EEVblog #779 - How To Measure Product Battery Cutoff Voltage

[LabSpokane]

Not that this should need to be done at this stage, but let's do it anyway.

Apple Wireless Keyboard      
MC184LL/B      
      
  V        %   Notes
============
3.20     100   
3.00     100   
2.81     100   
2.60     80   
2.40     17   
2.20     10   *Low bat warning
2.10     5   
2.05     0   still fully functional
1.99     0   ceases function

% is the remaining battery life as reported by OSX.  OS version 10.9.5. 

Test was run with the dreaded, external power supply with voltage monitoring via an Agilent 34461A with a current calibration certificate.  Voltage monitored directly at the negative terminal and approximately 12" from the positive terminal using 18 ga stranded wire to ensure minimal voltage drop.  Conveniently, the resistance of the wire is 0.22 Ohms, which provides a Thevenin equivalent source.  If you really need me to demonstrate the complete range of Thevenin equivalents, PM me.  Happy to source some current shunts and oblige. 

The maximum current draw was approximately 50mA during these tests. Average current draw during normal operation was about 5mA.  That would make the voltage drop at the positive terminal approximately 1mV less during normal operation and about 10mV less during peak draw (device initialization).  Neither voltage drop has a substantive impact on the results of these tests.

If you think I'm making this data up, contact me.  I will be happy to demonstrate this test, live, in person.  You come to me.  We'll even drop by the Apple store and buy new devices in shrink wrap, so no one will think I'm gaming these tests somehow.  We can have a local university host the trial if you like. 

=========================================================
So, Bob, let's recap:

This is what you're advertising:

Most devices only tap into a fraction of your disposable battery’s energy – about 20%.
Batteriser uses micro-circuitry that lets you instantly tap into the 80% of energy that is usually thrown away.

And that is completely, utterly misleading and wrong.  The Apple Wireless Keyboard drops out at 1.025V per cell.  At that voltage, the energy remaining in the cell is NOT 80%.  It is, in fact, approximately 8%.  Your claim is off by an order of magnitude. 

Care to start making some retractions, or are you going to wait for me to find a Garmin Dakota?

[TheAmmoniacal]

What about we here at the EEVblog forums go together and make a long list of cut-off voltages for devices in our homes? If 20 people get 5 devices we already have a spreadsheet of 100 things! Taking a simple average we would have a definite answer what the cut-off voltage is of "most" devices. Just make/model and cut-off in V/cell?

[EEVblog]

New video coming up, hold on to your hats folks!

[EEVblog]

What about we here at the EEVblog forums go together and make a long list of cut-off voltages for devices in our homes? If 20 people get 5 devices we already have a spreadsheet of 100 things! Taking a simple average we would have a definite answer what the cut-off voltage is of "most" devices. Just make/model and cut-off in V/cell?

Not a bad idea.
Batteriser have already conceeded that it is 1.1V

[LabSpokane]

What about we here at the EEVblog forums go together and make a long list of cut-off voltages for devices in our homes? If 20 people get 5 devices we already have a spreadsheet of 100 things! Taking a simple average we would have a definite answer what the cut-off voltage is of "most" devices. Just make/model and cut-off in V/cell?

Not a bad idea.
Batteriser have already conceeded that it is 1.1V

Yes, but they are *still* claiming that 80% of a alkaline battery's energy remains below 1.1V.  It's just monkey buggering mind boggling at this point.

[EEVblog]

So, Bob, let's recap:
This is what you're advertising:

Most devices only tap into a fraction of your disposable battery’s energy – about 20%.
Batteriser uses micro-circuitry that lets you instantly tap into the 80% of energy that is usually thrown away.

And that is completely, utterly misleading and wrong.  The Apple Wireless Keyboard drops out at 1.025V per cell.  At that voltage, the energy remaining in the cell is NOT 80%.  It is, in fact, approximately 8%.  Your claim is off by an order of magnitude. 
Care to start making some retractions, or are you going to wait for me to find a Garmin Dakota?

Well done. 
I've added this to my Blog page updates.

[EEVblog]

Yes, but they are *still* claiming that 80% of a alkaline battery's energy remains below 1.1V.

Quite true.
They have a total hotchpotch of claims now, it's complete folly.

[Muttley Snickers]

I have no knowledge of apple products but with all of the other deceptive claims is it at all possible that the video of the wireless keyboard was a fraud and that another tethered keyboard was used out of shot and the keyboard shown was not even relevant. I'm sure others will know if this is at all possible.

Muttley

[EEVblog]

I have no knowledge of apple products but with all of the other deceptive claims is it at all possible that the video of the wireless keyboard was a fraud and that another tethered keyboard was used out of shot and the keyboard shown was not even relevant. I'm sure others will know if this is at all possible.

No, I believe the video is perfectly legitimate. The battery was low, you pop it in the batteriser and the battery gauge shoots back to 100%, exactly as you'd expect of a boost converter.
The video of course shows no evidence at all that the keyboard lasts 8x longer with the a batteriser, just that it worked for a bit when you popped the batteries back in with the batteriser, which is exactly what you'd expect.

[Muttley Snickers]

Yes I agree, provided they have an operational batteriser and if this was the case then they should provide a proper technical video showing valid data and stop monkeying about otherwise it's just more TV home shopping garbage on the way.

Muttley

[pickle9000]

Have they disclosed the dropout voltage?

[EEVblog]

Have they disclosed the dropout voltage?

Of the Batteriser? Yes, 0.6V or so. Trying of course to make you think there is something worthwhile to be had below 0.8V. Indeed, I recall them saying that they went to the trouble to develop their own ASIC because of the shelf stuff couldn't go low enough.

[Chris Jones]

What about we here at the EEVblog forums go together and make a long list of cut-off voltages for devices in our homes? If 20 people get 5 devices we already have a spreadsheet of 100 things! Taking a simple average we would have a definite answer what the cut-off voltage is of "most" devices. Just make/model and cut-off in V/cell?

Not a bad idea.
Batteriser have already conceeded that it is 1.1V

Yes, but they are *still* claiming that 80% of a alkaline battery's energy remains below 1.1V.  It's just monkey buggering mind boggling at this point.

It's much more than 80%, you just need to pop it in the Mr Fusion, and E=mc^2. You do have a Mr Fusion, right?

[TheAmmoniacal]

Just grabbed the first thing laying on my desk that uses batteries (2xAAA), a Microsoft Arc Touch Mouse. Battery indicator blinks red at 1.07 V/cell, but it works seemingly without issues to 0.99 V/cell - shuts off dead at 0.98 V/cell. At 1.6 V/cell it drew 20 mA, and 30 mA at 0.99 V/cell.

[rollatorwieltje]

They are now probably trying to find an old Apple wireless keyboard, the model with 3 batteries had some issues with cutting out early.

[pickle9000]

I was looking around at the interesting side of this. I have never looked at the LTC3105 but a very interesting chip .25V startup is very impressive.

Anyway I wonder how much current they can deliver at the claimed dropout? If they have a real device, chip, whatever that can deliver the current then sell that. I guess if they did have such a thing then there would be no need for the batterizer.   

[McBryce]

Can we start our own IndieGogo campaign "To create a world free from IndieGogo scams full of marketing BS" with the goal "Fund to debunk all the idiotic campaigns here". The cash could be used to buy devices for test (wireless keyboards / GPS devices) and to fund the making of the videos

McBryce.

[AndreasF]

Can we start our own IndieGogo campaign "To create a world free from IndieGogo scams full of marketing BS" with the goal "Fund to debunk all the idiotic campaigns here". The cash could be used to buy devices for test (wireless keyboards / GPS devices) and to fund the making of the videos

McBryce.

 

[mexakin]

I am a bit tired of all this.

BAttestates very wrong things and are right know yelling to heavens, why the hell the engineering community jumps on them, while meanwhile there are at least 10 crowdsourcing campaigns going on with simliar if not worse statements.
I believe they deserve it

But cant we concentrate on something positive now, stuff that is brilliant and works well and additionally is brilliantly engineered, i would like that more, since we are never going to convince someone who backed some stupid campaigns in disbelieve, and the crowdfunding sites dont appeal to what is going on.


So its all by the old saying every day there is a dumb person staying up, you only have to find him and you will sell stuff, and only because the technical stuff is our domain, it doesnt mean we ourselves get fooled by carseller, vacacion sellers etc... its all circle

[Rasz]

I cannot understand how so many people backing this campaign can be so blind to the marketing bullshit.

...

Even my 21 year old daughter, who is by no means an EE or physics expert was saying to me – “That looks like bullshit to me Dad”… And that was without any bias or prompting from me. I simply sent her the URL and asked her if she thought it was a good concept.

This is exactly what she said:

“Good concept, but after googling it, some guy called Dave Jones has got some YT saying its bullshit.
I don’t understand exactly what he is doing or saying in some of his videos, but there is a forum site that has a load of people agreeing him.
The thing looks like a bullshit lie to me.”

see, you answered it yourself. Your daughter is clueless when it comes to EE, so she used heuristic of least resistance - wisdom of the crowd. Only difference between here and retards that backed this campaign is she used google and was lucky enough to stumble upon another crowd with a bit of clue. Most people stop when their own belief is confirmed, or search again ignoring conflicting information to avoid cognitive dissonance.

I just took a look at the "batteriser" site. Wow, just wow! A group of apparently successful, educated people running this! An awful lot of money has been spent on marketing and production "values." I wonder what kind of insurance they have, it's a class-action lawsuit waiting to happen.

crowdfunding haul is small fries, they are aiming at a buyout Google X maybe? :PPPP

[Rasz]

<snipped>
Only difference between here and retards that backed this campaign

"retards"? 

yes, people slow in the head

[EEVblog]

Anyway I wonder how much current they can deliver at the claimed dropout?

I've read that they claim 1A output current. Whether that's over the entire operating range though I don't know. You doubt it of course.
And of course they won't publish any data at all, let alone a full efficiency power curve.
These are EE professors, you think they'd be all ga-ga over the performance curves. So either they haven't measured them, or they have and they suck so won't show them.

[AmmoJammo]

Oh no, I got a dislike, how ever will I survive!

http://youtu.be/yuaA-rUBmEc

[FrankBuss]

So is anyone supporting the Indigogo campaign to check the product and measure the performance curves? I guess if Dave wants to buy it under his name, there might be some mysterious delays in deliver

[Fungus]

These are EE professors, you think they'd be all ga-ga over the performance curves. So either they haven't measured them, or they have and they suck so won't show them.

I wanna know how hot that thing is going to get.

(even under, say, 100ma load...)