Have You Ever Experienced the 'Lighter' Feeling of Spent Batteries?

[Mu naught]

I'm 99% sure this is a purely psychological effect, but I find it very interesting. I can't think of any way a battery could actually lose a noticeable amount of mass from being discharged, but to me when I go to replace a pair of spent batteries, they always feel substantially lighter than fresh ones.

I'm just curious if other people have noticed or experienced this effect.

 

[Borek]

They are lighter, but I doubt there exist balance precise enough to measure the difference. It won't be hard to evaluate mass change using E=mc² and battery voltage/capacity.

 

[pallidin]

...when I go to replace a pair of spent batteries, they always feel substantially lighter than fresh ones.

The only time I've "felt" that is when, say, I replaced a drained "no-name" brand with, say fresh Duracell. The only true reason for that difference is that Duracell is a heavier battery.
So, perhaps your phenomenon is more related to manufacturer differences.

 

[Frame Dragger]

The only reason I can think of for a battery to FEEL lighter would be a leak of the acid, and I think you'd notice that.

 

[Borek]

As far as I can tell there is no acid in replaceable batteries. Ammonium chloride (or zinc chloride) paste is slightly acidic, but calling it an acid is an exaggeration. Leaks from alkaline batteries are definitely caustic.

 

[Ivan Seeking]

Surely someone here has access to an old and new battery of the same make and type, and a scale or balance.

 

[pallidin]

Look, it's really simple.

New batteries are often "name" brands, whereas existing(in device) batteries are often the cheapest around. Those cheap batteries often have a lower weight. AKA cheap.

Since one does not often check(or hand weigh) the batteries of a working device until it goes down, when one replaces the batteries, the replacement batteries are usually more heavy due to manufacturer differences.

This is likely the reason for the confusion.

 

[Ivan Seeking]

No need for speculation when we can make a simple measurement.

 

[pallidin]

No need for speculation when we can make a simple measurement.

I do not think that any common scales could differentiate the electron weight loss, much less a human hand.

 

[Evo]

It's the loss of phlogiston.

I'm going to get banned now, aren't I?

 

[Ivan Seeking]

I do not think that any common scales could differentiate the electron weight loss, much less a human hand.

I don't either. So confirm the conjecture that nothing else happens that could cause a loss in mass. "We can't think of a reason why this would happen", is hardly a proof.

 

[Borek]

I do not think that any common scales could differentiate the electron weight loss, much less a human hand.

Electrons are not lost, whatever charge exits on one side enters back on the other.

 

[Borek]

It's the loss of phlogiston.

I'm going to get banned now, aren't I?

Yes. There is no phlogiston in batteries. I think the correct term is electriston.

 

[Ivan Seeking]

Electrons are not lost, whatever charge exits on one side enters back on the other.

Yes, I meant to add that it is a change in the binding energies.

 

[Ivan Seeking]

For example, is the paper used to wrap the batteries treated with something that could sublimate or slowly evaporate?

Before you look, if you don't already know, then any conclusions were premature.

 

[Frame Dragger]

Ok, replace "acid" with "electrolyte" and we have the same result. My point is that if you've ever picked up an old battery that has rusted through, whatever is coming out and burning your hand (and it DOES burn, caustic perhaps?) could "leak" or sublimate. However, that battery MUST be compromised! Think about it, if the **** in batteries could sublimate out, that would have included mercury for a very long time (and still in some cases), which as we all know, is no good to health.

Note, the OP did not say, "are spent batteries actually lighter" or, "why do my Acme brand AA weigh less than my Sony AA's" it is, "Spent batteries FEEL lighter?". The answer is NO! I think we can all agree that the human hand could never tell the difference.

I should ask as well, why is a cheap battery a lighter battery? It seems to me that using cheaper materials might make it heavier, as is the case with many batteries.

 

[pallidin]

Electrons are not lost, whatever charge exits on one side enters back on the other.

Through a load? Perpetual motion? Nice!

 

[Frame Dragger]

Through a load? Perpetual motion? Nice!

...And here I thought that the little bobbing birds were the only way to power my flux capacitor!

 

[Anticitizen]

This is a situation that could be very easily verified or nullified by experiment. Equipment: A handful of batteries of various manufacture, an accurate scale on which to weigh them, and a flashlight or something with which to deplete aforementioned batteries. Measure, deplete, measure.

Get on it, scientists.

 

[pallidin]

This is a situation that could be very easily verified or nullified by experiment. Equipment: A handful of batteries of various manufacture, an accurate scale on which to weigh them, and a flashlight or something with which to deplete aforementioned batteries. Measure, deplete, measure.

Get on it, scientists.

Electron depletion weight of a battery is too small to measure.

 

[Borek]

Through a load? Perpetual motion? Nice!

Think about it. Assuming your approach - that electrons are lost - is correct, after the battery have been used it will be charged, and we are talking about charges in the range of kC for the 1000 mAh AA sized battery. Calculate force with which two kC charges in two AA batteries placed side by side repel themselves. In your world grenade is safer than your TV pilot.

And there is no perpetual motion. Battery works as a pump - it pumps electrons through the load, pushing them from negative end and sucking through the positive end. Once internal energy of the battery is spent, it stops pumping.

 

[Dadface]

It was one of Einsteins favourite illustrations to state that an object when hot is more massive than the same object when cold.Paraphrasing this we could state that a battery when charged is more massive than the same battery when discharged.When the battery discharges there is no loss of electrons,there is a loss of energy.The resultant mass change can be calculated from E=Mc squared and is far too small to be detected by weighing techniques.

 

[Borek]

Electron depletion weight of a battery is too small to measure.

Mainly because it doesn't exist.

On the other hand... assuming it exists. 1000 mAh battery gives 1 A current for 1 hour. Thats 3600 C, or 3600×6.241×10¹⁸ electrons. At 9.109×10^-31 kg that means something like 2×10^-8 kg, or 20 μg. XP56 balance, made by Mettler Toledo, has readability of 1 μg and can be used to weight objects up to 52 g (AA battery weights around 23 g).

Looks like the effect could be easily measured (if it existed).

--

 

[Matterwave]

You see, when a battery is being drained, it's inflaton field interacts with the electromagnetic field created by the moving charges, essentially "reheating" the battery operated object while draining the battery of its mass. Although the inflaton field is extremely tiny in our current universe, the field interactions, through positive feedback processes, amplify the effects exponentially (e-folding # N is on the order of 4242). Add to this effect, the quantum fluctuations found within the vacuum energy if space, and you have a net effect which can decrease the mass of the battery.

Now, I know you must be wondering: "These amplification effects would eventually rip even the tightly bound atoms of the batteries apart!" The solution to this paradox is that the atomic bonds of the battery are borrowing energy from the so-called "attractor" which is bringing our M-brane closer to another M-brane in the 5th dimension. If this "attractor" potential were not present to bind our batteries together, the very fabric of the space-time continuum may rupture leading to the creation of micro-black holes (or possibly other exotic phenomena!). In fact, the observation that batteries don't explode spontaneously is one of the chief observational confirmations of the Steinhardt–Turok model of the Universe.

 

[Borek]

Apart from standard tricks - like reading first letters, every second word and so on - I even tried to read a mirror reflection of what you wrote. To no avail. I don't understand a word. I was not aware AA batteries are that complicated.

 

[Mu naught]

Hi guys, I just wanted to clear up any confusion. I'm not claiming here that batteries actually lose any mass when they are discharged - only that I have noticed that a pair of "empty" batteries - which I know to be spent - tend to feel lighter.

I actually think the cheap brand vs name brand idea someone mentioned is probably the largest factor, at least for leaving the impression that a spent battery "should" feel lighter, if you are accustomed to replacing cheap no name brands with name brands. I was mainly interested in the possible psychological affects at work, not how the batteries could physically lose mass (which as I said I'm 99% sure they can not).

 

[Borek]

Assuming 1000 mAh battery, working at 1.2V, I got 4.8x10^-14 kg.

 

[Dadface]

Assuming 1000 mAh battery, working at 1.2V, I got 4.8x10^-14 kg.

I get the same answer

 

[Topher925]

Alkaline cells are not sealed, they contain vents. This is to prevent the battery from exploding when heated or what ever else. If the battery is discharged deeply enough, pressure will build inside the cell and the vents will open allowing the gas to escape. This is the ONLY way that an alkaline battery can have a reduced mass under normal operating conditions.

Chemistries such as lithium polymer are completely sealed have the same mass no matter where they are in their life cycle. If there is a build up of gas inside the cell it just simply "puffs" like a blowfish.

 

[Borek]

This is the ONLY way that an alkaline battery can have a reduced mass under normal operating conditions.

Apart from Einsteinians 4.8x10^-14 kg.

 

[Ralph Spencer]

https://www.physicsforums.com/showthread.php?t=397828 < My own research in the past.

 

[pallidin]

Hey Ralph, that was an interesting read. Thanks.