A battery is a power source consisting of one or more electrochemical cells with external connections for powering electrical devices such as flashlights, mobile phones, and electric cars. When a battery is supplying electric power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons that will flow through an external electric circuit to the positive terminal. When a battery is connected to an external electric load, a redox reaction converts high-energy reactants to lower-energy products, and the free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells, however the usage has evolved to include devices composed of a single cell.Primary (single-use or "disposable") batteries are used once and discarded, as the electrode materials are irreversibly changed during discharge; a common example is the alkaline battery used for flashlights and a multitude of portable electronic devices. Secondary (rechargeable) batteries can be discharged and recharged multiple times using an applied electric current; the original composition of the electrodes can be restored by reverse current. Examples include the lead-acid batteries used in vehicles and lithium-ion batteries used for portable electronics such as laptops and mobile phones.
Batteries come in many shapes and sizes, from miniature cells used to power hearing aids and wristwatches to small, thin cells used in smartphones, to large lead acid batteries or lithium-ion batteries in vehicles, and at the largest extreme, huge battery banks the size of rooms that provide standby or emergency power for telephone exchanges and computer data centers.
Batteries have much lower specific energy (energy per unit mass) than common fuels such as gasoline. In automobiles, this is somewhat offset by the higher efficiency of electric motors in converting electrical energy to mechanical work, compared to combustion engines.
I have been trying to maximize the life time of my laptop battery. My approach to that is to almost use up the charge in the battery then immediately charge it. It is always annoying when the battery have 5% left, because that's when it hibernates automatically. Can I change the settings so it...
Hello,
I'm trying to learn about LiPo battery pack safety and was wondering if anyone could head me in the direction of some good sources of information.
In particular I'm trying to learn enough to safely re-build and extend a laptop's 6-cell (3S2P) pack, but hopefully to extend it to a...
Battery has positive and negative charges, will it be possible to generate electrostatic energy to my body by touching either sides of battery?
Thanks in advance for any suggestions
Here's the problem:
Consider the circuit in which a battery
with internal resistance r can be connected via a switch to a resistor
and capacitor in parallel.
Suppose that the capacitor is initially uncharged and then at time
t = 0 the switch is closed. After the switch is closed a...
Homework Statement
Determine the current through the 10-V battery.
[PLAIN]http://img69.imageshack.us/img69/8016/crct.jpg
The Attempt at a Solution
This is very confusing. I know the equivalent resistance of the circuit is 15 since all resistors are in series. So, the current drawn...
Homework Statement
Using an AC signal generator vs, a transformer with turns ratio n = 1, and a battery VB, sketch a circuit that will generate the output signal vout = vs + VB
Homework Equations
\frac{V_2}{V_1} = \frac{N_2}{N_1}
The Attempt at a Solution
Here's my sketch...
Does anyone know how to use an electric motor to charge a DC battery? I read on ehow.com that all you need to do is find a way to spin the shaft and it produces electricity that will charge the battery? Is that true, is it that simple?
When I was a kid listening to a transistor radio under my pillow late at night I used to wonder whether turning the volume down low would delay the gradual loss of battery voltage. My doubts centered in the fact that the volume control was (at least in those days) a variable resistor. I reasoned...
Homework Statement
Design a circuit to recharge a 1.2-V Ni-Cd battery from a car battery with a current of approximately 10 mA.
Homework Equations
The Attempt at a Solution
I was looking in the back of the book on this one and it had a simple circuit devised with a 12-V battery...
Homework Statement
In circuits, when we represent a battery we note by a long vertical line(positive) followed by a short vertical line(negative). But in some circuits, we follow a long line followed by a short line, again a long line and a short line with dots between them. What does this...
Homework Statement
An ideal battery with an emf of = 14.0 V is connected to a network of resistances with R1 = 6.00 , R2 = 12.0 , R3 = 4.00 , R4 = 3.00 and R5 = 5.00 . What is the potential difference across R5?
__R1__
__________R3__
__R2__
__R4_____R5__
__emf battery__...
I'm having trouble understanding how Ohm's Law applies to a battery that is being short-circuited. If the terminals are both connected by a low-resistance wire, then they should be at the same potential, since there's no resistor to cause a drop in potential. But the terminals of the battery...
Sorry if this is in the wrong section (it isn't homework). I am trying to form a basic understanding of electricity. Right now I'm attempting to figure out how to calculate how long a battery will last with certain devices.
I might be completely off base but here's what I've got.
12volt...
Homework Statement
An ideal 9V battery is connected to a resistive divider consisting of a 330 Ohm and a 600Ohm resistor. A 1.5V rechargeable battery in series with a 1.5k Ohm resistor is connected in parallel with the 330 Ohm resistor. The battery has a capacity of 1200mAh and is half...
Okay, so before when I asked a question about voltage multiplication, I was recommended a charge pump. But now I realize that creating a charge pump to get the voltage I want would be rather ridiculous. So, here is my problem: I need to get 1000vdc from a 9vdc battery, but I'm not entirely...
Hello,
I want to use a DC permanent motor as a generator in order to use it to charge a battery. This generator will be rotated by hand. The speed is varying as it rotates by hand. I would like to know what is the circuit that I could use it to charge 12 V chargeable batter?
Best wishes,
I am using this battery for a boat bilge pump. It's all working as expected, but what I am trying to determine is if my battery is suitable for the charger I have and if so, I need assistance decoding the CHARGING TIME chart (picture below) in my charger manual to determine how long I should...
I was wondering if it was possible to use, simultaneously, a 30 amp (or higher) charger on a car battery and a DC to AC (say, 700 watts) power inverter.
Where I live we have 8 to 10 hours of power outages in 2 hour intervals during the day. Instead of wasting money on expensive office UPSes...
if the machine requires 260A and if i take a battery of 1300Ah, it would mean that the battery is discharging at 1300 Amps per hour so if the machine takes 260 Amps then what happens to the rest of the current.
the motor takes 260Amps so does it mean that it will take total 260 Amps as long...
Homework Statement
Electric motor in put power rating is 17.5kw
Voltage is 48V
Battery is 7.5kw/h
Average W needed to maintain motor per sec is 1446.7W
Homework Equations
Motor: W=I*V > I = 364.58Amps
The Attempt at a Solution
My attempt: If 1kw = 3.6 x10^6J > 7.5 * 3.6 x 10^6 =...
A colleague of mine (who I trust is telling me the truth) just told me that he has seen a completely dead battery (a car battery) recharged so that the polarity was reversed from its original configuration.
I'm not well versed on the inner workings of a battery, but I thought the chemistry...
Homework Statement
Use Kirchhoff's junction rule to calculate the current supplied by the battery.
Homework Equations
attached a pic.
The Attempt at a Solution
Where do we start?
Hey guys!
I have two camcorders.
Cam #1: Power Supply: DC 7.2V (battery)
Power Consumption: 7.4W
Cam #2: Power Supply: DC 7.4V (battery)
Power Consumption: Doesn't say :( - but should be the same roughly.
How long can a "portable powerpack" with the following specs keep these camcorders...
12 v 7 ah battery charger urgent
hello everyone
i am getting stuck with 12 v 1 amp adapter and with 12 7ah smf leada acid battery .
i give supply from adapter to battery through 1n4007 and then from this batttery to my microcontroller kit.
by this my batteyr get charged and kit gets supply...
Homework Statement
Two 9.4 k-ohm resistors are placed in series and connected to a battery. A voltmeter of sensitivity 1000 ohm/V is on the 3-V scale and reads 2 V when placed across either resistor. What is the emf of the battery? (Ignore it's internal resistance)
Homework Equations...
I have built a battery charger for a cordless drill. It works fine, however, I would like to add an LED indicator to let me know when the battery is fully charged. I'm getting tired of checking the voltage across the battery all the time to see if the thing is charged. I'm not picky on how...
Hello,
If one had a resistance free wire and a battery with no internal resistance, how would Kirchoff's law be applied if the terminals of the battery were connected by the wire? Is this even an appropriate question? I know/believe current would be at infinity. I am still trying to fully...
I am wanting to build a small scale Redox flow battery as a fun project. I know there is a list of flow batteries right now and I am trying to decide on one where the elements used are economical as well as one where the watt density is reasonably high. At least twice lead acid anyway...
I want to charge a led-acid battery
it needs 12V DC
1.i have transformer to convert 220V AC to 12V AC
after that can i give 12V AC to bridge rectifier and from bridge rectifier
to battery terminals directly or should i use a filter to remove the fluctuations in DC ?
2. what should be the...
I have a simple question I hope):
My cordless phone handset works with two 1.2V rechargeable batteries, but the DC converter that comes with it and that is supposed to recharge the batteries has a 9V DC output ! How come ? Is it applying 9 V to recharge two 1.2V rechargeable batteries ?! Or...
Hi Everyone
I have a query, We have some low voltage (24v) led light strings that run off a 24v transformer (down from 230/240v - UK).
We wanted to run them off battery packs so we bought 2 x 12v (in series) batteries to make 24v.
When we wired up the batteries the lights were duller...
Nickel-Iron batteries are making a comeback in the renewable-energy industry. My personal interest happens to be for wind generator/solar power energy storage and also for a pendulum gear-driven clock design that I am working on where I need a minute amount of stored power to operate a small...
If I connect the +ve terminal of one battery to a terminal of a bulb and the other terminal of the bulb to the -ve terminal of an other battery, why doesn't it glow? There is still potential difference across the bulb's terminals and so the charge should flow.
I have two probes. They consist of a stainless steel cylinder inside another, one held by epoxy and one held by acrylic. I can measure a voltage difference between them. I have placed them in tap water and applied a 5V difference across them then disconnected the voltage. The problem is that...
I want to make an heirloom mechanical pendulum clock that is very tradition in design and yet will accurately work for centuries—and so I want to micro adjust the pendulum amplitude automatically and that requires some electricity, not very much electricity, but it will take some small amount of...
I have a Ford Escape Hybrid. it is a 330v battery with about 1.4kw of capacity. Currently there is no cost effective after market charger. Also my location in NYC does not allow me a "plug in" option.
I had an idea on how to access the battery pack to charge it, but I wanted to know if...
"D" cell battery gets hot
As a hobbyist, I was playing around with an MP3 player that uses a single alkaline AAA battery. I wanted to see if the player would still work if I attached a "D" cell battery to the device. I went to Radio Shack and puchased a "D" cell battery holder which has two...
I have a cordless electric lawnmower that runs on sealed lead acid batteries. It is on it's second battery, which has noticeable degraded performance and will need replacing soon.
My question is why the original battery, which was rated at 17 Amp-hours, lasted twice as long as this second...
So I am in the process of rebuilding my laptop battery for higher capacity cells. I would appreciate it if someone can help me understand the arrangement of the cells. From my research, each cell is 3.7V 1800 mAH Li-Ion cells. There are 6 of them in the battery pack. In this arrangement...
Hello all! :smile:
I have recently bought a new laptop. A problem that I had with my older laptops were that the battery broke quite fast, and I don't want this to happen anymore.
I have a 9-cell Li-ion battery, what do I have to do to let this battery live as long as possible? Is it...
Hi friends,
I don't have any electrical background. In my experiments I have 11 V Battery which has to power up PC104 which needs 5.3 V. Can please help me out how to step down the voltage.
Thank You,
Yawanth
We are working on some design ideas to hopefully eventually get our shop and home off the grid with independent power. We are in one of the best locations for wind generation but energy storage becomes an issue and a grid tie system is simply impractical and will not obtain our goals.
the...
Hello, I have a small (24 Watt) guitar amp which I'd like to retrofit with a
battery for outdoor playing. I actually study mathematics and do electronics
mostly as an hobby, so I may miss some fundamental things (i.e. bare with me). Basically, I have two little problems which I'd like help...
Homework Statement
I am trying to find terminal voltage of the batteries in the circuit shown. Homework Equations
V = IR
The Attempt at a Solution
The solution manual says that it's the battery voltage, v, minus the voltage drawn from the resistance v = I * R. I understand this.
I do not...
Homework Statement
A team on The Apprentice have to come up with a new electrical device. They propose a hand cranked dynamo to charge a battery which initially uses the residual charge in the battery to power the electromagnet, instead of a permanent magnet (the idea being that this...
Homework Statement
How long will it take the primary energy source to fully charge the battery pack from an uncharged state? (State your answer in hours, minutes and seconds, as appropriate.)
t = 378 min.
I = 100 mA
Homework Equations
Cb (battery capacity) = I x t
The Attempt at...
Firstly i need to heat a wire to around 20 degrees or over using a low power battery which could last up to 24hours.
what kind of wire is easiest to heat up?
would AA battery's work?
what would be a long lasting battery source?
can it be done?
please help me!
thanks