Good morning, all this is a three to four s: flying capacitors, balancing v 1.4 for battery types, ncm or lfp, and that's the size. So this is a cell balancing module using the flying capacitors technique, which is a green technique, green because or eco-friendly because it doesn't use resistors to just burn away excess cell voltage. It actually redistributes it between cells by passing it into capacitors and then back into adjacent cells. So i like this because it's eco-friendly, so how does this work? Well? Essentially, it just sticks a capacitor across a cell, let's say between b minus and b1 and then using switches which are all these mosfets here once that capacitor is charged up to the voltage of cell one.

It switches it so that it's placed across the voltage of cell 2 or placed across cell 2 and then, if cell 2 was a little bit lower in voltage. A tiny transfer of energy comes out of the capacitor and into the lower voltage cell, and this happens continuously, and i would imagine very quickly to transfer energy between cells to equalize their voltages. Now the technique can only transfer between adjacent cells but, of course, that ripples down the line, and so eventually all the cells covered by this are equalized. So i don't to babble on about this too much.

I actually want to get it wired up. I'm going to put it on this three cell pack: 3s lithium-ion pack. Now this works for both 3 and 4s, because common configurations for lithium-ion phosphate is four cells to get 12 volts. Uh, quite common for ncm is three cells to get a rather poor, 12 volts nominal 11.1, as you can see there, but that's quite common and they've implemented that using this diode, oh, let's get in a bit closer.

This diode, which i don't know whether you can see the pointy end, probably not yet right. The pointy end - is pointing to b4. So if you only hook up a three cell pack, um current can flow through into this end point down into the circuitry and fire. This circuitry up, so, let's just quickly, go through.

What's on this board um as well as that diode those, i think are poly fuses. I think that's what restricts this thing to 5 amps of operating current? We got uh sets of mosfets, i think they're in parallel pairs sitting next to each other, because i found that the gates were there's continuity between the gates. It's very difficult to check continuity on here, because the whole thing is conformally coated and you have to break through the coating before you get a contact, so it's all very difficult to uh to bleep out um. I think there are four mosfet driver circuits because you've got a chip.

Diode, capacitor, capacitor and you've got that four times chip die. Capacitor capacitor chip die capacitor capacitor chip, diode capacitor capacitor. So i think these are the gate drivers for these four sets of mosfets uh. There's a little sot, 23 5 pin there and i think that's the clever chip that does all the um switching well.

It may only be a bi-phase switch. It might just be move all the capacitors that way, then move them all this way. I don't actually know yet, but the run light is very near that chip. So i imagine that chip is driving the run, light um to tell you whether this is running or not, and then there's this little circuit here of three transistors and as yet, i'm not sure what that does.

But i have a hunch, but i don't want to get too bogged down with the operation of this thing or the circuitry just yet i mean i will because this thing is a very interesting device and i think it's going to be useful on in my particular Application, but what i want to do first is just get a a socket wired on to probably just b minus b1 b2 b3, because this is a three cell pack see if this thing fires up maybe take a look at some voltages. Maybe take a look at some currents who knows, but let's just get it working right, jst uh plug. I guess that is mail, four pins for the 3s lipo, i'm gon na solder. These wires come with the balancer and they're reasonably thick wires, probably just about rated for the five amps that this thing is rated for now.

This five ounce rating is interesting. I believe that these poly fuels are probably poly. Fuses are rated at five amps and that's what give this gives this a five amp limitation, but i doubt there's anything to stop this trying to shovel more than five amps if your cells are wildly out of balance, i think on the ebay listing for this. It says that well, let me have a look okay on the 8s version of this, which i have now also ordered: 1 amp.

If there's a cell voltage difference of 0.1 volts, that's 100 millivolts, 3.5 amps at half a volt and for 5.5 amps, which, strictly speaking, is over the rating of these fuses. I believe i don't know what these are. They have just a v on them. Is that v for five in roman numerals, probably not uh, five amps or 5.5 amps? It says on this particular ebay listing uh you'd need one volt of a cell voltage difference between adjacent cells right now solder, the wires to these four pins uh.

These tend to melt quite quickly and they will move around so i'll put the corresponding plug in there and that acts as a little bit of a heatsink, but also a physical holder to hold all these pins in place. While i solder some short lengths of wire, i'm not going to make them long, because i want to retain most of the length of this for when i use this somewhere else i'll. Do that off camera! Never wonder what nobody wants to watch me solder right. I've done that so that should plug into this except we've got the negative on the right end.

Yep seem to have black going to black there, so i'll just strip these back solder them in there and we'll fire the thing up right. That's all done, b! Minus to the black and we're running up to b3, like i say b3, will feed through that diode to power. The circuitry now there's a little run led on the back here. We're expecting to see that light up, there's also a run marking here, but that's a solder bridge now imagine you could put a switch on there um so that you could remotely enable or disable this thing, but we shall see right, let's flip it over, so that We can see the run light live power up, haven't rehearsed this.

Let's see what happens. Oh a little crack from here and you'd expect that, because there's a lot of capacitors on there and that's running so that should be equalizing. These voltages, we might have to have a look at that in due course now. What's interesting about this, is that this first set of capacitors appears to be connected directly across these wire points.

So i think what happened is i mean if you draw the theoretical circuit of this, you could get away with three capacitors and i think three sets of mosfets. There's obviously a lot more going on than that, and i think it's about impedance to the cell to the battery pack um. They probably couldn't get this thing to run efficiently by trying to transfer from cell to capacitor and back to cell. So actually, what you've got here is four capacitors mimicking or copying the cell voltages and um.

They do transfers between. I think, probably, these capacitors using these capacitors. I don't quite know why there are five here. It's a bit odd that run light still on um.

So i believe they're doing it for low impedance purposes, simply to shift energy into the capacitors and then that, of course, is mirrored on the pack eventually um. Now this run light. It is my opinion - and this is only an opinion at the moment - that this stays on all the time, even when the pack is completely balanced. The only time this will go off is if a voltage detector - and that could be these three transistors detects that the pack voltage is so low.

That there's a risk that this thing - and this thing has quite a high operating current uh - that this could drain the battery down to nothing. So this then goes into a lower power, sleep mode. It probably stops the clock, stops the switching to the mosfets shuts. Everything down as far as it can, but even then, there's still a reasonable operating current that this thing draws and if you look at the ebay listings, they do say only use it on battery packs that have oh, i can't remember something like 60 amp hours or More, oh they're, getting warm! Actually that's interesting yeah! Those capacitors are getting warm, but what about that? One? Now, of course, that might just be heat coming up from the mosfets they're, not getting warm well, not as warm nothing's, particularly warm under there, but the capacitors themselves are warm interesting now.

I can't do much with this setup, but what i can do, i think, is monitor the pack voltage, not the individual cell voltages, but the pack voltage with this thing yeah. So we got oh that scared me uh. 11.08. So it's probably saying it's a bit low.

That's fine 11.1 nominal. That thing isn't it so, let's plug that in and see how rapidly the voltage plunges down 11.08. It's flashing alternately, white and red right that has dropped to 11.0 ooh, seven stroke, eight. So, yes, it is pulling some current now, the only time i think that led is going to go off is when this pack gets to a voltage.

This thing times out, that's so low that this board tries to protect the pack from dropping to too low an overall voltage. That's what i believe. I don't think this light goes off when the cells are balanced just to the temperatures on these caps and it might have cooled down a bit um. Okay, so we'll run a dvm across here and look at the cell voltages or of course i could pull that out and plug it into the balance port on here.

Well, yes, they're all pretty similar um. This is not a brilliant setup, because what i really want to do is have the cell balancer on here. At the same time as having the voltage monitor, how can i do that? I'm just going to change the low voltage alarm so that it doesn't keep. Bothering me how about 10 and a half volts that should do it back yeah, so uh that symbol is no longer flashing.

That's better still thinking about how to parallel this into there. I'm sort of thinking some of these on some strip board. I don't know right. I've done this.

I've put a socket on there for the lipo uh long wires to here, because it's just measuring voltage short wires to here, because, of course it's handling current. So, let's plug that in see. If it all works in you go yeah that works. I can now see the cell voltages now, of course, they may not look balanced um, because this thing may not agree well.

Of course, this thing isn't really measuring voltage. This thing is just flying the capacitors around and redistributing the energy such that the voltages end up. The same so it depends on the accuracy of this thing, really we'll keep an eye on it. Oh, i don't really like the way the wires have all bent on the bottom.

There i'll get some hot glue on there. I think to brace it all. Well now, even with this, there really isn't much to see that run. Light is on no warmth there, because all the cells are very similar voltages uh.

Any discrepancy here is highly likely to be the measuring circuitry of this device, because this really can't be inaccurate because um, it's simply moving energy between cells based on their relative voltages. So it's got to be spot on unless there are minute differences in um on resistance of mosfets or things like that. You'd expect it to be precise. I think a setup where you can see absolutely everything that's going on would be more cells, a bigger balancer, a monitor to show all the voltages, mismatched cells to start with, probably but also the currents that are flowing through these wires.

It would be a good thing to have a an ammeter that has lots and lots of current readings all visible simultaneously and i'm kind of thinking, because these are all um different potentials. I'm thinking the acs-712 wouldn't be a bad idea, because they're, the current measurements are galvanically isolated from the the voltage and signal parts and then an arduino with an oled showing all the the currents that are flowing through these wires. But that would take a fair amount of time to set up. Perhaps the only thing i'm really interested in here is how long it takes for this module to drain this battery, and this hasn't been charged for years, uh down to a point where this turns off the run light.

So perhaps i'll leave this set up and just keep an eye on it and come back when the run light goes out. I may not catch it on video almost certainly won't. Now this module says that it's suitable for ncm, nickel, cobalt, manganese or lfp, lithium, ferro or iron phosphate, so because it's suitable for lfp you'd. Imagine that the cutoff would be at quite a low voltage, uh, probably lower than you might want for nmc or lipo.

I can't see that this circuitry is doing anything in terms of measuring voltage on a per cell basis. It can only be measuring the overall pack voltage there. Just isn't the circuitry on here for doing a per cell basis measurement. So i'm guessing it's just going to be a case when the pack voltage gets down to a certain low point.

This will shut off. This might all be a bit more visual if this were on super capacitors, for example, just been trying. This bulb. I've clipped that on to the most negative.

So if i put this across one cell, say cell one uh, that thing keeps timing out: cell one: okay, the bulbs on you can't see it. The differential voltage just below the pack voltage climbs up, as this is stressing the first cell immediately. I take it off that shoots straight back to that 14 or 15 millivolts that it's been on the whole time, so that i presume has to be the balancer. That's doing that, i don't have any other ground points on here that i can really get to maybe i'll solder a ground point onto my.

Oh no, i've um put hot glue on it now haven't i now. If i put this bulb across two cells, stay on right, there's the bulb. You can see it now. The deviation just isn't happening because i think the balancer is able to pull it back or hold it in balance, so it just isn't deviating.

If i do one cell, i think because the filament is so dim, that's able to pull it a considerable distance out of balance 24 millivolts. Of course, a low temperature filament has a much lower resistance. The minute i remove that straight back to the 13 or 14 or 15 millivolts that it's been showing. Yes, it's not a very good test.

Is it and now i've got the 9 capacitor supercap bank charged up voltages, all pretty close to 2.7 the active balancer with a little switch on the run pins here, but there isn't enough voltage across the capacitors. I could try them in pairs. I suppose yeah just not enough voltage for this thing to do anything. Hmm and now i've got the super capacitors um wired to this every two capacitors and i've charged it to 17 volts we're showing 2 volts per cell.

Unfortunately, cell 2 is slow to come up. Now celtic was the bad one before so i swapped it with cell 9 capacitor 9 and in the process of swapping them capacitor. What was nine but is now two also seems to have gone bad, which is driving me up the wall, because this will not run. I switch it on with my little switch and it will not run so is this monitoring individual cell voltages and it realizes that? Well, it's actually cells one and two, which is the first, that this thing sees and it's it's seeing both of them that one's quite low in it itself.

This one is so low. It's not showing up on it's not showing up on there at all. I don't know what the minimum voltage of this thing is, but of course, i'm well below what this is intended for: lithium iron phosphate and lithium, nickel manganese cobalt. So i can't even get this to work i'll have to think of something else.

But for the moment right, this is working. I've now got my six super capacitor bank. I can't really show that very well, but there it is six super capacitors. There's a volt meter on now.

I've taken it to 12 volts, that's 2 volts per capacitor. Those are the voltages this now turns on when you put it in run mode and that, presumably at quite high current is equalizing um. This is strapped across pairs of capacitors so that it can see around about four volts on there and it's balancing. But, of course, we've got to do this mathematically so 2.14 and 1.75 is that about the same as 2.07 and 1.85 and 2.04 and 1.88.

You do the math now. What i really wanted to see was when this is in run mode, which is there if i switch off the supply to the supercap, these voltages will fall away. Now there really isn't a load on here other than this vu, this voltmeter, but that's extremely high resistance, and this this circuit pulling energy out of these capacitors. Will they sink back quickly enough for us to see that run, light go off when well either the pack voltage, which is? Can we see it? Actually? Yes, i think we probably oh no.

That's on. I want to see the voltage oh come on. I've got dodgy button syndrome. No, we can't see the voltage if that's not on, i don't think um, but we can see the voltage on this meter approximately about 11 and a half volts, but at a certain voltage this should shut off.

But it's just all not very satisfactory. Is it because we're having to add voltages up here to see what they actually are? I haven't really got a load. I suppose i could put a load on there - hmm just one. Second, i have this bulb, but the other problem is: if i breathe, everything is going to fall off the desk.

So that's the other problem. Can i put that in there will it stay in there? Will it connect oh yeah there? It is. Oh, you can't see that, because it's not in shot, this is about to slide off the desk, because the the fifth wire is not connected any to anything. So that's dangling down, so i just want to see if that voltage goes low enough.

Does that run? Stop light go off and i can see the voltage has got to about 9 volts. These are plummeting down quite quickly because of the 24 volt bulb at some point or the sun's in my eyes now at some point that run light should go off, because this battery balancer has recognized that well either the pack voltage has dropped too low or an Individual cell voltage has dropped too low, but it's still on at the moment will this little yellow led go out? Oh, it is going out. It's fading out. It's gone off! So yes, at a certain voltage.

This is around seven and a half volts, and this is seeing that whole pack voltage now that's three cells yeah. This has gone off. So what's that, what's this darting about? What's that per cell um, possibly because this is cutting in and out seven and a half nine would be three volts per cell. As far as this is concerned, seven and a half is two and uh yeah.

That's now going flaky because it doesn't like these low voltages. Yes, i think this looked like it cut out at about two and a half volts per cell, which is about what you'd expect for a lithium ion phosphate stroke, nmc balancer, that's all i can do today. That's all i think i can manage. I need a better setup right.

Finally, i think i've got it. Oh, you can't see that very well, but anyway, that's just for me to check all six capacitor voltages to make sure they're, not drifting too far out of bonk 12 volts coming in across the capacitors. That's nominally 2 volts per capacitor. Now this is looking at them as pairs of capacitors, and you can see that they are wonderfully balanced, 3.92 volts and that's because the balancer is on balancing them at 3.92 volts now, that's 3.92 volts per pair of supercapacitors.

So there are three pairs, because this board has six supercapacitors, so the balancer is doing an absolutely wonderful job of balancing. Now, if i turn off the power supply, the voltage on the super caps will go down. I'll just check this to make sure that nothing's too high one of them is 2.2 and its neighbor is 1.6, but it doesn't really matter they're acting as pairs, and you can see as the voltage falls. The balancer is still balancing.

It's got 3.87 across the board. 3.86 across the board, 3.85, so they're, all tracking down together the three pairs of supercaps behaving as cells, that this thing will understand. The voltages of this thing behaves itself. This is actually quite good at working with these very low cell voltages.

Just can't see that can you cell 1 is 2.1 and cell 2 is 1.6 in terms of the pairs they're miles out of bonk within that pair, but the balancer is bringing them as pairs into wonderful balance. 3.77 3.76 they're almost moving together 3.75. They did, they all moved absolutely together. Didn't that time, 3.74.

Now at some point this will say: that's no good. That's not um high enough for it to be called a lithium-ion phosphate battery and this will stop uh running, but the voltage would have to get down to something like well. It was 2.5 volts. Wasn't it, i think we said so, i'm not just watching to see when the uh balancer stops running and we're down to 3.02 volts per cell or capacitor pair.

Will it drop out at 3 volts, i seem to remember it dropped out at about 2 and a half, so i'm not expecting it to stop running yet 3.0 volts across the board certainly seems to be working less hard to balance um. But it's hard to tell because i don't know what's accurate here and what isn't, but that's still running at 2.99 per cell. Well, i think that dropped out at about 2.65 volts per cell, so i've just turned on the power supply. This is coming back up.

There's a quite a lot of hysteresis on this um. It doesn't cut back in until the cells get a fair bit high. I was just wondering actually if these three devices here are tl431s, maybe but then it really should be looking at all four cells shouldn't. He not not not just three cells, so maybe not that's come back on at oh pretty much bang on three volts on one of them.

Now, of course, it's balancing them because they have drifted a bit and it's pulling them in pretty well three point: one: six, one: seven one, eight one: nine it's within a minute within 10 millivolts now yeah and it's pulled them all in turn, this back off. That's how to turn it off and just watch again when this drops out at what cell voltage this drops out, but i think it was about 2.65, but i'll watch. It again try and catch it, because i missed it last time right 2.74 on here, the yellow light is still on determined to catch to this uh visually and on camera 2.73. At some point this will complain, let's just say, i'm not getting sensible voltages they're completely silly, because they're down at like 1.5 volts, that's dropped out to all zeros.

Yes, it's complained and that went off absolutely at that instant 2.68. Something like that yeah! I don't know why it corresponded exactly to that. Maybe this suddenly pulled a burst of current or something but uh yeah about 2.68 volts. This drops out but doesn't cut back in until three point.

Oh, it was around three point: zero! Wasn't it? Okay, that's the voltage parameters of this thing, going into run and stop mode in another video. I will have to look at what this is capable of in terms of currents. That's much more interesting to me, but for this video, that's it cheerio!.