Batteries Definition and 456 Threads

What is fundamental physical constraint which doesn't allow the best (super)capacitors rival the best batteries in energy density? Or it could change someday?

Homework Statement What are the sizes and directions of the currents through resistors (a) R2 and (b) R3 in Fig. 27-42, where each of the three resistances is 4.0 Ω? Homework Equations ΔV=IR The Attempt at a Solution Equations: 1) ΔVB2 -(i1)R1 -(i2)R2 -ΔVB1=0 5V - 4(i1)...

Hi there I have just re-watched The Matrix (great movie) and one quote really stuck out to me: "The human body generates more bio-electricity than a 120-volt battery and over 25,000 B.T.U.'s of body heat. We are, as an energy source, easily renewable and completely recyclable, the dead...

a concept i can't grasp is the meaning of voltage for an electric motor. it seems all the motor needs to operate is a magnetic field which is generated by current. why does the electric motor "care" whether the current is fed to it from a 100V or a 200V battery? Isn't the concept of voltage...

I have a bit of confusion over how a bulb lights up in a simple DC circuit. My book says it's because the electrons within the filament start moving as soon as a battery is connected. My book also says that voltage is the potential energy an electron has. It says it gains this energy as it moves...

Hi, I bought 2-AA (with pins tabs) rechargeable batteries for a Braun electric shaver. Checked the polarity of the old batteries, marked it on the board, and soldered the new batteries accordingly. (In series.) First charge lasted 4 weeks. Next 3-4 charges lasted less and less. Now...

Let's say you have 2 batteries, both 1.5 V. If you put your red voltmeter lead on the + of one battery and your black voltmeter lead on the - of the other battery, and assuming the two batteries are not touching, the voltage you read is zero. I know this is a simple question, but why? Why don't...

Homework Statement For the multi-loop circuit as shown, assuming the capacitor is initially uncharged, find the currents in each of the resistors at t=0 after the switches are closed. So I believe there are 8 unknowns really because of the 8th branch with the capacitor. If you look at the...

Hello all - a quick question that I can't seem to find an answer to online that I trust... While the conventional current model describes flow of positive charges around a circuit, we know that current is actually the flow of electrons (at least in common metallic conductors). Which leads to...

is it possible to make a nuclear "battery" which works off nuclear not electrochemical reactions using berylium/graphite shielding?

I am trying to increase the strength of my electromagnet, at the moment by increasing the amperage. I have been using an old 12V motorcycle battery, but also tried with 10 AA batteries. I was wondering how I could connect the AA batteries to get a high current, so hopefully a stronger...

how to determine series and parallel connections in a resistors when multiple batteries are used?

Two Batteries In Series--Total EMF and Internal Resistance Homework Statement Two 1.50-V batteries—with their positive terminals in the same direction—are inserted in series into the barrel of a flashlight. One battery has an internal resistance of 0.260 Ω, the other an internal resistance of...

Homework Statement A. Make a prediction about the direction of current flow through each resistor. (6 points) B. What current flows through each resistor? (15 points) C. What is the voltage drop across R2? (4 points)Homework Equations Req=R1+R2+R3The Attempt at a Solution I'm sort of lost as to...

Hello Forum, Battery chargers are devices to put energy into a secondary (rechargable) bttery by forcing an electric current through it. The charge current depends on the technology and capacity of the battery being charged. The capacity of a battery represent the amount of electric charge...

I have a question that may seem odd, but I am really searching for an answer. I have several 37 volt lithium ion bicycle batteries that hold a lot of charge after being recharged through grid outlets. I also have an old RV that uses 12 volt appliances run from 12 volt lead acid...

Homework Statement Find the current through R1, R2, and R3 for the attached diagram. Homework Equations Ohm's Law V=IR I=V/R etc.

Homework Statement http://www.webassign.net/giancoli5/19_31alt.gif I was given this circuit and told that R=6.6Ω. Based on the information, I was asked to find the terminal voltage. Homework Equations Terminal V=Emf-ir Kirchoff's laws The Attempt at a Solution I used Kirchoff's...

I used to think I knew how batteries worked, but I've decided that if I did, I now don't. Being that chemistry is one of my worst subjects, I decided to evade all of the anion, cation, this, that, and other terminology that I find incomprehensible and totally unable to devote to memory. So...

When constructing a simple circuit with a battery, bulb and a switch, the placement of the battery is unimportant (I can hook up the battery + then - or - then +). So why is it that so many battery powered electronic devices only work if the batteries are inserted in a specific direction?

Homework Statement When you put batteries you place the negative terminals to the positive which supposedly "bumps' each electron to the next battery. However, the positive terminal is positive enough to neutralize the negative terminal and vice versa. Therefore, when I place batteries in...

circuit help -- resistors and batteries in a network Homework Statement (a) Calculate the current through each ideal battery in Fig. 28-41. (As a sign convention, assume the currents are "up" through each battery.) A (I1) A (I2) A (I3) Assume that R1 = 1.5 , R2 = 2.5 ...

Right now I'm doing an experiment for my EE about battery capacity. How would I be able to monitor the battery's true emf while discharging the battery at a constant current? Also, when I connect the battery in a circuit and discharge it at a constant current, I notice that the voltage across...

Homework Statement A circuit is constructed with six resistors and two batteries as shown. The battery voltages are V1 = 18 V and V2 = 12 V. The positive terminals are indicated with a + sign, The values for the resistors are: R1 = R5 = 73 Ω, R2 = R6 = 121 Ω R3 = 62 Ω, and R4 = 92 Ω. The...

Homework Statement [/B] A circuit is constructed with six resistors and two batteries as shown. The battery voltages are V1 = 18 V and V2 = 12 V. The positive terminals are indicated with a + sign, The values for the resistors are: R1 = R5 = 73 Ω, R2 = R6 = 121 Ω R3 = 62 Ω, and R4 = 92 Ω...

Homework Statement A circuit is constructed with six resistors and two batteries as shown. The battery voltages are V1 = 18.0 V and V2 = 12.0 V. The positive terminals are indicated with a + sign, The values for the resistors are: R1 = R5 = 64.0 Ω, R2 = R6 = 157.0 Ω R3 = 53.0 Ω, and R4 = 65.0...

If I understand it correct,energy of atomic electronic shells fusion cannot exceed energy of their breakdown.For example you need to spend more energy to break down water molecule than you receive energy when you burn hydrogen.Does that mean that energy stored in capacitors could potentially...

I know that AAA batteries (and batteries in general) provide a very low continuous current due to the chemical reaction. Is it feasible to charge a capacitor of say 25F (yes F not μF) from AAA lithium batteries...

Homework Statement Question: Find the current in the circuit shown. http://i1307.photobucket.com/albums/s599/JustOn4Fun/PhysicsFigure_zps39d4c66d.png Homework Equations Not sure if equations are necessary since it's a question testing the use of the following rules: Junction Rule The...

I am trying to find the capacity of a AAA battery by discharging it. How would I be able to discharge the battery at a 1A current so that I don't have to wait for a long period of time?

Hello everyone, I know electronics pretty well. I'm pretty good with that, but my physics and chemistry understanding of what is going on is a little weak. I'm trying to do a good Youtube video on Ohm's law and I want to have a solid foundation to my understanding. Not just V = IR, but...

Hi if you have a galvanic cell, with Zink at the anode and Cu at the catode, which force then makes Zn electrons go to the cobber catode?

Hi all. I was wondering, are lithium-ion batteries the best type of batteries for electric vehicles? I also remember watching a video of Elon Musk (from Tesla Motors and SpaceX) claiming that lithium-ion batteries are increasing their energy density by 8 to 9 percent every year. I googled...

Does anyone have any experience of the swelling of lithium-ion battery packs? Attached are photos of one that came into the workshop recently. The first is still in its Macbook and is genuine Apple, although you can see how it has forced its way out and distorted the case. The second...

First off, this isn't really a homework question, but I'd rather post it here and look like somebody trying to learn rather than being mocked at secretly in the engineering section. So my question is, how do batteries work, SPECIFICALLY? Down to the ditty-bit details. Every source I try to pop...

I have this dc heli called protocol. It charges from the remote which uses 6 aa batteries. So I got a 9 V wall wart. There's a couple problems with the wallwart when I used my analog multimeter to read the voltage it was reading 60 V. When I measured the batteries in the remote ball the remote...

Hello, I would like to know how you can calculate the current in a circuit with cells in parallel. When searching for this on the web all I get is current in parallel circuits, and not my specific question about cells in parallel. If there is maybe an equation, method, or link somebody could...

Homework Statement http://tinypic.com/r/e8v1ad/6 ^^ that is a photo of the circuit Homework Equations P = I*V , but i don't understand how to do it with two loops and two batteries like in this photo. The Attempt at a Solution I have calculated I1 to be .9, I 2 to be .15 and...

Dear Experts I bought a lithium-ion battery rated at 3.7v. I charge it with my existing phone charger rated for 3.7v batteries and charging at 4.2V. i like to know why are batteries are rated like this. That is, a 3.7V rated battery is actually charged to 4.1 or 4.2 when its considered...

Hello, I can't image what is the exact path of electrons in two or more batteries conncted in series... if electrodes are immersed into the electrolytes and chemical reactions should continously happen why the circuit in the picture down here has no activity ?

Does anyone out there know of a US based source or distributor for high capacity lithium batteries? 100Ah, 200Ah? 3 - 3.2 volts Everything I am finding is China, and the shipping is just outrageous. Thanks, pud

Homework Statement attached Homework Equations The Attempt at a Solution The first two were pretty simple, but I'm having trouble grasping why my guess for #3 was actually correct. Why are we ignoring the parallel battery/resistor combo up top and just adding the voltages of the...

Are there more joules in a bullet or a battery (in it's lifetime). I'm afraid I don't know bullet calibres but we can assume that we're talking about an AA Battery.

So I have learned that all batteries have an internal resistance which will limit the current that it can output, so that you can't discharge a huge battery in a split second because of that internal resistance. But what I am wondering is, at what point is it dangerous to draw too much current...

Homework Statement The circuit in the figure is composed of two batteries (ε1 = 9.0 V and ε2 = 5.0 V) and four resistors (R1 = 110.0 Ω, R2 = 40.0 Ω, R3 = 30.0 Ω, and R4 = 50.0 Ω) as shown. 1). What is the current I1 which flows through R1? 2). What is the current I3 which flows through R3...

I have some trouble understanding the equations that you get from Kirchoffs law when there are several batteries in a circuit. Consider a circuit with two batteries like the attached. Kirchoffs laws just gives ohms law for the two circuits as were they completely independent: U1 = RI1 U2 =...

I live off the grid and am looking to upgrade my battery bank. I now have 12 6v batteries. 4 are ran in parallel to make a 24v system. The rest are run in series to increase watt hours. is there a maximum amount of batteries I can run in a series?

Hello! this is my first post here,hope it's the good part of the forum. I have some questions and i would appreciate it very much if someone more knowledgeable than me could help me out. A while ago I saw a radio that was used without batteries,you had a wheel and you just had to spin it...

Hi guys (and gals) Say, i have a solar panel rated at 100w 12v with the following specs: Short circult current(Isc): 6.01A Open circuit voltage(Voc): 21.5V Optimum operating current: (Imp) 5.52A Optimum operating voltage: (Vmp) 17.78v Maximum power: (Pmax) 100W And I decide to...

I am drawing 12 volts at 1/2 amp for 6 hours a day off of one 12 volt car battery battery which is powered by a 2 amp solar charger voltage goes to almost 14 volts when charging I then added two more car batteries voltage is under 13 volts when charging with the same load is it better to use...