EEVblog #779 - How To Measure Product Battery Cutoff Voltage

[Fungus]

This whole thing is hilarious.   I liked Dave pointing out the barely if unused Weller iron just sitting there, and the scope connected to it's own signal generator with a badly compensated probe.

I'm not saying Dave couldn't have noticed those things by himself, but ... I know that other people pointed them out first in the forum.

(I might have been the first to point out the soldering iron but I don't really care enough to wade through all the messages just to make a point)

[AmmoJammo]

Going along the lines of ARSETRONICS.... What about BUTTERISER! 

"BUTTeriser BatterPOO"

yeah, I went there....

[TheAmmoniacal]

I'm not saying Dave couldn't have noticed those things by himself, but ... I know that other people pointed them out first in the forum.

(I might have been the first to point out the soldering iron but I don't really care enough to wade through all the messages just to make a point)

You seriously want credit for pointing that out? As if that's not the first thing everyone in here looks at!

[AmmoJammo]

You seriously want credit for pointing that out? As if that's not the first thing everyone in here looks at!

*randomly mashes the screen, looking for a "like" button*

[Svuppe]

But I'd really like to find out where that difference is coming from. It should be possible to get consistent data regardless of the power origin. The only thing I changed, apart from PSU to batteries, was my Fluke 187 that I had in series for current measurements while using my PSU.

Culprit found. It was user error (as in me): I used the 400mA range on my Fluke, so as a precaution I set the current limit on my PSU to match. BIG mistake 
The GPS only uses less than 200 mA (average), but it apparently pull some nasty spikes when it gets close to the cutoff limit. A big current spike and the 400 mA current limiter had it shut down prematurely. Using 2A current limit and removing the Fluke from the circuit, I now get the cutoff voltage to be 2.044V. Much closer to the battery measured shutdown (2.026V).

Attached is the current spike (with 400 mA current limiter):

[michael2]

Using a power supply, I consistently got shutdown voltages around 2.13 - 2.14V on my old GPS. But using batteries it lasted until 2.03V. Not a big difference, but still....

So better, not worse 

Exactly. If anything, it only helps the Batteriser that we are finding the cutoff voltage with a power supply instead of batteries.
But I'd really like to find out where that difference is coming from. It should be possible to get consistent data regardless of the power origin. The only thing I changed, apart from PSU to batteries, was my Fluke 187 that I had in series for current measurements while using my PSU. But that should not change anything, as I measured the voltage at the GPS battery clips like this:

The Fluke 187 is rated with 1.8 mV/mA typical in the 400 mA range. Did you use the 400 mA range?

[michael2]

The Fluke 187 is rated with 1.8 mV/mA typical in the 400 mA range. Did you use the 400 mA range?

Forgot to mention that the crude mV/mA unit is a tame way to omit the 1.8 Ohms rating... 

[Svuppe]

Yes, I did use the 400 mA setting, but as I measured the voltage at the GPS end (not the PSU end), I could have put tens of ohms in series with the supply and it still wouldn't matter.

[EEVblog]

FYI, posted on the other thread:
https://www.eevblog.com/forum/blog/eevblog-751-how-to-debunk-a-product-(the-batteriser)/msg732236/#msg732236
The GPS used is a Garmin Approach, not the Dakota.

[amyk]

Maybe when you're back on the clock, we can talk about how you decided to choose an ESR that was off Duracell's chart by a fair margin. You're citing 0.5 ohm as a "typical" ESR.  That's really a bold assumption since the below graph shows it at 0.3 ohms at full discharge.  Then you spout off about 1.5 ohms, because of cold batteries.

0R9 is, according to the PDF they link, at a temperature of -40C.

the typical effective resistance of fresh Energizer alkaline ... approximately 150 to 300 m-ohms at room temperature

The chart from the same PDF they linked shows 0R15 to 0R3 as corresponding to temperatures of 17 to -10C. Incidentally that is roughly the temperature inside an igloo.


At this point, after seeing all this bullshit, I'm wondering whether they're deliberately doing it, or just plain incompetent...

[LabSpokane]

FYI, posted on the other thread:
https://www.eevblog.com/forum/blog/eevblog-751-how-to-debunk-a-product-(the-batteriser)/msg732236/#msg732236
The GPS used is a Garmin Approach, not the Dakota.

The other reason I didn't order a Dakota is that I wanted a demonstrable result prior to the end of the Indiegogo campaign.

[LabSpokane]

Here's the first test. 

All power management functions disabled.
GPS+Glonass Lock
Screen brightness 100%

Run time:  11.23 hours
Battery Cutoff Voltage: 2.097V or 1.049V per cell

I have no idea *what* I would have to do in order to force this GPS to run down in two hours.  If this was the Dakota, with 80% of the battery life (20 vs 25), it would likely have run 8+ hours in this test. 

[Fungus]

I have no idea *what* I would have to do in order to force this GPS to run down in two hours.

Maybe the one in the video didn't run down. If the burden voltage of all the equipment they had attached to it is large enough* then it will shut down long before the batteries are actually dead.

(*) It only has to be 0.2V or so to cause premature shutdown and that's only about 1 Ohm of resistance.

[AmmoJammo]

I have a handful of these little boost regulators lying around:
http://www.ebay.com.au/itm/Mini-PFM-Control-DC-DC-0-9V-5V-to-USB-5V-DC-Boost-Step-up-Power-Supply-Module-WS-/321722956294?hash=item4ae82eba06

So I hooked one up to my two discharged AA cells, (wired in series) that I'd tested my gameboy with, in the video I posted earlier.

Unloaded, I had about 2.5volts for the two cells in series, but with the boost regulator, that instantly dropped to under 1volt... with nothing connected to the output of the boost converter.

efficiency? very poor! so unless they can get their efficiency to 99%, you're not gaining anything!

It did however then run the gameboy for 10 seconds 

[LabSpokane]

I know that someone is looking at the tail end of the graph and thinking that the battery is not fully depleted. You're correct. There's a *tiny* amount of energy left and the battery voltage will recover to the point that the device will power back on. So, I ran a subsequent test. It ran for 10 minutes. That's about 1.5% longer. Not 800%.

This would be even worse with an external boost converter since one is giving up about 10% of the efficiency. 

To conclude, this class of devices already have excellent battery management technology. The Garmin GPS series that use two AA batteries clearly already have a boost converter built in. Adding an external boost converter is not a plausible method to increase run time.

These devices do NOT leave 80% of the energy remaining in an alkaline battery after they reach cutout voltage of 1.05 to 1.10 V.

Attempting to use the battery beyond the initial cutoff voltage can only be expected to increase operation time by a few minutes, NOT hours.

I have now tested Batteroo's premise on the three major classes of specific devices they claim will benefit from their technology. Batteroo has already admitted publicly that low-drain devices such as remote controls will not benefit. My testing of these devices shows that none of them comes remotely close to reporting dead batteries while leaving 80% of the energy remaining in the battery. 

Since the premises are flawed, so must be the conclusion.

As I have already offered, I will reproduce these tests in person, if I am given reasonable time accommodations. You come to me. If there is a question, PM me.  I will respond.

[edy]

Just to point out a bit of irony... Batteriser just passed the 800% funded mark on IndieGogo, precisely the amount of extra battery power they also claim to get!

[EEVblog]

Just to point out a bit of irony... Batteriser just passed the 800% funded mark on IndieGogo, precisely the amount of extra battery power they also claim to get!

Which is of course wrong, because they also claim 8x, which is not the same as 800% 

[redshift]

I haven't noticed anyone post about their comments in PC World: [link]

There is a user named "EEAtlanta" that I suspect is also "not associated" with Batteroo replying to every negative comment in this article. Most of the replies are copy-paste but if you scroll down a bit you'll see this gem:

Dave Jones graduated from Dramatic Arts School. The inventors of Batteriser are professors of electrical engineering. Regarding your post, Batteroo released a video demonstrating why you cannot use a power supply box to "debunk" the Batteriser. Batteries and constant power supply boxes behave very differently: [youtube link]

That Youtube page also has a video of the Batteriser tested on flashlights. Check it out if interested.
Thanks

  Sorry Dave. I believe your credentials (not that you need them to debunk this rubbish...)

[amyk]

The appeal to authority is amusing, but EEAtlanta? That's where the "Batteriser Batteroo" guy (and his sockpuppet) claims to be from. Look here:

https://www.eevblog.com/forum/blog/eevblog-779-how-to-measure-product-battery-cutoff-voltage/360/

It's all ridiculously silly. They're just parrotting the Batteriser "debunking" video and not even giving any technical argument for why they think the Batteriser actually works...

[pickle9000]

The appeal to authority is amusing, but EEAtlanta? That's where the "Batteriser Batteroo" guy (and his sockpuppet) claims to be from. Look here:

https://www.eevblog.com/forum/blog/eevblog-779-how-to-measure-product-battery-cutoff-voltage/360/

It's all ridiculously silly. They're just parrotting the Batteriser "debunking" video and not even giving any technical argument for why they think the Batteriser actually works...

It's the Donald Trump response "Your a dum-dum, I'm right stupid"

Or the politicians 3 point plan.

Marketing...

[cbmuser]

Which is of course wrong, because they also claim 8x, which is not the same as 800% 

Uhm, yes, that's exactly what 800% are, a factor of 8. What else would it be?

1% is 1/100 of the basis value, 150% is 1.5 and 800% is 8.

[Rasz]

bateroo 'fan' is money spend wisely

http://www.paulgraham.com/submarine.html

at a time when we were assembling our own computers to save money, we were paying a PR firm $16,000 a month. And they were worth it. PR is the news equivalent of search engine optimization; instead of buying ads, which readers ignore, you get yourself inserted directly into the stories.

[EEVblog]

Which is of course wrong, because they also claim 8x, which is not the same as 800% 

Uhm, yes, that's exactly what 800% are, a factor of 8. What else would it be?
1% is 1/100 of the basis value, 150% is 1.5 and 800% is 8.

100% increase is a x2 increase.
200% increase is a x3 increase.
etc.
Try it on your calculator.
If I gave you 100% interest on your $1, you would have $1 + 100% of $1 = $2. A x2 increase.
Nobody says a x1 increase, it's no increase at all.

[Circlotron]

Which is of course wrong, because they also claim 8x, which is not the same as 800% 

Uhm, yes, that's exactly what 800% are, a factor of 8. What else would it be?
1% is 1/100 of the basis value, 150% is 1.5 and 800% is 8.

100% increase is a x2 increase.
200% increase is a x3 increase.
etc.
Try it on your calculator.
If I gave you 100% interest on your $1, you would have $1 + 100% of $1 = $2. A x2 increase.
Nobody says a x1 increase, it's no increase at all.

Nah.
100% increase is a x1 INCREASE, which is x2 final total value compared to the original.

[TheElectricChicken]

100% increase is a x1 INCREASE, which is x2 final total value compared to the original.

makes no sense when you try to express x2 increase.