Aldi's Ferrex 40V grinder PCB (with schematic)

[@gregorythomas333]

Kind of impressed at the amount of work & components that went into this "cheapy" device.

[@soundspark]

Lithium ion powered devices do need to meet safety regulations.

[@gregorythomas333]

@@soundspark They do in my house :)

[@markfergerson2145]

Remember that the cheapies are often made in the same factories as the more expensive ones. There is a nonzero chance that someone copied most of if not all of an expensive design for this.

[@anthonyshiels9273]

German engineering has a very good pedigree and reputation. We are looking at the likes of BMW, Mercedes Benz and Volkswagen. Aldi is a family owned company that was founded by Karl and Theo Albrecht on July 10th

[@anthonyshiels9273]

....1946 in Germany.

[@markusallport1276]

I learn so much from watching your videos. I still cannot buid my own circuits, but I understand them so much better now. I have however, learned enough to repair some circuits that have gone bad, so my watching has not gone to a complete waste. Thanks Clive, brilliant mind and your voice is tolerable to listen to while learning.

[@tomschmidt381]

Being involved in electronics since vacuum tube (valve) days it never ceases to amaze me how much complexity is being crammed into these tiny footprint devices now a days. Hope Clive and everyone else has a great holiday.

[@Len_M.]

You think normal stuff is impressive, you haven’t seen or not seen if you will, what the CPU technology has now. It’s crazy how many transistors they have in the crazy tiny 5nm or smaller packages. China is so far behind in that realm that it will be decades before they even hope to re-create something even in the 30nm+ scale. Let’s just say Chinas system doesn’t really have what it takes to have a robust R&D sector because well you know how they do stuff. That’s why they have such a big repurposing sector.

[@simonlathwell]

I've learnt so much from watching you Clive. As a qualified computer technician I understand computer motherboards quite indepth, but I also like understanding other circuit boards as well along with different components. I also like that you explain them in straight forward terms, and don't make it really difficult to understand what is doing what on a circuit board.

[@markfiddament9383]

The on signal to the MPU via 30k & 3k could also be used as a point to read the battery voltage at the same time - to an analogue pin.

[@FastAsFunk]

Ouch. What a complex deal that is. Can't believe there isn't a simpler way of managing a 5S2P pack that can also be operated in 10S1P mode. Great work Clive, thanks...!

[@LeifNelandDk]

Make it as simple as possible but not more simple than that. Everything is there for a good reason.

[@johnmorgan1629]

Merry Christmas, the Adi Ferrex grinder the gift that keeps on giving.

[@misterhat5823]

The "off" current will be closer to 15uA because the zener will clamp the gate voltage to around 10V. That leaves 30V across the 2M resistor for a current of 15uA.

[@KeritechElectronics]

Yay, the Pinkulator is back! It's been a loooooong time. Nice circuit, well made.

[@BedsitBob]

I believe its called the Kink Palculator. 😊

[@jkobain]

@@BedsitBob for real!

[@BedsitBob]

@@jkobain Yep, that's what Clive calls it.

[@dennisyoung4631]

Might make it easier to find???

[@jkobain]

@@dennisyoung4631 one of the reasons why Clive often prefers goods in pink: they're usually less desirable among casual male persons around him, thus are less likely silently «borrowed», if you see what I mean.

[@Robothut]

As complex as both the battery circuits in the first video were and this control for the motor are I am surprised that they are not using a 3-phase motor design like just about every other tool and toy out there. That would have added one more level of complexity to the product. Thank you for the teardown and explanation of what's going on in this tool.

[@julianstafford7071]

It's just a grinder so it runs only and always at full speed, a standard DC motor probably does that job best?

[@toolscientist]

Do you mean make it brushless? Brushless motors are more expensive than brushed motors (except maybe if they're sensorless which would probably stall a lot on a grinder) and you need 6 mosfets to drive a brushless motor.

[@willrobertson7778]

@@toolscientist Yup - a 3 phase BLDC motor is my choice for the Rolls Royce of motors in this sort of application but - as you point out - the motor itself and the 6 MOSFETs or IGBTs needed for the 3 phase H bridge driver to run it are both expensive. One of my professional chainsaws uses a sealed sensorless BLDC motor and it can give very good torque - I think some of the most modern microcontroller BLDC motor controllers have algorithms which can avoid stalls even without the need for sensors by monitoring feedback from the motor coils themselves in real time.

[@jkobain]

KZbin recommended me a video where a person assembles tiny computer based on a Raspberry Pi RP2040 microcontroller with two little touch buttons, a USB connector and a miniature OLED display - all into a small LEGO brick. And the most popular comment down there was about someone's grandma joking like twenty years ago they'll make computers so small you'd need to be careful not to vacuum them up while cleaning the house. And they managed to put three (even two in the battery pack) in such tools. It was hard to expect a little while ago, yet that grandma could foresee the future.

[@wrongtown]

Heh I saw that video too 😁

[@jkobain]

@@wrongtown and it can DOOM too! ;D

[@BedsitBob]

The Ferrex stuff is pretty good quality, especially for the price.

[@christopherduchesne9538]

Merry Christmas to you. Thank you for your ongoing content.

[@bigrstransport6783]

The thing that impressed me about this battery back is the components used to modify it

[@ThriftyToolShed]

Impressive reverse engineering indeed. I know that had to take a while. Thanks for sharing and Merry Christmas Big Clive!

[@divingquokka]

Merry Christmas Clive!

[@M1LAD81]

The activ energy batteries these Ferrex tools take is not bad. I bought one from Aldi for £26. Just so I could harvest the lithium cells. Nice samsung INR18650 -2500, 10 cells at £2.60 each, I think that is a pretty good deal. I use the batteries in various projects and use some in my LED Lenser H8R headlamp.

[@matambale]

Early Christmas morning, watching a Big Clive video - a real treat. Thank you Clive and Merry Christmas.

[@GranolaEngineering]

Always appreciate your in-depth analysis . Thank you

[@CraigPerry]

Always learn something on these videos, pretty interesting that so much is required for safe battery management.

[@TimPerfetto]

Wonderful Christmas present waking up to a new Clive video. Merry Christmas!

[@alunjones3860]

The diode across the motor does more than back-EMF supersession. It's a freewheeling diode. The motor's inductance smooths the current flowing through the windings, so it acts like buck converter.

[@willrobertson7778]

Many MOSFETs and IGBTs designed for this application have a built-in Schottky free wheeling diode so an external Schottky can be left out - I like to have an external Schottky though in the hope that it'll help reduce the heat dissipated on the MOSFET or IGBT chip. There's a gotcha in there though - multiple MOSFETs and multiple IGBTs can both work happily as teams in parallel, their resistance increases with temperature so they happily share the load out between themselves - but this does not apply to Schottky diodes - connecting several of the same specification in parallele it's likely that one will take most of the load and magic smoke will escape if it's assumed that the energy that the group can dissipate is the sum of the energy that each Schottky can dissipate...

[@zachkurth]

Thank you for the follow-up video, Clive. Merry Christmas to you!

[@peterthorneycroft1026]

Merry Christmas Clive.

[@dcallan812]

for just being a grinder, once you peel the skin back it's got a fair bit of circuity inside nice job 2x👍

[@markedis5902]

Merry Christmas Clive

[@electrake2063]

@3:40, I’m guessing the odd pad shapes are like that to show you the direction the wires that are soldered on are intended to go… to help with proper wiring separation and touting possibly?

[@craxd1]

A good lesson for those learning electronics in transistor logic for that circuit. It may help several now learning. BTW, that seems to be a good grinder, so I would reassemble it for use.

[@bigclivedotcom]

I did reassemble it afterwards.

[@theelmonk]

Leakage through 'off' will be a bit higher as the 10M is bypassed by the zener. (40-Vz)/2M

[@bigclivedotcom]

That's true.

[@OmegaSparky]

Yeah, that was my thought as well.

[@carlubambi5541]

Awesome tear down And Merry Christmas !

[@jamesg1367]

Great analysis. The tactics used to limit battery drain are quite sensible, for all that they raise the component count. That's good design. You unraveled several puzzles very adroitly here.

[@Derek_Garnham]

I wanted to check my understanding of the definition of the word ardroit after reading your comment (skill/cleverness). However when I just typed it into google the first thing that came up was battery packs. Serendipity or a clever pun?

[@jamesg1367]

@@Derek_Garnham 😂

[@crazydavidsmith]

Happy Dec 25th and Happy New Year Big Clive! 🎉 Thank you for sharing your knowledge with your awesome educational and interesting videos during 2022. Thank you for shining for us. ☀️

[@rpdom]

"I am OK pin". If they had used a socket instead of a pin it could have been an "I'm alright jack".

[@Derek_Garnham]

too funny

[@bokkenka]

The dovetail lock and captive tabs on the circuit board keep the connections from being pulled out. If you thought a 4 volt battery was "spicy" when short-circuited, try 40 volts and 2.5 amps!

[@tweed532DaveH]

Certainly complex for a 'Supermarket' Brand. I'm impressed with the Bosch AmpShare system used by multiple manufacturers in a sort of 'standardisation' arrangement. Oh we need these notebooks published too, so far used 5 'commentary assisted' diagrams in repairing or making items in the last year or so.. Ta!.(Most useful TV on Christmas Day 2022, (no licence anyhow, KZbin it is!)) 🎄🤔🤭👍🤣🇬🇧

[@yup-nope-yep]

Thank You Clive! :)

[@pepethefrog7193]

I got the 20V version of this grinder. I think normal people equate "40V" to "more power" since they do not know about the amp thing, so sellers use as many volts as possible even if it makes no sense. The 20V grinder is gutless compared to a 240V cable grinder, but the low weight of the 20V bat. makes it ideal for garden / outdoor use.

[@v8snail]

Yeah I'm not a fan of gizmos too gutless to grind my garden...

[@kapouszek7349]

You mean the brushless version?

[@rowwie7976]

Merry Christmas from South Gippsland Vic Australia

[@ruben_balea]

There are a few "traditional" brands that also label their tools and/or batteries "xxV MAX" 4V MAX: Black & Decker, Craftsman, Dremel. 8V MAX: Black & Decker, DeWalt, Dremel. 12V MAX: Black & Decker, DeWalt, Dremel, Makita. 16V MAX: Black & Decker, Skil. 20V MAX: Black & Decker, Craftsman, DeWalt, Dremel. 40V MAX: Black & Decker, DeWalt, Oregon, Makita. 60V MAX: Craftsman, DeWalt, Toro. 80V MAX: Makita. 120V MAX: DeWalt.

[@ianleitch9960]

Wishing you a wonderful Christmas Clive. Happiness and more than a ittle prosperity for the New Year,

[@AIJenkins]

Merry Christmas 🎄 BigClive! Thanks for the Christmas Vid! Always look forward to your exploration videos 🎁

[@97marqedman]

It’s Christmas morning with BigClive! Woo! Putting my other gifts to shame.

[@leybraith3561]

Nice job, really appreciate the work that must have gone in to the whole analysis. Curious that they have taken a lot of trouble with including the 'off' circuitry, there's no dynamic braking so there's little need for it. Might improve stability during a quick "on/ off/ on" transition but that could be achieved much more cheaply. Almost looks like they were looking for a justifiable way of creating a minute amount of discharge current to ensure a reduced product lifespan?

[@bigclivedotcom]

It's probably to ensure a solid reset for a fresh speed ramp when used again. The low processor current may keep it awake for a while after the trigger has been released.

[@leybraith3561]

@@bigclivedotcom Good point, sounds like the voice of experience. The ability of microprocessors nowadays to sustain a semblance of operation while consuming microamps is something I need to get used to.

[@nofider1]

Thank you Clive. Merry Christmas and all the best for the new year to you and Ralfy. :-)

[@johnwalton5576]

Very informative and interesting Clive. Thanks for your hard work, and I hope you have a very Merry Christmas!

[@stevencox75]

ive had an aldi rattle gun for about a year, it works great with no problems

[@DannyBokma]

Haha too cool! I was involved in / contributed to designing the battery side circuit, so I am curious about your next video!!!

[@johndododoe1411]

The battery side video was released first, it was a few days ago and quite detailed.

[@robssk855]

I've learned so much from your videos, I was just a humble audio amp. test engineer, your knowledge is formidable, happy xmas big man.🙂

[@Manu-nr1yt]

I wonder why they did it this way. Probably because they wanted the higher voltage option? As far as I know Bosch and Makita both have a full BMS including power cut out option inside the battery. Probably the same for Einhell. If you have either type of battery and want a different brand tool, then passive third party adapters exist to use batteries of another brand for your tool. Something like this would be a very bad idea for the Ferrex battery if part of the BMS is in the tool.

[@MsLancer99]

Yes I've used a battery powered angle grinder and the battery is getting low and I've just have a very small bit of cutting to do and it keeps self switching off. Then to change to a charge up battery, you have to find the battery that belongs that angle grinder because the others don't fit AARR

[@Deiphobuzz]

Very cool of you to share this. Maybe fun to compare it to the Lidl Parkside and Ferm AX power? Also two cheap 20V systems. I suspect they are all identical to eachother.

[@jacobtrapp3772]

HoHoHo, I hope everyone has a wonderful day on this beautiful Christmas morning, at least morning in the US anyway. Merry Christmas to all of my favorite tech nerds and geeks!! :)

[@micahnightwolf]

Someone should make a "big clive being a bear" compilation video. That "maw mosfet" would fit right in.

[@paulclarke7406]

Happy Christmas Clive

[@jimsvideos7201]

Merry xmas, Clive.

[@Damien.D]

That was a complicated and long journey for such a cheap tool. Pretty interesting designs with some odd choices.

[@tinygriffy]

The Battery PCB looked like some fancy autorouting KI had vomited on the board.. here seems to be something organic at work, but time must have been precious. Talking about beautifying things none usually sees .. ^^ Wish I could get some of that conformal coating, seems to be up to the task ..

[@TheAntibozo]

Be well, Big Clive. 🐿

[@d.t.4523]

Keep working. Good luck! 👍

[@strehlow]

Odd that they didn't power the MCU from the center tap between the batteries. Going from 18V to 5V would be easier than 36V to 5V.

[@Jeroen74]

You would need another set of contacts on the switch, and it causes unbalanced currents in the cells which is bad.

[@johndododoe1411]

@@Jeroen74 Or maybe a MOSFET between the 20V pin and the 7805, like an N-channel 2N7002 turned on or off by the switched 40V line. So +20V gate voltage on, -20V off, parasitic diode only conducting when there's voltage on the 7805 input capacitor and battery has even less voltage due to quick swap or failure.

[@Jeroen74]

@@johndododoe1411 That requires about the same number of components as the present solution and does not fix the current imbalance problem 😊

[@johndododoe1411]

@@Jeroen74 It does however avoid wasting the extra energy dropped by linearly reducing from 40V instead of 20V. As these packs support multiple load configurations anyway, any imbalance needs to be fixed by the charger refilling both halves even if slightly imbalanced by one or more tools.

[@Jeroen74]

@@johndododoe1411 Yes, it's not a very efficient design. Just that 7805 regulator alone needs about 5mA just to power itself. I don't know about the MCU current draw, but I wouldn't be surprised if total current draw would be somewhere around 15mA. I think that's a bigger imbalance than that what would occur with the multiple load configurations. The way they did it is the least risky way, but at the cost of more energy waste; a simple buck converter would be best, no imbalnce, less waste, but more expensive.

[@dglcomputers1498]

Talking about "tool" batteries, if they were cheaper then I think the new Henry Quick's battery looks somewhat interesting in that it has 13 contacts and is only a 25V battery, I'm guessing they've used multiple contacts for current capability, but it's interesting that they've gone for so many contacts when other cordless vacs (including their own) do not. It might not currently be made by them (it's made by King Clean in China due to factory constraints), but it's supposedly their own design.

[@bigclivedotcom]

I wonder if the charger has balancing in it that uses multiple battery taps.

[@dglcomputers1498]

@@bigclivedotcom Strangely not, the vacuum itself has all the contacts but the battery is charged from a simple wall wart with just a barrel jack that plugs in the side of the battery itself, @beko1987 has taken one apart but didn't open the battery. Sadly the one here is a wrapped Christmas present so naturally will not be getting disassembled!

[@AntonHinxman]

Very smart design

[@kellyeye7224]

Clive - can you look at the motor BRUSHES? I've previous complained to Aldi re their drills (same tool range) as the brushes are very 'insubstantial' and they fail - they actually melt! - when the drill is used for a lot of 'heavy' work. I'm not sure if the grinder is similarly constrained???

[@bigclivedotcom]

The grinder seemed to have decently sized brushes.

[@kellyeye7224]

@@bigclivedotcom So did the drill! But..... the brass holders were very, very thin and when they overheated the brushes 'fell out'....

[@curtishoffmann6956]

Oh that BigClive. Always with his nose to the grinder. He needs a holiday.

[@gambistics]

Great analysis, is there any more information about how the rough voltage regulator built from transistor and zener works?

[@bigclivedotcom]

Search for transistor voltage regulator. It's simple, but lack the extra thermal and overcurrent protections of a dedicated voltage regulator.

[@kareno8634]

Hi Clive! Happy Christmas! Thanks for bringing us schematics, perhaps efforts to get there deserves 3 Cheers! Is conformal coating usually hard removing, Oh, and Still read components? What do \ did you use, High proof Alcohol? Citrus Oil? Reminds me, ... Nice Chat last night! Too bad Ralfy missed Name i call Moonshine given me, *KO's OK KO.* lol Maybe... No. *Not to use* for Electronic coating removal. : } You done Good, I even seem to Understanding this, today anyway. *CHEERS to all!*

[@bigclivedotcom]

I tried a few things and resorted to laboriously scraping it off bit by bit.

[@TinC33]

Hello, great video, do you heave any idea whats wrong with mine, pcb look good, no demaged elements, but when i turn on the switch it do nothing but start tiny smoke from R7 resistor, do you heave any idea where could ve the issue, diodes are all ok... Thanks for any info.

[@bigclivedotcom]

That might suggest that the 5V regulator or something on the 5V circuitry has failed.

[@pdrg]

Would be interested to see a scope on the "data" pin

[@Raventail2]

How did you remove that conformal coating, Clive? The control board in my washing machine has it too. Made it near impossible to try troubleshooting it because I couldn't find out how to get that crap off of the board. I ended up ordering a refurbed control board just to get my washing machine going again.

[@bigclivedotcom]

Lots of gouging and scraping with a screwdriver.

[@mrrkrr]

That's quite a beefy MOSFET! Looks like it's rated for 130A at 60V :O

[@WooShell]

Current spikes on a brushed motor can be quite fierce, and oversizing that part costs only a cent or two more. Probably cheaper than having to do refunds..

[@1marcelfilms]

time to sneak in one of these in the cart during shopping to harvest the cells

[@robegatt]

A gate driver chip would have been cheaper than three transistors!

[@keithpattison6763]

Hello Clive, I have a 240 volt Ferrex disc grinder that sometime trips my RCD on switch off. I have had it apart and checked for shorts, etc and even replaced the capacitor fitted. Still trips out the RCD on occasions. Could a suitable voltage/current sized Schottky diode be fitted to this, as the tripping could be because of back EMF?

[@bigclivedotcom]

Does it actually have an earth connection? If it does it could be a spike going through a filter capacitor. But there's also a possibility that it just triggering flashover of a fault elsewhere. Your RCD may also just be old, as they can get more sensitive with age.

[@keithpattison6763]

@@bigclivedotcom Thanks for the reply Clive. The lead has no earth terminal and nothing else I have trips the RCD. I have another one of these grinders that does not trip, so I will take it apert and see if anything is different.

[@halbvoll1]

Wow, great job, how complex for that simple use, I would say overkill. But now I know if I have to repair it once, I'll simply bridge the mosfet

[@Daleeather1975]

Hello big Clive I have a Aeg 18 volt angle grinder that has stopped working. I have been told the common fault is to do with load sensing board that stops the grinder working Aeg has refuses to warrent the service and repairs to the load sensing circuit.

[@bigclivedotcom]

I'm afraid there's a culture of just selling new tools and not repairing stuff because of the expense of having a network of repair technicians, and the liability of selling replacement modules for DIY installation due to the litigation culture.

[@welshdave5263]

I've been playing with 3D models for using the 20V packs, I have 4 of them and don't want to have to buy a 40V pack to have this grinder. I want to model a 2x 20V to 40V adaptor. Do you think the tool would run with the T input from 1st, or 2nd pack?

[@bigclivedotcom]

If the NTC input is purely a thermistor then it would have to be the pack referenced to the tools negative connection. An adaptor like this may pose a risk of not just over-discharging one of the batteries, but possibly reverse charging it.

[@paulmccoy2908]

You’re overthinking the signal/ntc line. It really is just a bidirectional ntc signal. The only other communication that is necessary is “ok to send power” and “ok to receive power” by each device. Each one can signal “0” of those two states by either pulling the ntc signal OOR high or OOR low. The analog state of the line (as silence indicates acceptance) and it/they can switch around and read each thermistor and test the connection. That way either, both, or neither component can read and/or signal on the signal line digitally or as analog.

[@paulmccoy2908]

It’s a really simple yet robust system. I’m working on a universal tool battery adapter system to rule them all.

[@bikkiikun]

What would be the advantage of double the voltage (battery packs in series) vs. double the available current (battery packs parallel)?

[@kimchristensen2175]

The motor windings can be made with smaller gauge wire and the motor can run at half the current for the same output power.

[@bikkiikun]

@@kimchristensen2175 : Makes sense... And is kind of obvious, in hind-sight. Thanks.

[@radleytube]

Big Clive, my Aldi grinder has stopped working! I think it's something to do with safety turn off when there's too much load! However it was not under much load when it last worked. Have you any knowledge what it could be? Or ideas

[@marcin9739]

I have the same problem, any suggestions?

[@radleytube]

@@marcin9739 think you need to keep your eye on meters mate

[@marcin9739]

@@radleytube Big Clive please help us, maybe we can fix this 🙏

[@DJ_Cthulhu]

My local Aldi only had one of those Angle Grinders left (£19.99), the box had been ripped open and contents fiddled with, so I didn't bother getting it. Maybe I should've asked them for a significant price reduction. Happy holidays and other festive BS🖖

[@Derek_Garnham]

I hope it wasn't the one Clive returned to the store after making the video,

[@rickjljr11]

I bet the microcontroller puts itself to sleep and only draws a couple of microamps until it sees the "on" signal. the "off" circuit draws (40 - Zenner voltage) / 2 MEG maybe 15 uA?

[@McTroyd]

Interesting way to implement a soft-start circuit. I presume it's an effort to be nice to the motor over time?

[@Derek_Garnham]

a soft start on an angle grinder is preferable as the tool kicks less, allowing accurate work and fewer accidents, not just to be nice to the motor.

[@McTroyd]

@@Derek_Garnham That makes sense. Thanks for the explanation.

[@ricksampson6780]

Where are all the negative comments?

[@bigclivedotcom]

They have Xmas off.

[@ricksampson6780]

@@bigclivedotcom Cheers Clive, thanks for all your excellent reverse engineering work!

[@connorglen1939]

Did you put this back together i only ask because my choke wire had become burnt out and i could not get the joint off which is soldered to the brushes. I hope this makes sense 😅.

[@angolodiappla]

Always great videos Clive, been following since 2016. Can you maybe do a video on your printing techniques for making those colored photos of the pcb? I remember you saying years ago that you had a system that made it very cheap. Thanks!

[@johndododoe1411]

The cheapness comes from a non-HP printer that accepts bottled ink instead of overpriced cartridges that contain only a few ml each.

[@bigclivedotcom]

I use good lighting and an Epson ecotank bulk ink printer.

[@briandeschene8424]

In case you missed it, BC did post this video about taking his PCB photos… kzbin.info/www/bejne/gmfWcoZjrpdkrqM&si=EnSIkaIECMiOmarE

[@DesignedbyWill2084]

Nice to see conformal coatings being used on in expensive device. Have too many Multi x 1000 dollar industrial boxes that don't.

[@bigclivedotcom]

Are you aware of VOCs? Volatile/Vapour Corrosion Inhibitors. Basically a sponge or spray that releases an oil vapour that coats things with a molecular layer to reduce moisture issues.

[@mfx1]

I can't see what the "off" signal achieves given that the micro isn't powered when off?

[@bigclivedotcom]

It probably resets it instantly while residual charge remains on the microcontrollers own power supply circuitry.

[@mfx1]

@@bigclivedotcom Fair point, I wonder if that's the reset pin and the gate capacitance plus the 10nf cap might hold it in reset just long enough for the power to stabilise when the trigger is pulled so the 10nf cap and parallel resistor might be more for that rather than filtering. Not an issue for most things but power tools often get used in short quick bursts which might upset the micro.

[@olgakorbutssmile4531]

Morning Clive I have one of these grinders..its got a brand new battery and fully charged..won't switch on. Tested the switch with a DVM..OK Where on the pcb should I test for failed components?? Nothing looks or smells bad! Thanks in advance David

[@bigclivedotcom]

The MOSFETs seem to be a prime suspect.

[@olgakorbutssmile4531]

Thankyou.. I'll study your circuit explanation..that coating on the pcb is almost like from a hot glue gun.

[@jackcollins4259]

I have had one of these 40v grinders which I find does not last long in use so I have to have two batteries for even the smallest cutts I also have the 20 drills which I also use the high power 40 batt so would be nice to see what exactly is going on when a 40 battery is used on the 20 v device having said that just noticed another video with the battery see if that covers whats on my mind

[@bigclivedotcom]

They lack cell balancing, so it's possible that one or more cells has got wildly out of balance for some reason. Their voltages should match almost exactly.

[@johnj4860]

I've got a few Ferrex tools and a couple of 40 v batteries and a 20 v battery. Popped the 20 v one on my grinder and discovered the unit wouldnt start . After opening up the handle and checking for operation of the switch with no effect on operation it dawned on me the grinder is a 40 v machine and the 20 v battery doesn't complete the supply circuit. Must read the labels! 😖

[@tda2806]

I have these tools, the ID and T terminals are present on the charger. Would you like me to provide some internal pictures of the charger?

[@bigclivedotcom]

I have a charger here for disassembly.

[@saxby1448]

Is there any way at all ro run them off a normal say 18v 5ah battery ?

[@JWH3]

Many why does this stuff never make it to the US Aldi's... I'm gonna have to make a trip just on the off chance it is.

[@RustyorBroken]

Rather complicated for a grocery store tool. Imagine what Tesco has.

[@patricklyons7683]

Reheated pizza or bigclive ...

[@bigclivedotcom]

Both.

[@jameshancock]

Why would they do all of that circuitry instead of using a mosfet driver? The driver would be cheaper than all of that stuff and way easier to design.

[@julianstafford7071]

I always feel a little cheated that we skip over the chips. Perhaps you could cut one open and draw a schematic explaining how it works? 🙂

[@bigclivedotcom]

The chips are often microcontrollers, so quite complex.

[@julianstafford7071]

@@bigclivedotcom I feel you would be well up to it Clive!

[@ShadowzGSD]

🔔🎉🎅🎁🎄Squirrel

[@josephsaucedo8691]

Makita tool do the same thing seems like a copy or close to it. I liked there 20&40v in one battery Makita should of made a similar design.👍👌✌️🎄🎆🎉 Marry Christmas

[@johndododoe1411]

Is that a Kia Motors MOSFET?

[@bigclivedotcom]

I think it's just a component number, but it wouldn't surprise me if KIA also do electronic components.