How does battery chargers work?

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Discussion Overview

The discussion revolves around the functioning of battery chargers, including the principles of charging batteries, the role of AC and DC currents, and the implications of different charging methods. Participants explore both theoretical and practical aspects of battery charging.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether a capacitor is involved in the charging process and seeks additional resources.
  • Another participant describes the process of battery discharge and charging, suggesting that energy is merely transferred and noting potential hazards of overcharging.
  • Several participants discuss the concept of charging batteries from AC sources, with one asserting that there is no such thing as an AC battery and explaining the need for rectification.
  • There are mentions of transformers being necessary when the AC voltage exceeds the battery voltage, and the role of battery chargers in converting AC to DC.
  • Concerns are raised about the amount of current and voltage input to chargers, with participants expressing uncertainty about the implications of these factors on charging efficiency and battery health.
  • One participant emphasizes that the current supplied to the battery is limited by the battery itself and discusses the trade-offs between fast and slow charging.

Areas of Agreement / Disagreement

Participants express differing views on the specifics of charging methods, particularly regarding AC versus DC charging and the role of transformers. There is no consensus on the best approach or the implications of various charging parameters.

Contextual Notes

Some participants' statements contain assumptions about the nature of energy transfer in batteries and the technical requirements for charging from AC sources. The discussion reflects a range of understandings about electrical principles and battery technology.

Who May Find This Useful

This discussion may be of interest to individuals exploring battery technology, electrical engineering students, or hobbyists looking to understand the principles behind battery charging systems.

rsnd
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I mean do you input a lot of current and it has some sort of capacitor in it to sotore the charge? any links I can make use of?

Thanks heaps
 
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If this is not correct please inform me and I am sorry ahead of time. But if i remember correctly from my physics class the way the battery is used up is that the electrons from the negative end are all transferred to the positive end through a chemical reaction. The way you charge a battery is you reverse this process by giving the negative side a stronger positive charge making the electrons want to go back to the other side. To my knowledge there is no energy lost or given just transferred from one side to another. There is a limit to how many times you can reacharge a batter but it is a lot and you dotn have to worry about that. Also you could charge every battery but it wouldn't be wise to do it because the battery could explode spewing some battery acid around and That is not a good thing.
 
:bugeye:Hmm...how about AC batteries? e.g. If I wanted to store energy directly from an AC generator which is to act as a battery charger?

Thanks
 
rsnd said:
:bugeye:Hmm...how about AC batteries? e.g. If I wanted to store energy directly from an AC generator which is to act as a battery charger?

Thanks

There is no such thing as an AC battery. All batteries are DC.
If you want to charge a battery from an AC source, you must rectify the current. Noneed for a filtering capacitor, since the battery will act as a filter.
If the voltage ofthe AC source is much greater than the voltage of the battery, you will need a transformer to lower the voltage.
 
SGT said:
There is no such thing as an AC battery. All batteries are DC.
If you want to charge a battery from an AC source, you must rectify the current. Noneed for a filtering capacitor, since the battery will act as a filter.
If the voltage ofthe AC source is much greater than the voltage of the battery, you will need a transformer to lower the voltage.

Which is what, in most cases, the battery charger will do. It plugs into the A.C. and then outputs a D.C. voltage, and depending on the quality/expense of the charger, will also allow you to select various "current" ranges. That allows you to either charge the battery quickly, or more slowly. For an example, if it's the type of charger you use with an automotive battery, you might have a low current output of 2-10 amps, a midrange of 25 amps and a "heavy duty" output of 60 amps.
 
Well...thats a lot of current you are talking about! Please fix me up if i am wrong or there is a better way of looking at it! So It would not matter about what current/voltage I input to the charger, as long as I input a fare amount of each over time to make up for the energy I am trying to store for later use!

Thanks a lot!
 
rsnd said:
Well...thats a lot of current you are talking about! Please fix me up if i am wrong or there is a better way of looking at it! So It would not matter about what current/voltage I input to the charger, as long as I input a fare amount of each over time to make up for the energy I am trying to store for later use!

Thanks a lot!

If you are using an AC source, the amplitude of the voltage supplied to the charger is irrelevant. A transformer can drop the voltage to the value requested by the battery. The output voltage must be superior to the battery voltage in order to charge it, but the excess voltage should not be excessive, or you will damage the battery.
The current supplied to the battery is generally limited by the battery itself. AsBigBoa mentioned, more elaborate chargers, like the ones used in automotive batteries, allow a limiting of the output current and a longer charging time (fast charged batteries have their lifespan shortened).
The current input to the charger is limited by the output current.
 

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