battery

An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices.
When a battery is supplying 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, 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. erikatl

    So count me in for the 12 volt discharged battery problem

    I have been an almost perfectly happy MG4 owner since December 2022. A wonderful car. Returning from a two week flight to the Mediterranean, the 12 volt battery was dead and the car was towed away to our service centre. No cost for the towing (because of having a 3 year service agreement), but I...
  2. Gomev

    Is 'battery' getting in the way of battery things ?

    Just musing following reading another thread on here re Sodium batteries. The word battery conjures up images in my mind of torches being stuffed with Ever Ready D batteries (is it D ?), remote controls that last a year, buying rechargeable AA batteries that last 10 minutes when used with...
  3. M

    A little bit weird (mi/kWh increased to 9)

    A strange thing happened this morning whilst trying to charge my Trophy at an Instavolt charger. Payment accepted and confirmed, charger connected. Started countdown trying to connect after 40 seconds connected and then stopping message came up and charge full notice, but screen showed only 76%...
  4. EM11YLR

    1.5 T-GDI PHEV TROPY 5DR AUTO Battery question

    Hi, I bought a 2024 MG HS PHEV last week - only 6.000 miles on the clock. The only problam is when I charge to 100% i am only getting 30 miles range... I was under the impression it should be closer to 65 miles? Could there be a problem with the battery? Maybe its never been charged? Any...
  5. CyberNewbie

    Battery Pack and Battery Equalisation?

    The owners manual refers to charging time depending on whether you have a Battery Pack Type 1 or Type 2. I thought both models of the Cyberster had the same battery? How do I know what type of battery pack my GT will have? Re. battery equalisation, am I right to assume you just plug in at home...
  6. 5teep

    Sodium Ion battery

    This is VERY interesting news..
  7. GreenplatesGT

    Battery heating

    Does anyone know how to turn on the battery preheating while driving, for faster DC charging?
  8. M

    MG HS Hybrid battery drain

    Hi I took delivery of a new MG HS Hybrid on 27/6/2025. I have had to call MG assist 4 times due to flat battery. The car is going back to the dealer, but have requested a replacement vehicle. Has anyone else experienced this problem?
  9. M

    Does not charge above 40%

    Just brought my car to the MG garage. It turns out that my car does not charge above 40% (used different stations, speeds and passes) since a few days. Has anyone else had this problem? And what was your solution? The timing is very inconvenient, I was supposed to leave for a car camping holiday...
  10. D

    Ready but not Ready.

    Hi all, New here. I'm a Mechanic and have bought a faulty ZsEv. First off it had an isolation fault, due to water in the HV battery. That has been changed for a good used pack. The isolation fault cleared and the car now tries to go to Ready mode. When ready appears it then shuts itself off. The...
  11. L70

    MG4 Part Identification

    Hello, Does anyone know the name of this part of the MG4 please ? I think some rock tape on it. Have some people already changed it ? I also noticed that the plastic plates under the car are deforms and are very fragile. Thanks for your help.
  12. R

    49Kwh battery LFP?

    The MG dealer told me the battery is LFP but I couldn't find any official confirmation. Can you confirm that it is LFP? Thanks.
  13. Captain Slackbladder

    Large power banks

    Has anyone used large power banks to give themselves an ev boost? I was thinking of buying one for other reasons, but perhaps charging up on my overnight cheap tariff, and while I am parked up for a few hours away from home plugging the granny charger in and giving it a boost. Is this possible...
  14. R

    Why only 50% charge?

    Hi folks,my first time on here. My Mg4 trophy has recently been charging To just 50% max on home or public chargers. Does anyone know why?
  15. Alb

    What's the Record for maintaining Battery SOH at 100%

    I've posted about my own measurements via Car Scanner before but I got the official reading today at my 4th annual service and it's still 100%. Can anyone beat that?
  16. A

    MG4 Essence 64 Battery Preheating Advice

    Hey all I know this subject is old news but I’m late to the game. This is my first winter (Australian winter) with my car and I’m discovering just how drastically cold weather can effect battery performance. I tend to drive my car either in the early morning or late evening so it’s quite cool...
  17. C

    Battery Issues

    Hi. Anybody had any issues with their Battery (12 volt)? My Cyberster went back to the dealership and took 5 weeks to sort an issue out. When I got it back after two days the battery was knackered according to the AA.
  18. Seajays

    Had the Dreaded 12V Battery Drain Overnight

    So having never had an issue in the last year, and regularly checking the 12V battery every few months with a top up charger, I was happy that the 12V battery was good. Unfortunately on Saturday I went out on the dual-carriageway and it was raining, but not dark enough for the auto lights to...
  19. RTB

    Battery sign at bottom of pilot screen

    Hello all and thank you for all the help and advice that has been offered all very much appreciated for those who have read my posts you've probably guessed I'm getting on now, My previous vehicle was an Audi A3 Sport back I'd had it from new for 22 years and everything about it was straight...
  20. Patwww

    First Week MG3+ Questions

    New MG3 Hybrid+ picked up this week. Really nice experience so far, but ran into a few things that maybe more experienced owners can answer? We set the language to "German" via the "Entertainment" screen in the middle, and it shows everything in German. But the dashboard screen remains in...
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