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.
Does say a 1.5 volt voltage in a battery mean the change in electric potential as one electron goes from the negative terminus to the positive terminus? Does a larger voltage battery simply mean more kinetic energy through the load (hence more friction/heat)? Or does it have to do with...
For a physics project, we have to increase power to an automated wheelchair.
This wheelchair has:
Battery Capacity 2x60AH
Battery Needed (x2) GR 24
I know that this means there are 2 batteries at 60 Ampere-hours. I don't know what a GR 24 is.
Also, I don't know how to increase...
Hi,
I am trying to figure out how Li-Ion batteries operate in regards to efficiency. I understand they have rated voltage and current etc. and to operate them at these parameters if possible. However, I'm wondering is it simply the current that has effect on their efficiency. By Efficiency I...
Homework Statement
Does a flashlight battery have internal resistance? Explain.
Homework Equations
V = ε - Ir
The Attempt at a Solution
Yes, they do have internal resistance. This results in the open circuit ε being different than the voltage measured across the terminals if a current is...
Homework Statement
Imagine that you have a box of 9V batteries and a box of flashlight bulbs labeled 1.5V/3W for operational voltage/power. What is the ohmic resistance of the bulbs? Can you turn on the 1.5V bulbs without burning them out by using the available 9V batteries?
Homework...
Homework Statement
When a 10 ohm load is placed across the terminals of a battery, the terminal voltage is 11.0V. When a 100 ohm load is used instead, the terminal voltage is 11.9V. What is the internal resistance of the battery?
Homework Equations
V=IR
The Attempt at a Solution...
Battery "Explosion"
Hi Everyone,
My knowledge base is very limited when it come to electrical. I'm dealing with a simple charging system that has had problems.
We have a system ran by 2 x 12V 5Ah sealed lead acid batteries in series. They are to be charged with a Schumacher CR2. Of about...
Homework Statement
A 4.5 Volt is labeled: 4.5 V ; 1600 mAh (milliamperehour). This battery is the energy source of a chocolate lift. Find the number of kilograms of chocolater you can Transport with this lift up to the summit. The summit is 1000 meter above the valley Station.
Homework...
Homework Statement
Four resistors are connected in a circuit with a battery of unknown emf, as shown below. The battery is ideal, so it has no internal resistance. The current in the 30Ω resistor is 100. milliamps.
C) Calculate power dissipated by the 20Ω resistor in watts.
D)Calculate the...
Homework Statement
Suppose that you have a 9.0-V battery and wish to apply a voltage of only 3.5 V. Given an unlimited supply of 1.0-Ω resistors, how could you connect them to make a “voltage divider” that produces a 3.5-V output for a 9.0-V input
r=resistance of 1 resistor=1
R=Total...
Homework Statement
How can I measure the potential difference across two batteries? For example, if I put the batteries end to end, so the negative end of one touches the positive end of the other. And let's say both batteries have 3 volts and let's denote point A to B as the point from one...
I'm working on a project where I charge a 12 volt battery with a 12 volt solar panel. Links for the battery and solar panels are below. My question is how I should connect the two. The main thing I can find is that I don't want the solar panel draining the battery. I plan to put a diode from the...
Hi guys and gals,
This may be a bit off topic, but your community seems like the most adept concerning my topic.
In short, I want to build an emergency cell phone charger out of one AAA battery. Energizer has done this with one AA battery, so I assume that it is very possible...
For my MINI PROJECT
I need to get an LED indication for
full battery and
low battery
the circuit must be simple with components such as transistors,resistors..etc
Battery Details: 7.4v 1500mah li-on
I got a lithium battery pack for my ski glove. On high it last for 2 hour, 4 hours for medium but on low it only last 3 hours. Why does the battery not working long on high? Does the cold weather affect the batteries from operating at its peaks power. Would it be better if I use some type of...
Hi,
A local alarm company has given me a quote, and they want to connect the power to the alarm as follows:
The 30VA 16VAC transformer is connected to a 7ah 12V battery.
The battery apparently can run in AC mode, this was news for me.
The alarm requires AC power, and is connected in...
Homework Statement
I need to know what effect wire heating would have on the reading of the EMF of a battery, and how the heating effect can be reduced!
Homework Equations
V= IR
The Attempt at a Solution
Well I know that the heating effect increases the resistance in the wire...
Hi, I want to know what is the proper methods to prolong lithium battery life:
When Should I recharge the battery(at any level 90%, 70 or 40 etc)?
Should I charging it fully at 100%?
is true that discharging battery below 20% once each month is useful to boost battery life?
Hello guys, I have a problem charging a lead-acid battery.
I have a 0-30V 0-3A power supply. If I hook up the power supply directly to the battery (with a resistor and/or diode) and set the voltage to an appropriate level, the LA battery will only draw about 150 mA. After a few minutes...
If we had a battery with internal resistance 1 ohm and 9 V.
If we connected to just wires ( resistance 0) i will produce a 9 amps current. Is this the maximum current? If we connect to this battery a 0.5 ohm resistor (in parallel ) the total resistance will be lower than one, will the current...
I have a fisher price baby swing. It has 4 1.5v batteries of size D. I tried to convert it to a 6v DC charger but that didn't work. The charger specification is output=400mA 2.4VA. If someone can help me please to find a right charger as this doesn't work correctly and swing does not swing as...
I got this question ( i won't include a lot of details because this is not the homework forum) where i need to calculate the power dissipation due to internal resistance. What i did is , i calculated total V and total R and I , then i treated the battery as a normal resistance ( eg. a 1kohm...
I have an 800 amp car battery no load connected at anytime to a 10 watt solar panel with just a regular diode in between after 4 or 5 hours in the sun terminal voltage reads 16 volts is this good? Would a battery connected this way last longer than one that sits idle uncharged for 6 months?
John
For a uni project one of my concepts is to use thermo couple generators like these http://www.thermoelectricgenerator.co.uk/TEGinstallationandspecifications01.pdf on the exhaust to generate electricity to replace the alternator. The problem is i can't figure out how much current and voltage is...
There is a battery connected to a non ideal circular conductor wire.
What is the specific mechanism by which one electron inside the wire “feel” the presence of the battery because of electric field?
Hello everyone,
I'm stuck at a basic physics challenge that I randomly thought on the drive home from work.
The quick question is: how do i find out the amount of rechargeable batteries needed to boil water from room temp (20°C)?
My research:
A kettle uses a power cord connected to the...
I am trying to create a backup dc power supply that is charged by a battery which ranges between 10 and 21Vdc. The backup supply needs to output 20W (10V, 2A) of power for 5 seconds when the battery is disconnected. I have performed some research into how long the capacitor in the backup supply...
Lead Acid Battery "Internal Resistance" and Temperature
Hello,
I've reached my wit's end trying to understand the theory behind charging lead-acid batteries. I believe I have read over twenty different articles, maybe six hours worth of studying.
According to what I've read:
Charging...
Sorry for not using the question template, but I don't have any relevant information, like equations or solution attempts at this, since I literally have no idea where to start. Google has failed me.
This isn't necessarily a homework problem, but it is for part of a project I am working on...
I live in the USA and have an HP Laptop G62M Series.
I know I can buy a new Battery from HP but they are around $ 100.00 USA.
I looked at TigerDirect.com
And OutLetPC.com
But I am having trable finding my Battery.
Can anyone help me?
Hi Everyone,
I'm trying to make a homemade solenoid to lift a metal slug, and i have a 2000mah / 7.4 V / 20C lithium polymer battery. Is this battery going to be sufficient?
Here is a photo of my current setup without the battery:
side view
top view
Thanks in advance!
I have a diesel van that has a dual battery starting system. Each battery has 850CCA.
I have 75w of roof mounted solar panels that are running through a 100amp controller and charging an aux battery that has 55amp hours. All batteries are 12v.
I would like to be able to charge my aux...
Hello everybody :smile:
can anybody explain to me why there is potential difference in the battery (and when we say the potential difference of the battery is Va-Vb =12 v can both electric potentials be positive for example Va=20v and Vb =8v ) . From the last , can somebody illustrate to me in...
I have a pretty general question. If you look at battery packs, for example the Kolibri one below:
http://www.kolibri-ag.com/en/kolibrirack1.html
it's stated that the connection power can be up to 24 kW with storage up to 45 kWh.
Does this mean that power can be sourced at 24 kW from...
Homework Statement
A long, fine wire is wound into a coil with inductance 5 mH. The coil is connected across the terminals of a battery, and the current is measured a few seconds after the connection is made. The wire is unwound and wound again into a different coil with L = 10 mH. This...
Im trying to calculate if a standard car battery will be able to run 2 computers, 2 monitors, and some small hardware, and if so, for how long.
The entire configuration should be no more than 1000watts. (400 each computer, 50 each monitor, and 100 for small hardware). I can't seem to find how...
Hello I am in a bit of an engineering bind. I need to evacuate a small room of a flammable, explosive gas that is at a nominal pressure of 3 mbar by pushing it from room to another room (both at equal pressure). The environment is Class 1 Div 1. The rooms have valved piping that enable me to...
The question is:
Consider a thermal battery - a device for storing mechanical energy. Use two large containers as heat reservoirs where one contains ice and water in equilibrium and the other contains steam and water in equilibrium. Both are held at pressure=1atm. Energy is stored by using a...
Hi All
I am among the people who bought the nexus 7 without the data capability and pretty much the first generation of its kind when it first appeared at Google's store. After almost a year and a half I have noticed problems with the battery. It's not much of a problem as it is my annoyance...
Think for example a phone or any devices that shows the amount of battery power is left. It shows it as a graphic where you can deem whether it's full, 3/4 full, 1/2 full, 1/4 etc... or shows the actual percentage. What is that measure really showing you? Voltage? Amp hours left (which is the...
How is voltage between two plates, like in a battery, determined? When you have a 5V battery, is that the potential difference between a point on the positive plate and a point directly across from it on the negative plate? If so, that means they have to be parallel in order for the calculated...
I just got my hands on a solar battery charger with a set of usage specifications that makes me believe it will only be useful some four days a month and will take more or less such time to charge a single set of batteries, despite promises on the contrary in the instructions. Since the case is...
Hi,
What will happen if I connect an ideal battery across two ends of a superconductor?
Assume all contacts are ideal, lossless.
Is the current infinitive?
I have 2 batteries for my mobile, and forget which one is new and old.
The standard volt is 3.6 V, and I measure the voltage using any standard electric meter.
Battery A has 3.86V
Battery B has 3.77V
Does anyone have any suggestions on whether it is possible determine the new battery based...
I have a 75w 2meter mobile transceiver (Yaesu FT-2900R – 13.8 volts DC, 15 Amp max draw, min draw is .3 A-.7 A ) that I would like to use in a camp type setup. The power source will be Two 12volt batteries (not dedicated) on a small enclosed utility trailer, which will be 20’-50’ away from the...
Hey!
A couple of friends and I are building an electrical miniature cable car, kind of like this:
(attached below in case the code doesn't work)
We're mechanical engineering majors and love this kinda thing but we just started out and don't really know much yet, so we're just looking for new...
Radioactive material ionises the air around it.
Carbon nano tubes have an extremely large surface area, & could possibly "store" the ionised charge.
If a volume of carbon nano tubes is wrapped around a core of insulated radioactive material, can a potential difference exist between the...