EEVblog #779 - How To Measure Product Battery Cutoff Voltage

[Xenix]

In Batterisers latest video they claim that using a constant current load is the incorrect way to test the battery because the the load fluctuates in a real device. If a device instantaneously starts drawing high current the battery voltage will drop below the cutoff voltage due to the internal resistance of the battery switching off the device. I'm guessing their theory is the boost converter will help regulate the voltage so it does not drop below the cutoff voltage of the device while the batteries are still good.



EDIT: or maybe they are using a flux capacitor or some type of over unity device

[Shinobot2]

Newbie here.

Considering I have a battery connected to a load drawing a constant current of 100mA, and the measured voltage at the battery terminals is 1.3V. So 1.3V *100mA=0.13W.

Now I connect a boost converter, after the battery,let´s say it´s 100% efficient,  and the output voltage rises to 1.5V, with the same load drawing 100mA, 1.5*100mA=0.15W.

So the battery will discharge faster, at the same ratio as if was new.  Like, when you look at the battery graph of voltage vs time, voltage decreases way faster when new.

Is this wrong or right?

[EEVblog]

The response video is a hoot. Did anyone notice that in the GPS test, their ' smoking gun', the device didn't 'fail' like they stated, it just popped up a notification saying the backlight cannot be at full brightness due to the battery level.  They are saying that the device FAILS at this moment.
The GPS is a Garmin Approach G3. I found a review of it here. It says this notification displays when the device's battery level is at 1/2 to 3/4 of full capacity.  The device still functions even when it is below 1.1V per cell.

We kept getting a warning screen that the battery power was “too low for full backlight”, even when the battery meter was showing between 1/2 and 3/4 of a charge remaining. ... One really annoying glitch – when the G3 batteries are near the threshold charge level for triggering a warning screen that battery power is insufficient for full backlighting, the device seems to frequently change its mind about whether there actually is sufficient power or not…and thus, it will re-display the warning screen 2 seconds after it just showed it to you and then again…and again. Once the charge level drops comfortably below that threshold, the problem seems to go away.

http://www.criticalgolf.com/reviews/archived-products/garmin-approach-g3-review/

Yep, it's been discussed on here before, but good to see that review confirm it. Seems they utterly goofed that experiment. And that is their big one, the one that proves they can get 5 times the battery life 

[EEVblog]

Newbie here.
Considering I have a battery connected to a load drawing a constant current of 100mA, and the measured voltage at the battery terminals is 1.3V. So 1.3V *100mA=0.13W.
Now I connect a boost converter, after the battery,let´s say it´s 100% efficient,  and the output voltage rises to 1.5V, with the same load drawing 100mA, 1.5*100mA=0.15W.
So the battery will discharge faster, at the same ratio as if was new.  Like, when you look at the battery graph of voltage vs time, voltage decreases way faster when new.
Is this wrong or right?

That is correct. More power is being drawn from the battery = shorter life. It's an inescapable fact. What the Batteriser relies on in this case is being able to operate down to a lower battery voltage and hence use more energy form the battery than the product would normally.

[Mr.B]

What the Batteriser relies on in this case is being able to operate down to a lower battery voltage and hence use more energy form the battery than the product would normally.

Which you have proven to be a wrong hypothesis on multiple occasions due to the fact that there is SFA energy left in the battery once it gets down to what most devices have as a cutoff voltage.

They just don't get it... Or maybe they do, thats why they construct videos to avoid the real answer.

Thanks Dave and the rest of the community here for providing sound and scientific education.

[Halcyon]

As Dave very correctly pointed out in this video, you don't measure the open circuit voltage. Even I learnt this in Year 10 High School electronics! On one hand Batteroo / Batteriser seem to ignore this fact, yet on the other hand, they rely upon a product's own power meter (which is of course measured under load by the product itself) in a poor attempt substantiate their claims.

I have come to the conclusion long ago regarding the folks at Batteroo: They are either complete liars and are deliberately being deceitful and misleading or they are simply uneducated when it comes to electronics. I think I'm leaning towards the former.

[Mr.B]

Busted -> Buttsed

[Red Squirrel]

This just gave me an idea for a kick starter.  Put a magnet in one hand of the monkey and a coil in the other and you have a perpetual self charging clapping monkey battery charger!

[Mr.B]

LOL...
Use a rare earth mag to generate more than you put in... over unity...
Race you to the kickstarter... hang on, indiegogo have free money even if the target isn't met... I will use them to attract the suckers...

[SL4P]

Don't touch the monkey's butt.
Or alternately - lets try 240VAC up there - it could be a suitable end to this saga.

[joseph.anand]

You forgot the following disclaimer:
"No monkeys were harmed in the filming of this video. Howeve we cannot guarantee the same of Probes's Uncle."



We seem to be having two threads here the EEVblog 789 and the EEVblog 779. The EEVblog 789 video links to the EEVblog 779 thread. While someone has started the EEVblog 789 thread.

[Fungus]

Taking money from a VC really is a Faustian bargain.

Only if your product is 100% fraud.

[Fungus]

What the Batteriser relies on in this case is being able to operate down to a lower battery voltage and hence use more energy form the battery than the product would normally.

Which you have proven to be a wrong hypothesis on multiple occasions due to the fact that there is SFA energy left in the battery once it gets down to what most devices have as a cutoff voltage.

Nobody's measured it yet,  but... it's probably true that Batteriser extracts more overall energy from batteries.

OTOH the math says you'll get a shorter battery lifetime as a result.

Those two statements aren't incompatible.

Batteroo is obviously promoting the first one but everybody else should be looking at the second.

[timofonic]

Poor monkey! Take care of his butt! Look for some anal damage, maybe he's going to need some vet care!

It's funny they are so academic and show less and worse TE than yours!

Nice video, they have no way to lie anymore with false claims. Despite of that, stupid groupthink is an infinite resource!

Here's a product idea:
1. Research to make a device that can convert stupidity and lies into energy.
2. Make a Kickstarter for that product.
3. Tons of profit!

The monkey battery charger seems a funny idea too.

Are you going to make a nice t-shirt if this? It would be cool!

[SL4P]

.Are you going to make a nice t-shirt if this? It would be cool!

Now that would make a good crowd-funding project... lots of subscribers waiting on here!

[Circlotron]

Here's a product idea:
1. Research to make a device that can convert stupidity and lies into energy.

You would be lucky to get five percent efficiency.
Convert the other direction would get 100% for sure.

[sakujo7]

Nobody's measured it yet,  but... it's probably true that Batteriser extracts more overall energy from batteries.

OTOH the math says you'll get a shorter battery lifetime as a result.

Those two statements aren't incompatible.

Batteroo is obviously promoting the first one but everybody else should be looking at the second.

The instructions should say only to use it once the product is already failing...but if the cutoff is low enough, users will quickly notice exactly how much extra life they get, and that it's not anywhere near 800%.

[sakujo7]

If a device instantaneously starts drawing high current the battery voltage will drop below the cutoff voltage due to the internal resistance of the battery switching off the device.

I have a great idea for a kickstarter - the batterthinger! It's a battery sleeve made of capacitors bidirectional energy stasis devices! It boasts 99.99+% efficiency, and the ability to magically smooth out those pesky current spikes, to make old products with leaked capacitors work again for a short while! Money please.

[Wolfgang]

Hi Dave,

These people live from the fact that stupidity is the largest renewable resource available to mankind.
I am afraid that they will not be willing to admit all they do is a hoax until somebody comes up and charges them
for fraud. The ultimate test is near anyway: After the stuff appears on the market the monkey with the batteriser in it will definitely give up way earlier than the monkey without batteriser. Repeat the same for the remote control, the GPS, ... you chose. And then, the game is over. So, keep calm and relax. Thruth will have its way ...

[boffin]

How many people would buy a t-shirt of Dave's "MONKEY UNDER TEST" diagram?

[SaabFAN]

You can't leave this lone, can you?

[McBryce]

I'd prefer if it said "Now where did I leave those probes??" or something similar under the monkey.

McBryce.

[silent]

That monkey thing reminds me of one scene from the movie I have seen long time ago... Don't know why... Maybe it's because the product is just as stupid as the movie. 

https://youtu.be/O09K8EmURhM?t=23s   (2:56)

[SaabFAN]

Has anyone pointed out the problems with the Indiegogo-Campaign to Indiegogo directly?
The policy for campaigns prohibits misleading statements btw.

[ralphd]

The study cited by Batteriser found a statistical relationship between the 10-Ohm loaded voltage after 30s and the capacity (see pg 6).
http://www2.ife.ee.ethz.ch/~rolfz/batak/ICBR2003_Zinniker.pdf

They don't even mention the open-circuit voltage, probably because it has no material correlation with remaining capacity.