Hi In a recent video, I demonstrated measuring the battery cutoff voltage in various electronic products I think I did like 10 different products and got an average value of about one volt or just over 1 volt something like that per cell for a typical modern electronics product and everyone knows. Yeah, that's pretty much how products are designed these days to have a battery cutoff voltage around about that one volt figure. And as I've done in previous videos as well, the usable energy in the battery drops off in about naught point eight volts. So if you want to maximize the battery life in your batteries, should design your product to work down to no point eight volts per cell.

But somebody put out a video claiming that I did it completely wrong, that it wasn't valid, and that you can't measure the cutoff voltage of a product with a power supply as I did it. And that's completely puzzling because not only is using an external power supply the correct way to do it, it's pretty much the only practical way to do it unless you want to actually sit there and watch the battery discharge itself. So for the very few people who actually don't get it and think that using a power supply is the incorrect method, let's go through it and see why it is the correct method. Here's how you measure the battery cutoff voltage of your product.

So let's take a typical product: a symbol clapping monkey Please excuse the crudity of the moment. Didn't have time to build at the scale or to paint it. Now a typical product like this, when you shove the batteries in here, it does what monkeys do and then it finally gets to a point where the product doesn't work anymore. Now this could be it just stops clapping.

or it could be an active modern product that actually monitors the battery voltage and tells you when it's finished. Just like this wireless microphone I'm using right now to record this. It's got a low battery LED on here and once that kicks in, well you stop using the product. Otherwise the functionality is not guaranteed.

So we're going to call that point the battery cutoff voltage. and as I showed in a previous video from Modern electronic active electronic product might be typically 1 volt per cell. and if it you use multiple cells, multiple batteries in your product, then well this is Purcell voltage and let's take it as 1 volt. So you might have some an active cutout detection circuit, a comparator for example in a voltage reference inside your product that when your battery voltage gets down to that one volt here, then it turns on your low battery, detect lead or shuts down the product.

Or do you know, stops functionality does, whatever. So how do you test this product? Whether or not you designed it yourself, or whether or not you've actually bought the product and you want to measure where it actually stops functioning at what battery voltage? How do you do that? Well, there's actually only two ways to do it. One is to stick the battery in of course, and then go in there and shove some probes up there and try and actually measure that itself. or run some wires out and measure it.

Well, you can have the battery external and you just run some wires in like that, and then you measure your voltage your battery terminal voltage right at that point there, because you want to eliminate any drop in the resistance in your leads like that. and well, you can sit there and wait for that voltage to discharge, discharge, and discharge until it gets to the point where your low battery detection LED comes on. All the product stops working and well, that can take a long time, and that's why hardly anyone does it that way. That's why you use an external power supply.

So instead of hooking your battery up like that, you do exactly the same thing. You just hook it up to your power supply like that. And once again, ideally, you should measure the battery voltage right at the battery terminal there, rather than relying on the voltage measured on your power supply because there might be a small amount of resistance in there, maybe a tiny amount of contact resistance, But for a lowish power product, that really doesn't matter. You can actually rely on the voltage reading of your power supply.

So then you just drop the power supply voltage slowly until your low battery detect LED turns on or your product stops working and then you can read off Eva from your power supply. Or if you're doing it because it's a high draw product from a meter connected directly as close as possible to the battery terminals there. Bingo! you can read off the cut off voltage. It's that simple.

But like I said, somebody named Li batteries I have put out a video saying that this is an incorrect method of measuring the cutoff voltage of a product. We have been asked questions about the validity of measuring the cutoff voltage of battery operated devices with a power supply. Claiming that using a power supply to measure the cutoff voltage of a product is wrong and misleading at best. To use a power supply to show a battery operated devices cutoff voltage ignoring the battery's internal resistance is wrong and misleading at best.

Unbelievable. I will show you why that statement is demonstrably untrue. and using a power supply is the industry standard method for measuring the cutoff voltage of a battery and why it is equivalent to using the battery itself. Now, they claim that the reason it doesn't work and you can't use a power supply is that batteries are inherently different to power supplies.

And yes, that is completely true. As I've explained in previous videos, a power supply effectively has zero internal resistance. It is designed to deliver large amounts of current over a large operational voltage range, so you can approximate any internal resistance to effectively zero. But that's not the same for batteries.

Take a regular double-a or triple-a battery, for example. It's also got an internal resistance just like a power supply has a tiny little bit you know, like milli ohms or something like that internal resistance. Well, a battery actually has quite a large internal resistance. It's also called the ESR the equivalent series resistance, but we'll use the term IR for our internal resistance of the battery.

So it's like having a little series resistor inside physically inside your battery like this before it gets to the external contact like this, and the internal resistance for a double. our triple-a battery is around about a hundred to three hundred million millionths when it's fresh, 300 odd milliohms. Once it's gets to its end of its discharge, curve down here. And here's a graph from Giarrusso showing how that internal resistance changes with the battery discharge curve like this.

and I'll just make mention of that. The internal resistance: the ESR of a battery is comprised of two different things. now. I Have done a video on this which I'll link in.

Down below, it is the combination of the electrical contact resistance that's you know, the little worlds inside, and all that sort of stuff, which is particularly relevant to a multi cell battery like a 9-volt battery. for example, that'll have six for a cell's inside it. There's all that extra contact resistance, and that's why the internal resistance of a 9-volt battery is higher than a double-a or single double A or triple a cell. But it also, and most importantly, is also comprised of the what's called the ionic resistance.

Now, this is a complex subject. It's the electrochemistry of the cell itself now. I Have actually done a video quite some time back looking at the ionic resistance of a battery, so click here if you want to see that one. So to keep this video simple, we won't get into the complex details of how the electrochemistry inside our battery works.

Suffice to say that you can actually simplify it to an equivalent series resistance and internal resistance value. and that's a common thing to do in the industry. You don't necessarily have to know how the chemistry works inside to know that the internal resistance of a battery causes a problem. So okay, the internal resistance of a battery is much higher than a power supply.

We're talking several orders of magnitude higher. So wouldn't that make a difference when you're measuring measuring the battery cutoff voltage? Well, no, it's not. And here's why. it's a very simple and obvious thing.

Now, let's assume that the lead resistance in here is negligible for both cases. Okay, for the power supply and the internal resistance of the battery, this has 300 million internal resistance. Say, this one has effectively zero. So why doesn't it matter that this is 300 millions and this is zero.

It's because we can't measure that point and we can't measure that point in there of the cell where we can which I'll explain in a minute. But for the purposes of running the product, you can't That's why I said you have to actually measure directly on the battery terminals of the product. And when you do that when you measure on the battery terminals, that by definition okay is the battery cutoff voltage of the product. Because you can't measure this value in here, it only matters what the value is in there because the internal circuitry you've got for your product actually has a voltage reference in there.

and that's what's determining what shuts off your products. So it's the battery. It's the voltage on the battery terminals here. It's got nothing to do with this internal resistance.

It's a complete red herring. And the other reason why this internal resistance here doesn't matter for the cutoff voltage is because look at the data sheets for any battery at all. Every single data sheet for every battery ever produced shows a characteristic discharge curve that is under load ie. the voltage on the terminal of the battery.

After the internal resistance, they cannot give you a characteristic curve of effectively before then internal resistor. It doesn't exist. This internal resistance is all part of the electrochemistry inside the cell like this. so it's meaningless to talk about the voltage of a battery when it's not loaded.

So I Showing here on this discharge characteristic curve here. the battery voltage when it's fresh for a single alkaline cell, might start at say one point six volts open circuit voltage. And that's why the I've got two curves here. The blue one is the loaded terminal voltage ie.

the exact curve that you'd get in the datasheet for a given constant power drain, constant current drain, constant resistance, drain, or whatever it is. And then I've got a green curve in here, which is the unloaded terminal voltage, which is the curve you would get if you had to pull out your battery each time from your product, measure it with a multimeter, which is effectively an open load. There's no load on it and measure the unloaded voltage, then put it back in your product, and then a minute later, take it back out and measure the battery voltage again. Unloaded.

Okay, so you can actually get two characteristic curves like that. So the green one, of course, is going to have a higher voltage, because when you put a load on a battery like this, this internal resistance, of course Ohm's law. It's going to drop some voltage, and that voltage is going to be the differential between those two curves there. So this is why it's fundamentally and demonstrably wrong to measure the open circuit unloaded voltage of a battery when you're talking about discharge curves.

battery cutoff voltage is and everything else. because it's meaningless because you're not loading down the product and you're actually not taking into account that internal resistance. it. It's so fundamentally wrong.

Nobody in the industry does it like that. you can't. It's wrong. And as I said, and I'll repeat.

This is why the manufacturers only publish loaded voltage curves, because all you can get is this terminal voltage here. and when you design a product, all that matters. All that matters is the voltage on those terminals. And this is why it's fundamentally correct to use a power supply to measure the cutoff voltage of a product.

Because you're effectively you've got zero ohms in there. Okay, you're putting that voltage. You're forcing the voltage right onto the terminals there. You've got no internal resistance whatsoever.

So you're actually measuring the true cutoff voltage of the product by doing that. And like I said, if you really want to, yes, you can use the real battery and you can hook it up to the product and you can sit there, twiddle your thumbs and wait. and wait. and wait days, months, a year, or whatever until it happens to get down to the cutoff voltage of your product.

But nobody's got time to do that. So you just hook up a power supply. It is fundamentally the correct way to do it. So if you remove your battery from the product after you've used it, and then measure the terminal voltage with you of multimeter which is an open circuit, then what you're measuring is this green characteristic curve.

Here, Effectively, you're measuring it by not taking into account the Sr20 products actually being powered. What is the point of that? It it's It's just completely silly and we fundamentally wrong. All that matters is the battery voltage there on the terminals when it's under load. Of course, that's the only thing that matters because that's what you're testing.

You're testing the product during its operation. So if you take the battery out and your battery voltage recovers because there's no current flowing through your battery like that to give an internal drop that is not an accurate measurement. This is fundamental stuff. This is hobby level stuff.

I Learned this when I was like seven years old. It's not hard to measure The battery voltage. not under load is demonstrably wrong. You cannot argue it.

You cannot argue it. To do so is just to make a complete fool yourself. So by saying that batteries are different to power supplies. Yes, they are.

But that is a completely pointless statement when you're talking about battery cutoff forage. Because as I said, all that matters is the terminal voltage here. So yes, they're different. So using the power supply to measure the cutoff voltage is actually taking into account the internal resistance of this battery.

Unlike the claim that they're made, that it's not taking into account the internal resistance it is, it fundamentally is I Don't know how much simpler I can explain it, it's just. ah. So let's actually go and take a look at this better Iser response video because it is actually a direct response to my debunking video and also my better Iser explained blog article down here. So let's have a look.

They've actually confusingly made two different videos here with this clapping monkey thing trying to prove that by using a power supply to measure the cutoff voltage is incorrect. But really, there doesn't seem to be any major difference between the two except of the ND and why they've called this one a conclusion here. So we're going to take a look at it curiously. it is on not at the battery's YouTube channel, but the batteries are battery channel which they actually claim if you go to the About tab.

disclaimer: we are not in any way affiliated with Better or Battery. We are simply a fanpage. Yet it has all their official videos and everything else and they also talking the first person that their thanks to all our supporters. blah blah blah I Don't get it.

And by the way, if you're after some laughs, go and look at these supposed fan submitted videos. These professionally produced fan submitted videos here which extol the virtues of the better. Iser Oh goodness there's even Nature Man down here Crikey because they do make very specific claims on this video that the batter Iser has come under skepticism due to a flawed test I Eat my test in which a power supply was used to debunk the battery so there is no other video out there. so there.

Obviously this is a response to my video. So I'm happily making this response video to their video. and by the way, I tried to comment on their most recent video, but they deleted my comment. Yeah, but I'm more than happy to have them come onto my videos and and discuss it all they want.

Leave all the comments they like I don't delete comments I don't delete comments on the forum or my blog site. so they welcome to come in and discuss it anytime they like. and in this Yahoo Makers article, they interviewed better Iser and Mr.. Ruppert This is what he had to say about me discussing the Eevblog video.

He says: I think he's a good guy. Thank you. You're a good guy too. I Just think he didn't know enough.

Really? I don't know enough. like I Just showed that using a power supply is the correct industry standard method for measuring battery cutoff voltage and you're claiming it's not. You're basically the only one on the planet who claims it's not and I don't know what I'm talking about? Okay, well at least I know enough not to. Why go around claiming that there's 1.5 volts of energy and that many devices stop functioning around the 1.3 volt mark.

goodness? And then when everyone including myself had to try and tell you that no, the cut out voltage of a product is about one point, one volts under load finally came out on your website and here it is I screen captured it. You admitted that the secret is that most 1.5 volt batteries drained to about one point one volts under load. Thank you for agreeing with me, but then of course you went and remove that and changed it and removed any reference to that one point One volts. but thankfully it's still in your frequently asked questions down in here.

At least you left it in at admitted that products do actually cut out at one point one volts. I'm glad I was right about that in my video. So let's look at their final conclusion again. To use a power supply to show a battery operated devices cut off voltage.

ignoring the batteries internal resistance is wrong and misleading. at best. batteries behave different from power supplies. Well, I Just spent the last fifteen minutes explaining that yes, batteries do behave different from power supplies.

But what's your point? You're not stating anything of value there whatsoever. It's basically just one big straw man argument to set up the idea that yes, you're technically right, batteries are different from power supplies. And then somehow that proves and debunks my entire debunking video because I got it wrong. But you never once in the video as we'll see, do you actually explain how to measure the cutoff voltage.

So let's go and have a look at the rest of the video and see how you sort of try and justify this old won't show the whole thing I'll just cut it out various parts that aren't actually relevant. Power supplies can source a huge amount of current while maintaining constant output voltage. Batteries on the other hand, are not capable of maintaining the constant voltage when it is connecting to a device that draws current due to the internal resistance of the battery. Its terminal voltage will drop when connecting to a device.

Oh yeah, of course that's why I explained in the video that all that matters is measuring measuring the actual terminal voltage, battery terminal voltage of the product under test while its operating ie. under load. This is precisely the my battery manufacturers published discharge curves under load because that's the only measurement that matters and it takes into account the internal resistance. Oh, so you're interested in this monkey.

First of all, who is this guy? It says on the YouTube video that is a professor of Electrical Engineering Okay, I'm sure he is, but hey I Can't believe he's saying this first. I Gotta set it to 3 volts because each battery is one and a half volts now. I Don't know about you, but take a look at this soldering iron here this well a solder and I it looks like it's never been used and who the hell just leaves the thing lying on a bench like that? And where is the solder? if I didn't know any better. I'd say that they just set up his bench as a just a promo video shot and I just couldn't help but notice the oscilloscope.

Look at the square wave they've got there and you can see that all they're doing is measuring the compensation on the front of the scope and it's probably the worst compensation I've ever seen. They don't even know how to compensate the probe. Hilarious. sorry had to point it out so we got the power supply set at 3 volts.

Now we can see how he behaves at the same voltages. Two fresh batteries. Oh yeah, Nope. I'm sorry.

it's not the same as the voltage of the two fresh batteries because it's not taking into account the internal resistance of the battery which will cause a drop. It's unbelievable. You make the claim that I'm wrong cuz I'm not taking into account the internal resistance of the battery. You're the one who's not taking into account the internal resistance of the battery.

Oh so now let's turn it down to two and a half volts, still move in and make it a lot of noise, and again still making a lot of noise at two volts. Down at one and a half volts and starting to slow down a little bit and slowly going down on the voltage and he's stopped moving at point Nine volts. This demonstration shows that with a power supply, the monkey will operate even when we bring the voltage down all the way to zero point. Nine volts.

Wow, that's pretty awesome isn't it? I Love! This monkey can work down to 0.45 volts per cell. Incredible awesome. However, when using two batteries with a total voltage of 2.5 volts, the monkey will not operate. We check the voltages of to used batteries.

The first battery voltage measured at one point, Two, Three, One volts, What are you doing? You do not measure the battery voltage when it's not under load. It does not tell you you're not taking into account the internal resistance. As I said, this is hobby level stuff. This is Battery 101 stuff.

For a professor to not know that you can't do this is just. oh. it's incredible. These are used batteries.

You don't know how much energy is left in that battery, how much the internal resistance is going to affect the monkey under test. We measured the second battery at one point. Two, Six, Seven volts. This monkey uses two batteries in series so you have to add the voltages together resulting in 2.5 volts being supplied to the monkey.

2.5 volts is not being supplied to the monkey because when you turn the monkey on it is a load. It loads down the voltage voltage. You get a drop on the internal resistance. unless you measure the voltage on the terminals of the battery probe right up the monkeys ass.

you are not measuring anything. This is just so fundamentally wrong. It's - Wow Look, you even say this on your own website. Here's your frequently asked questions.

We had: quote: Wikipedia Look when the source delivers current, the measured voltage output is lower lower than the no load voltage which is what you just measured. You measured the no load voltage and you're saying that to point that no load voltage is being delivered to the monkey. Unbelievable how you can possibly say this in the video when your own frequently asked questions where you try and explain. this says completely the opposite thing where the internal resistance of the battery as I've just spent 15 minutes explaining will actually cause a drop and you won't get it As you claim that 2.5 volts it's going to be much much lower causing the monkey potentially not to operate at all as we'll see in a second and then flip it to on and you saw it.

tried to go play stalked So we'll see if a if it can go. you know, second time just give it another shot. Yeah it it tries but it can't. It can't go.

Well, that's not the least bit surprising. This is a high drain device, this clapping monkey and obviously the internal resistance of those batteries. because you're using already, you know, half dead or 3/4 dead batteries or whatever that it does not have the capability to power the monkey because there's too much loss in the internal resistance. And this is completely obvious.

The entire premise of your video has been to show that there is a difference between a power supply and a battery as I explained right at the start of my video. Of course there is, but this does not explain why at all. There is nothing in this video to explain why using the power supply is the incorrect method for determining battery cutout voltage, which is all that matters. You haven't even done the fundamental first principle thing of measuring the battery voltage, putting the probes in there when the batteries are in there.

This is an unbelievable begin a mistake. It's so embarrassing. If you did this at a job interview, you'd be booted right out. If you did this in made this mistake in an exam, you'd fail.

If you made this mistake in a job, you'd be booted out or looked at very strangelets as I said, this is hobby level understanding to measure the battery voltage under load. It's absolutely incredible. This is one of the greatest strongman arguments I've ever seen. It is just face palming li dum.

It really is. But if you didn't know any better, you'd take this video. No, yeah, that sounds okay, but it's just fundamentally wrong. just take a look at this energize a double-a battery sheet.

It shows the industry standard test for different types of products: toothbrushes, portable lighting, and toy. In this case, you know this clapping monkey. Yeah, it might get eight or ten hours life or something like that. So look at that discharge curve of that toy.

This is under load. Like a high discharge current. Every time it it bangs those cymbals together, It's just gonna die because of the internal resistance of the battery. It can't recover.

There's no more, not enough useful energy left to actually provide enough voltage to operate the device given the required current draw. And if you actually did this test properly and actually measured the battery terminal voltage inside the monkey when it was operating, you would see it actually dropped below that that point four, five volts or would in Purcell or whatever it was that you measured with the power supply. That's how this testing works. That's how I Spent fifteen minutes explaining it to you.

but you didn't do the right test. You didn't probe it or you did a shove the batteries in there. Mmm. So it doesn't work.

Of course it doesn't work because it's a pulse load. Look at the thing for the toy here. It's designed be one hour per day. You put in those used batteries in the toy and start to deliver a pulse load.

The electrochemistry inside the ionic resistance cannot deliver a low enough resistance in order to clap those cymbals. Battery 101 stuff. And of course, you would expect the monkey to work with the power supply because it's got no internal resistance. It's an ideal battery, so it's gonna deliver as much current as needed, as much pulse current as needed.

There's no ionic resistance in there. Of course, batteries are different is stating the bleeding obvious in this video and then trying to claim that the whole method using a power supply is wrong. Clearly, do not fundamentally understand the concept of measuring this. Unbelievable.

There's not a single credible engineer in the industry who will agree with this video. Not a single one. Go find me one. Please prove me wrong.

So that's it. I've had enough I Don't know what more to say about this laughable Strawman video. It is. It's got to be a parody.

Surely the the joke's on all of us. it. This cannot be serious. I Don't know how anyone could put their name forward and actually say this sort of stuff.

If I said this I'd be laughed out of the industry. Anyway, leave your comments down below. I'll link to the forum down below where you can discuss this thing. and as I said, better eyes are more than welcome to come in here and discuss it and try and prove I'm wrong.

I'm happy to always be corrected I Won't delete your comments unlike what you did to me. So I didn't really want to do this video. It had enough of The Better Riser and their silly claims, but I just couldn't let it stand. They were presenting fundamentally wrong and misleading information exactly the claim they made about my video.

but in this case it's demonstrably true that they are incorrect here. and being deceptive, it's fundamentally wrong. There's no way anyone can stand behind this either. They should be totally embarrassed if I did this.

I'd be I wouldn't be able to make another video again I'd be laughed out of the industry. Unbelievable. Anyway, this is my response: I Hope you enjoyed it, hope you found it interesting and educational. Catch you next time you.

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