EEVblog #779 - How To Measure Product Battery Cutoff Voltage

[apis]

They have a video of a GPS.... but their graphs of the current measurements seem really wack.... for some reason, it shows the current draw with the standard battery randomly dropping at one point...

Yeah, looks really weird, I don't get it either.

[LabSpokane]

I have someone at Garmin helping me with the engineering data on the GPS. I have yet to find a unit to test. If there is someone in the Spokane, WA, USA area that has a Garmin Dakota and could loan it to me, please PM me.

I will have an Apple keyboard tested by this evening. I'd like to suggest that we start a separate thread that is limited to data only from Batteriser's claims.

[RFZ]

They have a video of a GPS.... but their graphs of the current measurements seem really wack.... for some reason, it shows the current draw with the standard battery randomly dropping at one point...

Yeah, looks really weird, I don't get it either.

It's not random, it is when the GPS reduces the background light and tells you to replace the battery

[apis]

They have a video of a GPS.... but their graphs of the current measurements seem really wack.... for some reason, it shows the current draw with the standard battery randomly dropping at one point...

Yeah, looks really weird, I don't get it either.

It's not random, it is when the GPS reduces the background light and tells you to replace the battery

Ahh, yes, that makes sense... And you might be right that they have added enough series resistance that they confuse the GPS's low battery detection.

[LabSpokane]

From:  http://batteriser.com/batteriser-technical-qa/

They're still sticking to the 0.5V claim.  The circuit might work to 0.5V, but as has been shown ad nauseum, there is essentially no energy left in the battery below 0.8V.

The long existence of DC-DC converters is "proof" that the Batteriser will work.     No Bob, it's proof that you can't do arithmetic.  If I daisy-chain two 90% efficient DC-DC converters, the overall efficiency is 81%.

But wait!  We have a small victory.  Batteroo now admits that the quiescent current of their device will actually be detrimental to the battery life of devices such as remote controls, whose users typically go years between battery changes.  So, Bob, you going to remove the photo of the remote control from your Indigogo page?  See below if you've forgotten.  https://www.indiegogo.com/projects/batteriser-extend-battery-life-by-up-to-8x#/story

I noticed that you're still sticking to the Apple Trackpad as a device that will benefit, even though I've shown that to be wrong.  The cut out voltage is 0.95V, and it is fully functional to that point. 

By tonight I will have tested a fresh-out-of-the-wrapper Apple wireless keyboard.  I have it in-hand.  Any wagers on the dropout voltage?

So, we're very nearly to having disproved nearly every claim you're making about these devices.  I'm going to cede you the cheap flashlight, the RC car, and John Boehner's monkey.

Batteriser Technical Q&A

Question 1: In the articles I have seen about Batteriser, your CEO claims that most battery operated devices stop working at around 1.3 or even higher. I have seen videos online that someone connects a power supply and shows that some typical devices work down to 1.1V or even lower, showing LED’s on a device still blink at that level. What is the explanation?

Answer: There are multiple aspects to this issue. Let’s start with the less complicated aspect:

1. Just because LED in a device is blinking, it doesn’t mean the device is fully functional. In one of our experiments with an RC remote, at 1.3 volt the car would only go forward, but not backwards. We use the voltage that the device is no longer fully functional as the cut off voltage rather than the voltage that the device’s LED is still blinking. In yet another example that most people can relate to, we all have had experience with our TV remotes. Once a battery gets to a low level, even though the LED blinks, you literally have to walk right up to the TV for it to work. Again, the batteries are considered dead by most, long before LED’s stop blinking. So the levels demonstrated in experiments like that are artificially too low.

2. Using a Power Supply to detect, where a battery operated device stops working is wrong and misleading at best. A power supply has 0 ohm impedance and can supply high current at a constant voltage. A typical AA battery has internal resistance called ESR (Equivalent Series Resistance) which is vastly different than an ideal power supply. Most electronic engineers are not very familiar with intricate details of the inter-workings of batteries and its equivalent circuit models. Batteries have an internal impedance or resistance (ESR) that plays a major role in operation of a battery in a system. To Quote from Wikipedia: In use, the voltage across the terminals of a disposable battery driving a load decreases until it drops too low to be useful; this is largely due to an increase in internal resistance rather than a drop in the voltage of the equivalent source (source: Wikipedia). In other words, when a battery is perceived to be dead in a device, it is most likely NOT because the battery is fully depleted of energy, rather it is largely due to voltage drop across this internal resistance of the battery. I will get into more details below.

3. The third aspect may be the difference in definition of the voltages being quoted. There are two distinct ways of looking at voltages that people discuss but sometimes mistakenly interchange. One is the Open Circuit Voltage (referred to voltage at no load condition) and the other one is the Closed Voltage Circuit (referred to voltage under load condition). The two numbers that are quoted from the CEO and your question is an example of this incorrect interchange.

To fully appreciate the totality of the picture, Let us talk about ESR (Equivalent Series Resistor). To understand how ESR interacts at a circuit level, let’s go to Wikipedia:

A practical electrical power source which is a linear electric circuit may, according to Thévenin’s theorem, be represented as an ideal voltage source in series with an impedance. This impedance is termed the internal resistance of the source. When the power source delivers current, the measured voltage output is lower than the no-load voltage; the difference is the voltage drop (the product of current and resistance) caused by the internal resistance.

A battery may be modeled as a voltage source in series with a resistance. In practice, the internal resistance of a battery is dependent on its size, chemical properties, age, temperature, and the discharge current. It has an electronic component due to the resistivity of the component materials and an ionic component due to electrochemical factors such as electrolyte conductivity, ion mobility, and electrode surface area. Measurement of the internal resistance of a battery is a guide to its condition, but may not apply at other than the test conditions.

In use, the voltage across the terminals of a disposable battery driving a load decreases until it drops too low to be useful; this is largely due to an increase in internal resistance rather than a drop in the voltage of the equivalent source.
To learn more, please, visit Energizer’s technical Bulletin at http://data.energizer.com/PDFs/BatteryIR.pdf. The data from this bulletin shows that the typical effective resistance of fresh Energizer alkaline cylindrical batteries will be approximately 150 to 300 m-ohms at room temperature. It further shows that at very cold temperatures, this initial internal resistance value could be as high as 900 m-ohm, or roughly 1 ohm. This resistance further increases as the battery is used. Therefore the ESR value of a fresh new AA battery has an approximate range of 150 m-ohm to 900 m-ohm depending on temperature, chemistry, types and brands of batteries. While a resistance of 1 ohm may be considered insignificant and ignored by some people, we will see that it plays a major role in the final analysis as highlighted above in the Wikipedia description in the paragraph above.

For the sake of this analysis, assume 0.5 ohm as the internal resistance, which is a typical value for a battery at 1.3v (Open Circuit Voltage). If a device draws 400mA of current, the drop across this internal resistance is around 0.2v. This means that the device would see only 1.1V at the terminal of the battery.

The third aspect of the question is that when Batteroo’s CEO talks about batteries stop functioning at 1.3V, if you place that battery in a device described above, under load, the terminals of the battery would provide only 1.1V to the device and that is where the questioner agrees the device stops functioning. This is most likely the source of the discrepancy between what you stated as the low range of operation of devices vs. what is quoted as the open voltage of the batteries by the company.

Going back to your question that there are devices that operate at 1.1V but based on what we just showed this device will not function because it needs to have current supplied from a battery with terminal voltage of 1.1 V. This means that the device would not be functioning properly around 1.3 V open voltage circuit (i.e. open circuit voltage of 1.3 v minus about 0.2v drop across ESR would produce a battery terminal voltage of 1.1 v seen by the device) …. Therefore the battery open voltage circuit must be 1.3 v or higher.

This is an important point which plays a significant role and has been missed and ignored. In other words, once a device with the operating point of 1.1v stops working, and the battery is pulled out and measured without load, the meter would show 1.3V. This has been a source of confusion for some people that hopefully is cleared.

To emphasize the point, ignoring the internal resistance of the battery leads to wrong conclusions. For example, some who ignored the ESR, would wrongly assume that a device that has an operating cut off voltage of 1.1V, can be serviced by a battery at 1.1V Open Circuit Voltage. It is noteworthy that the internal resistance of the battery increases to over 1.5 ohm in a non-linear fashion at room temperature (depending on many factors, and could be significantly higher at colder temperature.

 

 

Question 2: I measured a used battery voltage using volt-meter and showed 1.2v. This toy can work all the way down to 1.1v but it is not working. Why?

Answer: The fact that your battery is not working indicates that the closed circuit voltage is seen by the toy when is turned on is less than 1 volt. This suggests that your voltage drop across the internal resistance (ESR) is greater than 0.2 volts.

This 0.2 voltage drop is multiplication of load current and the ESR value of battery which indicated that the battery has high ESR and/or your toy is drawing a few hundred milliamps of current…

Let us say your toy is drawing 300 ma and the battery ESR is about 0.7 ohm, then your toy sees the terminal battery voltage to be under 1 volt; (i.e. open circuit of 1.2v minus the voltage drop across ESR 0.7 ohm times 300 ma is equal to closed circuit voltage of about 0.99 volt which is under 1 volt)

 

 

Question 3: The relationship between current and voltage makes it impossible for a boosted battery to deliver such great gains, up to 8x. Besides the example below, there’s this one from Reddit: “In order to increase the voltage supplied to the target electronics, you would have to draw more current. Therefore as the battery voltage droops, the current draw will increase. Alkaline battery capacity is greatly affected by the current the cell is subjected to, with effective capacity dropping off a cliff as the current consumption increases.”

Answer: Every system, boosted or not, has voltage and currents relationship and to say: “The relationship between current and voltage makes it impossible for a boosted battery to deliver such great gains, from 5x to 8x” is meaningless. However the most important aspect of extending the life of the battery has to do with how much of the energy left in the battery and how much of that energy can be harnessed after the battery is considered dead, depending on the specifics of devices and load conditions. Obviously to get these types of gains implies that there is significant amount of energy left in the battery as it is discarded. That could be improved by better device design that allow the circuitry to work at lower voltages, and there are devices in the market that are better than others and therefore the mileage would vary based on such factors.

It is true that as the voltage drops, there is some increase in the current. However that current is being consumed from the energy that was in the battery and was going to be discarded at the point it was perceived to be dead.

 

 

Question 4: How does flash light benefit from Batteriser?

Answer: There are two types of devices, one with Passive load and the other with Active load:

1. Passive loads such as Flashlights that draw the current out of the battery until it is depleted, but the intensity of the light becomes too low for it to be useful. We measured the intensity of the light from a flashlight on a side by side comparison of, with and without Batteriser. They both started at 60 lux and after two hours, the flashlight utilizing the Batteriser maintained its 60 lux light intensity while the flashlight without Batteriser decreased its intensity to 25 lux.

2. Active Loads such as electronic devices that usually have a cut off voltage.

 

 

Question 5: There are some well-built devices have dc-dc conversion (or similar power management) built in, so Batteriser wouldn’t help. For example, this comment was made on Reddit: “For something like a GameBoy, it actually DOES include a good switching power supply, which is why it got great runtime out of those batteries. The DMG01 was quite happy down to nearly 3V (less than 0.8V per cell, anyway).”

Answer: The question above is an actual proof of why the Batteriser is going to extend the life of the battery. The assertion that a GameBoy device is benefiting from a DC-DC and getting “great runtime” is a validation of the concept of the Batteriser. There are systems that have or may have designed these types of converters inside their electronics. Such devices are usually expensive and putting the added cost of the electronics is offset by the competitive advantage gained relative to their competition. As well, this example implies that the system must have 4 AA batteries. There are regulators in the market that would boost voltages at these levels. Batteriser uses a boost circuitry that can work down to 0.5v. You will not find any solutions in the market that allows systems with single battery boosting capabilities. Batteroo had to design a custom IC that allows boosting of the voltage from 0.5V and currents of over one Amp steady state at very high efficiency. In many systems that use one AA battery, there is no solutions in the market to provide the same benefits of extended life.

 

 

Question 6: In low-drain devices like (I assume) a TV remote, the actual shelf life of the battery will be over before the Batteriser delivers noticeable gains. For example, this comment on Macworld: “Since most batteries (excluding some lithium types) have shelf lives of say 5 years or less, then taking a low drain application scenario where the batteries will naturally last two years or more (i.e. a remote…), then boosting the battery life by the claimed 8X would mean your 5 years shelf-life battery would be “good-to-go” for up to 40 years! Doesn’t take an engineer to tell you “it ain’t gonna happen!!”

Answer: Batteriser does work with voltage and current, regardless of the chemistry. We have seen improvement even with lithium battery. For those folks that change a battery every 5 years, we recommend not to utilize Batteriser technology. However if you are like most of us living in an average household having 25 battery operated devices and having to continuously change batteries, Batteriser would certainly be a good choice to extend the time between battery changes by 8x depending on the end device.”

Hopefully, this article will put an end to all the guessing and skepticism coming from the market. All the official testers and researchers found the product to be extremely effective. Only those who have not seen or tried the product are claiming the product can’t work. The Batteriser team suggests all skeptical hobbyist or engineers should buy the product and try for themselves, starting at only $2.50 per unit.

[AmmoJammo]

And they've raised another 8 grand overnight... I assume consumer laws don't come in to play for indiegogo campaigns, so if it's not fit for purpose, or doesn't do as described, the consumer can't do a thing?

[qno]

I think that this is someone who took the Joule Thief idea and took it a step further.

The Monkey is not the best load to demonstrate.
I guess there is a motor in there and motors are notorious for needing 8 times the nominal current to start.
The motor in the monkey is under load when it starts so start current is even worse.

Maybe it is a good idea to put a variable resistor in series with the power supply and increase the resistance to demonstrate the  battery terminal voltage drop under load.

[SaabFAN]

What they should've done: Speak about the Pulse-Currents and the associated voltage-drop, causing devices to fail/deem batteries dead. Wouldn't help them to hold up the 8x more energy from a battery, but at least nobody would laugh at them (so loud)

btw. 17 hours ago, they claimed that the correct way is to put a battery into your device and measure at the battery-terminals with the device active and then log the data to find out when the device can't function anymore.
I answered if they would wait for a year if the device is a low-power device - looking forward to their answer

Screenshot of that statement attached.

[LabSpokane]

I answered if they would wait for a year if the device is a low-power device - looking forward to their answer

Screenshot of that statement attached.

Answer: Batteriser does work with voltage and current, regardless of the chemistry. We have seen improvement even with lithium battery. For those folks that change a battery every 5 years, we recommend not to utilize Batteriser technology.

They've already backed off the claim that the Batteriser will be good for low-drain devices such as remote controls. See the clip from their FAQs above.  It will be interesting to see if they answer you.

[AmmoJammo]

I answered if they would wait for a year if the device is a low-power device - looking forward to their answer

Screenshot of that statement attached.

They've already backed off the claim that the Batteriser will be good for low-drain devices such as remote controls. See the clip from their FAQs above.  It will be interesting to see if they answer you.

But then the question is, how high is a high drain device?

if the device needs 500ma at 1.5volts, and now you're trying to boost the voltage from 1volt, up to 1.5volts, now you're drawing 750ma, at 1volt... which is going to last about 5 seconds before the voltage drops to a level that can no longer run the batteriser.... so as far as I can see, in a high drain device, you're going to, at best, get the same run time.... assuming you extract a tiny bit more power from the battery, this will be cancelled out by the loss of efficiency....

and I'm posting my video link again!

[ElectroWomble]

This response vidio from them makes me more cross than the original product.  Having a product that dose nothing is one thing... but putting out factually incorrect info is much worse. We should complain about this behaviour to the university where this professor lectures.  It dose bring that university into disrepute.

[Hugoneus]

I am still blown away that someone with a Ph.D. would knowingly undermine their profession by supporting a false claim. Or unknowingly support a false claim. I don't know what is worse.

[AmmoJammo]

The monkey is a toy. It is an ideal load to use because parents by lots of batteries for toys. The battery marketing over the last 30 years has used toys in TV commercials. Just about everyone has heard of the "Energizer Bunny".

But thats just it.... while the toy may run slower, its still going to work, whereas, if you're boosting the voltage, to maintain it, you're actually going to be drawing more power from the battery, resulting in a shorter run time!

If anything, they should have made a device to buck/boost the voltage to 1.2volts, to maintain the performance over the battery life, and possibly increase the run time, although in reality, you'd still most likely get no increased run time.... and still, this only applies to resistive loads...

[apis]

If anything, they should have made a device to buck/boost the voltage to 1.2volts, to maintain the performance over the battery life, and possibly increase the run time, although in reality, you'd still most likely get no increased run time.... and still, this only applies to resistive loads...

Yeah exactly. There are IC's that use less power at lower voltages so a down-converter make sense if you wan't to prolong battery life, in fact a linear regulator might be better than nothing. But ideally such circuitry should already be part of the device if it's well designed.

[edy]

We are looking at certain scenarios where the Batteriser will help. A device that needs a nominal minimal input voltage (perhaps to overcome forward voltage drops from various components) simply to be able to function.... Yet the anticipated trade-off in current is not enough to make the device stop.

For example, if the toy needs 1.1 V and can still work at as low as 200 mA, and the battery is capable of supplying 300 mA but is only producing 0.9v, the limiting factor is the voltage being too low. Throw in a booster and you may creep above the 1.1v minimum yet although the current would drop down from 300 mA to maybe 250 mA it would allow the toy to keep working a while longer until it drops below 200mA.

It seems like we need to meet both conditions for the Batteriser to even have any hope. So it seems highly device dependent and although it may compensate for the voltage by boosting it, you are still not going to know if your particular device will demand higher current (which the boost in voltage may have lowered the current below the minimum threshold) .

And ultimately it will not last long, as the current dropout will accelerate quickly after that.

[firewalker]

The batteriser will work 24/7? I think it is a disadvantage for devices with sleep modes or devices like remote controls (time_on << time_off).

Alexander.

[AmmoJammo]

For example, if the toy needs 1.1 V and can still work at as low as 200 mA, and the battery is capable of supplying 300 mA but is only producing 0.9v, the limiting factor is the voltage being too low. Throw in a booster and you may creep above the 1.1v minimum yet although the current would drop down from 300 mA to maybe 250 mA it would allow the toy to keep working a while longer until it drops below 200mA.

But if the battery can do 300ma at 0.9volts, chances are its going to do 1.1volts with only a 200ma load... so all the batteriser is doing, is boosting the voltage, to decrease the (final) current, to end up with the same power anyway....

[EEVblog]

Did they say what university he was from? I don't remember seeing it if they did. It is embarrassing to watch this unfold but I disagree that it is serious enough to damage the university. The veracity of the technical content to my mind is of far lesser significance than the possibility misleading statements were made in pursuit of commercial gain.

As someone posted earlier
https://www.eevblog.com/forum/blog/eevblog-779-how-to-measure-product-battery-cutoff-voltage/msg729972/#msg729972
It appears to be this guy from CSU East Bay, and he does not appear to be a professor, he just graduated last year:
https://www.linkedin.com/in/christopheruken



Dr. Roohparvar is however a professor at CSU East Bay

[EEVblog]

So, we're very nearly to having disproved nearly every claim you're making about these devices.  I'm going to cede you the cheap flashlight, the RC car, and John Boehner's monkey.

We have not see any prove at all the Batteriser actually works or gives any improvement in operational life in either an RC car or the Monkey.

[LabSpokane]

So, we're very nearly to having disproved nearly every claim you're making about these devices.  I'm going to cede you the cheap flashlight, the RC car, and John Boehner's monkey.

We have not see any prove at all the Batteriser actually works or gives any improvement in operational life in either an RC car or the Monkey.

I'm being a bit facetious with those.  The keyboard will be tested tonight.  I'm not going to waste my time videoing it, but will post a table that anyone could duplicate.  I'm even tempted to order some 0.1 to 0.3 ohm current shunts just to prove that the physics matches the math when we apply Thevenin's Theorem and create an equivalent source.  Once the keyboard is concluded, there will only be one, "800%" claim left:  the Garmin Dakota.  That's the last, rickety-ass leg of the stool that this charade rests upon.

[LabSpokane]

I am still blown away that someone with a Ph.D. would knowingly undermine their profession by supporting a false claim. Or unknowingly support a false claim. I don't know what is worse.

Shahriar,

That's what really has a bee in my bonnet.  This guy is a tenured professor.  We grant academics that type of security, freedom, and relative immunity on the basis of trust.  If this is how they choose to use and abuse that trust, what is left?

[EEVblog]

All the people up in arms here in this forum are engaging in a group hug to feel good about themselves.

No, it's just what we do on an engineering forum, we discuss the finer technical points of engineering, it excites us 
The average punter isn't going to read this forum even if it was linked to them. Just like the average punter isn't going to sit through one of my Batteriser videos, they's tune out in 10 seconds.
Doesn't mean we shouldn't discuss it though, it has great merit to those who want to know the details.

[apis]

When I was a kid I had a toy called Matchbox Scorpions. <...> You asked your parents for new batteries not when they were empty but when you got tired of the slow refueling stops and sore fingers.

I predict the next video will feature a certain Mr. Chris Uken explaining that the batterizer will put an end to sore fingers. I wonder what kind of test setup they will use, maybe they can reuse the robot finger.

[edy]

I agree with Dave's earlier comment... All this chatter does help us electronics nerds to learn about certain fundamental principles - I couldn't care less if this forum necessarily altered the number of sales of the Batteriser by the folks on IndieGogo. Most have already made up their minds. They need to educate themselves. As the proverbial saying goes "You can lead a horse to water, but you can't make him drink". From a selfish personal point of view, I just like exercising my brain muscle here and getting a more firm intuitive grasp on electronics and engineering.

There are a few things that I feel (in the context of other massively disgusting IndieGogo scams - take "Airing" for example... https://www.indiegogo.com/projects/airing-the-first-hoseless-maskless-micro-cpap) make the Batteriser look like an Angel in comparison.  Firstly, Batteriser *only* took in about $230,000 so far. Maybe they'll get up to $300,000, maybe $400,000. But not $1,000,000+ like Airing did. Secondly, the product is coming out in a few months.... There is a Fall 2015 Timeline Ship To Backers? - are they still on schedule? We will all get the product soon enough and be able to test it hands on! The "Airing" is not going to be available until mid-2017 and beyond... If it even gets developed (they have no prototype even). At least Batteriser has a prototype. Thirdly, the cost for the Batteriser is quite minimal. Seems like *most* backers for Batteriser are in at the $20-40 level... And they are getting them at about $2-3 a piece. Not bad, even if you want to hack the parts later and it is not a huge amount to lose on some total crap. The minimum "Airing" funding level for any product gets you into the $70-120 range at least.

Why am I comparing the two? Well, the "Airing" is a complete pile of nonsense that doesn't exist, fairy-tale land, with a team of people who are part of another defunct company take-over (with lawsuits also searchable in the U.S. legal files) and they took advantage of people with a medical condition to promise them a "Star Trek Fantasy" product.... And even after NUMEROUS INDIEGOGO COMPLAINTS nothing was ever done. They completed funding to 896% originally and now are "InDemand" and raising more.

So honestly, in the grand scheme of things, the Batteriser while it may be a complete pile of marketing B.S. and may only have a marginal benefit in certain situations, all-in-all the devastation it will cause on the poor unsuspecting backers is minimal. I feel like these Batteriser backers in a way are paying for my electronics education... because I've learned a lot from this entire fiasco. And the University professors and the University really, when it comes down to it, could use the cash more than anything it does to the so called "reputation". They are in it for the money.  

[Mr.B]

Understand and agree with you edy.

@mojo-chan said on May 08, 2015, 11:53:05 PM in the Projection watch on Indiegogo thread - "IGG should be investigated for fraud. They ignite stuff like this for profit."

I just wanted to repeat that statement here...