Wow, what a battery

[FrankiethepillParticipant @frankiethepill]

Saw this advert on fleabay

One h*ll of a battery, 900 Ah if my maths is correct. Could start a Saturn V with one of these. Wouldn't want to accidentally want to short it out….

[FrankiethepillParticipant @frankiethepill]

[Enough!Participant @enough]

The Questions and Answers further down the page are interesting, including this:

-Question: Why does Power Bank have no print capacity(mAh)?

-Answer: If we printing capacity, the product can not be allowed to transport by the plane, we hope you can understand this.

… and the warranty is 3 months. Since it originates in China it'll probably take most of those 3 months to get to you.

[not done it yetParticipant @notdoneityet]

That shows just how much an Ah value is without the voltage supplied.

Was it Howell who started a nuclear reactor all by himself by pressing a button (and a milliammeter sprung into life&#128578?

Rutland Water was inaugurated by someone pressing a button to power a relay to power a breaker that started a pump.

It’s that little bottle of champagne that pushes the boats off from the drydock, into the water, all by itself?

[Howard LewisParticipant @howardlewis46836]

Even longer now!

Richard, don't compete with me for "Cynic of the Week"!

Howard

[Neil WyattModerator @neilwyatt]

Posted by Frankiethepill on 03/04/2020 16:01:01:

Saw this advert on fleabay

One h*ll of a battery, 900 Ah if my maths is correct. Could start a Saturn V with one of these. Wouldn't want to accidentally want to short it out….

I guess the output voltage is 0.005mV…

[Anonymous]

m = micro = marketing b*****ks

The spec, for what it's worth, states the voltage is 5V.

Andrew

[Nigel Graham 2Participant @nigelgraham2]

I once worked for a small electronics company that made a lot of equipment for Government labs, the Royal Navy etc. One year it gained a couple of contracts for making some special test-equipment for the old Central Electricity Generating Board's R&D lab, and our designer visited the customer to discuss what was needed.

he returned very impressed with two things he saw on a tour he was given. One was a flash-over test on a 132kV transmission-tower ("pylon&quot insulator. The other was a battery made to give a high direct voltage at very low current and even less noise to drive for some particular experiment. It consisted of a great stack of PP9 cells all linked in series!

[Michael BriggsParticipant @michaelbriggs82422]

It might have enough power to light the wick.

[John OlsenParticipant @johnolsen79199]

If you wanted to charge it in the advertised 10 to 12 hours you would need to put in 90 Amps!

Buying stuff on the Internet is the modern equivalent of buying from those ads on the back of comic books.

John

[Martin WParticipant @martinw]

I note that they say before first use charge for 10-12hrs. If we assume that the unit is supplied in a fairly discharged state, the input charging voltage is 5v, see USB cable supplied, and the output voltage is 5V standard USB then the charge current would need to be something approaching 90 amps. Therefore I suspect that the charging cable they supply must be fabricated from a superconducting material. My problem is that I don't have to hand 100 amp 5V power supply to suit, that said I wonder if Tesla might be interested in the technology as a stack of these 'small' batteries would have the ability to power a car and not take up too much space.

Then it might be that my thoughts may be incorrect and, as Andrew says, the info is just a load of "b*****ks"

John you evidently type faster than me

Martin

Edited By Martin W on 04/04/2020 01:13:12

[Clive IndiaParticipant @cliveindia]

Posted by John Olsen on 04/04/2020 00:55:17:

….Buying stuff on the Internet is the modern equivalent of buying from those ads on the back of comic books.

John

Are we talking about such worthy contenders as Gamages or Headquarter and General supply?

No harm in it really – the spec is so obviously nonsense it's not worth working it all out.

Much of the Chinese stuff will fail if you drive it to the full spec.

Example – the variable mark/space ratio speed controllers that the uninformed call PWM. Cheap and cheerful, good value and they work, but don't try working them at their rated output for long.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Clive India on 04/04/2020 08:28:15:

[…]

Example – the variable mark/space ratio speed controllers that the uninformed call PWM.

[…]

.

Leaving aside the battery nonsense, Clive … Please consider me amongst the ‘uninformed’ regarding PWM

I would be genuinely grateful if you could clarify.

MichaelG.

[David ColwillParticipant @davidcolwill19261]

Much of the Chinese stuff will fail if you drive it to the full spec.

Example – the variable mark/space ratio speed controllers that the uninformed call PWM. Cheap and cheerful, good value and they work, but don't try working them at their rated output for long.

No you are wrong. It's just that you have misunderstood "rated output".

In China this means maximum value attained before failure. This value only has to be maintained for 1µs.

David.

[FarmboyParticipant @farmboy]

Long before we were inundated with Chinese imports I was once very tempted to buy what was advertised as a "2MW Laser Pointer"

[Neil WyattModerator @neilwyatt]

It's amazing what a PP3 can put out. As a teenager we used them to light little bits of Brillo pad for "unspecified purposes".

A few days ago I removed a defective power switch from a multimeter using my hot air rework gun. I forgot to remove the battery first, the leads melted with the confusing result that after removing the hot air brown some literally billowed out of the PCB until Io realised what was happening.

My workshop had to be abandoned because of the nasty fumes and it stank well into the next morning.

Neil

[vintage engineerParticipant @vintageengineer]

27 PP3 batteries will give you 243 volts dc!

Posted by Nigel Graham 2 on 04/04/2020 00:07:20:

I once worked for a small electronics company that made a lot of equipment for Government labs, the Royal Navy etc. One year it gained a couple of contracts for making some special test-equipment for the old Central Electricity Generating Board's R&D lab, and our designer visited the customer to discuss what was needed.

he returned very impressed with two things he saw on a tour he was given. One was a flash-over test on a 132kV transmission-tower ("pylon" insulator. The other was a battery made to give a high direct voltage at very low current and even less noise to drive for some particular experiment. It consisted of a great stack of PP9 cells all linked in series!

[SillyOldDufferModerator @sillyoldduffer]

Or could they be genuine, sort of?

Intense research into battery technology for at least 30 years, first for laptops and mobile telephones, now because of the increasingly urgent need to replace internal combustion engines in cars and to store erratic green electricity.

Considerable progress has been made! The batteries in USB rechargers are the same technology as those used to power electric model aircraft – high capacity and light weight rechargeables. Battery powered flight? Not in my young day!

900000mAh isn't equivalent to 900A for an hour; I doubt the batteries chemistry is up to that, or it's terminals! The capacity still seems unlikely to me, but is it unrealistic compared with the energy density of petrol, about 46MJ per kilo?

Anyone else up to checking the maths? What's 900000mAh at 5V from a 280g battery compared with 46MJ from 1kg of petrol?

As these things are only £10, I might take a punt and measure one! As their main purpose is recharging mobile phones, I guess the max amps output will be in the USB as power-supply range, no good for starting car engines! I suspect they won't last long either – the warranty is only 3 months.

Almost everything I learned about battery capacity at school is out-of-date. Super-capacitors were ruled impossible. NiFe cells, gone. Zinc Chloride, almost gone. Lead Acid – much improved. Since leaving school, Daniels, Weston and most other special types, gone. Mercury, gone. NiCAD almost gone. Today, Lithium rises; it's a battery Jim, but not as I know it…

Dave

[Anonymous]

Posted by SillyOldDuffer on 04/04/2020 11:00:35:

Anyone else up to checking the maths? What's 900000mAh at 5V from a 280g battery compared with 46MJ from 1kg of petrol?

A very simplistic calculation says the battery is better per unit mass. But in reality that's nonsense since I don't believe the battery is anywhere near 900Ah.

Battery chemistries have made big strides over the last few years, but the fundamental energy capacity hasn't kept pace. Lithium batteries compare well on Wh/kg since lithium is so light. A lot of the work on batteries has gone into reliability and charge/discharge cycles. It's no good having a sooper dooper electric vehicle if the battery dies after a few hundred cycles, or even several thousand.

Andrew

[Perko7Participant @perko7]

My only question is, what date was the ad posted. If 1 April then I guess the obvious answer is……….

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Perko7 on 04/04/2020 11:58:36:

My only question is, what date was the ad posted. If 1 April then I guess the obvious answer is……….

.

I didn’t bother checking … but there are many similarly rated alternatives listed.

Given that 9000mAh would be quite reasonable, I presume it’s just an innocent typo that has been repeated.

It has provided some amusement here; but I wonder how we would fare, drafting an advert in Chinese.

MichaelG.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Andrew Johnston on 04/04/2020 11:30:23:

Posted by SillyOldDuffer on 04/04/2020 11:00:35:

Anyone else up to checking the maths? What's 900000mAh at 5V from a 280g battery compared with 46MJ from 1kg of petrol?

A very simplistic calculation says the battery is better per unit mass. But in reality that's nonsense since I don't believe the battery is anywhere near 900Ah.

Battery chemistries have made big strides over the last few years, but the fundamental energy capacity hasn't kept pace. Lithium batteries compare well on Wh/kg since lithium is so light. A lot of the work on batteries has gone into reliability and charge/discharge cycles. It's no good having a sooper dooper electric vehicle if the battery dies after a few hundred cycles, or even several thousand.

Andrew

I'm becoming more sceptical by the second! This supplier quotes an energy density of 135Wh/kg. for Lithium Polymer cells as sold for mobiles and laptops. Their largest battery is 4000mAh in a 7.5×50×100mm package weighing 81g. Three of them would be close to the weight of the alleged 900000mAh packages, giving only 12000mAh capacity. That seems more realistic.

The 900000mAh units only seem to be sold by ebay, which is suspicious, and one of them says this in the small print:

'Manufacturer's Nominal Capacity: 900,000mAh; Actual capacity: ~15000-18000mAh'

This is akin to my latest invention, a new tyre rubber which lasts up to 10 times longer. Completely true; in independent tests my wonder tyre material lasts up to 10 times longer than a banana skin!

Dave

[Michael GilliganParticipant @michaelgilligan61133]

Too late to edit my previous post

**LINK**

https://resources.allsetlearning.com/chinese/grammar/Big_numbers_in_Chinese

MichaelG.

[Robert Atkinson 2Participant @robertatkinson2]

This is not a mistake, it's deliberate deception. It is the same as a recent thread on 2TB USB sticks.

If it's too goo to be true it's probably a scam

Read the sellers feedback especially negative.

Robert G8RPI.

[Michael GilliganParticipant @michaelgilligan61133]

There are dozens, if not hundreds, of ebay Sellers offering the same sort of silly numbers, Robert.

Do you have any actual evidence that it deliberate deception ?

Personally, I am prepared to give them the benefit of the doubt … for now.

MichaelG.

.

Correction: Thousands of listings on ebay UK

Edited By Michael Gilligan on 04/04/2020 18:46:42

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