How Safe Are These "External Power Banks" Used for Topping Up Your Phone ?

[Alan de Enfield]

 

An overnight Virgin Atlantic flight from New York to London was forced into making an emergency landing after a phone charger triggered a fire on-board.

All 217 Passengers had to abandon the Airbus A330 when firefighters were called to the plane at 9pm last night in Boston.

Smoke appeared in the cabin only 25 minutes into its journey to Heathrow from JFK airport, information from Flightaware showed

The police believe a mobile phone power bank may have caused the fire.

“Preliminary investigation suggests it is a battery pack consistent in appearance with an external phone charger”, a police spokesman told reporters after the incident.

 

https://www.telegraph.co.uk/news/2019/07/05/virgin-atlantic-london-flight-makes-emergency-landing-phone/

 

 

[WotEver]

Great... so that’ll be something else that’s banned from flights then...

[Rob VP]

About as safe as any other Lithium battery. There have been similar incidents with e-cigarettes, laptops, phones etc..  Thankfully quite rare.

[Jen-in-Wellies]

Lithium batteries have a bad failure mode. Once they start to internally short circuit, the current flow increases and they heat up. Then the Lithium catches fire. Airlines don't like them for obvious reasons. They have to let them on board as part of passengers luggage and say a laptop in a suitcase in the hold, or a phone, or power pack in someone's cabin baggage can be dealt with by the on board fire fighting capability.  Cabin crew with extinguishers, or fire suppression in the hold. They don't like big batteries, or someone sending lots of them together as air freight as this can overwhelm the fire control equipment and could lead to death and destruction. Even aeroplane builders have had problems installing them themselves to power on board systems, but they arrange for a failure to hopefully not lead to disaster. Airlines have banned specific models, like the recent Samsung that had a bad reputation for self immolation, but a total ban is less likely with their customers gadget addiction. Cheap and nasty no-name gadgets are more likely to fail this way, but even the big brand manufacturers get it wrong sometimes.

 

Jen

[MtB]

I cant really make much sense of the photo. Doesnt look to me like a burned out battery pack. Too much engineering! 

 

Is it a ‘stock’ photo of a random small fire perhaps?

 

[DandV]

Lithium batteries pack an awful lot of energy in a small package, so if they go rogue, they go really rogue.

I also suspect that with phone charging packs there are an awful lot of small name manufacturers with minimal quality control and no real brand reputation to protect.

So I bet airlines and their flight crews don't like them for good reason. I would much sooner they are removed from any aircraft I fly in. At the moment, the comprise is, they must be in hand luggage as fires in the cabin are more easily extinguished.

[Alan de Enfield]

19 minutes ago, Mike the Boilerman said:

I cant really make much sense of the photo. Doesnt look to me like a burned out battery pack. Too much engineering! 

 

Is it a ‘stock’ photo of a random small fire perhaps?

 

Dunno.

But there is quite a lot of 'engineering' in these things - they have to convert the Lithium 3.7 volts to USB 5 volts so there in a mini -transformer, many of them have 'limiters' so you cannot overcharge them, apparently some of them have sensors so you don't overcharge your 'appliance'.

 

That may be why 'cheap Chinese' ones are £6.99 and similar Ah rated 'quality' branded ones are £40+

A clue as to the 'quality' is the fairly obvious "500,000 mAh" (or similar figure) quoted on the cheap ones. A credit card sized battery is unlikely to be able to provide 50Ah.

 

https://www.ebay.co.uk/itm/High-Capacity-500000mAh-2-USB-LCD-Portable-Power-Bank-External-Battery-Charger/192687185701?hash=item2cdd0d1f25:m:mlTsXPsIwUArzVgyYTr_zaQ

 

I have tested my 4000mAh (presumably rated at the battery voltage of 3.7v) and it gives me ~ 2750 mAh (2.75Ah) at 5v.

The 'theory suggests it should be about 2.9Ah

[Onewheeler]

2 hours ago, Mike the Boilerman said:

I cant really make much sense of the photo. Doesnt look to me like a burned out battery pack. Too much engineering! 

 

Is it a ‘stock’ photo of a random small fire perhaps?

 

Looks like a burnt out seat to me.

[cuthound]

I have a branded 20,000mAh one in my car to drive the dash cam. It sits behind the sun visor and thus avoids dangly wires in my field of vision.

 

In the couple of years thst I have had it, it has proved to be very reliable and never so much as gets warm.

[Alan de Enfield]

9 minutes ago, cuthound said:

I have a branded 20,000mAh

To be honest, I'd be surprised it were anywhere near 20Ah at the 5v output (which is what we want to know)

I bought a 30,000Ah one and it actually turned out to be 4Ah (at 5v) I think that to avoid being accused of lying, they give the Ah (mAh) at some ridiculous low voltage, so, although they don't quote the voltage it is based on it is (maybe) 30,000 mAh at 0.4 volts.

 

I test mine by fully charging it.

I have a USB (5v) Desk-fan that is rated at 500mA, and a USB voltmeter / ammeter.

Plug Fan into power-pack

Switch on and note the ammeter readings every 30 minutes (or so) until the fan stops.

 

The reading is normally ~0.4A, so if the power pack runs it for 10 hours it is (in my workings) a 4Ah battery.

 

'Wh' would be a far more reasonable figure to quote

[Jen-in-Wellies]

19 minutes ago, Alan de Enfield said:

'Wh' would be a far more reasonable figure to quote

Flame height? Blast radius? ?

Edited July 7, 2019 by Jen-in-Wellies

[cuthound]

1 hour ago, Alan de Enfield said:

To be honest, I'd be surprised it were anywhere near 20Ah at the 5v output (which is what we want to know)

I bought a 30,000Ah one and it actually turned out to be 4Ah (at 5v) I think that to avoid being accused of lying, they give the Ah (mAh) at some ridiculous low voltage, so, although they don't quote the voltage it is based on it is (maybe) 30,000 mAh at 0.4 volts.

 

I test mine by fully charging it.

I have a USB (5v) Desk-fan that is rated at 500mA, and a USB voltmeter / ammeter.

Plug Fan into power-pack

Switch on and note the ammeter readings every 30 minutes (or so) until the fan stops.

 

The reading is normally ~0.4A, so if the power pack runs it for 10 hours it is (in my workings) a 4Ah battery.

 

'Wh' would be a far more reasonable figure to quote

I agree Wh would give a more realistic capacity.

 

Might try testing mine against a known load, it lasts months in the car powering the dashcam whenever the car is moving.

[Alan de Enfield]

51 minutes ago, cuthound said:

Might try testing mine against a known load, it lasts months in the car powering the dashcam whenever the car is moving.

 

Interesting answer to a question posted to an ebay seller of the 500,000mAh  (1/2 million mAh) power packs.

 

-Question: Why does Power Bank have no printed capacity (mAh)?
-Answer: If we printing capacity, the product can not be allowed to transport by the plane, we hope you can understand this.

[Machpoint005]

8 hours ago, WotEver said:

Great... so that’ll be something else that’s banned from flights then...

 

Can't see a problem. Phone batteries last a long time if the bloody phone is switched off, and proper mobile phone batteries can last well beyond lunchtime next Thursday (i-thing owners take heed).

1 hour ago, Alan de Enfield said:

 

Interesting answer to a question posted to an ebay seller of the 500,000mAh  (1/2 million mAh) power packs.

 

-Question: Why does Power Bank have no printed capacity (mAh)?
-Answer: If we printing capacity, the product can not be allowed to transport by the plane, we hope you can understand this.

 

You would hope that on the basis that a safety sticker of some sort actually exists, no sticker would mean no flight!

[Alan de Enfield]

24 minutes ago, Machpoint005 said:

no sticker would mean no flight!

 Would it (in reality) ?

 

More likely not marked with its capacity because then there is no come back when its only 500mAh

[WotEver]

52 minutes ago, Machpoint005 said:

Can't see a problem.

So the fact that I can’t take a mobile charging unit on a business trip abroad isn’t a problem to you? It is to me.