What is Charger: Definition and 107 Discussions

A battery charger, or recharger, is a device used to put energy into a secondary cell or rechargeable battery by forcing an electric current through it.
The charging protocol (how much voltage or current for how long, and what to do when charging is complete, for instance) depends on the size and type of the battery being charged. Some battery types have high tolerance for overcharging (i.e., continued charging after the battery has been fully charged) and can be recharged by connection to a constant voltage source or a constant current source, depending on battery type. Simple chargers of this type must be manually disconnected at the end of the charge cycle, and some battery types absolutely require, or may use, a timer to cut off charging current at some fixed time, approximately when charging is complete. Other battery types cannot withstand over-charging, becoming damaged (reduced capacity, reduced lifetime), over heating or even exploding.
The charger may have temperature or voltage sensing circuits and a microprocessor controller to safely adjust the charging current and voltage, determine the state of charge, and cut off at the end of charge.
A trickle charger provides a relatively small amount of current, only enough to counteract self-discharge of a battery that is idle for a long time. Some battery types cannot tolerate trickle charging of any kind; attempts to do so may result in damage. Lithium ion battery cells use a chemistry system which does not permit indefinite trickle charging.Slow battery chargers may take several hours to complete a charge. High-rate chargers may restore most capacity much faster, but high rate chargers can be more than some battery types can tolerate. Such batteries require active monitoring of the battery to protect it from overcharging. Electric vehicles ideally need high-rate chargers. For public access, installation of such chargers and the distribution support for them is an issue in the proposed adoption of electric cars.

View More On Wikipedia.org
Recent contents Top users
  1. G

    Solar Panel Charger Project: How Do Modern Smart Chargers Work?

    The Maker Greetings, I saw a slew of discount solar panels and I want to use one to power my iPhone or possibly netbook. I’ve researched this but it seems the more I learn the more I realize how little I actually know. There appears to be a wide variety of charging circuits and methods...
  2. A

    Why does this NiMH solar charger work?

    I'm new to electronics and have been looking into building a solar cell charger for NiMH batteries. I got hold of a pair of small solar panels rated at 5v open circuit voltage, and 100mA short circuit current. I confirmed this under bright sunlight with a multimeter. Each panel will easily...
  3. M

    How Does a Battery Charger Work and What Causes Overcharging?

    I'm thinking about all types of charging (LiIon, lead acid, etc.). I get the basics...but would really enjoy more info on the subject. Also...one thing that confuses me is how you can "overcharge" a battery...and how you can supply too much current (amps) to the battery. Since its generally...
  4. R

    Understanding Charger Circuits and Diode Voltage Drop

    Dear Experts I just connect a diode to a battery rated at 4.2 volts. The diode takes about 0.8volts ( i thought should be 0.7v but measurement says 0.8v) and the battery is currently at 3.12v. The supply voltage is 5v dc. After some time, if the battery reaches 4.2v, would current...
  5. B

    Why Phone Charger Makes High Frequency Sound

    Hi. I noticed that my phone charger (output: 5V DC) makes a constant high pitched noise when plugged into the wall. It's not too loud but you can hear it when you are within maybe 4 ft of the charger. When I plug my phone in, it starts making intermittent noises. I was wondering what this could...
  6. R

    Mobile phone emergency charger

    Dear Experts I bought a single-AA battery emergency cell phone charger. It is rated at : output : 5.6 v +/- 5% current : 400ma I plugged it to my samsung note and the phone detected the current and showed it was charging. At that time, the battery was charging from 75% level...
  7. R

    Faraday Flashligh = Cell Phone Charger?

    Hi, I am an engineering student, and I have an idea for a project, but I am not sure if it is viable. I want to make an article of clothing such as a jacket with several mini faraday flashlight-esque devices inside. They would be connected, and would charge a cell phone or other electronic...
  8. Z

    Maximizing Wireless Charger Efficiency

    hi... now I am in progress to do a wireless charger pad by using coil. so I've seen a lot of project regarding to this wireless charging. do u have any idea how can i make it more efficiency? meaning that how can i get a maximum power transfer while transferring the power from Tx to Rx...
  9. M

    Voltage limiter for Cockroft/ walton cap charger

    Hello, I'm trying to design a capacitor charging circuit using a Cockroft-walton voltage doubler circuit. My mains voltage is ~220 Volts and the output would be 220*2 = 440. My capacitors are rated for 500V which means that they can be charged safely to about 400V. Is there a circuit...
  10. M

    Hand crank generator battery charger circuit

    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,
  11. O

    Battery AH and Deep Cycle type & Charger suitability

    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...
  12. G

    How can I create a continuous UPS using a 12V 7Ah battery and an adapter?

    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...
  13. L

    Creating a battery charger indicator

    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...
  14. F

    Hybrid Battery Charger Question/Idea

    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...
  15. O

    Charge lipo battery packs with a li-ion charger?

    charge lipo battery packs with a li-ion charger? hello. i am wondering if it is possible to charge lipo battery packs with a li-ion charger. for example what i eventually want to try is to replace the li-ion batteries of my laptop with lipo battery packs. so if i remove the original...
  16. V

    Samsung mobile charger difference in power

    Hi friends, I have a samsung mobile charger with specifications as Input: 150-300V AC and 0.15A Output: 4.75V DC and 0.55A So now by P=VI the input power is 36W (taking 240V AC and unity PF) and output power is 2.6W. So my doubt is why there is such difference the power of i/p and o/p...
  17. F

    Air compressor calculations for engine super charger

    I am an engineer but have a rather dumb question regarding superchargers for engines and probably compressors in general. Most specifications are give as XXcfm at XX psi. I am trying to understand if this truly means we are moving that amount of air at the rated psi or if that means that...
  18. J

    Charger could be there connected to mains all the time

    Hi Suppose my phone charger is connected to the mains but the phone is not connected. The circuit is not complete because the phone should be there to make the connection complete. That means current is not flowing? That would mean the charger could be there connected to mains all the time...
  19. K

    Can I Use a Different Charger for Xbox?

    Sorry if this question is really stupid. I tried to look for calculators but wanted to be sure. I have an original Xbox but no power cord for it, however I have an extra power cord for something else that fits perfectly. I want to know if I can safely use it. Xbox: 100 V - 127 V ~ 2.1A...
  20. A

    How Effective Are Human-Powered Chargers for Everyday Use?

    Homework Statement Can some one please help me out on this, i can't seem to get my head around it. Regards, Rob
  21. E

    Li+ battery charger chip without buck

    hi I want to design a 4 cell (16.8V) lithium ion battery charger. The normal chips available have built in buck (reall buck or synchronous buck) or at least control circuitry for buck with external mosfets. This is necessary as wall adapter/source input voltage are higher and unregulated...
  22. K

    Battery Charger using LM317

    I'm designing a battery charger consisting of an LM317. The regulator will charge three batteries successively, for example, when battery 1 reaches a terminal voltage of 13.8, a voltage comparator will activate a relay that will switch on the second battery while switching off the switch for...
  23. M

    Too Long on the Battery Charger

    What happens if re-chargable batteries are left too long on their chargers? is there a fire risk? do some of them such as the ones used for moble phones and chordless power tools have some sort of cut-off safety mechanism?
  24. D

    Turbo Charger Design: Compressor and Turbine Blades

    Hello can anyone please provide me with some insight about turbo charger design? Specifically referring to the compressor and turbine blades? My inquiry is more directly aimed at the number of blades. On different turbos they use different numbers of blades and I'm wondering if a higher number...
  25. S

    Why Does My Battery Keep Running Down in a Closed Loop Charging System?

    Hi i embarked on a project to design a battery charging system using an alternator, an electric motor and a battery all connected in a closed loop. The battery powers the electric motor and in turn the electric motor powers the alternator and finally the alternator charges the battery. My...
  26. A

    Work done by a battery charger

    Homework Statement To recharge a 5V battery, a battery charger must move 7x10^6 C of charge from the neg. to pos. terminal. How much work is done by the charger in joules? Homework Equations QV=U The Attempt at a Solution If the battery needs to be recharged, isn't the potential...
  27. R

    How does a battery charger know when to stop charging?

    Dear Experts, I am fascinated how a cell phone battery charger knows when the battery is fully charged such that it cuts off the power to prevent further charging. If its based on sensing a particular voltage has been reached, i wonder how is that achieved? Or is it achieved by measuring...
  28. N

    Can a 50Hz Transformer Handle High Frequency Capacitor Charging?

    With all courtesy to Mr William Nechefski for this circuitry. I have gone ahead to build this circuit. Everything is the same except the transformer. I had a old transformer with was used to step down from my 50hz mains. Primary 12-012 Secondary 0-230V Power 12VA My transformer has a...
  29. zoobyshoe

    What is the correct polarity for a phone charger cord?

    I sat the leg of my chair directly on my phone charger cord and severed it in two. Now I need to know what polarity the part that plugs into the phone is supposed to be. It's a small, flattened kind of plug, sort of like a mini USB plug. Is there an engineering convention that...
  30. G

    Electrical How difficult to build a DIY Lithium Ion Battery Charger?

    Not asking for a schematic, more a notion of roughly how challenging this will be.
  31. N

    AC Battery Charger: Exploring its Effectiveness for Charging Batteries

    AC battery charger? Is there such a thing as being able to charge a battery, using alternating current, or would the sweeps invariably be ineffective in giving a charge to the battery?
  32. O

    Do I Need a Resistor to Lower Voltage for a Solar Cell Phone Charger?

    I'm planning on making a simple solar powered cell phone charger for a demonstration speech in my gen-ed speech class because it seemed like it would be fun at least. The best solar panel I could find for cheap has an output of 6v and 50 mA. My cell phone charger has an output of 5.0v and 700...
  33. 0

    Swap batteries between an experiment and a charger

    I would like a switch to seamlessly swap batteries between an experiment and a charger. Here is the description of the switch I am looking for. Originally I1 is connected to O1, I2 to O2 and so on. On turning the switch these things should happen in order: 1.) I3 and I4 are disconnected...
  34. K

    How does a battery charger work?

    I have little idea on how a battery charger works but i'll just state here what I think is the case and then state my queries. When you receive an AC input from the mains there is first a step down transformer which lowers the voltage - then there is some regulation and it is converted to DC...
  35. V

    Accumulator Battery Internal Resistance & Charger Potential: A Doubt

    This is in continuation to https://www.physicsforums.com/showthread.php?t=330495 The question that initiated my doubt reads this -- " the internal resistance of an accumulator battery of emf 6V is 10 Ohm when fully discharged . as battery gets charged up , its internal resistance drops to 1...
  36. A

    Capacitor Charger | LED Illuminate when Complete

    I'm looking to assemble a capacitor charger in a nice, durable enclosure. I already have the DC to HV DC converter. I'm just looking, now, for a way to indicate when the capacitor is fully charged, practically identical to how a flash-enabled camera indicates when its capacitor is charged and...
  37. B

    How Do NIMH Chargers Detect End of Charge?

    i am intersted in the end of charge detection(-deltaV) on some NIMH chargers, i would like to test that effect on some chargers. I got some chargers(like GP Smart power bank, GP H500,etc...),all the chargers i have use the drop of voltage as end of charge detection, so what i did is, I...
  38. U

    Can a TRIAC be used to reduce power consumtion for a charger?

    If my understanding of triac's is correct then the triac will conduct current until the amperage flowing though it drops below the threshold. If that is true would adding a triac before the primary induction coil reduce power consumption? If it did, how would the you reestablish the...
  39. S

    Discover the Best 12V Solar Charger Circuit for Your FYP Project"

    hello all...i just get my fyp...the title above... can someone help me find the circuit?
  40. U

    Can a laptop charger be made vampire-proof with a timer and check circuit?

    I am trying to build a vampire proof laptop charger. Vampire proof meaning that the charger will not consume power when it is not needed. The simplest way to do this is to unplug the charger. However the charger is often in hard to reach places, and unplugging it means climbing over...
  41. D

    What are the best settings for charging a 24v 12ah Lead Acid Battery?

    Hi, can someone tell me what are the optimum settings for a charger to charge a 24v 12ah Lead Acid Battery? I know that the voltage stays the same. I just need to know what current will cause the faster charging and, at the same time, won't destroy the battery.
  42. B

    Li-Ion Constant Current Constant voltage charger

    Hi I need help designing a constant current constand voltage charger for li-ion batteries. Anyone have any help? Whats the best method of constant current. It will be high current over 1 Amps Thanks
  43. S

    Which Laptop Charger is More Efficient for a 65W Rated Laptop?

    A laptop charger rated 19V 2.64A and another rated 19V 3.42A what advantages would one have over the other.If I am using it for a laptop rated 65W
  44. M

    Old Battery Charger for RC Car in Wichita KS - Can it Charge Ni-H Batteries?

    moe in wichita ks i have a old battery charger, about 15 years. it is for charging 2 or 4 ni-cad AAs, 500 ah, for a radio control car. input 120/60 9w. out put 5.8 volts 500ma dc, charge time 1 hr. my Q is can this charger work on ni-h batterys? thanks
  45. S

    6volt backup battery circuit with auto charger

    hello every one! due to frequent power outages in my area, the lan switches at different locations stop working. so either the light is out or the switch is not working which is really irritating. so can some one help me with a circuit that can supply 6 volts for the switch in case of...
  46. N

    What is the simplest circuit for limiting charging of 1.5v batteries?

    I have a cheap set of wireless headphones where the base unit supplies a voltage to the headphones to charge the 2 AAA NiMh batteries. However it has not cut-off point, ie. it'll charge indefinitely destroying my rechargeable batteries. I'm looking for the least complicated circuit that will...
  47. J

    How Do You Calculate the Variable Resistance for Optimal Battery Charging?

    Homework Statement http://img2.freeimagehosting.net/uploads/bf073a5eb1.png http://img2.freeimagehosting.net/uploads/bf073a5eb1.png Determine the variable resistance R if the 25 Watts to be absorbed by the battery (0.035 ohm resistor and the 10.5 V element). Homework Equations V = IR P =...
  48. Z

    Automatic Charger Circuit for 12V 10A Battery

    Homework Statement i need to build a circuit which can charge a 12V 10 A battery to reach a votltage A and then stops charging until it reaches a voltage B it will rechrge again . i want to do this using thyristor Homework Equations The Attempt at a Solution i found a circuit...
  49. N

    Electric Fence Charger for Securing Trash in Truck Bed

    I recently had trouble with cats getting into the back of my pickup and tearing into the trash bags I have before I can dispose of them. I decided to hook up my spare electric fence charger, which puts out a pulse about every second. The bed of my truck has a plastic liner, so it's insulated...
  50. ranger

    Can a wireless charger eliminate the hassle of tangled cords?

    There have been a few posts about wireless power transfer here on PF, so some of you may find this useful. I came across this post in another forum about designing a wireless battery charger. The author gives a rather through description of what's going on and why he's doing certain things...
Back
Top