EEVblog #779 - How To Measure Product Battery Cutoff Voltage

[LabSpokane]

All of his publications seem to be in physics. I don't see anything in electronics.

Quite true.  I'm operating on the assumption that setting up a simple laboratory experiment should be a skill that a working physicist should be qualified to handle.  His ability to draw correct conclusions may be limited by his experience.  But, for him to make such a statement, I would *hope* that physical testing was performed and that he could share the protocols and results. 

[Hugoneus]

All of his publications seem to be in physics. I don't see anything in electronics.

Quite true.  I'm operating on the assumption that setting up a simple laboratory experiment should be a skill that a working physicist should be qualified to handle.  His ability to draw correct conclusions may be limited by his experience.  But, for him to make such a statement, I would *hope* that physical testing was performed and that he could share the protocols and results.

I wholeheartedly agree. Anyone with a Ph.D. should understand the scientific method and if something is outside of their expertise they should abstain from commenting.

[TheElectricChicken]

@TheElectricChicken
That's the funniest thing I've seen in a long time! Great work!

thank you.

We do need permission of David L. Jones who drew the monkey I think, and possibly someone can take pics of their scope and upload it so I can make one that is pure PD or CC license, but I think nobody cares. I am very glad I can help you get a second laugh from David's funny monkey.

[Fungus]

All of his publications seem to be in physics. I don't see anything in electronics.

Quite true. 

Yep. Only a physicist would build a huge screen-poking machine to test the GPS instead of looking in the menu for a 'stay awake' mode.

Definitely not an EE.

[Falk]

All of his publications seem to be in physics. I don't see anything in electronics.

Quite true. 

Yep. Only a physicist would build a huge screen-poking machine to test the GPS instead of looking in the menu for a 'stay awake' mode.

Definitely not an EE.

Yeah, but maybe this is part of the "trick". When waking up the GPS, it draws a pulse current. If there is a flaw in the battery voltage monitoring (hardware or software), it will show an premature "low bat warning" (i.e. when it measures the voltage on the huge current spike). Any good designed device will NOT benefit from batteriser, since it can deplete any battery down to its fully discharged level.

[Kalvin]

Time to do some experimenting. Not too complicated if you can open the poor monkey and solder two wires with that unused Weller shown on the video.

Just open the monkey, solder two wires to the battery terminals inside the monkey in order to be able to measure the actual battery voltage when the monkey is being used. Hook the wires to the multimeter so that you can see the battery voltage at every instant.

Then perform these two tests:

1. Using the power supply measuring the cut-off voltage just like in the Batteriser's video

a. Dial 3V to the power supply.
b. Turn off the monkey.
c. Connect the external power supply to the monkey's battery terminals.
d. Record the voltage on the multimeter. Should be the same as the power supply ie. 3V
e. Turn on the monkey.
f. Record the voltage on the multimeter. Should be still the same as the power supply ie. 3V
g. Reduce the voltage until the monkey goes zombie.
h. Record the voltage on the multimeter. You have just measured the cut-off voltage (approx 1V).

2. Using the used batteries, just like in the Batteriser's video

a. Measure the battery voltages. Should be around 1.2V each, so the combined voltage is around 2.4V.
b. Turn off the monkey.
c. Insert the two used batteries into monkey.
d. Record the battery voltage on the multimeter. Should be around 2.4V.
e. Turn on the monkey.
f. Record the voltage on the multimeter. The monkey may not be moving as the batteries are used. The loaded battery voltage may be less than 1V.
g. Turn off the monkey.
f. Record the voltage on the multimeter. Should be around 2.4V as the batteries are not loaded any more.
g. Think hard. Magic? No.

[LabSpokane]

And the Batteriser saga takes a turn for the utterly surreal.  This was just posted on their YouTube page:

Pls stand by we are in a process of releasing a video with the technical explanation for all engineers on how Batteriser works, while at first glance, it seems implausible, I am sure that real genuine engineers will appreciate our whiteboard technical discussions along with simulation, data matching battery companies spec sheets, in conjunction with device data. Of course, those whose revenue will be reduced by our technology will do everything to divert attention

"real genuine engineer"  - This is a joke, right?!  Exactly who grants such a degree?  What is the accrediting institution?

Nobody said that a boost converter is implausible.  We're telling you that the battery management technology in today's electronic devices is already very good at extracting energy from batteries.

I'm telling you that I have tested the devices that you have selected as leaving 80% of the available energy while reporting a dead battery.  And I'm finding out that these devices, are in fact, using 90 to 95% of the available energy in the battery.  Your claims regarding Apple's wireless trackpad and keypad do not match the data that I have obtained using standard practices.

Your device cannot work as claimed on the Apple trackpad and keypad because there is not enough energy in the battery once the battery reaches the device's cutoff voltage.  I need not know anything about your device's internals or topology to come to that conclusion. 

It is time for you to start retracting your claims.

[LabSpokane]

Sigh...

Bob Roohparvar
2 hours ago
@csmurp 77
we agree with you that voltage under load would be different from no load condition, which was the whole point of the Monkey video to demonstrate that batteries are different than power supplies. The use of a bench power supply (with no current limit setting) to determine device cut off voltage is inaccurate. Prior to our video release, the most important battery parameter, its Internal Resistance , was being ignored.
Pls stay tuned for our next video explaining technical details.

So Bob, what current limit would you like me to use?  Do tell.

[RFZ]

Just found my really cheap (actually free ^^) radio controlled clock / weather station already starts to get really dim at 1.29V per cell...  Guess it's time to order a pair of Batterisers 
And yes, measured in device under load

[pickle9000]

Just thinking, I wonder if the purpose of this whole exercise (the batterizer guys) was to fund a company? I'm not thinking with Indiegogo but using some other types of investors and this is all just an advertising campaign to get other investors. 

If this is the case then hopefully this will put a bit of a "monkey wrench" in the plan and slow them down.

Anyway I do like to see people saying "prove it". This is a great thread. 

[Kalvin]

The external power supply with the output voltage set to 2.5V, connected in series with a 4 ohm resistor models the two used batteries quite well according to the video: the operating current was around 400mA at 2.5V and the monkey stopped moving at 0.9V. This series resistance is used to model the batteries' internal resistance. Reducing the resistance from 4 ohm to 0.5 ohm models the fresh batteries quite well. As the batteries get discharged, the internal resistance increases gradually from 0.5 ohm to 4 ohm and more. So, you can use a power supply to model batteries after all.

[edy]

Wait! We got it all wrong!    I think I know how the Batteriser works!

So you know how all these devices can work even when each battery is down to only 1.1 V? Well we are "wasting" all that extra voltage by using brand new 1.5 V batteries in our devices! How much? Well 0.4 V of extra "energy" is in each battery that is not even needed because the device will happily continue functioning even on 1.1 V per cell. 

 

So the Batteriser  "throttles down" the voltage on the battery and therefore extends it's life... It lowers the voltage from 1.5 V per cell to what the device needs to just barely stay on (say 1.1 V) and that "extra" 0.4 V that it saves can then be recovered and used later on to drastically extend the life of the battery.  Yes! I think that is the magic behind it!

[German_EE]

Another datapoint for you all. Chinese manufactured DCF77 clock and remote weather station:

Main Unit 2 x AA cells measured at 3,32V before test (under load)
At 2,2V reception of remote unit failed
At 2,19V reception of DCF77 Time Signal dropped out
At 2,11V screen died

Remote Unit 2 x AAA cells measured at 3,21V before test (under load)
At 2,5V Bluetooth transmitter stopped
At 1,86V display died

So, I have a desk unit that will work down to 1,1V per cell and an outside remote that works to 1,25V per cell (the bluetooth transmitter probably drags it down). Not bad for an old set of batteries.

[Kalvin]

Wait! We got it all wrong!    I think I know how the Batteriser works!

So you know how all these devices can work even when each battery is down to only 1.1 V? Well we are "wasting" all that extra voltage by using brand new 1.5 V batteries in our devices! How much? Well 0.4 V of extra "energy" is in each battery that is not even needed because the device will happily continue functioning even on 1.1 V per cell. 

 

So the Batteriser  "throttles down" the voltage on the battery and therefore extends it's life... It lowers the voltage from 1.5 V per cell to what the device needs to just barely stay on (say 1.1 V) and that "extra" 0.4 V that it saves can then be recovered and used later on to drastically extend the life of the battery.  Yes! I think that is the magic behind it!

Buck-boost converters work just like that. They can produce constant output voltage even if the battery voltage drops or increases.

Modern electrical devices typically operate as constant power mode, which means in practice that if the battery voltage increases the current consumption will be reduced - and if the battery voltage drops the current consumption increases. Using a buck-boost-gimmick wouldn't produce any real advantage here.

For a device using an electric motor, there will be some advantage though. When the battery voltage increases, the current will increase too. And reducing the battery voltage will reduce the current as well. But reducing the battery voltage will make the motor veryy slooooowwww...

This video "Flash light test with The Batteriser" gives a hint that the output voltage will stay constant as the actual battery gets discharged, so there is boost-regulator inside.



As the actual battery voltage drops the current drawn by the boost-regulator needs to increase in order to keep the output voltage constant. Funny enough, this will discharge the battery a bit faster as the discharge current increases.

Please read Jay_Diddy_B's thorough analysis and excellent simulation on what this means in practice:
https://www.eevblog.com/forum/projects/modeling-an-alkaline-battery-in-ltspice/msg731360/#msg731360

As the battery discharge curves show there is very little energy left after the battery voltage has reached the 0.9V cut-off voltage. This means there is hardly any energy left in the actual battery. If there is no energy left, even the Batteriser cannot do any magic tricks here. 

[FrankBuss]

So, you can use a power supply to model batteries after all.

That wasn't the point. The point was to measure the product battery cutoff voltage. And for this it doesn't matter if you use a battery and wait until the terminal voltage drops low enough and the monkey stops moving, or if you lower the voltage of a power supply.

Modelling a battery with a power supply and a resistor might work, but I think this needs to be proven. I guess a battery is not exactly as linear as a resistor with low and high currents, and complex loads like the monkey might make it more complicated. But if there is still a current flowing when the motor stops moving, the cutoff voltage would be the same. Otherwise it could oscillate a bit (motor stops, no current flows, battery recovers a bit, motor starts again). But nevertheless you can always say at which voltage the device stops operating. But you might need an oscilloscope (not measuring the test square wave output) to do it right for complex loads.

[AmmoJammo]

Just found my really cheap (actually free ^^) radio controlled clock / weather station already starts to get really dim at 1.29V per cell...  Guess it's time to order a pair of Batterisers 
And yes, measured in device under load

We found one device that will actually benefit from the batteriser!

Of course, if you fit them when you're replacing the batteries, the inefficiency will probably result in them running the cells down just as fast anyway.

[Jay_Diddy_B]

Hi group,

I have presented a fairly detailed analysis, using LTspice, of the combination of Alkaline batteries and a battery_booster in this thread:

https://www.eevblog.com/forum/projects/modeling-an-alkaline-battery-in-ltspice/msg731360/#msg731360

Enjoy !!

Regards,

Jay_Diddy_B

[TheAmmoniacal]

How many of the users here have backed Batteriser on their indiegogo just to get your hands on some of these? Do we have any recourse if they don't ship? I don't want to give them money!

[Kalvin]

Hi group,

I have presented a fairly detailed analysis, using LTspice, of the combination of Alkaline batteries and a battery_booster in this thread:

https://www.eevblog.com/forum/projects/modeling-an-alkaline-battery-in-ltspice/msg731360/#msg731360

Enjoy !!

Regards,

Jay_Diddy_B

You have made great job!     

Coincidentally I just wrote in my post above, before I read your electronic game simulation:

As the actual battery voltage drops the current drawn by the boost-regulator needs to increase in order to keep the output voltage constant. Funny enough, this will discharge the battery a bit faster as the discharge current increases.

[AF6LJ]

How many of the users here have backed Batteriser on their indiegogo just to get your hands on some of these? Do we have any recourse if they don't ship? I don't want to give them money!

I haven't and I believe every product deserves to live or die in the free marketplace.

[pickle9000]

How many of the users here have backed Batteriser on their indiegogo just to get your hands on some of these? Do we have any recourse if they don't ship? I don't want to give them money!

I haven't and I believe every product deserves to live or die in the free marketplace.

I think that is what's happening.

[Kalvin]

(snip) ... I believe every product deserves to live or die in the free marketplace.

Placebo works:



But in this case the placebo-effect may not keep your monkey running longer, though. So it may be a hoax or a scam.

[Wolfgang]

Good work, making it clear that the batteriser is utter crap. One more thought, however:
Quite some loads do not draw a constant current or have a constant resistance over time,
 but instead they need more current to start off than they need to operate continuously
 (e.g, DC/DC-converters, motors, ...). This means that a battery with an increased internal
 resistance due to ageing will not be able to start off some loads that run OK from a
 DC lab power supply with zero internal resistance. Thats very plausible. The ridiculous
 thing is now that the batteriser makes things worse than better; a load (motor, converter, ...)
 that could marginally start from a battery will not even have then chance to start with
 the batteriser, because if needs even more power from the battery than the original load
(efficiency is never 100%) and the drop due internal battery resistance will be even higher.
 The batteriser people are just crooks trying to extract money from uneducated users.

[edy]

One interesting aspect to this entire campaign is the production side. Does anyone know if it is feasible on the scale of the number of Batterisers being produced that they can get the costs so low? I assume the components are cheap, but assembly, creating all the tools for a production line, etc... Fascinating to see that in progress and whether it can be done for the $300k-400k I assume they will get funded, and still turn a profit. Unless they are expecting some venture capitalists to throw in some money for a cut as well.

[Jay_Diddy_B]

Hi,
The device would be more useful for higher current applications. At low currents the quiescent current of the Battery_booster' may draw more current than the load.

At higher currents, I am not sure if the boost regulator will fit into the available space.

Jay_Diddy_B