"8x Extension" Claimed for Alkaline batteries

[jkraai]

http://www.pcworld.com/article/2928997/batteriser-is-a-250-gadget-that-extends-disposable-battery-life-by-800-percent.html

the concept isn't earth-shattering, but it is a reusable way to get a lot more of the potential chemical energy out of regular alkaline batteries

guessing a big battery mfg will soon be marketing a quadruple-life battery at triple regular price

[beernutz]

That is awesome!  Wonder if the same principles apply to other battery chemistry.

Hope it pans out.

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[jim kraai]

yes.  the article talks about using it on 1.2v Li cells, also, and it put out 1.5V

it's basically just a voltage regulator, but in new packaging

[David Champion]

I am somewhat skeptical on this. I can see that it might extend the useful battery life some, but I think they are a bit ambitious on the 8x increase.

Maybe they're using a perpetual motion machine and a solar powered roadway?

-dc

[jim kraai]

the 8x is definitely stretching it, yes.  surprised The Right Reverend Ray hasn't chimed in on this yet, he must be distracted ;-)

ugly, flawed logic follows ...

if a battery is normally useless (having dropped below a voltage potential) after using 20% of its energy capacity, then it has 80% of the energy capacity remaining

of that 80%, about half will be used up by the voltage regulator circuitry, so that means that 40% remains, which is 2x the original 20%

so I would expect a (1x + 2x) 3x battery life extension

hence my line in the first email of this thread:

> guessing a big battery mfg will soon be marketing a quadruple-life battery at triple regular price

[Ray Scheufler]

I guess I will chime in since Jim called me out.

I agree with Dave, 8x seems like quite a stretch.  Unfortunately I have not played with alkaline cells to know how they handle discharges, but the internet comes to my rescue because someone else has already test this and I can reference his work [1].

There are a few different things to consider. 

First, what is the real cutoff voltage for your widget?  Most (complicated) widgets are running their battery input through some form of massaging circuitry and probably actually have a wide window that they can operate.  Most simple widgets (aka flashlights) will just keep running but get dimmer until they batteries really give up.  I think the 1.4V cutoff listed in the article is a little bit high.  Looking at the actual discharge curves if your device threshold 1.3V then there is still half of the chemical energy left in the battery.  This chemistry appears to hold its voltage pretty well until it knees just under 1V and then it tanks.

Second, what is the effiecency?  A decent switch mode converter can get around 90% effiecency. At lower voltage the switch mode converter has to work harder and pull more current to achieve the boost ratio.  This quickly becomes a vicious cycle because the more current you pull from a cell the more it drops which means that your boost ratio needs to increase which causes more current.  This will decrease the energy left in the cell by a bit.

I have a couple of major problems with this idea as a whole.

First, how much noise does this inject into the device?  This is a very tiny switch mode converter which means that the inductors and capacitors are very small and can't hold much energy so therefore can't prevent much ripple.  Normally batteries are considered a very stable voltage source so filtering may be reduced on battery powered devices.

Second, as a user I have no indication that my batteries are almost empty.  This boost conversion is done at the cell level so the device always thinks it has a full battery until the cell is totally dead and I have to replace them.  It means that I can't plan ahead to replace the batteries.  I either have to keep extra cells on hand or be willing to go without by device until I get new cells.

[1] http://www.powerstream.com/AA-tests.htm

Ray Scheufler

[jim kraai]

TL;DR:  so you're saying 3x is more likely than 8x

[Ray Scheufler]

Sure.

Ray Scheufler

[Nabil Hanke]

I have to struggle to recall when I last used AA cells. Wait no. Two weeks ago I replaced the junk harbor freight cells in my optical tachometer with new harbor freight ones. Mind you, it was probably more than a year of inactivity with the device. It is possible that a button has been pressed while stored. This machine appears to only activate while the button is pressed. But my point of questioning is to know what this fantastic 83x battery extender does for inactive life. Is it completely off when not supplying current to the outside world? 

And more importantly, will it fit over my iPhone so that I can stop wearing my foil hat?

Thank you,

Nabíl

[Justin Richeson]

AA cells?  EVERY. GORRAM. KID'S TOY.  Especially the noisy ones your want to take a sledgehammer to.

[Ray Scheufler]

Hey Dave, is that annoying noise maker thing powered by AA batteries?  Perhaps we could get 8x the annoyance from it.

Ray Scheufler

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[David Champion]

The Thingamagoop? That's not annoying, it's a lovely sound.

And it uses a 9-volt battery.

-dc

[Bailey Mader]

Justin needs a screwdriver and a pair of wire clippers, not a battery extender. 

"sorry, it must have broke...."

[Justin Richeson]

It's because I have a screwdriver, soldering iron, and many other tools, my son comes to me with something:
"Broken.  Fix It!"

[Patrick Mcgillan]

When gkids bring me their dead AA batteries, I give them fresh and use
their old ones in my wireless mouse. They usually last up to a month
after quit working in their fancy toys. Just my FWIW note.

Patrick

[jim kraai]

gonna guess gkids are either google kids or "the McG kids"  :-)

[Brooke Hedrick]

Or grand-kids.

Sent from my iPhone

[jim kraai]

that's entirely too reasonable

[Jeffrey Ollie]

Dave of EEVblog: it's baloney.

EEVblog #751 - How To Debunk A Product (The Batte…: https://youtu.be/4iEshd6izgk

EEVblog has a lot of great electronics info so check out his channel.

[David Champion]

There you have it. 100% of Daves polled find this full of some kind of ground pork sausage.

-dc

[beernutz]

Yeah, the sample size DOES seem a little small.  8)