Inside a new style eBay tool battery - with schematic

The circuitry in these generic battery packs for the unbranded cordless power tools on eBay is actually OK. Given that you can usually purchase an extra battery with a kit for just £5 more it does make me consider how much markup the prominent brand names like DeWalt, Makita, Milwaukee and others are making on their "consumable" batteries. Even with prominently branded cells it doesn't justify over ten times the price.
The design of this unit is similar to the Ryobi batteries in that it contains the battery protection circuitry, and can cut off power to the load directly. This actually makes them very viable for use in other custom applications. Many other brands rely on the tool to cut off the power draw when the battery signals it. The reason the Ryobi batteries have this feature is because they are backward compatible with tools that were intended for use with NiCd cells.
The chip seems to have been aimed at these packs, and it's most basic schematic is breathtakingly simple. I wonder if they've added the filtering circuitry for greater voltage monitoring stability with high current peaky loads associated with power tools.
I'll take the new chainsaw apart in another video. My general experience with generic power tools so far is that they perform exceptionally well for their low cost. I'd guess they're probably used by Chinese construction workers.
The charger will also get its own video. I'll guess it's a very basic switchmode supply with opto feedback and probably charge status indication monitored by sensing the voltage drop across a current limiting resistor.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- www.bigclive.com/coffee.htm
This also keeps the channel independent of KZbin's algorithm quirks, allowing it to be a bit more dangerous and naughty.
#ElectronicsCreators

[@cooperdove9929]

I really just wish I was smart enough to fully appreciate these videos

[@bigclivedotcom]

Keep watching and it will all start to make sense.

[@woody442]

The rabbit hole is deep but at some point it gets actually enjoyable.

[@orion310591RS]

Hah I remember times when I had struggles to understand him, but eventually after 100 videos I started to understand. The thing is Clive explains HOW it works, not WHY it works. It may sound the same but its not. Example 9:18 filtering circuit, he mentions what it is and how it works, for spikes, but he doesnt explain why capacitor and resistor are parallel and tied to ground, etc etc... In general, Clive doesnt explain on novice level (which is good), but it may result in novice struggling to understand him (temporarily).

[@merlynsfire1275]

at we're smart enough to watch them ;) :)

[@m0rtifiedpenguin]

It’s like maths. Don’t try to understand everything at once. But keep watching and do the “exercises” eventually it will start to click together

[@ianhosier4042]

I like the way the brand of the battery on the thumbnail is kaboom

[@oliverer3]

@@ianhosier4042 it's not even that far fetched given that there are battery brands like "UltraFire".

[@abitofabitofabit4404]

The 13-page Chinese full datasheet on page 11 shows a full reference design, including those series resistors on the pins. The good stuff is always in the Chinese datasheet...

[@oliverer3]

Most important thing I learned playing Shenzhen I/O

[@zh84]

3:41 "I roughly know what I'm gonna see inside. Air, mainly." It reminds me of the time Dr Ashens took apart a cheap clone games console and discovered that the manufacturers had put a big metal weight in the case to make it feel heavier and classier!

[@jamesharmer9293]

I used to be a BT engineer back in the day. They put big metal weights in the early push button phones for much the same reason. They also had to put weights in the handsets so that they would actually hang up the call when you put the phone down.

[@Roy_Tellason]

@@jamesharmer9293 I was given some phones for scrap a while back (lightning damaged), and yes, I did encounter some of those weights in there.

[@mpf1947]

@@jamesharmer9293 Although, in the case of those phones, the weights may have been moreso to keep them from being slid by the wires than to make them feel more expensive.

[@rowanjones3476]

I’ve got an LED bedside lamp with a weighted base. To be fair, without it you’d end up pushing it across the table when pushing the touch controls on it. The case and active components weigh nothing, nor do they need to.

[@carlubambi5541]

@@zh84 Bell cable and internet provider puts weights in their cheap remote controls mAll they do is make the remote break faster from impacts on the ground from dropping them

[@davidedwards9157]

The "prominent brand names" do make good money on their batteries, but what goes in also costs more. Big difference is that the big-name batteries are going to have cells of known providence with very precisely defined characteristics that will meet or exceed the rated values (seriously, a lot of the off-brand stuff is made from whatever cells are cheapest on the spot market, and the spot market has a huge problem with fakes and uprating). The casing tends to be a significantly better polymer, the internals have things like insulating sheets and thermal fuses, the bus bars are significantly larger in cross-section, and the quality of the battery terminal welds is vastly better. There also tends to be a lot more expense on things like load testing, lifecycle testing, drop testing, and so on. I use tools from one of the Prominent Brands pretty much daily, and have a mix of real and knockoff (half the price) batteries; the knockoffs are fine for things that don't put a huge demand on the battery (radio, worklight, etc), but they just die horribly if I try to use them in a high-draw tool (looking at you, angle grinder...). Meanwhile, the real batteries chug right along. Also, the off-brand ones tend to have a much shorter lifespan, as measured in number of recharge cycles.. The real ones will usually last about 18 months of regular use, while the knockoffs, despite not getting worked nearly as hard, often don't make it a full year before it becomes glaringly obvious that they aren't holding anything approaching a full charge. (And we're not getting into the industrial-sector tools, like Hilti, where they have a product line where the battery stores diagnostic information for the tool and uploads it to the charger during the normal charge cycle so that tool managers can identify and replace tools before the guy using it on the assembly line is aware of the problem.)

[@DJTrainR3k]

As someone who as done 2 years of Li-Ion battery pack manufacturing, those welds are not only abhorrent in strength and quality (They just full sent a popped weld on the bottom right, which essentially only has a *half* weld holding it on!) just by visual inspection, a single weld is poor practice. Industry standard is 2 sets minimum. I bet with just a single drop from arm height the welds will shear. The nickel is also probably plated steel which is a bad idea for high drain tool batteries, though in this particular case it's probably okay since the little saw won't draw too much. That's all not even mentioning the elephant in the room of relying on solder mask as insulation between cells! That was the craziest part to me.

[@MrHimer12]

Maybe depends on batteries I have disassembled some of them and better copies tend to use 0.3mm pure nickel strip and welds are strong, hard to remove. Damn, wish I could spot weld 0.3mm but max my welder does is 0.15mm and I have to sandwich strips in stronger packs. I have an idea for this problem but this requires some moneh...

[@Uncle-Duncan-Shack]

Reaches for the Kapton tape and begins fidgeting. Thanks for sharing, it is educational and entertaining as always.

[@bigclivedotcom]

That's exactly what I added.

[@pomonabill220]

The strap on the B3 terminal is VERY close as well! They could have put a strip of fish paper under the battery terminal that crosses the copper.... that would cushion the clip and helped with possible shorting.

[@jamesharmer9293]

Clive seems to be doing a lot of chainsaw stuff lately. Should the locals be worried ?

[@bakedbean37]

Maybe he's just thinking of trimming his beard. What could go wrong? 🙂

[@Richardincancale]

Just swap Texas for Douglas…

[@reggiep75]

The KZbin Overlords will be watching close to make sure nothing odd happens.... especially with chainsaw being mentioned.

[@markfergerson2145]

No more than usual. Between Fanny wossname with the flaming farts, the wiffler, and carbonating liquids that probably shouldn’t be carbonated, if they were going to come after him with pitchforks and torches they already would have. I wouldn’t give them good odds though.

[@paullewis252]

That may explain why he is often supporting a band aid on his left hand...... I love his videos and especially his sarcasm. He just needs to learn to speak Australian so we can fully understand 😆

[@sajidmohammad3190]

That's why brand is a fact. I have been using a "Total" brand cordless impact drill from 2020. No issues at all. Last January, 2024 both of the batteries just died while drilling. When I checked I found out that 1 cell from each pack went to 0v. So I just replace the cells with Panasonic ones and now it is all fine. But the main thing is, it is well built. They have none of the problems shown here. PCB traces are good, nickel strips are well designed specific for the battery pack. A good product actually.

[@CheapCheerful]

I was in Thailand recently and Total is big there, has retail stores in shopping centers etc. Good quality/price ratio.

[@sajidmohammad3190]

@@CheapCheerful Yes, very good quality products. We have ingco, tolsen, harden too.

[@GannDolph]

The battery midpoint taps should always be designed to effectively be "fused" as near to the cells as possible. Major brands accomplish this by either using thin wires , highly narrowed down nickel strip, or SMD resistors on a flexible pcb mounted over the cell ends. The fact that these guys pulled full width nickel (steel?) strips for midpoint-voltage-sense right up to the BMS PCB is a flagrant violation of battery safety 101 ! It's these kind of fouls that causes most of the battery fires and thus the new laws showing up that prevents us from having ebikes indoors in major cities.

[@spongerobert]

I see so many Chinese "portable power stations" and powerbanks that have pretty beefy batteries and absolutely no fuse/protection. I had one from a "reputable" brand (Jackery) that died because of a faulty charger and then when I took it apart to reuse the battery I realised that the BMS had an exploded mosfet but as I poked at it it started smoking again. Basically it was still trying to dump the entire battery pack to a dead short because it had no fuses and luckily something else failed.

[@lukahierl9857]

And Bosch is like: what are you talking about?

[@michaelseitz8938]

Damn, the spot welding is another point of failure and a possible fire or explosion 😱

[@greengreens9936]

Are the nickel strips spot welded directly to the PCB?

[@BrendonGreenNZL]

​@@greengreens9936 I know; I couldn't believe it either. But; if they're spot-welded to the PCB, does that mean they're soldered to the battery? 🤔

[@jaro6985]

@@greengreens9936 No there are small SMD pads that the nickel strip is spot welded to. You can find them even on $1 BMS boards.

[@jamesmartin2325]

With this, and the chainsaw videos, can I request a spin off series, similar to the ‘Will It Carbonate’ called ‘Will it Dismember’ whereby Clive tries to cut through various items with the cheap (slightly dangerous) hand chainsaw. Start simple with items like twigs and branches, then move on to more exciting things like frozen joints of meat, lithium cells, Ralfys flat cap etc.

[@ferrumignis]

...fingers, arms, legs...

[@davidmiller3709]

As a hobbyist I have skirted round electronics for years now. Mains projects are doubly trebly quadruply safe, no reg is left unexamined. It is like painting-with-numbers, I am very good at doing stuff, but haven’t a clue what’s going on. Actually, that describes my life.

[@meechmushrooms]

“Yes, there was a bit of a spark… ✨ _exciting_ ✨” God, I love Clive. 😄

[@LawpickingLocksmith]

I bought a cheap whipper snipper and it came with 2 similar batteries. No matter how dodgy they are built, actual fires are rare. Thanks for the great reverse engineering.

[@janami-dharmam]

my drill from IBELL uses the same batteries

[@Poult100]

I like the 'over-zooming' as I tend to watch your explorations on my phone. With a cup of tea. First thing in the morning, in bed.

[@bigclivedotcom]

That's why I zoom in a lot. For the phone viewing.

[@TonyLing]

0:25 That's interesting. The lube pump is commonly seen as a petrol primer bulb on garden tools.

[@Ray_of_Light62]

Hello Clive, Can you make a video about the LIDL batteries and chargers? They have a 20 V and a 12 Volt battery line. All the batteries use 4.2 V 2 Ah 18650 cells. The 20 V 4 Ah battery costs 25 pounds and has a 2P5S configuration, and the Battery Management circuit also provide cell balancing. Nowhere in the instructions says that for cell balancing to work, the battery must be left in the charger for several hours after the charge had ended. Thank you Anthony

[@bigclivedotcom]

I have one of the old unbalanced and new balanced versions here. The primary difference is the discrete one-chip-per-cell balancer. The way they work is to bypass full cells with a resistor to allow the others to balance slowly at the end of the main charge.

[@Tsiikki]

Lidl 20 V 8 Ah battery with BT is good. Too bad we don't get brushless tools (Black premium) here in Finland. Casings aren't as good as like Makita, but good enough for that price point!

[@user-zz4to5kq1q]

This kind of battery is from small factorys. They do not have design team and just buy case, battery, pcb from other factory and assembly.

[@CheapCheerful]

Interesting, thank you.

[@LeslieSmart-e4p]

Hi Clive, Brilliant video as usual. One thing about these "21v" batteries, is that they are not actually 21v, Thy all have 5 cells in which is exactly the same as the 18v batteries from branded names. Even fully charged they do not supply 21v. The circuitry doe not boost the battery output. There are hundreds of cheap Chinese tools with these batteries all purporting to be 21v. I actually purchased a drill and when I found the batteries were not as described I requested the correct ones from the seller. After many Emails, no 21v battery was forthcoming and a full refund was given and they did not require a return.. Keep up the good work Clive.

[@bosstowndynamics5488]

In their defence, DeWalt to this day continues selling their tools in some countries as 20V using the exact same reasoning, and 4.2V peak per cell does mean that *technically* the pack does have a peak voltage of -4.2V- 21V even if that's never going to be delivered in the real world once factoring in voltage sag and such

[@dieseldragon6756]

Maybe 21 _Chinese_ volts is equivalent to 18 _British_ volts? 🇨🇳⚡🇬🇧😉

[@ibmezouar]

I really enjoy your videos sir, especially ones about battery packs, thank you!

[@rancillinmontgomery2480]

My dewalt packs were failing and I found replacement cases on Shoppee that come with nickel strips and bms just add quality lithium ion batts. Got one that holds 15 cells and another that holds 10 21700 cells. Back in business!

[@ricoma6037]

Thanks for sharing your knowledge and time!

[@curtishoffmann6956]

All praise design errors! It's the one thing keeping Big Clive in business!

[@dieseldragon6756]

Nice to see Big Clive doing reviews of low-budget _elemental_ technology now... 😁 🌬 The tool is as light as *Air,* 🌎 The charger has no *Earth,* 🌊 The product was as cheap as *Water,* and 🔥 Need I say more about the battery? 😉

[@jdmccorful]

Enjoyed your explanation on operation of batterypack.

[@stevengill1736]

After hearing about all these lithium battery fires, I have a lot more respect for well designed chargers! Cheers..

[@ChiEKKUsama]

Oooh, 21 volts; one more volt than normal! That's probably what they were hoping people would think.

[@urugulu1656]

no the charger is intended for a nominal 18V battery but 4s of NMC (w/ terminate charge vtg of 4.2V a pop) just so happens to be 21V at the spot.

[@fluffyblue4006]

This is why I tend to open up these kinds of batteries. To inspect them, and to fix dodgy assembly work. I'd rather not use that one, as is. Depending on how hard it is to open them up, I might also add a balancing connector and RC-style power connector, so I can charge them with a balancing charger, every now and then. If the pack is easy to open, I just add temporary balancing leads whenever I feel like rebalancing the pack.

[@fanplant]

standing by to see the wart filled with air. I could tell in the vid it was light as a feather

[@bigclivedotcom]

Just released it on Patreon.

[@zebrasprite]

I’ve always had a sneaking suspicion that the markups on Makita/DeWalt/prominent tool brands are entirely arbitrary. I sincerely doubt that the circuitry, and the manufacture costs, would warrant a 50-80 pound price to make any profit. Stuff like this is a bit of a confirmation for me, I think.

[@--_DJ_--]

All that marketing doesn't pay for itself!

[@Tsiikki]

At least there's someone to call if you somehow manage to burn down your house with a genuine battery! Crappy batteries are a real safety hazard and they die when you need the tool most..

[@bosstowndynamics5488]

The markups aren't so much arbitrary as market researched targets based on setting the highest price they think they can get away with. It's unfortunate that it's so hard to find a middle ground between these ultra cheap low quality units and the fairly high quality but not actually that much more expensive to produce name brand packs Edit: Ryobi probably gives the game away the most, since they do several tool bundles where the batteries are borderline free when compared to buying the tool separately, and that's a like for like comparison with the exact same first party batteries

[@--_DJ_--]

@bosstowndynamics5488 I can see ryobi taking a small hit on a tool and battery combo to get their foot in the door for home gamers. Mind you they all do that to some extent.

[@notsonominal]

oh my, that looks very exciting!

[@vaughanellis7866]

I'm glad you covered this battery pack as I was considering buying one of these hand chainsaws, that missing charge terminal would indicate that they were considering making the pack Makita compatible as there are other versions on Ebay what claim the packs are Makita charger compatible.

[@janami-dharmam]

Foxconn pays Indian workers exactly half of what they pay their chinese workers. That says a lot.

[@Tsiikki]

Batteries don't probably like the ~ 10 Amps from real charger 😅

[@Fridelain]

All resistors are fuses, in a way. As seen in MacBooks, were the actual fuses are the least likely to blow.

[@--_DJ_--]

Not just macbooks. I've seen a few 4090s with huge holes burned in the PCBs that still have their fuses intact.

[@jasnic2131]

Nice shout out to another channel I watch as well clive being "project farm" 😊

[@TheHatevessel]

Ah what a treat. I bought a frankly brutal garden strimmer the other day that use these very batteries

[@_dev_null_]

Best channel on YT.

[@dimitar4y]

oooh I like this chainsaw tool. The oil pump is a big plus.

[@frogz]

funny timing, i JUST got some genertic lithium ions battery packs from goodwill that i plan to re-build some nicad tools with

[@piconano]

Leaving out the NTC just boils my blood. I think an SMD NTC is less than a 3 cents in 1000 pcs. Talk about penny pinching!

[@ianendangan7462]

Same battery i used with a fan. Great for high fan flow during hot days and it last 3-4 hrs low power.

[@JohnSmith-gs4lw]

I’ve found with almost all those mini chainsaws that the trigger is designed to be pushed with the middle finger. Try it, and you’ll see that there is a notch (or choil) for the forefinger in front of the trigger. Don’t know if that’s good or bad, but they are easier to hold if you use it that way.

[@WooShell]

oof.. that design just asks to explode, with it relying only on the insulation of the solder mask..

[@veraxis9961]

I once had an unbranded power bank fail catastrophically in my backpack because the positive battery contact was laying across a ground plane with only soldermask separating the two. It did, eventually, blow the track clear, but not before melting through the case and producing tons of smoke. When I pulled the smoking power bank out of my bag, I could see the battery wire glowing red hot through a hole melted in the case. With the number of overlaps in that tool battery pack you have, I would be very nervous about it myself.

[@ooltimu]

That unpopulated terminal is used by Makita to check the temperature. It should be at or slightly below the full battery voltage. I built a few batteries on my own using these kinds of BMSes and Makita tools don't work with them since that pin doesn't have the right voltage. What I've done was to disconnect all the traces from that terminal and short it to the positive. The Chinese have basically repurposed that terminal for charging. I've even seen some knockoff Makita chargers that have only that pin connected and they don't actually work with real Makita batteries, only with these types. Also because of the female jack terminal these batteries don't fit on original Makita chargers because of the yellow terminal.

[@ssmedia]

Got a really neat cordless hydraulic cable crimper of AliExpress, cost about £400 in all. It came with makita clone batteries but I got an adapter to use it with my dewalt batteries! It came with 2x 5ah batteries and I'll probably use the 18650s out of the for something else, I was pleasantly surprised by the build quality of them though..

Interesting, the noname strimmer my mother bought has two of those batteries included. It was the first time i saw those battery packs with a barrel jack to charge it.

[@d.t.4523]

Thank you, keep working.

[@dcallan812]

Getting slightly better but still not fantastic safety measures. The track issue's you pointed out Tab B2 also looks very close to B1. Solder resist is not much use as an insulator. interesting look into how to charge batteries 2x👍 I had to tidy up my area after a technical goodness "(e-waste)" landslide 🤣🤣

[@jtveg]

Thanks for sharing. 😉👌🏻

[@McTroyd]

Pleasantly surprised they didn't cost cut the hell out of that protection circuit. Would have been good to have the NTC, but a single string of batteries isn't likely to get THAT hot in most cases. Pity about the layout. Maybe in the next version? 👍

[@johnspear3452]

It would be good to see a genuine makita lxt video, see if they are that much better.

[@gf2e]

I have a couple knockoff Ryobi batteries. They have spring clip tabs on the sides. Most, if not all of them, don’t have any insulation between the ends of the cells and the large metal springs. If you manage to press the spring in too far, it’ll short out two cells. The springs are held in place so that won’t be a problem, right? Oh, wow. The springs are held in place by pieces of tape. About as robust as masking tape. I open them up when I get them and add kaptan style tape, and epoxy to hold the tabs in place. The nice thing about Ryobi batteries is that they have built in MOSFET low voltage protection. So I can connect them to random circuits and not worry about draining them too far.

[@Cooper_42]

"air, mainly" 🤣

[@dieseldragon6756]

To be f *air,* you could say the same thing about most Apple products... 🌬🍎😉

[@Cooper_42]

@@dieseldragon6756 especially the old iMac3g! Things are pretty tightly packed nowadays.

[@LifeRunner4000]

The big brands like DeWalt, Milwaukee, Makita and so on definitely make an absolute killing whenever some poor sod buys a single battery or two. I had to buy a single 18V 5Ah Milwaukee battery years ago and it was about £150 at the time, keep that price in mind because a year or two later I bought a battery/charger combo. Six 5Ah 18V batteries with a charger that could take them all at once, for about £350. You get the same thing with those package deals where they sell you a sawzall and a drill with batteries, a charger AND a "free" M12 battery thrown in just so they hook you on that front as well, typically a pack like that is also around £3-400. The markup is absolutely ridiculous.

[@marjon1703]

The lead out of the charger is Copper Coated Aluminium and in my experience, insulation spit, twist and short to FUThiss. One of my China tools is a 1/2 inch (with 1/4 inch hex drive in the centre) impact driver and it is a superb tool that takes huge punishment. For an ebay cost of £35. Batteries working well but the charger is the weakest link.

[@MsLancer99]

I work for a Heritage Railway and we use a lot of cordless power tools and they have come a long way, where we could use a power tool for only two or three hours max and the battery is flat and now the power tools have more power and we can use the power tool for four to some times five hours before they need to be recharge but these are the upmarket tools and cost £ 160.00 up to!

[@geoffgeoff143]

Be interesting to see inside a Milwarkee battery with all the smart data stuff.

[@ianharrison7862]

My partner bought an unknown brand compact chainsaw that came with a couple of these battaries. Ir runs for a couple of minutes and then the chainsaw acts like battery is running flat, going slow and then stopping completely. Leave it for a little while and it's fine for a couple of mins again. Suspected some protection kicking in somewhere (either heat or power draw related) which is a shame as others have used similar tools and found them really good, which is why they suggested them to her. She has bought another compact chainsaw now and will see if that is any better. I was shocked when I picked up the charger unit as it's so light I was expecting it to be empty and a fake charger, but does actually seem to charge the battery somehow. Will be interesting to see your strip down of the charger.

[@Robothut]

I do not like that B2 tab sitting on top of the B- solder mask either. I guess it's time to take your snips and trin it back a bit. Maybe you could slide a thin piece of plastic "from packaging" in-between the metal clips to add some protection there as well. I just ordered a $29 dollar version of the mini chain saw from amazon in the USA. I will be checking out the 2 batteries it comes with for sure. Thank you for the tear down and heads up.

[@Tegelane5]

It is further development knock off 18V Makita battery, @ 2:42 this odd missing connector is needed on Makita tools. On those it has to be connected to +, it signals to tool that battery is OK. So this is "inspired" by Makita but no longer can be charged or used with Makita tools/chargers. This missing pin is used on Makita chargers for charging aswell (atleast on slow 3A chargers).

[@ketas]

finally chainsaw with actual safety interlock. imagine falling and grabbing it... my ryobi mains one has that. and it also had automatic oiler instead of manual hope yolo oiler. it's implemented by solenoid in series with motor. restricts it's usage angle tho

[@PCBurn]

Ah, that makes me leery. I believe the negative was what scorched on my cheapie (untrusted, fortunately) Amazon pack. In this one that would've been potentially very unfortunate. On mine it just meant a quick trip to the parts bin.

[@davidfalconer8913]

I like the [ Robbie the robot ? ] oil squeezer , for some reason ( ? ) ............... DAVE™🛑

[@alexstone691]

Those chinese battery chargers are basically regulated supply with an op-amp checking if the voltage has reached the wanted voltage, and they often come overvoltaged and kill cells, at least in my experience

[@ianhosier4042]

Early failure simply mean they can sell more of them and make more money

[@bigclivedotcom]

The pack itself should shut off the charge. I've already made the video about the charger (coming soon). No op-amp.

[@tw11tube]

Ouch, that reminds me of the chinese power tool that came with a NiMH battery (those were the days...) and used a LM324-based CI/CV charger. Who the heck told them CI/CV is the correct charge procedure for Nickel cells?!

[@kissmiasma95]

Your camera is really great. It's almost unnecessary to do the zoom picture now. My parents' biggest fear when I was a young child was which electronic device would be disassembled next when they weren't looking hahaha.

[@007floppyboy]

I have a similar mini chainsaw, got it about a month ago. It works well, there is a thermal trip strapped onto the motor to detect if that is getting too hot. I am now going to check the battery and alter if that strap is too close to that track. DO I add a thermistor, well I think I will.

[@andygozzo72]

looks similarly close on the other side, i'd run a bit of superglue in those gaps to act as a bit of an insulator!

[@stevebabiak6997]

1:25 - on the left hand side, terminal B1 and B3 look to have the same dependence on the solder mask serving as insulation.

[@StephenBelcher-sr3zk]

Great shooting Clive:” Fingers And The Brains

[@janosnagyj.9540]

3:30 I recently bought some power tool off Ali and the first thing I noticed when I took the charger out of the box that it is _unrealistically_ lightweight! They must have found the way to produce antigravity and this charger must contain _loads_ of it 😅 Can't wait the video to see actually what is inside! Don't make me wait for too long for it! Just one moment, please! 🤣

[@bigclivedotcom]

Video already made and coming soon.

[@BrendonGreenNZL]

My guess would be a capacitive dropper and a rectifier. Line isolation? No, that sounds too expensive...

[@ehsnils]

B3 connection tab also has the same problem as the B2 connection tab. Might be that the tab width has changed after the PCB design since the tabs looks like they are unusually wide.

[@ross9580]

Clive, there's a handheld fan popular in Asia which has battery management you might find interesting. Search SAPI N15b portable fan and you'll see some images. It has no low voltage protection but uses the digital percentage 'meter' to cut power when it counts down to zero. I tested the two 18650 parallel cells at just 937 mAH combined and replaced with batts with cells totalling closer to 5000 mAH. There's charge protection to 4.2v but when the meter counts down to zero the fan shuts off with higher capacity batts still reading 4.0v. Unexpected 🤦

[@bigclivedotcom]

The expected cell capacity may have been baked into the software. Some devices can self-learn if the cells are charged in them, starting from low charge (3V).

[@smalcolmbrown]

Thanks :)

[@gary_rumain_you_peons]

One thing I've noticed on eBay, locally at least, is that the vendors (all Chinese, of course), don't sell these batteries separately. Not even if you want to buy a new replacement pack. No idea why. But they do sell the circuit boards.

[@bigclivedotcom]

In the UK they can't ship just a battery on its own due to very ill-conceived postal regulations. But they can ship them with or inside a product.

[@cgoad]

"I accidentally triggered that. It was quite interesting." Another Clive understatement?

[@errolfoster1101]

I bought a small chain saw and a line trimmer one came with the same battery as these but the one that came with the chainsaw has a battery voltage test button other wise the same batteries

[@dimitar4y]

1:09 I don't think they're meant to be that close, I bet there's a unit out there that the guy put way too close, and one gentle knock later, ..... Fireworks!

[@charlesgould8436]

Looking forward to diy air purifier!

[@peterthebricky]

Good to see one with oil

[@rgbii2]

Hard to tell for sure, but it looks like the B3 tab is really close to the B1 pad. Not as bad as the other you mentioned, but closer than I'd like.

[@KernArc]

Is spot welding battery tabs directly to PCB pads a good idea? I think that’s the first time I see it done like that. I don’t think the risk of lifting a trace is high, given the today’s generally decent PCB manufacturing standards, but don’t they run a risk of corrosion caused by a high current running through small surface interface area between two dissimilar metals? Unless that’s exactly the point: a smart self-destruct timer, of course 😉

[@maximredoran3983]

Batteries on Xiaomi and Ninebot e-scooters are usually made in a similar way, just tabs from batteries spotwelded (usually 6 spots) to BMS daughter pcb. I assume it's made for mechanical reasons and to avoid routing 12 to 15 wires (not counting thermocouples) through the whole battery.

[@bigclivedotcom]

There are metal pads soldered to the PCB for spot welding to.

[@user-yn8mz5bf9y]

I agree their is not enough clearance between those two contacts

[@lethalz9]

Yep, not enough gap between those tabs. Add a few accidental drops and some vibration and those batteries are going to short out quick smart

[@ZeedijkMike]

Isn't it not "just" the whole battery pack that has been placed wrongly (a couple of mm too low). I supose that the battery taps should cover the hole area with all the smsll through holes. All the other taps are also misaligned

[@rasungod0]

I would be interested to see what it did on a Makita charger. Since the real ones do have balancing which would make it last much longer.

[@MrHimer12]

Those boards do not balance cells and they tend to discharge the battery to flat zero when left for too long. I have some collection of chineese tools and I have made my own "beanz" battery for those tool. It had only one row populated and to be honest those cells can give 15 amps I have tested them but in combination of about 1500mAh capacity well, the result is not so spectacular. I have depacked that battery, bought ten HB6 LG cells, they are also 1.5Ah but they deliver 30A with no problem. Only problem I had is that I had to use 0.15mm nickel strips because my welder won't tack anything thicker securely do basically I did 2x0.15mm sandwich in theory this pack gives 60 amps and chineese SDS drill was happy with that battery comparing well to the stock condition I had been given with the tool. Milwaukee, dewalt, makita, etc uses 0.3mm pure nickel strip but I guess that sandwiching strips is somewhat equivalent of that. I have come to one idea for those batteries, they have excellent spot to grind with dremel and place JST-XH connector there and I am going to do it because I have abundance of really good RC chargers lying around. Overall, charging them with that light brick is fine when cells are in balance. If you have those batteries it would be wise to take cover off and charge each cell from the pack manually to 4.2V even with TP4056 and then operate normally. There's still lot to cover about those batteries, building then etc. Right now I am planning on trying out those spotweld boards, beefing them up with extra fets and then pairing them up with huge 100C lipo sandwich and maybe then I will be able to conquer thick pure nickel strips. Only one I have right now is BIFRC DH20, spot welds 0.15mm very well but 0.2? Forget about it.

[@Alan2E0KVRKing]

You could carefully cut the overhang off the tab with a dremel to open the clearance maybe.

[@rimmersbryggeri]

You could but that's not the reason you buy a tool with a battery. Unless you are clive, possibly.

[@pwapwap]

And a squirt of hot melt under the tab to stop it bending down and wearing through the solder mask.

[@daliasprints9798]

I love using dremel cutting tools a few mm away from lipo cells...

[@jaro6985]

@@daliasprints9798 Make sure you use a metal cutting wheel for extra fun times.

[@Alan2E0KVRKing]

@@daliasprints9798 You'll be OK as these are not LIPO

[@Dog-whisperer7494]

Clive you look at the connections you will find in is compatible with Mikita . Ie the battery will fit and power a Mikita tool and the that tool in your video will work on Mikita batteries.

[@Lazmanarus]

Makita.

[@Roy_Tellason]

I like the oiling setup on that saw, which is lacking on the recently purchased Ryobi saw here. But those things you take issue with in this video make me not want to go near this battery.. Too much chance of a fiery end to it!

[@jimbo5728]

I ALWAYS open up "impossibly cheap" products containing high energy density batteries, to find and fix anything dangerous.

[@peterdevreter]

I stick to original Makita batterys. It's the old 18v system, but after 4 years all my packs are still working fine. If one eventually fails I'm glad because I can pull one apart! Curious what's in side. 😁

[@the44thcosmic_galaxy25]

Yes more more Clive more battery-related videos. Maybe street-lithium

[@srrandall88]

Hey Big Clive, please can you do a video on the 2 types of Ryobi batteries circuitry protection etc. In South Africa we get a completely different tool and battery and feels cheaper than what's available in UK. Our tool colour and battery system is completely different.

[@ccdimage]

I just left a comment on your other chainsaw video about the cut off switch. I think your old broken chainsaw has a cut off switch on the handguard if it is like a normal chainsaw.

[@junkerzn7312]

The extra resistors / caps on the taps... ah, just a voltage buffer since the equipment the battery runs during operation is probably a motor, to prevent the voltage from jumping around too much. The resistor would also serve to protect the cells from a chip short. The very high valued resistor divider.. 3.3Mohm. Hmm. I can think of two things. First, they are limiting leakage current from the charging source via the protection diodes on the CO pin to a value below the chip's nominal quiescent draw, to avoid overcharging. Second, they might also be limiting vampire current draw when the chip is outputting a logic low on CO. It depends how CO is configured. Is it left turned on or is it set as an input to poll the CHARGE+ voltage to detect charger presence, then switched to an output to enable the charger? -Matt

[@Eden_M]

I discovered that 18v Makita tools with "Star Protection" won't work with these packs as is, on these generic BMS boards, C+ contact has to be jumpered to the main positive and voila, angle grinder works. Not sure if it's good for the bms tho.

[@JorgTheElder]

When would they use the third big mosfet pad by the big mosfets?

[@bigclivedotcom]

Probably for higher current tools. It may have been a design option in case the MOSFETs they used had too high a resistance.

[@charlesgould8436]

I have L ion jump starter for a car with a drain. It is good