Test/Review of USB battery box EE Power Bar

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HKJ
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Test/Review of USB battery box EE Power Bar
USB battery box EE Power Bar

This power bank is free to use in UK if you are a customer at EE, Orange or T-Mobile. It is possible to swap the power bank in any EE shop to a fully charged one.

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The specifications are:
  • LED Indication tell you how much power left
  • Capacity: 2600mAh
  • Output: 1A maximum
  • Input/output voltage: 5 volt.
  • Battery: Rechargeable Li-ion




How does it look

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The power bank is delivered in a yellow/gray cardboard tube.

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It contains the power bank, a usb cable and a instruction sheet.

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There is two connectors, a micro usb for charging the bank and a large usb for power output. The two connectors are very close, it is only possible to use one at a time.
The led is for flashlight usage.

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One the side of the box is 4 leds to show power level and a button.
Pressing the button will show the power level and turn on the output (Usual the output will turn on automatic when loaded).



Measurements
  • When charging the four leds show charge state and one of the leds is flashing.
  • Pressing the button will show charge status on the four leds.
  • The output will turn on automatic when loaded.
  • The status led will not be on when output is used, except if button is pressed.
  • Physically it is not possible to put both charge and discharge connectors in at the same time.
  • Output is coded as USB charger (DCP)
  • Flashlight led is turned on/off with a double click.
  • The flashlight can show both steady light and a slow flashing, use double click to change.
  • When flashlight is on, usb output will also be on.
  • One of the power bar led will start flashing when battery is nearly empty (3.3V).
  • USB output is turned off at about 3.15V on battery.
  • The flashlight uses about 20mA
  • When output is off, it will drain 0.1mA from the battery.
  • At around 2.5 volt on the battery the circuit will be switched off, reducing the drain to about 1uA


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The first test is a load sweep to get an idea about the performance. The power bank can easily deliver the rated 1A current, but there is no overload protection in it.

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The 10 ohm load is about 0.5A. The box delivers 1600mAh as expected and the voltage is nice stable at about 5 volt.
Note: Specifications always list battery capacity, output capacity will about 60% compared to that, due to the voltage difference between battery (3.7 volt) and output.

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With the load increased to 1A the box has some problems keeping the voltage up when the battery is nearly empty. The voltage stays within the limits. The higher load has also reduced the capacity a bit (as expected).

5ohm

Looking on the output with an oscilloscope show little noise, it has 12mV rms noise and 80mVpp noise at 1A.

10ohm

At 0.5A the noise is down to 7mV rms and 50mVpp.

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The specifications says the box need 1A when charging, this looks about correct. The cell need about 2600mAh to be filled.


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Adding some series resistance, equivalent to a long cable or a weak charger do not reduce the charge rate.



Tear down

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I could not break it open, but had to cut it.

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The battery is from Cham Battery Technology a Chinese manufacturer.

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This side of the circuit board contains all 5 leds, the charger chip (U2) and usb input connector.
The two chips (U4, U5) is probably handling some battery safety.

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The other side of the circuit board contains the controller (U1), the boost converter (U3, L1, D1) that converts from battery voltage to USB voltage and the output usb connector.

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Conclusion

Mostly this battery bank look well designed with good over discharge safety, but the missing overload safety can give problems if the box is used with a defect cable or phone (I wonder if you can get a damaged cable swapped).
The capacity is not very large for usage with a modern smartphone, but the possibility to swap it for a charged one in the nearest EE shop do help (if there is an open shop in the area). The swapping means you might get one with a well-used battery, i.e. less capacity!
Using a Chinese cell in the device is interesting. The quality on Chinese product varies from very god to very bad and it can sometimes be difficult to know what you get and it is rather important with LiIon batteries to get a good quality. I supposed EE or their supplier has verified that they get good batteries.

It is a fairly good power bank and the possibility to swap is interesting. I expect this will be very useful to many people, but it is no competition to a 4 cell power bank that you remember to keep charged.



Notes

The power bank was supplied by a reader for a review.

The first batch of these was 2 million unit and they was "sold" in no time. Many millions more are on the way (EE has about 25 million customers).

Read more about how I test USB power supplies and chargers

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Edited by: sb56637 on 06/25/2015 - 11:50
R
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Hi Henrik, the teardown is showing some great detail. It's nice that these ‘Power-bars’ also include a Torch/Flashlight feature (5mm LED). So a real lygte-info mash-up device! Quite why they’d bother putting a crappy 5mm led into an 18650 powered device I don’t know!

 

It was the unknown quality attributes of these 18650 Lithium-ion powered ‘Battery-pack’ devices which worried me. These devices are very popular here in the UK because EE (mobile phone network) has been giving them away for free to millions of customers.

 

Do we think they even know or considered the potential risks and inherent dangers of cheap Li-ion cells and whether it would be wise to trust unknown cells that have been handled by others prior to their advertised in-store device swap feature...

 

I was especially interested in any analysis of this Chinese cell which will be carried around by millions of people in their pockets, bags, etc!

Many thanks again; I very much enjoy and appreciate your work.

'R'

R
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HKJ wrote:
USB battery box EE Power Bar


DSC_0366

The battery is from Cham Battery Technology a Chinese manufacturer.


Using a Chinese cell in the device is interesting. The quality on Chinese product varies from very god to very bad and it can sometimes be difficult to know what you get and it is rather important with LiIon batteries to get a good quality. I supposed EE or their supplier has verified that they get good batteries.

 

Looks like it was only a matter of time:

http://www.independent.co.uk/news/uk/home-news/ee-power-bar-medical-student-left-with-serious-burns-after-charger-explodes-like-a-firework-10420686.html

 

EE power bar: Medical student left with serious burns after charger explodes 'like a firework'

Kate Emslie has been left with serious injuries to her hands after the device exploded in Aberdeen


http://metro.co.uk/2015/07/28/ee-power-bar-charger-explodes-like-a-firework-and-burns-student-5316348/

A medical student has suffered serious burns after her phone charger exploded and set her bedroom on fire.  See CENTRE PRESS story CPBURNS.  Katy Emslie, 26, was using her laptop to recharge a portable EE power bar when it shot out "like a firework" and flew across the room on Thursday night.  She said the charger crashed into a wall, charring the carpet behind it and causing a fire under her bed.  In a panic, the medical student tried to extinguish the flames with her bare hands, leaving them badly burned.  Katy, from Aberdeen, suffered a partial thickness burn which was treated in accident and emergency for 10 hours.  Her blisters were deroofed which allowed the fluid to drain out and her hand was re-dressed.

The charred remains of the EE charger (Picture: SWNS)

Read more: http://metro.co.uk/2015/07/28/ee-power-bar-charger-explodes-like-a-firework-and-burns-student-5316348/#ixzz3hDlUWbY7

hank
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No offense meant to the injured medical student, but this is the sort of story that makes clear why this is a problem: people really don’t know what they’re buying and using.

Quote:
In a panic, the medical student tried to extinguish the flames with her bare hands, leaving them badly burned…. She said: ‘I was charging my EE power bar through my Mac computer overnight and at I was woken up by something which sounded like a firework …
Rolz
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Thanks HKJ for the review.

On the subject of LiIon safety I too agree there is a lack of widespread understanding of the dangers of Lithium Ion Batteries. Although many products are well designed and safe to use we see lots of poor quality chargers hit the markets and find their way to consumers. Many/Most people assume the manufacturer has produced a product that is totally safe, but as we see with some of the findings from reviews such as HKJ, this isn’t always true. I’ve used many LiIOn batteries for torches in the last 5 years(?) and more recently a few power banks and never had an issues. For even longer I’ve used LiIon in mobile phones (late 90’s?). I still take care with such batteries as I’m aware of what happens when things go wrong.

will34
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hank wrote:
No offense meant to the injured medical student, but this is the sort of story that makes clear why this is a problem: people really don’t know what they’re buying and using.
Quote:
In a panic, the medical student tried to extinguish the flames with her bare hands, leaving them badly burned…. She said: ‘I was charging my EE power bar through my Mac computer overnight and at I was woken up by something which sounded like a firework …

If someone’s logic leads to extinguish a fire with his/her bare hands, no electric device is safe enough!

hank
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Well, I know enough not to do that with a li-ion fire.

But I’ve “swatted out” any number of little blazes in upwards of 6 decades — oh, well, I grew up in a simpler time.
Remember learning you could pass your finger through a candle flame without burning the skin? Big deal when we were very young.
Low temperature fire in lightweight stuff can be swatted out before it gets established — so we learned.

Pine needles, scraps of paper, dry grass, that sort of thing. Catch it fast, or see it get away while trying to find a tool.

It was often safer to swat out a fire than to take off a shirt to wale away at it — less chance of scattering the fire, less criticism for ruining the shirt too.

Reminds me of the time a guy drove one of those newfangled catalytic converter cars into the middle of a field full of tall dry grass and parked it — and of course got out of the car just in time to see he’d started a fire under it.

So being well prepared he grabbed the fire extinguisher out of his car, pointed it between the wheels —- and blew flaming debris for thirty feet out the far side, so the whole field burnt up fast.

Ya gotta know what you’re messing with.

People don’t. Almost nobody knows how to safely extinguish a li-ion fire. Or even knows not to inhale nearby ….

Soooo — how many of these batteries are out there? Is it UK only, or worldwide?

Halo...
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hank wrote:
Or even knows not to inhale nearby ….
This is why I sometimes feel it’s good to keep li-ions in a metal box (with a couple ceramic tiles inside if you have them). If you only use new quality cells (Pana,sanyo,LG,samsung,sony) then it feels like overkill. But in the very unlikely event of a problem you do not want to have to worry about flames, you only want to worry about getting your lungs the hell out of there. :ghost:

I happen to an have P100 organic vapor, acid gas (hydrogen fluoride) filter for my respirator so I’ll come back as soon as I put that on.