What is Battery life: Definition and 30 Discussions

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.

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  1. dRic2

    Low battery life in sleep mode

    I have a 6 years old MacBook air, still running the OS of a couple of years ago. Lately, battery life is going down (around 4.5 hours of light/medium use) so I mainly use it as a desktop computer, connected to an external monitor. However, when I leave it in sleep mode (still on, but shell...
  2. Ozen

    Increasing the Battery Life of an LED Circuit

    Hello Everybody! I am new to electrical engineering and only had 1 formal intro class on the subject (albeit I did very well in it) and have found myself in a position where I need to design a circuit for a micro reflex sight I have been designing. So let me first describe how my competitors...
  3. M

    Can rechargable Li-ion batteries be rebuilt?

    After so many cycles, rechargeable Li-ion batteries powering electric cars go bad. This I know. I am wondering what goes bad? Is it the electrolyte, the electrodes, or both? And in general, could it be possible to take these degraded battery components and fix them? Thanks in Advance! Mike
  4. L

    Operating a portable ultrasound machine in -30 degrees C

    Dear friends. I am a cardiovascular health researcher writing on behalf of my research team based in Copenhagen, Denmark. We plan to conduct a high-altitude field study on cardiopulmonary function assesed by ultrasound on Aconcagua summit in near 7000 meters altitude. Reports say it will be...
  5. G

    Battery life using 6000 watt inverter

    I have four 125 ah batteries powering a 6000 watt inverter. The inverter is supposed to have a no load draw of 2 amps. I have a 12 amp 120volt Ac load. How long should I be able to operate before drawing my batteries to 50%
  6. T

    Rate of battery life varies with charge?

    Batteries and rate of charge? I have an IPad. It 'seems' that when he battery if fully or mostly charged it lasts proportionately longer than when less charged. For instance, all things equal, the battery takes a shorter time to drain from 30% charged to 10% than it does from 90% to 70%...
  7. N

    Hybrid CIVIC 2010 without hybrid battery

    Hello Guys and Girls, I wanted to know if my HYBRID HONDA CIVIC 2010 would still start up and run if my hybrid battery pack dies ? If it gets started and i am able to drive it, will it affect the car anyhow (apart from few MPG less) on a long term ? Thanks in advance. N.R.
  8. P

    Does battery life decrease as current increases?

    I'm shopping for a battery-powered USB charger. Someone on Amazon says that as current (amperes) increases, battery life decreases exponentially. He says that using a charger with a current of 500mA gets you 30% more total power from the AA batteries than if you used a charger with a current...
  9. N

    Having 12V (cig. lighter) power supply on Suzuki GN125H

    Hello Guys My baby is a Suzuki GN125H (Bought in year 2013). I have been pondering for a while to have some kind of dash cam installed on her. Thus I thought to have a power supply installed so as to get power for the dash cam (only to be used when the motorcycle is ON and running). My...
  10. K

    Battery Charging: Impact on Battery Life

    Please if we charge battery with high voltage like the battery charge voltage 4.2v and we supply 5v, is that will reduce the battery life. Thank you
  11. A

    Optimizing Battery Performance for Increased Power in Automated Wheelchairs

    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...
  12. J

    Lithium Battery Life: High Setting, Cold Weather & Insulation

    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...
  13. S

    Questions about charging lithium batteries (to prolong battery life)

    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?
  14. ElijahRockers

    Detecting Remaining Battery Life

    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...
  15. A

    Calculate Battery Life - Get the Answer Now

    Hello, I have this circuit: And I'm using this battery: http://www.tme.eu/en/details/bat-6f22_gp/batteries/gp/gp-1604g/# How long will the battery keep supplying the circuit? Thanks !
  16. Q

    Battery Life Cycle: Explaining DoD vs Life Cycles

    Hello, I have seen graphs of Battery's DoD (depth of discharge) vs Life Cycles. But at the same time, "life cycle" is defined as the no. of COMPLETE charge-discharge cycles that a battery can perform before its nominal capacity falls below 80% of its initial rated capacity. Here's the...
  17. Square1

    Automotive Car battery life - playing radio

    How long have you ran your car battery running on "lowest key position", just playing the radio. How long do you think a 05 model should have it's battery last for this. Range? :]
  18. C

    Small GPS devices with long battery life

    Hi guys, I'm interested in developing a small gps receiver that I can fit into a certain object so that when it gets stolen I can send a text to it, find the coordinates and track it. The sixe of space for the gps device to sit in would be approx ∅30mm, length is not an issue. I am not an...
  19. R

    Solar panels - Direct charging and battery life

    Dear Experts There are solar charging devices in the market for electronic devices. These contain some electronics which I suppose is to regulate the power or as controller. Lets say I have a 6 volts device and I have a solar panel rated at 6v. If without any electronic controller...
  20. B

    Maximizing Laptop Battery Life: Tips & Tricks

    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...
  21. P

    What is the estimated battery life?

    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 =...
  22. N

    Maximizing Battery Life: Tips for Storing Electronic Devices

    So I know that when an electronic device powered by batteries is turned off, the batteries actually continue to move charge and will lose energy over time. I keep emergency flashlights in storage and I usually put one battery in them backwards so that a circuit is not completed. What I want to...
  23. rhody

    ITouch application: disable video, keep audio saving battery life

    I have a first generation Apple iTouch 16 GB, and frequently download podcasts to watch and listen to. With over 1 million applications written, I have searched in vain to locate an application that will allow you to launch a video, and instead of displaying video and audio to suppress the...
  24. J

    Calculating Battery Life: Is 0.05 Hours Correct?

    I am trying to determine how long a particular battery will last for my application. These numbers are just for an example. Battery stats: 12 V 7 Ah Application 1700 W Power=Current*Voltage 1700W = Current * 12V Current=141.7A Time = 7Ah / 141.7A Time = 0.05 hours Is this...
  25. B

    Accurately Calculating Battery Life

    :confused: Hello Could you tell me is there a way of accurately measuring battery life? Basically I have a listening device, it requires 2 x AA batteries, say 2400mAh each (so...4800mAh in total). I am aware you can ‘estimate’ battery life by determining the device’s current consumption...
  26. C

    Can Lead Acid Batteries Be Used in Parallel for Optimal Performance?

    Hello, I have 2 24V lead acid batteries in parallel to make a power supply for my circuit. I want to do some drain tests, and plot a curve for % energy remaining vs. time. The load on the battery isn't that large, and I don't want to have to supervise my experiment for 12 hours solid. Im...
  27. TheStatutoryApe

    Wireless Mouse Battery Life Issues

    I bought a fairly cheap wireless mouse a while back. With the batteries it came with it lasted quite some time, at least a few months, before it died. I bought new batteries from the store that were on sale and put one in. About a week later I found that the usb plug had come detached from...
  28. H

    Laser pointer and battery life

    I got a 5mW (class 3A), 650nm laser pointer yesterday and it came with 3 AG-3 button cells and over a day, it was on for about 60 seconds, maybe more however I noticed the beam wasn't as bright as it was when I first put it on. Over 30 seconds worth of use, it seemed to dim further until I...
  29. N

    150w inverter, 60w draw, car battery life?

    Using a 150w inverter to power the mac mini & LCD monitor in my truck camper. My Kill A Watt meter shows that the draw (on regular home power) is about 55-60 watts, or .05 KWH per hour. Can I assume that I could use this set-up for several hours, if need be, without danger of depleting my...
  30. DaveC426913

    Should I buy an aftermarket battery for my old Sony Ericsson T200 phone?

    My Sony Ericsson T200 cell phone is ~4 years old. (I know, vacuum tubes and dial knobs). It is no longer made. Thus, they no longer make the batteries either. My battery's life has become quite short, lasting only a day or two without use (it used to last all week), so I'd like to replace it...