure it does touch the battery and uh, see what the capacity is.

Nominally 768 W hours, but I'll test it with the electronic DC load. So let's put the camera here. which I might turn it around a bit so you can see the BMS. So I've got to bring these arms out now.

I don't know whether the metal work on the front here is connected to there I Suppose I could check it, but uh, it's not connected yet so it doesn't really matter. but what I don't want to do is bridge that ring terminal across onto this metal work. Um, so I'll just be wary of that. Let's bring this other one up and screw it onto there.

and then when I tighten these. nothing should move. so I really want to pull this that way towards the left so that those ring terminals can't bridge over onto the front metal work. Uh, okay.

actually that could go a little bit higher. so let's loosen these and just angle it up. tighten those then I got to tighten these nuts. Uh well.

I can sort of half tighten them with this uh nut spinner. That's probably good enough now. I'll point the camera up a bit. I've got to plug in my uh cable now don't know whether you can see this.

I'll bring the camera around. Uh, just in there printed on the PCB. It's upside down, but it says B minus so it's definitely negative at this end. Uh, okay, everything's double and treble.

Check. Let's go for it. Okay, so that's the BMS plugged in. Nothing went pop Excellent.

So let's just rotate this battery on my desk right? So the discharger I've made up some nice long cables. so that's the negative. So I'm going to wrap that around my camera mount and plug it into uh p Min So that's pack negative there. and then positive is here.

Uh, that can go up in here actually can't it? And yes, there's a voltage on the discharger. see if I can bring that into shot without touching anything so you can see there's 26.1 8 Vols on the discharger. it's set to 2 amps. It's not a huge current, so let's start that you have press it twice for some reason.

Uh yeah, that's got 2 amps. Power is 51 Watts can't read that very well, can you? uh, what's that purple one? Oh resistance. that's effective resistance. energy in wat hours is counting up.

The temperature should be going up of the heat sink and then eventually this fan will come on. But yeah, that's doing a 2 Amp discharge. But the important thing is that that uh, electronic DC load can pull current through this. BMS Let's see if that's getting no, that's Stone Cold Well, I suppose at 2 amps, Uh, could I raise it up a bit? I probably could.

Let's try raising this up. So 2 amps is in the green and the setting for current is on there. So that's 3 amps, 4 amps, 5 amps so you can see the green is going up to 5 amps. This thing regulates itself to maintain that current it's in CC constant current mode.

Okay, that's putting five amps. Uh, that should get the heat sink warm quite quickly. Yeah, it's heading up to 37. I've got the fan set to come on at 40.

Okay, the fan has now come on and I can feel a blood of warm air on my hand. So that's working and the BMS is happy with 5 amps, it's an 80 amp. BMS so it should be happy with 5 amps. Um, I could probably run this up to about 10 amps.

This cable I think is rated at 14. Banana plugs are good for 10. Should we try 10 amps, don't think anything should blow up. Oh, we've gone over the 150 wat power limit.

Okay, uh, no, that's not what I wanted to do I wanted to bring this down to 8 amps and yeah, nice blast of warm air there. but yeah, it seems good for I don't know. up to 10 amps. Okay, I've raised the camera up so now we can see the volt meters.

It's not on at the moment, but I'll switch it on at 8 amps and we'll see what those voltages drop to. Um, oh, it's still moaning about this 150 watt limit. Can I switch it on? No, Because it keeps going. Let's bring it down to 6.

M I think I have to clear that error first. Yes, of course this is about 25 volts. Uh, under load. and so 6 amps gives you 150 watts and that's the limit of this discharger.

Actually, it's it's a 150 watt unit. Um, so what I'll need to do is add another module onto it. So I'll bolt that onto the left hand side. Um, I'll find the bolts and screw that on.

Then I can relink it with that little red uh jumper, tell it that it's a 300 wat unit and then I should be able to do this 10 amp current test right? I've got uh, the two modules on here now and I've set the overpow limit to 300 watts and it seems to have sensed the little link there. So now let's try it. Uh, at 10 amps, uh, 10 amps? Okay on. So that's pulling 252 Watts 10 amps, 25 volts and we'll see what happens.

Uh, when the fans come on. So the wat hours is uh, going up quite quickly. 17.6 7, 8, 9, 18 I can zero those out by pressing these two buttons. Fact: Let's I think you have to press and hold them for a bit.

That's it. A little green Banner comes up. Um, Okay, so that's putting 10 amps. Are these wires getting warm? You'd think they would be at 10 amps.

Oh, it's off. Switch it back on see whether these are getting warm, but the BMS certainly seems to be doing its job. It's not getting warm at all, so that's encouraging. That's a good sign.

Uh, the fans are now on. Uh, these wires do feel a bit warm, but then they're being warmed by the air blowing through this heat sink down here. are they? Is it warm over here? Oh, a little bit warm? Yeah. BMS Uh Oh, not warm at all.

That's Stone Cold Yeah, everything seems to be holding up at 10 amps. That's quite impressive. What are the meters showing? Let's tip this down. Uh, they were all at 3.29 I think or 3.3 They're now down at 3.2 3.18 Remember, this is an arc of voltages, so these ones at the end will read a little bit lower than the ones in the middle because they're not very accurate.

Simple as that, right? Here's the new Uh balancer. So let's get this out of its bag. Uh, slightly different colors on the wiring. They didn't use any white wires on this one.

They obviously ran out of white cable, but the balancer should be identical. Uh oh, that's been cell taped up. now. This one has slightly different capacitors.

These are 2200 Microfarads 25 volts. I Noticed on these up here that they were 6.3 volts. Um, which doesn't give it much margin if you, um, put the voltage of two cells across it. I mean the mosfets blew up anyway.

I don't know uh whether this would make a difference having 25 volt capacitors, but anyway, should be a drop in replacement. Should fit the same footprint. So let's swap that out, right? That's the new balancer there. Um, I've used the same cable obviously because I've got all my banana plugs on it.

Uh, now to connect it. which I'm going to do on camera. why not so black into there? Uh White which is over this side because this connector also is reversed. It just uh was how it ended up being white into blue.

blue is the new white green Next, that should be the third one. I Think it is green. That little green LED should come on while I'm doing this. of course.

uh. yellow next. So that's there. Then there's this bunch of three here which is the green.

yellow and white. So green is the next one that looks okay. yellow is that one yellow goes in there. White goes in the blue.

Uh, green is the last. but one yeah, looks okay Green in there. And and I mean the reason this blue last time was because I didn't put the voltages sequentially across the unit I Just put some arbitrarily, probably a low voltage cuz the white wire shot over there somewhere. Um, anyway, last wire red and that goes to most positive.

so that's it now. balanced and BMS So yeah, that's it. kind of finished. So now what I want to do is all this uh, charging and discharging, measuring the wat hours and doing all that stuff.

but that's going to take a long time and you won't want to watch that so I'll do that off camera. So for this video, Cheerio.