Thanks to bigclive we know what's inside batteries. It's fire.

Speaking of Ukraine, Kyiv: whoever watches Dave's videos in Kyiv, who lives on 2nd floor in building #15 on certain street close to city center, are you here? I've heard the sound of Dave's videos multiple times from the window that is next to the upper entrance to the building. Just wanted to say hi.

24:40 Books are great. Books work when the sun comes up. You can drop them from head height and they still work. I like my old TI reference books.

Of course it is everyone's favorite segment :)

I love mailbag, finally back in business.

Dave! You dont need another tab welding machine, you already got my kWeld - remember? Time to assemble rhat I guess? :-)

That heat shrunk battery pack including the BMS looks identical to one of my colleagues ebike pack ...he had a cell die ..it's like defusing a bloody bomb replacing a cell in those ...or maybe I'm just a nervous nelly. That cut off connector would have gone to the charge state LEDs if I remember correctly. I'm pleased to see a company giving a second Life to li-ion batteries. Edit Should have waited a bit longer ..you came to a similar conclusion anyways..

"Component quality and consumer protection? We're recycling First-World castoffs for emerging markets - what do you expect?" I especially love the universal death-dapter for the 220V out. By the way, I think the "pink-y" anodized color is meant to mimic rose gold, which is fairly popular in Indian costume jewelry. I think Adam Savage would get a lot of mileage out of the Marvelous Magnetic Machines book. Looks right up his alley for his One Day Build series.

The cut off BMC wires are for a display if you are using it as a battery bank.

I love Keith’s work. Glad he gets a shout out!

I dont even understand more than half of what is said in this channel, but I like the mailbag videos, because I can see Dave's reactions to things he gets, and its always fun :)

13:00 - Turn the screw the opposite direction when re-assembling (until you hear the click), the turn the correct direction and the screw should go back into the same threads that were cut the first time. Ask Fran about this.

The last zero in the cell designator indicates that it is a cylindrical cell, so it should not be omitted.

lol...i am waiting for years on you building this tap welding kit somebody send you....it may finally becomes true :D

I really like seeing the lab pictures sent in by viewers.

32:25 haven't seen dave so happy in a while

The robotics book actually sounds worth buying! I know some of the stuff already from university, but would love to see it combined into a project

Thanks for the video link about Lundgren, Dave, it was interesting. Cheers :-)

Holy heck it's been a minute since a mailbag.

I can't say I'm impressed with that powerbank. Feels a bit Aliexpress. That's a modified sine. Generates hvdc then chops it up. Means smaller, cheaper inverters but... Meh

Briliant end of the day - watvhing the EEVBlog ;] Nothing better to even think of

I recognize that 18650 module from the first battery bank, the whole thing is from one of those BIRD scooters. Those cut off wires are for a battery indicator

So many resources in this mailbag wow !

We use thermal paste and sil pads there is a significant difference in performance and i have seen it on a number of SMPSs as well

I love when you smelled the book to see if it was full of BS!

Sagan could probably program a computer at his age, Dave. He should be able to build one too, right?

That book on motors is pretty sweet.

I have Chibi's book, and I love his content. Love to see him get a spot on the mailbag!!

Perhaps the silpads were added to provide electrical isolation, as an afterthought?

Great video, and lol the Paul Hogan knife.

19:33 I'm disappointed in the fact that the length matching wiggles second from left and right are not mirrored but the other ones are. It's not symmetrical 😱

This took me over an hour to watch due to pausing to read the books. Just me? 😃

The most Aussie I've ever seen you is at 16:15 love your work Dave.

Mailbag is life

For the first product in this mailbag, the battery assembly that is covered with the black thing, is actually a Ninebot ES2 battery pack (electric scooter)! See this kzfaq.info/get/bejne/oq-ihJyUy7DMYZ8.html

My 91 Mazda got recalled a few years back because the grease in the ignition lock dries out and can catch fire - lol -.

Charge it up and loop the output back into the input. How long would it run for?

14:46, nice little model Sterling Engine above the pulse gen. I have a couple of those as well. :)

3:10 Rose Gold

Looking at how old that R&S gear is I wouldn't be surprised if the VNA and spectrum analyzer were Transputer driven. R&S used them to offload signal processing tasks from the main CPU to help improve real-time performance.

Try out a K Weld for those lithium batteries?

Damn all three (nvm, 4 lol) of those books look awesome!

Thanks. Had been a long time. I like the first powerbank! Seems all repurposed parts and made something usefull instead of just scrapping it. Just wondering how big the serials of those are. 100 sets the same and then 50 a bit different parts maybe? Must be pretty labour-intensive to make these.

I want to see some waveforms on that inverter. It's not a sinewave inverter with the 494 and ka7509.

I'd like a review of the battery pack inverter

Another time you could of used the striped screw remover. You must take that trip to Bunnings to pick up a set.

The LED outputs are probably a bar graph output for a similar or previous product. I wonder if they worked out a deal with a UPS manufacturer for parts.

What's that signal simulation PCB at 38:40 in the background? I can see the R&S logo but can't find any information about it.

hey Dave sir can you explain the topology of that first big battery (inverter) you teared down. I am thinking that they are converting the battery voltage with that transformer to 220V using high frequencies and so that's why they used that ferrite core transformer and they are rectifying it to HV DC and they are switching it with those 4 mosfet probably in H bridge to then convert it to 50/60Hz. if you know please explain it to me sir. and if not, can it be done that way?

The cells looked vertical stacked longway and to short for 18650 ?

The Marvelous (sic) Magnetic Machines book looks great, but isn't available outside the USA

3 books at row and another one comes later.. Sweet and great way for publicity.. 👍

Get a battery tab spotwelder they are awesome

Came here to see the tiny unboxing knife. ;)

"Newfangled Git stuff" - one Linus Torvalds is giggling 15 years ago :)

There a way for the South African market to get access to those power stations?

Dave, you should try and characterise the 4680 Tesla cells and compare them to the 2170s! Would be cool to see the discharge curves

The cut connector could be a battery tester section. 4 led leads, a b- and a "BUT" which could mean battery under test?

Couldn't help peak at the spoilers.. that marvellous magnetic machines looks great, good book fest this time... also would like to see how the amazon print on demand service works... surely one of your viewers might be able to get some behind the scenes :)

Fabian's black lab PSU reminds me of college 😃

good stuff ;)

Love mailbag. However I kept falling asleep during book-club reviews :O\ No worries. You'll find your mojo again. It's out there somewhere. I believe in you. Cheers.

Hi Dave. I love what you do and I've learned a lot from your videos. But I cringe every time you mention a "PTC" in the input of power supplies: those are not PTC's, they are NTC's so they limit the inrush current at cold start, then heat up.

17:33 "I´m usig this device to distribute the sync signal and 10MHz square clock signal for multiple SDR receivers." Hm, is he trying to build a passive radar to "see" some stealth fighters?? 🤔🤔

A book mailbag special.

Was one from Grant Searle? He's a legend on modern homebrew 8bit computers.

“that’s a knife” right Dave?

You better unroll that cell!!! 😈

Damn first time I've noticed the futuristic logo with sfx in the end

batterizer done kinda right 👍

If you are interrested about Practical Hardware Pentesting book, it's on Humble Bundle with many other security and pen testing books. You get many books for cheap, less than 15$ for all or you can pay more if you like to support. Not affiliated with them anyway, just telling my observations.

Talking about self discharge, is there ways to reduce it. I have a work light that runs on a single cell and loses its charge after a month.

It's square wave output, mainly Chinese products, design for Asian rural/urban use

The texas motor is called "nodding donkey"

Hello! Long time no see!

11:29 - maybe this aku board is also refurbished/reused, why not?

I think 'ichigo' translates to 'strawberry' in English, if I remember my rarely used Japanese correctly..

Using thermal compound and pads together is not only pointless but BAD because the coupling gets much worse by using both together! FAIL!

The power bank was a bit sketchy.

I bet that powerbank is one hell of an RFI generator! Looks like absolutely no effort whatsoever was made toward any kind of EMC compliance. No CM or DM filtering on either the input or output of the charger SMPS, nothing on the inverter circuit either.

Favourite Palarva

0:20 RoLol saying thanks holding a huge knife in hand 🤓😆😁 dare not reject my thanks

Any suggestions for useful esp 32/esp8266 projects and ws2812b

I'd want Ethernet, USB, and HaitchDMI in addition to the choices on the "multimeter."

It would not be unreasonable to create an EEVBlog Literature Channel :D edit (Dave sitting inside hundreds of book stacks resembling wafer structures ... reading us something about Mosfets out of a very old Book so we can all fall asleep and have sweet dreams)

Finally got notification...

If you used two TV screens with the split behind Dave's talking head, it'd look pretty seemless.

What's that board @38:36?

31:37 did it hurt not to say "rubber baby buggy bumper" ?

That is one dull knife - hard time just cutting the Kapton tape (16:43).

35:52 "You pass butter!"

nice tear down wheres the mailbag

The TBD should be HPIB.

LIFEpo4 Lithium Phosphate batteries can they be imported in to Australia I can only find stuff on Lithium Cobalt Manganese Oxide 49v at 30amps to power an e-bike motor?

(11:30) It´s me or the negative wire has a dry joint ?

Carefull where you put that little knife or you'll never find it again

Welcome to everyones second favourite segment! Bookbag!

Chibi=little, akumas=devils.

You need to buy some keysight test equipment

"cute scope" lmao