EEVblog #779 - How To Measure Product Battery Cutoff Voltage

[EEVblog]

Another in a series of battery tutorials, Dave explains how to correctly measure the battery cutout voltage of a product.
And how to take internal resistance of a battery into account.
And also a detailed response to a video from Batteriser claiming Dave is wrong in using a PSU to measure the battery cutoff voltage, and why this is complete folly.

Full playlist of battery related videos is here:
https://www.youtube.com/playlist?list=PLvOlSehNtuHtj5Ubhx7govoBfNkyUO4Pp

[TheElectricChicken]

I loved watching the vids on this one yesterday I think it was, and the teardown of perfectly good scam equipment, I wait for the van in my suburb 8-) I'll haggle so well that they will pay me !

What I would love to see more of is how to hook up batteries to my arduino project with a solar panel or other power supply and have the arduino charge up it's own batteries which it runs from. There are billions of charger circuits and powered circuits but next to none that charge their own batteries like every appliance you buy seems to do. How can you do what a mobile can do,  that is, charge the battery it runs on. I'm not asking you or anyone to design one, I'm just saying I would LOVE to see something like this, generally. An arduino with a little animation on it's LCD saying it is charging, or a solar powered one that can say how much power it has stored in it's own battery.

The other thing is I'd like newbies to know that non-rechargeable batteries can be recharged at a much lower rate for about 6 times the life (or 6 times less environmental mess).

Ahh, glad I got that off my chest. keep up the good work 8-)

[dr.diesel]

Batteriser damage control, ie, make up anything to still con people.   

[EEVblog]

There are billions of charger circuits and powered circuits but next to none that charge their own batteries like every appliance you buy seems to do. How can you do what a mobile can do,  that is, charge the battery it runs on.

Did I do something like that in the PSU design series videos?

[TheElectricChicken]

Did I do something like that in the PSU design series videos?

Thank you, I will find them and find out.

I have limited internet, and haven't looked over all your videos yet. I found your videos from the ones about Colin Mitchell. I built maybe 2 or 3 TEC-1's and a microcomp and many other items too. Great fun. Awesome interview too. I saw that alladins cave of desoldered parts, and wished I would set up a big harckerspace for everyone and find things like that. Ah, if only we had perfect health and 10 lifetimes.

keep up the good work !

[PeterL]

Nice BUT! (Baboon Under Test)

I can't wait to see Batteroo's reaction to this one. Besides the annoying fact that they are probably gonna earn money with all their nonsense, this hole story it's quite amusing.

[Artlav]

You said it exactly why no one will put their name under it - they will be laughed out of the industry!
You are all cowards who don't want to speak The Truth about the Great Battery Conspiracy, and instead you wave your stupid physics and ohm's law to obscure the truth.
[sarcasm off]

Seriously, that batteriser video is quite funny when watched as if it was a parody.
Dead-pan humour have it's charm...

I'd love to see this whole batteriser thing turn out to be one big PSA on "how gullible you people are".
That would have a tremendous education value...
We can dream, right?

[PeterL]

Did you mean whole story or was that a clever pun. 

Hmmm, I have to be honest, this mistake was caused by the fact that English is a foreign language for me...
But I see it now 

[nitro2k01]

Too much waffling in this video in my opinion. Not speaking on my own behalf, but regarding people who watched Batteriser's video and then found yours. They might just give up. You should have condensed it to 10 minutes tops.

[sakujo7]

Why didn't they show the batteriser making the monkey work again with those two batteries?

[EEVblog]

Too much waffling in this video in my opinion. Not speaking on my own behalf, but regarding people who watched Batteriser's video and then found yours. They might just give up. You should have condensed it to 10 minutes tops.

Yeah I know. I wanted it to be mostly tutorial, and the Batteriser ranting got a bit carried away in the end.
I couldn't have been bothered to go back and redo it to make it shorter though, so it is what it is.
Same can be said about my original debunking video, but it's a process thing, and I wanted to show the thought process. Same thing here. I hope it's valuable as a general tutorial video, and that was the real intent.

[dr.diesel]

Why didn't they show the batteriser making the monkey work again with those two batteries?

LMAO good point, there was still a couple hundred % more claps left unused, batteriser to the rescue.

[vlad777]

So they just clarified their claim about that 1.3 volts; they mean under no load.
(What good is that for their device ,I don't know.)

[TheElectricChicken]

I can see the laboratory power supply tutorials, I don't think I explain very well. Here is a drawing of what I mean.

[Psi]

I think what they were trying to say was that, if you have a device with large peak currents, eg motors, they will lock up as soon as the battery cant handle the current peak any more.

The powersupply will supply the peak current without a problem and power the device down to a low voltage. Whereas the battery will keep dipping past cutoff voltage as the peak current hits.

Like if you had a device that tried to pull 10A from some AA's for 0.2S every second. It might stop working as soon as the batteries fresh-state ESR had disappeared with 90% capacity left in the battery.

Which is of course true. But is a moot point because any attempt to boost the battery voltage in this situation will make the problem worse by trying to draw even higher peak current. 

The only thing that would extend the battery life in this situation is a capacitor/supercap to buffer the peak currents. They would be better off selling that to clip across a cell. No issues of quiescent current to deal with.

That's the battery failure mode i see often in my logitech harmony remote control. When the batteries are getting down you only get a few repeated button presses before the mcu reboots from the IR tx led current burst.

[EEVblog]

So they just clarified their claim about that 1.3 volts; they mean under no load.

Yes. Several time now since I released my video they have finally admitted that their 1.3V claim is masured with the battery open circuit. Their entire product is based around this incorrect method. They explain it away as misunderstanding:
From http://batteriser.com/faq/

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.

and from here:
http://startupdope.com/the-batteriser-hype/

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.

[Jay_Diddy_B]

Where can you buy a 'Clapping Monkey'? My Agilent Electronic Load is out of calibration, and I am looking for a replacement. I would need a 0.1% monkey. Do they come with calibration certificates?

I suppose the high end monkeys can hold the probes for you.


A battery that measures 1.27V unloaded on a DMM is dead.


They missed an opportunity to take the very same batteries and power the 'Standard Monkey' using the Batteriser.


Showing the 'Standard Monkey' doesn't work with dead batteries, doesn't show that there is any energy left in the batteries.

 

Jay_Diddy_B

[vlad777]

I can see the laboratory power supply tutorials, I don't think I explain very well. Here is a drawing of what I mean.

I'm guessing that when you plug the charger ,device switches to working off the charger plus it charges the batteries.

Edit: Try searching for simple UPS (uninterrupted power supplies) circuits.
         Try Google images "ups schematic"... and find simple ones...

[amyk]

I liked the play-by-play commentary on the Batteriser video in the second part - it really makes things obvious, especially when you point out how they didn't measure the voltage under load of those batteries.

Did anyone else find the announcer's voice in the Batteriser video really annoying to listen to?

[Muttley Snickers]

Ironically some handy reference material to be found if you are prepared to probe a bit deeper.

www.szkingkong.com

[EEVblog]

They missed an opportunity to take the very same batteries and power the 'Standard Monkey' using the Batteriser.

Probably because it doesn't work. The Batetrieser would have to draw the equivalent in power (+ conversion) in extra current, so it's even worse for the already near dead high ESR battery.

[daqq]

How dare you argue with results gathered using the Industry Standard Monkey!?

(Great video Dave, keep em coming!)

[EMC]

Nice one; however, no mention of the financial backgroud.  Also, no discussion of the stainless steel sleeve.  Probably for good reason.   Why isn't this sort of scam treated as a criminal activity.

[AF6LJ]

This whole subject is entertaining, the Batteriser is an example of a product that seeks to take advantage of the general public's lack of knowledge when it comes to basic science. With that said; it is a time honored tradition to take advantage of the public's ignorance when hawking a new product. An informed public, is an empowered public.

[mcinque]

This kind of video are really fun and hilarious. I really like all of them. I really like your palmfaces and your determination.
Very, very nice are the pauses on the original Batteriser video with your comments; If I were that guy, I would run to hide me. I think that persons like those of Batteriser, deserve this kind of reply videos.
p.s. At the first time, in their original video, I didn't see the "unused" soldering iron on the bench, it's obvious that it's all scripted