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

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Why do we use capacitors when batteries can very well store charges?

Can batteries be used instead of capacitors? I am trying to figure out a basic, superficial and any obvious difference between the two.
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1answer
402 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?
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1answer
115 views

Why the EMF of a battery doesn't depend on distance between the two electrodes?

I have read that resistance of a conductor is directly proportional to its length. So, the EMF of a conductor (electrolyte of battery) should increase with increase in length/distance between the ...
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2answers
29 views

Calculating average energy stored in Li-Po battery

I'm currently sourcing Li-Po batteries and need to find an average mAh per cm3 to implement it into my product. From what I read (wikipedia), the energy density of Li-Po ranges from 250 to 730 W.h/L ...
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2answers
36 views

2600mAh Battery Charging Time

I've spent a very long time trying to work this out, but some websites seem to conflict the information - or I'm completely missing the point. I have a rechargeable battery: 2600mAh 4.2V max charge ...
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1answer
38 views

Why can't I series 5 D Cell Batteries to achieve 7.4 volts?

I appreciate this site that is allowing me to get an answer to a phenomena I am witnessing. I'm trying to series 5- D Cell Batteries. However I cannot make it completely through because the middle ...
3
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1answer
266 views

If I charge a battery using a much higher current, 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
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1answer
68 views

A reliable aluminium battery that charges in a minute. What's the catch?

This article Ultra-fast charging aluminum battery offers safe alternative to conventional batteries, phys.org. reports on the finding by a Stanford group of an aluminium-ion battery that can ...
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0answers
23 views

What are the reactions that take place inside battery at the quantum level?

I was just studying about how a battery works on the internet and found out that there are reactions of chemicals which make the electrons move. But what exactly happens inside a battery (lets take a ...
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1answer
119 views

Why is voltage added when batteries are connected in series but not in parallel?

As I understand, the different voltage between two object is caused by the total different charged between two object. Thus, the higher extra electron between two opposite charged object, the higher ...
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2answers
7k views

Why do two connected 1.5-volt batteries become a 3- volt battery?

Why two connected 1.5 volt battery become 3 volts? 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, ...
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1answer
50 views

Need help understanding a simple circuit in-depth

I would like to know more in detail what's really going on in a simple circuit like this. I think I understand it, but I have a lot of things mixed up and others aren't clear to me. I'm going to ...
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2answers
87 views

Why is there electric field OUTSIDE a battery?

Correct me if I'm wrong, but a battery's electric field is like an electric field of a capacitor consisting of two parallel plates. But we know that the electric field outside the two plates is zero. ...
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2answers
86 views

Why is the voltage of a battery equal to the emf?

We know that there is an electric field inside the battery that works against the moving electrons of a circuit. But there is also the chemical force of the battery that at some point become equal. ...
2
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1answer
57 views

Why doesn't the potential drop as a $E=\nabla V$ inside a circuit when there is no resistor?

Considering that an electric field exists outside a battery and inside a circuit, shouldn't the potential drop while we move along the wire even if there is no resistor ($E=\nabla V$)? I am asking ...
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1answer
52 views

Why do resistors always cause a voltage drop equal to the voltage of the battery

Consider a wire connected to a battery. Now,potential is analogous to the energy of the particles.And potential in a resistor drops because of the friction inside the resistor(considering there is no ...
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2answers
29 views

Multimeter reading between wire & air

Why does a multimeter show 10-20 V(AC) when I connect one of its cables to the hot wire of a 220 V(AC) plug while the other cable is in the air? Also why does this not happen with a 5 V battery? (It ...
0
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1answer
39 views

Why does Li+ ion move to cathode in Li-ion battery?

when Li-ion battery is discharged or being used, the positive lithium (Li+) ions move from anode to cathode through the electrolyte. Meanwhile the electrons move in the same direction through the ...
3
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1answer
121 views

Is it possible that a battery goes flat faster in a cold environment?

I own an old iPod Classic with original lithium-ion polymer battery and I use it primarily while running. Recently I discovered that when a temperature outside is low, usually below 5 C degrees, the ...
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1answer
33 views

In a circuit, if voltage is established at both terminals, then how can components use up this voltage? [duplicate]

Suppose we use a 9V battery. Then the voltage between these two terminals is 9V. In other words, it would take 9 J of energy to move +1C of charge from the (+) to the (-) terminal by the electric ...
3
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1answer
41 views

Creating permanent magnets with minimal resources?

Okay, so this is kind of a goof-off question, but it's part of an of educational game that I've been playing with myself for years. If you don't want the background then skip to the horizontal rule, ...
2
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1answer
43 views

How should one interpret $\vec{f}=0$ in an ideal battery?

In a circuit there are two forces that act on the charges to keep the current uniform through out,$\vec{f}=\vec{E}+\vec{f_s}$, where $\vec{E}$ is the electrostatic field and $\vec{f_s}$ is the ...
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1answer
114 views

Name of battery voltage when load connected/disconnected

If I had a 3V battery, and when no load connected it reads 3.2V, and with a load 2.8V (just a hypothetical example), what is the name for these two terms, with a load or no load? I know the voltage ...
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3answers
6k 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 ...
3
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1answer
91 views

Why are charging times so long for Lithium-ion batteries?

Why do rechargeable batteries (e.g., mobile phone batteries) need sometimes several hours to be fully charged? In other words, what are the physical constraints that don't allow me to charge my iPhone ...
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0answers
34 views

Li-ion Battery charging

Why are constant current mode and constant voltage mode needed when charging Li-ion batteries? Why do we apply saturation charge even after the cell voltage reaches 4.2V? What exactly is 'I-sense' in ...
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3answers
4k 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 ...
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1answer
45 views

What is the equivalent of the “amount of fuel” for a battery?

I am trying to make a performance diagram of an electrical powered device vs range, speed, etc. I want to compare it using the equivalent of fuel for a battery? I am not sure if it is just voltage... ...
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1answer
98 views

Am I correct in saying this about a battery?

I recently answered this: Q When a battery, by performing work on a charge, moves it to the higher potential, why doesn't the charge move through the battery and return to the low potential, ...
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1answer
45 views

Battery charging using a windmill?

i want to charge 4*(12V/100AH battery) using a 3*( 12V/5AMP GENERATOR ) which is drawing its power from a windmill. these battery have to heat 500 litre of water from 30 celcius to 50 celcius how ...
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1answer
36 views

What does A (EN) stands for on a battery? [closed]

I have seen many large car and trucks batteries where there example stands 200 Ah maraton battery 1200 A (EN). What does A (EN) mean?
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2answers
2k views

How can you calculate (or convert) the Wh of a capacitor whose energy is given in Farads

When trying to compare the energy in a battery to the energy in a capacitor, the units don't match up. How can one compare a battery whose Ah are 10 and Voltage is 3 (for a total of 30 Wh) to a ...
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1answer
7k 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 ...
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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 ...
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4answers
427 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 $\epsilon = i \cdot r$ and saying ...
0
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1answer
36 views

What are the consequences of connecting a non-ideal conductor to a battery in open loop?

Suppose I have a battery with $\Delta V=5[\mathrm{V}]$. Now I connect a piece of a metal wire to the "+" side of the battery only. Let's assume that the ambient air is not conductive at all: Are ...
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4answers
261 views

Why doesn't current flow when the wire is open?

I realize this may be a hard to answer question but we are currently studying current in our school. One thing that struck me was why the heck doesn't it flow when the wire's closed? When you connect ...
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1answer
138 views

Why the bulb does not glow in this configuration of batteries?

I connected a bulb to a battery positive terminals with positive and negative terminals with negative . It glows as it should but when i connect the positive terminal of the same bulb to the positive ...
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3answers
5k 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.
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0answers
88 views

I have got some weird data after a homemade battery experiment

Okay, so i've been searching for some time, for perpetual motion machines of the second kind. So things got into my mind, such as this homemade solar cell. And i thought in my mind:" It's not the ...
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4answers
3k 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 ...
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3answers
247 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, ...
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0answers
105 views

How does a battery work?

How does the positive terminal of the battery attract electrons? Does the electric field emitted by the positive terminal attract the electrons?
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3answers
18k 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?
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3answers
82 views

How is voltage increased from a battery?

I have recently watched a video about a powerful Octa-copter that uses 30,000 Volt brushless motors to propell, the batteries however look quite small about a 19v laptop battery. How is the voltage ...
0
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3answers
96 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 ...
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1answer
44 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 ...
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2answers
842 views

How can a portable 5V battery charge another 5V battery?

For a device that is portable and can charge an iPhone 4 or Nintendo 3DS: http://www.amazon.com/New-Trent-iCruiser-IMP1000-Blackberry/dp/B003ZBZ64Q I wonder, if this device outputs 5V, and iPhone or ...
3
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2answers
277 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 ...
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0answers
59 views

How can a paper battery behave like a capacitor?

I was trying to understand how paper batteries work and came across some explanations saying that the paper battery can also behave like a supercapacitor on account of its ability to discharge and to ...