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batteries

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 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. A

    URGENT No LED display on honeywell cm921 batteries all replaced & Checked. Ant thoughts pls

    No LED information on a Honeywell cm921. Batteries all changed & checked, any ideas pls. Can they be repaired or is it a new one required
  2. P

    Rechargeable Batteries For Drills?

    I have an older Bosch cordless (14.2V NiCad I think) which has been lying unused due to the battery pack dying. I noticed I can get replacement aftermarket batteries for it, but was wondering if anyone knows whether I can "upgrade" to a Li-on battery pack and if so, would they be compatible...
  3. H

    Flouroen NiMH 18V Batteries for DeWalt

    Bought 2 of these NiMH 3AH batteries on eBay for my aging dewalt tools. The batteries are made in China and look and feel like good quality items at a very good price. But be warned, they are rubbish. Both batteries from the off didn't seem to last as long as I hoped and I was constantly having...
  4. C

    Honeywell DT90E

    I replaced my old bellows type room stat a year or so ago with a Honeywell DT90E. All very good until this morning when it started cycling on and off about once per second. I took batteries out - they are still good - put them back and now all is normal again. Has anyone seen this before?
  5. M

    new dill required

    hi my dewalt drill has packed in my bugdet is £150 any ideas screwfix have some but dont know which is good or bad need it for my plumbing job thanks
  6. missplumb

    heat batteries.

    anyone seen these, they are still in development for use on district heating, but are available for hot water. Weve taken a single unit which will give upto 100ltrs of water at 60 degrees before the batteries are depleted. i think the technology is still off abit as to get the equivalent of a...
  7. M

    Can anyone please help me get my heating to work? I'm cold

    Hi, I hope it's okay to ask this on here! I have a Worcester green star 37cdi boiler, I still have hot water but heating is not working. I think it might be the wireless stat as I just changed the batteries in it. It's a pretty basic stat glo worm make. The only buttons on it is a up and down...
  8. Tommo25

    Milwaukee vs makita

    I like the look of the Milwaukee brushless fuel. How does it compare to the heavy duty makita version? Also which brand would you choose when looking down the range of tools for the future I.e. Circular saw. So that you can interchange batteries. Both milwaukee and makita are know to be market...
  9. Stanios

    Makita Battery Died

    Just had one of my makita 18v batteries die on me. Had it plugged into makita torch and it discharged untill light went out so maybe that has something to do with it. Put it on charge and it started flashing red and green. Any way to repair them or is it a goner?
  10. R

    Makita batteries

    Does anyone use the Makita lxt range? Genuine batts are £50+ fit bl1830 Copy batts £20 Is it a case of buy cheap but twice? Any experiences? Thx Rct
  11. R

    Battery operated sensor taps

    Ive been asked to replace 12 mixer taps with sensor taps in my local doctors surgery. Ive been looking at the ones that run on AA batteries rather than wired to the electrics. Does anyone have any experience with these, are they any good? Thanks
  12. W

    Hilti 15.6V drill driver with two batteries and charger

    As in title, one battery very good, the other fairly good but wont hold as much charge as the first. Drill in very good condition. Overall good cosmetic condition and well looked after. Includes carry case and charger £100 ono
  13. jaydebruyne

    Wireless Room Stats

    Went to a job today reporting of no heating. Heating only boiler with a cylinder for dhw - s plan. After creating demand on the water, confirmed the pump and boiler was fine. After testing I found the wireless receiver to be at fault - I bridged the common to the call and ran the heating, all...
  14. R

    Fein 18v cordless multimaster

    Hi guys, advice please....I have a lidl special multi tool/cutter but fancy getting a cordless Fein 18v as I hate cords, firstly are the cordless versions any good? They state that they are as powerful as corded. I have Bosch 18v everything but I'm liking the look of the Fein better due to Fein...
  15. Atouchofgas

    Metabo

    I see that metabo have released there new LIHd batteries with 6.2a, at a cost of £166 wonder if I should invest and get some batteries. What's the rest of the tool companies making?
  16. finchy01

    Ryobi lit-ion batteries dead.

    Hi all. I've not used my li-ion batteries for a good few months and they now won't hold any charge. At first I thought it was the charger as none would charge, but trying a different charger I'm getting the same problem. I've seen that you can boost them but not really sure what that entails. I...
  17. C

    How do you charge your rechargeable tool batteries?

    I was thinking of having a permanent set up in the back of the van for recharging batteries as I drive, using the power from the vehicle, so there will be no messing about or forgetting to put the battery on charge overnight Anyone got anything set up like this? Or any advice? I know this...
  18. L

    British gas stat

    Hi does anyone know the make of a common wireless stat by british gas? Its says british gas on the stat and receiver. Its an oldish wireless stat and programmer. I know it if I see it, but can,t find it on the net. It has 4 batteries. Lost the bloomin make in the van. Need to reset it tommorow...
  19. Z

    good 18v cordless?

    hi all, any recommendations on a good cordless 18v drill within a bugdet of £90? the one i have now just cant do the job anymore lol thanks zack
  20. P

    Winter vs batteries

    Do you all take your power tool batteries in from the van of an evening to prevent them getting damaged by the cold if indeed that is possible? Thanks in advance
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