EEVblog #822 - World's Worst Tablet Computer Teardown

[Augustus]

Over 450.000 views and counting... Not the record yet but it has the potential   

Thought the "student apprentice" theory was the most convincing. Plus, maybe done by a software guy.

[retrolefty]

Over 450.000 views and counting... Not the record yet but it has the potential   

Thought the "student apprentice" theory was the most convincing. Plus, maybe done by a software guy.

 Well it sure wasn't done by anyone considering themselves hardware guys. The soldering shown of the batteries looks like someones very first attempt at soldering.   

[6581]

The comment about a battery holder is fairly stupid as well, Dave, since those have the risk that any jarring or drop will make the batteries disconnect.

I've done a battery pack using holder + zip ties and at least it handled just fine inside a motorcycle. Sure, not your first choice for production run, but in a small quantity for a prototype kind of device - at least much tidier than the vomit we saw on the video.

[Smokey]

... but have those demonizing the battery pack ever soldered batteries? 

This ties in with the Metcal thread.  The big Metcal tips solder to battery terminals no problem without dumping too much heat into them.  Now I'm using my own precision calibrated eyeball to measure what I mean by "too much heat" but I haven't had a soldered battery explode on me yet so I think I'm good to go.

[Chipguy]

I had to solder batteries myself in the past for prototypes, but what I did was to go into town and get some AA cells with already attached soldering lugs.
Here are some examples from a German online store:



This still does not look pretty (in my book) but I don't have a spot welder and I had no time to wait for a customized battery pack from my usual supplier.
Still much better than the Esinomed Desinomed demonised hackjob 
For those who want to know (in Germany) who does customized packs, starting at 1 pcs: http://www.goeke-shop.de

Example: 3 Cell 3.6V NiMH pack, 3800mAh, 18650 size (dia 17mm ; lengh 67mm) temperature sensor (Epcos), temperature fuse (Pepi, resettable) and 3 pin Molex connecter (PC fan type) costs around 20 EUR, fully customized in small quantities.

[rs20]

I had to solder batteries myself in the past for prototypes, but what I did was to go into town and get some AA cells with already attached soldering lugs.
Here are some examples from a German online store:

...

This still does not look pretty (in my book) but I don't have a spot welder and I had no time to wait for a customized battery pack from my usual supplier.
Still much better than the Esinomed Desinomed demonised hackjob 
For those who want to know (in Germany) who does customized packs, starting at 1 pcs: http://www.goeke-shop.de

Example: 3 Cell 3.6V NiMH pack, 3800mAh, 18650 size (dia 17mm ; lengh 67mm) temperature sensor (Epcos), temperature fuse (Pepi, resettable) and 3 pin Molex connecter (PC fan type) costs around 20 EUR, fully customized in small quantities.

None of these things are available from the corner store.

[Chipguy]

None of these things are available from the corner store.

Ok lets see, if I want a custom self made weirdo AA battery pack in weirdo shape, TODAY with parts from a local shop:


12 pieces available


4 pieces available


Ok that one is a problem, so I would need to go without and come back in 3 days

And finally:

6 meters available, that's more than enough.

I am not bothering to look up the molex connector since around the corner of that shop are man PC part shops.
I could just go in there, get the worst PC fan ever and cut the leads of.

So I could just get into town today, get everying beside the temperature switch that I might just get from another shop and I would be able to make a battery pack TODAY.

Edit: Doh... I need to find out if it's possible to resize the images.. they are much larger than the thumbnails on the website.

[rs20]

I'm talking about my corner shop. Ain't never seen those batteries with tabs for contacts before in my life, let alone in any shop that I know I can walk into nearby.

[bktemp]

None of these things are available from the corner store.

Ok lets see, if I want a custom self made weirdo AA battery pack in weirdo shape, TODAY with parts from a local shop:

I don't think there are much local shops in Prutting selling this kind of stuff...

Except from that, let's asume this project was done by a student. Most likely they gave him the computer module + display + touchscreen controller and he had to add only the battery + power supply and put everything into a nice looking case. As a student with almost no experience he maybe didn't know about batteries with welded tabs or he bought the batteries and tried to put them into a battery holder, but later he realized it does not fit into the case. Because he did not want to buy new ones or he had no time to do it, he soldered them together. It is certainly not the best way to do it, but the quickest and often the only solution when you need to make it working right now.

Many of us here on the forum have many years of experience in designing and building electronic devices. But this tablet computer clearly looks like it was built by somebody with much less experience. Therefore it is a bit unfair to criticise every detail he could have done better. Yes, it looks bad, but it works and it looks ok from the outside. That is more important.

[Chipguy]

I'm talking about my corner shop. Ain't never seen those batteries with tabs for contacts before in my life, let alone in any shop that I know I can walk into nearby.

DOH!

Ok, my shops are in a bigger city. Not huge but in 2013 official 514.137 people lived here.

[continuo]

These "lugged" cells are readily available at most stores who sell rc model stuff. At least here in Germany. You usually wont get them at regular shops. Using the right tools (iron with some serious oomph, fat chisel tip) it's also usually no problem to solder wires to regular double A's. This hackjob looks like if it's done with a 15w firestarter, equipped with a 1mm pointy conical tip and using high melting lead free crap. A full 5 out of 5 facepalms 

[Chipguy]

Prutting only has 2300 inhabitants.
The next "Conrad electronic" is 50km away, in Munich. Ok that one hour drive almost.
Rosenheim in nearer though, around 60.000 inhabitants. I don't think they got an electronics store that would sell those.

Well, from a infrastructure point of view that company is pretty screwed. However since most of the stuff is coming by parcel anyway it does not make a big difference.

[Yansi]

If you reverse the name of the company Esinomed what do you have??

Demonise!

Wow that's one heavy joke

[ivan747]

Prutting only has 2300 inhabitants.
The next "Conrad electronic" is 50km away, in Munich. Ok that one hour drive almost.
Rosenheim in nearer though, around 60.000 inhabitants. I don't think they got an electronics store that would sell those.

Well, from a infrastructure point of view that company is pretty screwed. However since most of the stuff is coming by parcel anyway it does not make a big difference.

50km, one hour? I thought this was Germany

[Brumby]

Google directions from Prutting to Munich offer the shortest route of 75.7 km, taking 1 hour.  It's about 53 km as the crow flies.

... depending on exactly where in Prutting and Munich we aim for.

[Chipguy]

50km, one hour? I thought this was Germany

It's Munich 
Just for the heck of it I just asked Google how long it would take to get from Prutting to Conrad Electronic in Munich.
Google answered: 59 mins (including 5 mins for traffic).
Sorry, sorry, I was 1 minute off 

[Brumby]

... and that's not taking into account stops for petrol or taking in the scenery.

I wouldn't mind checking out Bavaria.  One day, maybe.

50km, one hour? I thought this was Germany

It's Munich 
Just for the heck of it I just asked Google how long it would take to get from Prutting to Conrad Electronic in Munich.
Google answered: 59 mins (including 5 mins for traffic).
Sorry, sorry, I was 1 minute off 

That's OK - I just did the same - and it gave me exactly one hour.  Your estimate was spot on in my book.

[ivan747]

50km, one hour? I thought this was Germany

It's Munich 
Just for the heck of it I just asked Google how long it would take to get from Prutting to Conrad Electronic in Munich.
Google answered: 59 mins (including 5 mins for traffic).
Sorry, sorry, I was 1 minute off 

Oh Germans 
I bet both estimates are accurate to 30 seconds.

[Klomderper]

Esinomed - LOL Spell it backwards. DEMONISE-portray as wicked and threatening.

[Cyberdragon]

It was the 11th one that happened to not spontaniously explode when charged. It looks like it was built by chinese children out of salvaged parts. It's probably either a white van scam or something homemade because someone needed a tablet, like now...like right now, so they built one out of stuff lying around and used a blowtorch to solder.

[Godzil]

Just the screen and the ITX (or whatever the format) PC board would be interesting to keep!

[CatalinaWOW]

In my hometown, a large but not very developed Chinese city, almost every bare cell seller in both of the 2 major electronics markets, offers spot welding and cell packing service.

Anyway, an improper, just work, transformer style spot welder costs <$100 if bought online, and can be build <$5 from a broken microwave oven.

Here in the US you can find this service in very modest size cities.  Batteries+ does it for example.  But not rapidly.  I have had a several day wait.  They just don't have enough of the business to staff the service full time, or to provide very much capacity.  So if the guy who runs the welder is out, or if a local contractor just came in and got all of the batteries for his portable tools redone you have a long delay.  Same story for the welder.  Cheap, but by the time FedEx delivers it the weekend is gone.

[drussell]

Here in the US you can find this service in very modest size cities.  Batteries+ does it for example.  But not rapidly.  I have had a several day wait.

Try Interstate Batteries if you have one of them near you.  The one here will custom build or rebuild a pack while you wait and their cells are top quality (as are their lead-acid automotive batteries, etc.  Great batteries!)

Personally, I usually just do it myself and just solder them (use a hot and fast iron or a gund) even though I have equipment that could be used to spot weld them.  Hardwiring and soldering leads to a standard / alkaline battery was proper standard procedure in most VTVMs back in the day (power for the resistance ranges.)  There's really nothing wrong with soldering to batteries as long as you do it correctly

[f4eru]

There's really nothing wrong with soldering to batteries as long as you do it correctly

Of course it's WRONG !! it's very dangerous !!
Under the plus pole nipple or each and every rechargeable cell sits an overpressure valve (this is why there are holes in it)
when you solder on the nipple, the pressure valve seal material gets overheated, and melts.
Often, the valve then sticks, which is very dangerous, the battery can explode if treated wrong, instead of making a controlled electrolyte release !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 


The right way to do it is to use a spot welder for batteries, and zinc strips. You can get very cheap chinese ones from the usual sources.
Alternatively, get batteries with tabs, and solder the tabs ! That's safe, as long as the tab edges don't rub against the isolating sleeves of the batteries.

[gildasd]

There's really nothing wrong with soldering to batteries as long as you do it correctly

Of course it's WRONG !! it's very dangerous !!
Under the plus pole nipple or each and every rechargeable cell sits an overpressure valve (this is why there are holes in it)
when you solder on the nipple, the pressure valve seal material gets overheated, and melts.
Often, the valve then sticks, which is very dangerous, the battery can explode if treated wrong, instead of making a controlled electrolyte release !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 


The right way to do it is to use a spot welder for batteries, and zinc strips. You can get very cheap Chinese ones from the usual sources.
Alternatively, get batteries with tabs, and solder the tabs ! That's safe, as long as the tab edges don't rub against the isolating sleeves of the batteries.

I agree.
Our uni makes it own custom LI-Ion battery packs for solar boat racing.
We use a the pedal spot welder picked off a junk heap somewhere and it works great.