Devices to store chemical energy and convert it to electrical energy.

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22
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4answers
3k views

Why do 'dead' batteries work again after exchanging the places of the batteries in an electronic device?

My camera, which is powered by two AA batteries in series, would not power on. I removed the batteries, exchanged their locations, and the device worked again - for another 15 minutes or so. The ...
18
votes
3answers
522 views

Why can't batteries be charged quickly?

Charging of laptops, cell phones take so much time. Why can't we make such batteries easily/commercially which are charged more quickly? What's the thing behind this limiting?
11
votes
1answer
3k views

Does the mass of a battery's change when charged/discharged?

... and if so, how much? Is it possible to detect it, or is it beyond any measurement? I'd say there are two possible scenarios (depending on the battery type) and both seem interesting: The battery ...
9
votes
5answers
19k views

What is the difference between a battery and a charged capacitor?

What is the difference between a battery and a charged capacitor? I can see lot of similarities between capacitor and battery. In both these charges are separated and When not connected in a circuit ...
8
votes
3answers
1k views

Why aren't betavoltaics and alphavoltaics batteries widely used?

Betavoltaic batteries are devices which creates electricity from beta radiation of a radioactive material. Alphavoltaics operate similarly, using alpha radiation. The concept was invented roughly 50 ...
7
votes
3answers
2k views

Path of an electron through an electric circuit

When a potential difference is applied across a conductor, and if an electron moves from the negative terminal of the battery and reaches the positive terminal, then I want to know if the electron ...
6
votes
3answers
944 views

What happens if I throw a battery into water?

Today I have by accident thrown a AAA battery into a bucket of water. I fished it out of the water immediately (within 20 seconds or so) and nothing notable had happened and the battery is still full ...
6
votes
1answer
231 views

Empty batteries magically resurrect after reinserting them

It happened to me quite often (most recently with my wireless keyboard) that a battery stopped to work and then, if I unplug it and then plug it back in it works again, not just for a couple of ...
5
votes
3answers
8k views

What happens when we connect a metal wire between the 2 poles of a battery?

As I remembered, at the 2 poles of a battery, positive or negative electric charges are gathered. So there'll be electric field existing within the battery. This filed is neutralized by the chemical ...
5
votes
2answers
5k views

What happens to a fully charged battery, when you continue to charge it?

If I leave my cell-phone charging the whole night, it will be fully charged after a while. What happens with the battery and the excess energy I add? Also, I noticed my charger emitting a different ...
5
votes
4answers
1k views

How electron movement produces current,instead of having a slow drift speed

Just need a clarification here, how the current is produced due to the movement of electrons, in an external circuit,having a very slow drift speed. Normally in a battery there is high potential ...
5
votes
3answers
1k views

What's the difference between Capacitors, Ultra-Capacitors and Batteries

Capacitors are known to hold and release energy very quickly, unlike the slower release that batteries exhibit. If one were to bunch many (1000's of) capacitors together could they function as a ...
5
votes
2answers
2k views

How can a circuit function with two negative battery terminals facing each other?

Here is a drawing of the circuit that is confusing me: I don't quite understand how batteries work in this diagram. If a battery has a negative and positive terminal, there must be a barrier ...
4
votes
3answers
9k views

Different batteries connected in parallel

If we have 2 batteries one of emf x and the other is of emf y and we connect them in series we get an effective emf of x+y. But what if we connect them in parallel, how to calculate the emf now?
4
votes
1answer
3k views

short circuit an alkaline battery

i'm not doing anything related to physics, but i'm just curious : What really happen when i short circuit an alkaline battery ? some article in the net shown that fire/explosion can be happened when ...
4
votes
2answers
952 views

How many grams of explosive are equivalent to the energy in a battery?

In the movie Terminator 3: Rise of the Machines, Arnie's fuel cells were twice shown to be extremely devastating when their stored energy was released. In real life, how many grams of, say, gunpowder ...
4
votes
3answers
185 views

Why do batteries work?

Consider diagram A. In diagram A a car is at the top of a cliff. Gravity is pulling it down, but it does't move since its on a flat surface. Even though it would be at a lower potential at point B, ...
3
votes
2answers
3k views

If we charge a capacitor can we discharge it into a battery?

I have read that we can charge a capacitor using a battery, but can the vice versa happen? My project needs to show a battery being charged through a fully charged capacitor.
3
votes
2answers
4k views

Why two connected 1.5 volt battery become 3 volt

Why two connected 1.5 volt battery become 3 volt? If one battery plus side is connect to minus side of another battery, there should be a current flow between them until no free charge move anymore, ...
3
votes
1answer
57 views

What maintains constant voltage in a battery?

I know there's lots of questions that address similar situations, (Batteries connected in Parallel, Batteries and fields?, Naive Question About Batteries, and the oft-viewed I don't understand ...
3
votes
1answer
232 views

Lifetime of battery

If I directly connect two terminals of 3V battery (negative to positive) using copper wire, would it lose all its charge faster compared to another 3V battery that is used to lighten a 1.5V bulb?
3
votes
2answers
179 views

Why batteries in serial don't discharge each other?

A question that I've asked myself for long time about why batteries in series work as they do. I'll try to explain: If you take two batteries, let's say A and B, and you put A's anode touching the ...
3
votes
2answers
870 views

Why is there no current flow when i connect two opposite terminals of two separate batteries

I don't understand this..maybe there is something wrong with my understanding of battery or electricity. I am learning about electricity more deeply this time. So please spare with me... So lets ...
3
votes
1answer
155 views

Does recharging a battery at a lower temperature lower its internal resistance?

Does temperature affect the internal resistance of batteries? And does charging a "frozen" battery allow it to charge faster than a warm or room temperature battery?
3
votes
2answers
118 views

Why do batteries become weaker

I was thinking about my phone (Sony Xperia Z2) and when I put it to charge and remove it, the phone says "Please remove the charger, to save battery life," which is very intuitive question for a ...
3
votes
2answers
75 views

How can a fruit be used as a battery cell?

Fresh fruits can be used as batteries for glowing bulbs, but how this is possible? I mean how can electric charges flow through fruits? Do they contain chemicals like cells?
2
votes
2answers
190 views

Mechanical work to required battery power

I have a very practical question where I've calculated the mechanical work needed by a simple mechanical system by solving the line integral $W = \int_C \ F \ dx$. However, since I have a black spot ...
2
votes
2answers
61 views

Why are large batteries described by their power?

Reading about renewable energy sources, I came across the idea to use huge batteries as a temporary storage to be able to deal with the fluctuations that e.g. solar panels might produce. The most ...
2
votes
5answers
22k views

Charging 12V 150Ah battery

I want to charge a 12V battery of 150Ah with a solar panel. The solar panel specs is 12V, 25 Watt. Can anyone please provide me how to calculate that how much time it will take to charge the battery? ...
2
votes
4answers
1k views

Do Alkaline batteries, $\mathrm{NiMH}$, rechargeable alkaline, Lithium $\mathrm{AA}$, all have similar MAX POWER?

So in physics, one smart teacher told me, $$ V = IR $$ or $$ I = \frac{V}{R} $$ but it is not always true, because $P = VI$ and each power supplying device (such as battery) has a "maximum power" it ...
2
votes
3answers
450 views

Why doesn't Lenz's law predict the behavior of a rod on springs in a magnetic field?

This comes from one of the free response questions from the AP Physics B 2014 exam. 5. (15 points) A conducting rod of mass $m$ and length $L$ hangs at rest from two identical conducting ...
2
votes
3answers
438 views

Can I charge a capacitor using 2 batteries?

1 capacitor, 2 separate batteries (Battery A and Battery B). Connect A+ to one side of the capacitor and B- to the other side of the capacitor. A and B are not connected, there is no closed circuit. ...
2
votes
1answer
92 views

Do batteries lose charge?

Say I have a charge of +q and -q on the positive and negative terminals of a battery. If I connect wires to each terminal, but don't connect the wires (essentially creating an open circuit), the ...
2
votes
4answers
243 views

What is a “gravitational cell”?

I am not a physicist, and I don't understand the details of electromagnetism. Anyhow, I was looking for how the batteries work in Google. So, I came across this article: "How batteries work: A ...
2
votes
2answers
144 views

Static discharge out of 3 volts button battery

I am starting to get interested in static electricity I have found this which is very cool but I do not know how I can control the output voltage. ...
2
votes
1answer
110 views

If I charge a battery using a much higher amperage, can it explode?

If I have a 12V 4Ah lead acid battery and use a battery charger that, let's say for example, can charge 10A, 50A, or 100A. If I theoretically turned it to 100A will the battery explode? I understand ...
2
votes
0answers
104 views

What are the physical limitations on energy density for a useful, safe battery, and are we anywhere near them?

Energy storage seems to be a fairly major bottle neck in technological development at the moment, especially for important things like clean-energy powered transport, but also for consumer goods. Are ...
1
vote
3answers
70 views

How can there be a voltage when there is no current?

I'm told at school that the Electromotive Force (e.m.f) of a battery equals the potential difference between the terminals of the battery when there is no current. How is that possible? How can there ...
1
vote
2answers
272 views

Simple ohms law on a battery ? Paradox or conceptual error?

Suppose we have a regular pencil battery which supplies DC voltage $V$. Say we take copper wire and connect the ends of the battery to an $R$ ohms resistance. Then Ohm's law tells use the current in ...
1
vote
2answers
609 views

What is the volume of gases liberated when a battery is charged?

Apparently Hydrogen/Oxygen are liberated when a Lead-acid battery is charged. If true, how does one calculate the expected volume & rate at which each gas is liberated when a battery is charged? ...
1
vote
1answer
35 views

Hydrogen extraction efficiency of newish nano particle AA battery

The internet is ablaze with the new nano particle based extraction method of converting water to hydrogen. In 2002/2003 when I was 16 there was a similar craze about a lawn mower motor which ...
1
vote
4answers
3k views

Capacitor Charging and Discharging when connected to the ground

When we charge a capacitor using a battery and then remove the battery, the plates of capacitor becomes charged. One holds positive charge and the other one gets equal negative charge. o. k. ? Now ...
1
vote
2answers
45 views

What is the difference between a circuit with a resistor and one without it in energy terms?

In Fundamentals of Physics (HRW), an equation is derived for the current in a circuit in terms of its emf and resistance by the 'Energy method'; that is, deriving emf=i.r and saying that the work done ...
1
vote
2answers
45 views

If batteries are a source of energy, would not lower-valued resistors cause a violation of the conservation of energy?

Here's the conundrum I have been facing. Yesterday I asked the question: how can batteries constantly motivate electrons to complete a circuit? (What maintains constant voltage in a battery?) After ...
1
vote
2answers
254 views

Physics of batteries (volts vs charge)

Car batteries are usually 12 V. What is the difference between buying a car battery and hooking up a bunch of cheap household batteries in series? Both would register at 12 V. I assume that cars need ...
1
vote
2answers
3k views

Does the 'mAh' rating of a battery have something to do with its power?

I'm curious about the 'mAh' of a battery: how can this impact the power of the battery? I've done some research on the internet, and most of the articles I found explain about the 'amount of charge ...
1
vote
2answers
46 views

Is battery capacity proportional to Ampere-hour in every case?

Suppose I have two batteries one inside the laptop with 2.5 AH giving a backup for around 2 hours. The battery is external inside a UPS system with 7.5 AH. Since it has thrice the capacity of the ...
1
vote
1answer
45 views

Battery Capacity vs. Battery draw

Pardon my ignorance but I just can seem to find an Answer to my question and I hope that you can help me. What is the equation for calculating how long a Lithium Battery can supply a device? For ...
1
vote
2answers
213 views

Battery and current confusion?

How exactly does a battery produce a current in the circuit connected across its ends? I dont want to know the chemical reactions in the battery core, but just the essence of it. I believe it doesn't ...
1
vote
2answers
143 views

Why isn't this capacitor charging?

Let's say you have a parallel plate capacitor and you connect one plate to the positive terminal of a battery and the other plate to the negative end. So this is like a static situation, you have a ...