Hello a little while ago. Uh, July I think it was I did a review of this uh Buck converter this big 50 amp butt converter. It's the Jun 8650. Well, today I'm going to open it up and we'll have a little look inside.

I'll also open up the little remote control unit Um, which is this which has its own built-in battery? So first things first, let's remove this plug. Uh, in order to get the casing off and then on the bottom, there are these four screws. So I'll get those out removing the four screws on the bottom of the box. and if I take the bottom plate off, then we can see the underside of the PCB.

Now that doesn't simply drop out because there's a cable attached to this front panel uh, keyboard Bo and display. So what we do is we drop this down and then I think yes, the little slide switch there has to be coaxed out. Uh oh. Also, there's a fan cable because there's the fan there, right? The cable that I need to remove is this multi-way cable that's plugged into a socket behind this little Wireless unit and it's quite difficult to get to with the wireless unit in there.

So I'm actually going to take that out and we'll have a look at that in a moment now. I can get to this cable so I'll ease that out. Uh, then I can pull the fan cable out and now the board comes out of the box. So Inside the Box It looks like this little uh oh, is that a 5vt fan? No, it's a 12vt fan.

And there's the little um, seven segment display and and key driver. And that chip is a 1638 which I seem to remember is just a segment and key driver chip. Here's the little uh, wireless receiver or transceiver. I Suppose 16 mahz Crystal Now the chip is not identifiable because it's got this sort of blob covering.

but it does look very much like an Nrf24 L1 Plus so it's either that or something very similar. But unfortunately I can't definitively identify it. And here's the Buck Converter board and everything on it is really huge. So we've got two very large inductors there.

Uh, two large capacitors which are 2200 microfarads 100 volts. um I can't remember what the input of this thing is I'll just check. Okay, input voltage range: 10 to 75 volts. maximum out output is 0 to 60 Vols and the 8650 is 0 to 50 amps.

So looking at this, uh, my guess is that there are essentially two parallel Buck converter circuits because we've got two inductors and then if you look here, we've got DT DT So my guess is that that is Diode transistor Diode transistor. So each Buck section has an inductor, a diode, and a transistor, and that is essentially the circuit of a Buck converter. These two capacitors are both on the output um, and they're either side of the current measuring uh shunt here so that you've got a stabilized voltage across that shunt capacitor big one on both sides of it. This is clearly the input capacitor cuz it's up near the input connector.

now. A lot of the components on here, particularly these uh, eight pin devices, have had their tops ground off so they're not identifiable. The microcontroller here is an St. Microcontroller I don't suppose it really matters.

Uh, precisely what version it is. There's a mosfet down here. it's an Irf Uh 640 I think it is and a polyfuse and I think this circuitry here is something to do with the Um shorting of the output capacitors. There is a a A function in here which allows you to have the output capacitors um, forcibly discharged.

uh I can't remember what it's called Now yes, that's right on here. It's called quick response and you can set it on and off and if you set it on, then it quickly discharges the caps and I imagine it does it using this mosfet here and in the manual it's got a different name. It's called Fast discharge, but I think it's essentially the same function. In fact I know it is Cu I've checked it Okay, couple of other things.

I Wanted to point out the connector here. The four-way connector is a uart output and from my sort of looking at the Uh tracings, I've worked out that the four connections on here which are ground VCC uh, receive and transmit go to these four points on this little header board and if you take this off now, it's set High there I must remember that don't want to put it in the wrong place cuz for some reason that that connector five way um I Imagine the extra connection might be if this is used as Rs485. so maybe it's a 12vt uh input. Yeah, possibly this just has a transistor and a couple of resistors on it.

So I imagine it's mostly passing through from the microcontroller to this uart output because there's not much uh, well, there's no level translation required for uart. So perhaps the other header when you get the Rs485 version has level uh Converters on this little header board. but I'll plug that back in. and then the only other thing of interest is this switch.

And this is of interest because this switches the unit on and off. Now clearly it doesn't intercept the main input Uh current because that would be mad. No what it does and I've traced uh this through is it takes V in positive which I believe is this Trace Here that's the positive side of the cap, isn't it? Yeah, cuz that's negative V in positive runs down here on one of these tracks, goes to the switch, then goes through a shocky diode and then it's used to power up. uh, a buck converter which I think is this one here and that might be an XL semi or something like that It's going to have to be a 75 volt Buck converter and I know XL semi do one of those.

So this switch just simply applies V positive that you put in on this connector through a diode to this Buck converter. and of course once that powers up, it provides the 12 volts for the fan. This connector here provides uh 5 volts. it might be 3.3 probably 3.3 to the microcontroller and so all the circuitry Powers up and then the Buck converter starts operating.

Now there are two modes you can have. you can have that it uh enables the output on bootup or that it doesn't en a the output on bootup and you have to manually enable it. But yeah, that switch Powers up this little Buck converter circuit and if you're interested in the big semiconductors on the back of the heat sink, well, the two diodes are MBR 40100 uh PT the transistors for some reason have been uh etched or Mill to uh cover over their identity. Now I'm going to come back to this Um little slide switch uh in a later video because I want a remote control I want to remotely switch this Buck converter on and off and I believe that that's perfectly possible I want to do it with a relay um and I believe what all I need to do is take uh V in which of course is available externally and uh bypass this switch.

This switch can be left in the off position which I believe is there? uh bypass this switch. You can see a little Trace running from the switch up to the anode of this diode. So just feed V in externally through a relay to the anode of this diode that will power up the little Buck converter circuit which Powers up all the uh low voltage circuitry and switch this unit on. So I will come back to that switch at a later time.

Okay, let's take a look at the wireless control panel. Now there's going to be another wireless transceiver in here. Um, of course there's also going to be a battery in here because you can charge this up via this DC Barel Jack And then when this but converter's powered up, the two units talk to each other and you can use this as the interface. Uh, rather than using the top panel uh, seven segment and keypad display four screws in the back of this.

let's get them out and have a look inside shot of me unscrewing the screws. that one's a bit tight and taking them out and inside. Here we have a Lipo um which is 3.7 Vols 2,000 Mah that's 2 Amp Hour Uh, looks like it's got a little protection circuit board on it that's plugged into the main. PCB We got another radio transver here.

no Is that four? Yes, that's eight pin so I can't get that wrong. Uh, that plugs into there so I can take that out and then this. Well, I mean it's what you'd expect, isn't it? It's an LCD uh ribbon cable somehow attached. Oh, it's just soldered actually soldered onto the PCB Uh, there's a microcontroller here, almost certainly an St.

Let's have a quick look. Oh well. The micr controller has been etched so has this chip actually. but they haven't done it very well and you can see what it is.

It's a Ch340, which is a oh, it's a U to USB Oh yes, of course there's a USB type B connector here. so this is the Um USB interface for this connector. Don't entirely know what that does I mean It could be used presumbly to upgrade the firmware on the microcontroller. I Don't know cuz charging is done through this.

DC Barrel Jack You might be able to charge it through here as well. Yeah, you probably can. What's that? That's probably a diode, isn't it? So you can probably charge through here or charge through here. I'm not 100% sure.

So yeah, all The Usual Suspects on here. I'm not going to remove this board because that's going to disrupt all these. Keys There's a rotary encoder there. Oh yes, that's soldered in.

There's the three connections there and the two, uh, mechanical connections. There's a buzzer that's not been fitted because it was probably really annoying. So yeah, there isn't a huge amount on here. That's unexpected.

It's pretty much exactly what you would expect. Uh, the wireless module on this one. Again, the chip is obscured. but it does say A210.

There A210 I Don't know whether that identifies this is any particular. I mean it's it's. almost certainly a 2.4 gig transceiver. You can tell that just from the antenna.

Let's compare it with a NRF unit. Yeah, I mean the antenna uh, size and shape is identical. That's the NRF 24 L1 plus same crystal. Almost identical layout.

If it isn't an NRF it's something extremely similar. Um, now I've taken a week off making videos. Uh, last week. so I SP spent some of the time making up cables and this is one of them.

It's xt60 to these square blocks which were banana plugs, but I've cut off the banana plug bit and the idea of these is that they fit into these caged terminals. Sort of like that. Uh, so I just wanted something to uh, fit nicely into there and that converts it into Xt60. Um, now as you can imagine, I'm going to be coming back to Uh doing a bit of uh stuff with this unit.

So I wanted to just take it apart, remind myself how it all works inside and so that's what's inside this. Uh Jun DPM 8650 I think it's 8650 RF Actually because of the wireless communication thing. uh, giant size 50 amp Buck converter. Um I did make another video where I showed this in use and a little bit about the operating system.

I I'll put a link to it up there so you can watch that as well, but that's it for this video. So cheerio!.