Hello, Let's take a look at this 18650 cell charger from the point of view of thermals. what gets hot and what doesn't and we'll have a look at this through the infrared. P2 Pro Thermal imaging camera. So thermal imaging camera at the ready.

Let's put the macro lens onto it, plug it into my phone, and away we go. So mode is charged. stop at 3 volts only relates to discharging, so this will actually charge to 4.2 Let's get this thing started. and the right hand cell is the cell that's charging.

Let's see what's getting hot. Overview of the PCB It's out of focus because I've got the macro lens on. You can see a little bit of residual warmth up in the resistors. But the two things which are getting hot are this eight pin chip right adjacent to the cell that's being charged and that's a Tp4056.

So it's a purpose made cell charger. It's up to about 50 degrees C 8 Pin Uh, Small outline package. Now there is one other item that's getting warm and it's down here near the USBC input. You need USB 5 volts to charge the right hand cell.

You can't do it from the left hand cell because there's no Step Up regulator. But yeah, that's clearly a diode and that's getting warm up to 53 degrees. So that's what gets warm when you're charging this cell. Here's the Tp4056, the little eight pin small outline package, and the diode that was getting warm is this one.

So the current from the USB type C connector is obviously going through that diode into the Tp4056 that's set for one amp. You can see it there. 0.97 and the cell on the right is being charged now. I Think we know what's going to get warm when this cell discharges? It's going to be these two big resistors.

But what about these two mosfets here? Because they're obviously used to switch these resistors into circuit across this cell? Well, let's find out. Let's uh, stop the charging. Let's check, change the mode. Uh, which is there to discharge? Let's start the discharge that's discharging.

Let's look at the thermal image. Okay, the resistors are up to about 50 degrees. now. You can see that those are the resistors.

Now what about these two mosfets? That I was interested to see whether they're getting warm? Uh, one of the mosfets is uh or here and you can see that that's not being troubled at all. The other one is uh, there. You can see the outline of the mosfet. You can see it's eight legs.

You can see the top mosfet quite clearly now. But no, they're not getting warm at all. so they must have a nice low on Resistance. So there's an overview of the board without the macro lens.

The resistors are now up to 56 degrees and with the macro lens, we can get in nice and close a couple of centimeters maybe three so that you can see lots of detail in the components you're looking at. So that was a quick look at what gets hot and what doesn't on this 18650 cell charger and discharger. Cheerio.