So, somebody by the name of Phil got in touch with me and said
"Would you like one of the notorious EE PowerBanks".. and .. yes.. hell yeah
I actually would like one of the notorious EE PowerBanks which were recalled.
Now, to give you some background on this. When 4G came out, the 4G data standard for mobile phones
Several companies merged together under the name of EE and they went 'old school' sales tactics
They sold people on two year contracts. Lots of disgruntled people at the beginning...
But.. that's in the history, that's what happened.
However, one of the things they did as part of the contract they gave you an EE PowerStick
err.. is that what they call it? I think its an EE PowerStick
and.. its basically a power bank with the torch that you can double click it and the LED lights
double click it again, it flashes. Double click it again it goes out.. and its got the little indicators on it.
This one's actually showing one flashing LED because I've deliberately run it flat because I'm going to be opening this shortly
Because we should explore what's inside..
However, the idea was that you got the power bank and it wasn't just a case of
you know.. take it home and re-charge it and use it to charge your phone while you're out
If you're out and about or you're traveling and you're phone was running flat and your battery power bank was flat
You could go into an EE shop and you could hand it over and they'd take it out of the rack and they'd just give you another one and plug this one in to charge
which seems like a good idea
Now, there were unfortunately a couple of incidents.. at least a couple of incidents with these
which burst into flames. One most notable one was under a lady's bed whilst she was sleeping
and she woke up with flames exploding from under the bed
and she panicked as you'd do and she grabbed it and ran out the house with it and threw it outside
but in the meantime, she'd burned her hand quite badly and she really did burn it quite badly
and it ultimately, the picture was sent.. she took a picture as you do these days
of the burn and sent it to the newspapers.. and it was just... everywhere
and suddenly the EE PowerBanks were the worst things since sliced bread
you know they were "DANGEROUS DEATH TRAP EXPLODING DYNAMITE POWER BANKS!!"
And, there are other pictures of other ones gone on fire and it makes you think..
and in a sense, it was a good idea, but in another sense.. you just don't know what sort of abuse these things are getting
because there are a couple of ways you can abuse power banks.
and.. the biggest weakness of power banks..is
If you have the lithium cell.. so I'll just draw a cell like that
and you got the negative going out, you've got a control circuit
and you've got the little choke that steps the voltage up and then its controlled by the control circuit
and then the output is 5 Volts. Thats the bit thats used to actually boost it up
And also charge it..charge the cell
So, I'll draw another lead in there.. just thats the charging lead.. ..blah blah etc..
and another.. yeah.. I'm going to far aren't I.. but anyway.. besides the point
What happens, one of the biggest weaknesses with these topologies so to speak is that
if you overload it, if you short that output then, although the chip can say
"Oh, short circuit, I'll turn off the 5 Volt switching power supply.."
You still unfortunately have this choke in series, which means that there's still current flowing and depending
on the impedance of the choke and the resistance of the choke in this case
It could pass a lot of current and it can smoke the choke.. it can damage the cell and cause problems
The most likely case of causing the short circuit in the output is cheap USB leads and the people saying..
"The phone doesn't charge properly but if you wiggle the lead it does charge"
If your lead is doing that.. then get a new lead, because you know
If you short out a power bank it's.. it's.. generally putting it under a lot of stress, the lead could go on fire
The power bank could go on fire. It's all "bad things" really..
The other thing about this topology of this circuitry is that if someone plugs in a non standard load
or if they plug in their phone and just leave it in and then it runs flat
Even after the point that the cell here has dropped about the 3 Volts or just under
the chip'll say "Right, OK, thats it, cut the cell off, we don't want to discharge it any further"
all it can do is stop boosting the voltage up to 5 Volts.
But, if you've got a resistive load across that or some other load that can draw current continually right down below the 5 Volt level
Then even with the booster circuit switched off, you can still have current flowing through the choke.
So, there are a few different situations that the cell could have been abused
so.. Good idea.. but if you don't know the history, you know, you go into EE and you get a new power bank
and you think, you know, you know, its just your power bank, but you just don't know its history behind it
It could have actually suffered damage in the past
So vallient effort, but it just backfired a bit and they ended up withdrawing, ended up recalling them all
with the bad media coverage. So lets see if we can open this one and take a look inside and do some tests.
So .. umm.. I'm going to use this 'ReGizmo iSesamo' type tool thing
which, its a tool designed to prise these things open and basically its got various angled edges
a sort of stainless steel strip, buts its also got the tip just chamfered slightly
so its designed to slot into things and open them. And I really don't know.. how..
this is going to open up. Its certainly.. its leaving lots of dents.
I don't know if this is... err.. If I don't get this open in short measure
I shall pause the video because otherwise it could turn into a very long video
and this does, this does seem... right up to now it seems to be quite tight
It ain't poppin' open.
Which is probably a good thing really..
I've got a horrible feeling I'm going to have to pause the video and then use violence to open this
I'm not sure if you can stab yourself with this, I've not tried it yet, but er, that could happen
It probably will happen on video at some point
Yeah.. this isn't opening, I'm going to have to use violence. I'll be back shortly...
ok.. that was quite interesting. It took quite a lot of force to open that
I had to get the 'Vice of Knowledge' into it and it failed
It ended up being the .. er.. the 'Grips of Overindulgence' complete with the 'Anti Explosion' tray.
just because it did get a bit hairy at one point
I mean seriously EE.. you used glue to hold it together.. I mean SERIOUSLY?
Oh not to worry.. its open now.. and its still not yielding its contents
The battery is kind of like stuck in there and I'm going to have to snip a wee bit further I think
but right at the moment I'm seeing what looks like the standard, very standard little four pin chip thats used for
controlling the switcher. And.. err.. little, other little chip in the back for controlling the LEDs
that tell you what sort of level its at
So, I've not got it out yet. I mean I really, its not coming out in a hurry
Its glued in.. completely. The battery is glued in as well. So.. err. I'll be back in a moment..
Right, well as you can see, it took the Dremel to get in
mainly because somebody put a sticky pad right in the back and completely stuck this module in
but I can get rid of the pie dish that I use to contain lithium explosions now.
And.. there are quite a few chips in this
It seems actually outwardly at the moment it seems quite a good robust circuit design without tracing all the components out
There is one slight.. well two slight issues involving two chips here
This chip, which I think is probably controlling the LED flashing functions and the state of charge indicator
its completely unmarked, but lets assume its a micro-controller and its just controlling those functions
It might even be a dedicated chip for this task.. but
Its unmarked, I don't know
Theres also another tiny little chip here called
AT548, its a six pin chip and its associated I think with the choke for boosting the voltage up
Other than that, for the protection of the cell
Its got the classic DW01, cell protection for protecting against over charge and under charge
With a dual MOSFET, so technically speaking
the scenarios I described, the case of over discharging it.. its unlikely if its got that circuitry.
It looks as though its got full proper MOSFET isolation of the cell
If, you know it gets over charged or over discharged, and then for charge control
theres a TP4056, which is the charge control chip, with a resistor that you use to set the actual charge current
So, outwardly it looks quite a good unit. It makes me wonder
have they just been unlucky. They probably put out millions of these
and maybe one or two had that issue
It could even have been caused by people using dodgy leads.
So, at the moment I'm going to come out in EE's favour in the quality of construction
It does seem ok, but I'm going to do some further tests
I'm going to charge it up, I'm going to over discharge it for a start
I'm close to the fully discharged anyway
and then I'll fully charge it up and we'll see what voltage it goes to and whether it just keeps creeping past
that voltage or not.. So, yup, I'll be back once I've done those tests.
Well, I've done some tests on this now
and the cut off voltage when you're discharging it is almost exactly 3 Volts
which is good, thats very good.
And, when you charge it up it cuts off at about 4.23 Volts and then settles back down to 4.15
so, again, nothing to worry about there. I left it on continuous charge just to see if it would go up
any higher, but no. It does that thing. It goes up to 4.23 then settles back and then just doesn't take anymore current.
which is good
I've also tested it with various loads. Now its worth noting that it charges
when you plug it in to charge, the little TP4056 chip here
is set for about 500 milamps charging current
Now I've got a load on it at the moment with this little load tester which is
theoretically pulling an amp, but its actually pulling .9 amp
at 4.86, the voltage from this has dropped down to 4.86 volts.
And if I switch it to its two amp test, it drops right down to pretty much the battery voltage
at 1.43 amps. That kind of suggests this thing is rated just for 1 amp output maximum
And I have stuck a modest length of USB lead in it and then shorted it with that amp meter
at the other end, and it drew 2.5 amps and didn't seem that bothered by it
So I reckon if I pulled much more current.. If I'd really overloaded this.
Its got the DW01 with the MOSFET which provides that protection. So, you know what..this..
is actually
quote a robust little circuit.. you know ..as these power banks go
Oh, heres another thing. Quite often with the cheap power banks, the connection coming out from the negative end
is just a metal strip, sharp metal strip
In this case its a silicon rubber sleeve, sleeved cable
You know, everything about this actually suggests
that its a good quality power bank
With lots of protection circuitry in it
So.. umm.. I can only guess that the ones that failed either had some catastrophic failure
I mean.. could it be the cell's bad but you know, why would they cheap out on the cell when they spent so
much on the actual control circuitry.. umm..
I'm not really sure. I wonder if its just a fluke that just a couple of them did have a catastrophic failure
Was it the unit itself that went on fire. I think it was as opposed to the lead that was plugged into it
I'm not 100% sure..
But from what I've tested so far, it just does seem to be quite a decent design.
Its not some cheap crappy thing
that is likely to fail, so, I'll come out on the side of EE here
and say that, yeah, you know, this seems like a decent quality power bank.
Its not like they skimped. So, I'm not sure what happened with the other ones
It seems a shame that now they've withdrawn them, they've basically done a recall
on potentially millions of these units. I'm not sure how many they put out
And that just seems wasteful.. particularly if they're just going to destroy them. It just seems like a bit of a...
a bit of an over-reaction
but, ultimately I guess they were just sort of stinging at the negative bit of publicity the got in the press
because the press just jumps on these things
So, yeah.. Its a shame, it seems a good quality unit. Its just a bit unfortunate
that a bit of absolutely microscopic percentage of them had problems
whether that was just, you know..
random, or just you know, if it was just, if there was some fault in that instance
but yeah... its a shame really, cos it is as i say, quite a nice unit