EEVblog #1099- BattBump - Dumbest Kickstarter Ever!

[timelessbeing]

I estimate the efficiency is at least over 80%.

I think you're dreaming



Result @ 4:06

[nctnico]

I estimate the efficiency is at least over 80%.

I think you're dreaming

No. I have hands on design experience with wireless charging (and products in the field). I get better efficiencies than shown in that graph at ranges of 20mm. At smaller ranges the results can be much better. The graph you linked to is complete BS.

[timelessbeing]

Feel free to post the results of your real world tests.

[GeorgeOfTheJungle]

Feel free to post the results of your real world tests.

https://en.wikipedia.org/wiki/Inductive_charging
https://en.wikipedia.org/wiki/Wireless_power_transfer

[ogden]

The graph you linked to is complete BS.

I would say - graph does not convince. Here's data from real datasheet of real chip stating that 80% is what you can get over quite wide range of delivered power:

[timelessbeing]

Feel free to post the results of your real world tests.

Real world independent tests with real world devices. I'm not interested in wiki articles about theory or marketing data done by manufacturers in the lab.

[nctnico]

In many cases you can get even better performance than claimed in application notes because the circuits are more geared towards cutting costs than getting the best efficiency. Look at the LM5116 (from TI) for example. The eval board does 95% efficiency at best. In one my designs in which I have used this chip I get between 96% and 98% efficiency at power levels north of 500W. Ofcourse the circuit has been optimised for maximum efficiency because it was necessary to meet thermal requirements. With a total power input of around 15kW those few percent really count.

[timelessbeing]

circuits are more geared towards cutting costs than getting the best efficiency.

In other words, real life with actual consumer production devices.

The eval board does ...

Yawn!

[maxwell3e10]

With a total power input of around 15kW those few percent really count.

You can't compare the efficiency of a 15 kW circuit with probably ~$1000 BOM with few watt circuit for consumer electronics with limited space and ~$1 BOM.

[ogden]

I'm not interested in wiki articles about theory or marketing data done by manufacturers in the lab.

Specification published in the datasheet is committing for manufacturer. TI do not want bad press in a form that proves that they fake datasheet figures. That would be devastating for business. TI do not want to get into any trouble with huge consumer electronics manufacturer that could potentially want to cover losses due to TI chip that does not deliver promised performance. Datasheets of decent IC manufacturers are much more reliable source than "independent" reviews done by tech journalists who may not even know what they are doing.

[timelessbeing]

Take a closer look at the disclaimer on the datasheet.

TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information.

[wraper]

Take a closer look at the disclaimer on the datasheet.

TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information.

Now open any other datasheet and read the same thing  . If you have nothing useful to say, better say nothing at all. All datasheets must lie, but your graph of unknown background must be true  .

[ogden]

Take a closer look at the disclaimer on the datasheet.

TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information.

So what. Every legally sane company puts legal disclaimer on virtually any public paper they release. It means that particular paper is not legal agreement between issuer and one who reads it, yet does not automagically mean that contents are lies. I better take data from datasheet with legal disclaimer than data from journalist who most likely is paid by manufacturer of winning product.

[edit] P.S. "Use at your own risk" disclaimers that warn about injuries or death does not mean that it is warranted to get injuries or die.

[timelessbeing]

I have produced two sources that found the empirical real-world efficiency to be around 60-65%. Their data even agreed.

You have produced nothing but estimates, theory and datasheets which are worthless. 

[ebastler]

I have produced two sources that found the empirical real-world efficiency to be around 60-65%. Their data even agreed.

Well, in fairness, you have produced
(a) a chart from an undisclosed source, measured (?) under undisclosed conditions, and
(b) a video from a permanently excited, permanently tense guy (who happens to have a large number of Youtube subscribers), who measured one particular gadget. 

[ogden]

You have produced nothing but estimates, theory and datasheets which are worthless. 

If you think reputable manufacturer like TI can blatantly lie about main figure of their product - so be it. I just disagree with you. Further debate about "worthless datasheets" seems to me as pointless waste of time.

[GeorgeOfTheJungle]

I have produced two sources that found the empirical real-world efficiency to be around 60-65%. Their data even agreed.

I know that's ~ true because I did the maths with my Nexus 5, buuut, that does NOT mean that it's got to be always this way, everywhere: it can be done better. If you mean that a wired connection should always have less losses then yeah, but wirelessly it can be done better than with 40% losses.

[nctnico]

With a total power input of around 15kW those few percent really count.

You can't compare the efficiency of a 15 kW circuit with probably ~$1000 BOM with few watt circuit for consumer electronics with limited space and ~$1 BOM.

No but it just shows that datasheets & applications notes from TI are conservative. Also with some design effort you can make very efficient wireless charging circuits so you can rest assured that you can get the performance as shown in the graph from TI in real world (consumer) circuits.

[timelessbeing]

(a) a chart from an undisclosed source, measured (?) under undisclosed conditions

It's easy enough to find. The study was commissioned by the WPC -- same people who came up with Qi.

https://www.wirelesspowerconsortium.com/data/downloadables/1/5/2/7/john-perzow-efficiency-of-wireless-charging.pdf
And here's the math
https://www.powerelectronictips.com/measuring-wireless-charging-efficiency-in-the-real-world/

(b) a video from a permanently excited, permanently tense guy

It's called "acting". His name is Mehdi Sadaghdar and he's an electrical engineer.
I believe his results most of all, because they're impartial, and are closer to real world conditions.

[timelessbeing]

If you think reputable manufacturer like TI can blatantly lie about main figure of their product - so be it.

Maybe not blatant lie. I'm sure somebody somehow got those numbers. Let's call it a "stretch". You measure things under absolutely ideal lab conditions that nobody will ever have.  All manufacturers do it in every category because it sells more product. You did not know this?

with some design effort you can make very efficient wireless charging circuits so you can rest assured that you can get the performance as shown in the graph from TI in real world (consumer) circuits.

 

[timelessbeing]

Here are results from Richtek. A company that makes wireless power receivers. I'm sure you've heard of them.





Application Note: https://www.richtek.com/Design%20Support/Technical%20Document/~/media/AN%20PDF/AN036_EN.ashx

[ogden]

You measure things under absolutely ideal lab conditions that nobody will ever have.  All manufacturers do it in every category because it sells more product. You did not know this?

Every buyer of the chip is looking for measurements in ideal lab conditions of just thing alone. Engineers of the customer usually have option to get evaluation board to verity performance and see that datasheet figures are not as you say "stretched". If needed - they can get help from Field Application Engineer (FAE) remotely or on-site. You did not know this?

Yes, 80% is just wireless transfer efficiency. Remaining "real world" parts of phone charger are not ideal as well, but hey, their efficiency is not 80% which would result in overall 64% (80% from 80%). Modern power converters are at least 90% efficient. So I would say that 70% could be "real world" number that we can agree on.

[timelessbeing]

I should agree because you picked a number out of thin air?

I believe Mehdi's 62% because that is the only impartial test with everyday devices (they look modern enough) that I have ever seen. I welcome anybody else who wants to try.

I agree with Dave. I think this idea is stupid and that it won't come to market. If you want the charging to be more convenient then just have a dock with a magnetic connector.

Now I had a friend that had a phone with swappable batteries.(I can't remember the model)  The large thin rectangular battery just slid into a slot at the top. And it was a still a nice a slim portable phone. That's something we need to bring back.

[Rasz]

I agree with Dave. I think this idea is stupid and that it won't come to market.

but it just did 

[ogden]

I should agree because you picked a number out of thin air?

Don't worry, you don't have to agree about anything. Consider I pulled numbers from Richtek paper.

I think this idea is stupid and that it won't come to market. If you want the charging to be more convenient then just have a dock with a magnetic connector.

Phone->phone charging is pointless gimmick, but wireless charger is very good idea. BTW it actually works. You did not know?

The large thin rectangular battery just slid into a slot at the top. And it was a still a nice a slim portable phone. That's something we need to bring back.

Right. Bring Nokia 5110 back. In last century when it was popular, it was nice a slim portable phone. 

[edit] Just noticed disclaimer you were talking about - it is on "PACKAGE OPTION ADDENDUM" page:

The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.

It is about chemical composition of materials, not efficiency numbers