Good morning, all this is uh from lidl. It's a parkside, 20 volt battery for amp power. This is for their 20 volt power tools. Now this one has cell balancing so we'll open that up.

Take a look at the cell balancing circuitry and compare it with the 12 volt battery, which is a 3 cell. This is a 5 cell. Well, it's 10 cells actually 5 across the top 5 across the bottom, but i'm just going to show you some footage. I took in the little store because there is a huge variety of the two amp hour and the four amp hour batteries, and particularly the chargers, take a look at this 2m power batteries: pac 20a1, no cell, balancing pat 20 b1, which does have cell balancing 4 Amp power batteries, pap 20, b3, with cell balancing and up here, pat 20 a3 without cell balancing and battery chargers, plg 20 a1, which is 2.4 amps.

Here we've got plg 20 a4 2.4 amps, and here we've got plg 20b, one which can do 4.5 amps. If it's got the bigger battery, that's a confusing array of stuff, if you're not sure what you're looking for. So, it looks to me like they're, throwing in some of the older uh non-balanced batteries at the same price, um just hoping to clear old stock. I suppose for people who don't really care about this sort of thing, i do, though, anyway, let's get this thing open and um.

Oh, that needs to come out and take a look at how the cell balancing works. Now, just comparing the previous uh 4 amp power battery with this one tall, intense purposes, they look identical. We've just got the a3 indicator there and b3 on the new one. Okay looks like torque screws.

So let's get this uh. This is interesting. Look they're calling it 4 amp hours, 20 volts 80 watt hours, but of course, 80 watt hours. Um is multiplying 20 volts by 4 amp hours.

Well, these cells don't stay at 20 volts for very long. They really should be doing it at um, 3.7 times 5. Not 4 volts times 5. So it's a little bit cheeky right.

Screws are out uh. How easily does this thing come apart? Oh very easily, indeed i'll just take the spring. Oh no! That's fitted on there quite well um! Oh, that's a fuse! Isn't it with the hole cut in the strip of metal? And oh look at that? It looks like the little uh tester board. The state of charge indicator is on a connector now seems remember.

These were quite difficult to get apart on the previous version. I'll just have to watch back a video. Well, this little board is extremely neat. There are two little studs uh going through the ball, but that just is on a four pin.

Connector, that's really really nicely done. In fact, i'm gon na open the old battery just to compare how it was done on that previous one. Yes in the old one, it's very different, there's a pair of wires running up to a board which is up in a groove on the lid there. I seem to remember it was quite difficult to get out, so let's give that another try, yes now.

The reason this was difficult to get out is because under these illuminated covers, there's this sort of light guide, plastic, molding and the surface. Mount leds are actually sat up inside it. So to get this board out, you have to bend it away from the plastic molding and then slide it up out of these grooves. But it's really hard to do and i don't think i'm going to bother the new one is so much better.

Look at that. Yes, this is just so much better done and they haven't insisted on having the oh, it's hard to see, um the plastic light guides that run up into these lenses. Well, they're, not lenses. They're just covers i'm quite so close to the pcb surface.

Mount leds they've left a sensible gap so that this slides in nice and easily it's just so much better done yeah. This shows it a bit better. You can see that sliding out without it being trapped, underneath that little bit of plastic molding so get the b3 version of this 4 amp hour battery. If for no other reason, then this wonderfully implemented state of charge indicator, i mean it's only three leds.

It's not exactly very sophisticated, but moving on to the cells. Let's have a look. So these look like they're branded parkside on one of them. You can just see the k before side uh, something 18650p 2000 milliamp hours, 3.6 volts.

They say inr, 19, stroke. 66. I'm not entirely sure what that means. Uh.

The date is 2021, 01, 16. So back in january this year - and i don't quite know what hash 4 volts means either, if indeed, that is 4v for volts. So this is a five s array: five cells in series. You can see that the top and bottom pair are simply paralleled on both sides so giving you the four thousand milliamp hour capacity right.

Let's take a look at some of the electronics, so the main chip is an lgt 8p30 they've put a blob or something on it, but you can still read through that. This is a 5 volt regulator, it's just a 78 l05 and there isn't a huge amount else on here other than these 6 pin or 5 pin, i think, they're. Oh, i can't see whether they're six or five pin, but these four here are marked c3. Now the 12 volt battery had two chips: um again of this sot.

Well, i'm not sure that it is a salt 23, because they're smaller than that, aren't they that's a sat23. So this is a smaller form factor six pin chip, but it had two of these c3 chips, so this is clearly the balancing chip, because this one's got four of them now, unlike those little cell balancing boards that have inductors on them, there are no obvious inductors On this board um, there are possibly some capacitors down here. I suppose these could be inductors but they'd be a very tiny value, but no they look like capacitors to me. So maybe this is a capacitive transfer chip, but i think it would be quite difficult to find data on this um.

There are another couple of chips here, i'll just try and get the numbers of those and these ones which are six pin. All three of them say: 72k, so do they work in conjunction with the c3s to do the balancing? These are actually five pin, there's a six pin footprint underneath them, but they only seem to have five pins. This middle pin on this side doesn't seem to be implemented, so i'm just going to open up the 12 volt cell balancing battery to see if it's got well, two of the c3s and one of the 72ks and uh. Yes, that seems to be exactly what it has a couple of these c3 chips and this one actually isn't a 72k, but it's a k72.

So i don't know whether they changed the naming convention for this chip between these two batteries were made, but it seems that's the way. This works there's a k72 in this case and a couple of the c3s and then on this one. We got four of the c3s and three of the 72ks. Now this battery pack doesn't appear to have any cut off mosfets because you can trace a path from the most positive terminal here down to the positive connector and then from the negative connector through the fuse and down to the most negative terminal on the battery.

So i believe that the low voltage cut off mosfets must be in the power tools and in fact i've just opened up this sort of air blower thing, and you can see here on this board that there is a pair of mosfets down there. Let's just try and take that out yeah, so two mosfets they're, probably in parallel and some sort of eight pin chip here, which might do the voltage measuring um to cut this tool off when the battery voltage gets too low. And then i do remember when i took apart the dual 20 volt battery charger, that there was a pair of mosfets in there uh sort of back-to-back mosfets, which would of course be used as the cutoff for charging this battery. So when the terminal voltage went above a certain level, then the charger would cut it off.

So yes, it certainly looks like this 20 volt series doesn't have any of that cut off stuff in the top in the battery. It's in the tool and in the charger completely different to the 12 volt battery. Yes, here in the 12 volt battery, we've got the high current path is through these two big mosfets and the big current sense resistor. So that's ground through the current sense resistor through the two mosfets to this point here, which is p minus, so that's the negative of the pack.

Let's pull that out. Actually, oh, i can't pull that out. Yes, i can bear with me um. Yes, the negative of the pack, because um there's the negative terminal, there's the big black wire that runs up to there and then on the charging side.

We've got another pair of mosfets here, which uh the path is from ground. That's the most negative terminal of the battery through the smaller current sense resistor, through these two mosfets through these two diodes and out to this terminal here, which runs down to this t connector and that's how this battery is charged. It's charged between positive and t. There isn't actually a connector in the charger for negative, so this is the um.

Well, when you charge it current flows in through positive, conventional current in through positive uh through the three cells that brings you to this ground through that current sense, resistor, and then these two mosfets and these two diodes and back out to the t terminal. That's the char, the path for charging this, but the battery has cut off both on the charging side and the discharge side, not so much in the 20 volt battery strange decision. So that's what's inside the park side. 20 volt.

This is the 4 amp hour, but they also do a 2m power power tool battery with the new uh plug-in state of charge, indicator board, which is simply wonderful and very minimal electronics, certainly no cut off stuff. Apart from this uh, this fuse, if you uh, put a direct short across the output terminals um, but with cell balancing. Now i wonder when the cell balancing takes place at all times, which is possible or is it happening when the battery is being charged uh or does it happen when it's being discharged, that's less likely, i suppose so put this back together and that just simply drops In there, it's simplicity itself to take this part and put it back together again just align the spring, with the uh release catch there and that's it. Yes, okay, let's get these screws in so 25 pounds for this 10 cell pack, that's 2 pounds.

50 per cell they're 2 amp hours and with minimal electronics in here, apart from the balance circuitry and that protective fuse, this could be the basis of building some sort of power bank um. I was just looking at these these standard spay terminals - i don't have the opposite apart from these piggyback ones, so i'm just going to bend one of these out and then you can use these to connect to these terminals. So you could build your own multi uh pack, bank of batteries using these pre-assembled things, they're they're, actually quite handy uh. It's going to see if this 24 volt bulb illuminates my pockets wires into the connectors.

Yes, it does so that's fine!.