Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [batteries]

An electric battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy.

An electric battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy. Each battery consists of a negative electrode (anode) that holds charged ions, a positive electrode (cathode) that holds discharged ions, an electrolyte that allows ions to move from anode to cathode during discharge (and return during recharge) and terminals that allow current to flow out of the battery to perform work.

There are primary cells, which are not rechargeable, and secondary cells, which are. Common types of batteries include lead-acid, alkaline, NiCd, NiMH, and lithium-ion.

Further reading

An Accurate Electrical Battery Model Capable of Predicting Runtime and I–V Performance (2005)

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Batteries. Why use 9V?

With all the technology available today with being able to boost voltage efficiently using SMPS, why do we still use 9V batteries? Is there some secret advantage with them that I am unaware of? If you look at the size as well, the 9V is just big…
MCG
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I am a quadriplegic. Would it be possible to power my ventilator humidifier with a battery?

I am an absolute novice in regards to electrical engineering, and so I am hopeful your expertise can guide me in the right direction. I know this is an unusual post for this forum, and so I thank you in advance for your consideration. First, let…
starbucksguy
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Does mAh measure how long a battery would last?

I know mAh tells how much milliamperes a battery can deliver in an hour. But does that also tell how many hours the battery would last? Sorry but I don't really get it. If we're talking about a water tank, to my impression, mAh is like how big the…
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Negative voltage on AA battery

Last night I pulled the battery holder out of a toy RC car to test the voltage with my meter. The pack has 4 AA batteries. The combined voltage at the terminals of the pack was well under 1 volt, and then I tested each battery individually. These…
Carl Raymond
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Are coin cells a suitable replacement for AA batteries?

I am currently using AA batteries in my projects but would like to look at cell batteries for my next project, due to their compactness. Apart from the physical appearance, how do cell batteries differ from the more chunky AA batteries? (I am…
Mr. Hedgehog
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Why are so many batteries 3.7V?

This seems like a very common voltage. I remember older batteries used more round numbers like 1.5V or 3V or 9V. 3.7V seems very arbitrary but seems to be everywhere.
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Adding mAh when wiring battery cells in series?

When combining battery cells in series, the voltages of the cells are added to get the voltage of the final circuit. Do the mAh add up, or stay the same? For example, suppose you have two 3.7V cells, each with 200 mAh capacity. When connected in…
Mark Harrison
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How can embedded systems estimate their battery status so precisely?

As I understand it, the terminal voltage of batteries changes a little on charge/discharge, but these changes are minimal compared to other effects (temperature, minor manufacturing differences, recent charge/discharge history, etc). But even the…
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How can I tell how much juice a LiPo battery still has in it?

Suppose I have a circuit that draws its power from a LiPo Battery. I would like to know how much power the battery still has in it. Ideally a circuit of power level to voltage will be best .. this way I can connect the output of that circuit to a…
Atrigen
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What electrical design reasons are there for making rechargeable batteries non-removable?

There are lots of consumer devices that run on rechargeable batteries and have those batteries non-removable without disassembling a device. The most notable example is I guess an iPhone. Making a battery non-removable has these advantages: simpler…
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Battery (Li-SOCl) voltage varying with orientation

We are using this 3.6V Lithium battery (ER14505) to power the micro controller circuit in one of our devices. The device is capable of reporting the battery level. Since the controllers brown-out threshold is at 2.7V we use the range from 2.9V-3.5V…
Rev
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Do batteries lose voltage as they're used up?

V = IR Resistance stays same, and I know as a fact that I (or current) decreases (my stuff runs slower on old batteries). So could a 9 Volt battery turn into a 1.5 volt one?
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Why is no capacity indication on regular batteries?

On every rechargeable battery there is an indication how big the capacity is (for example 2500 mAh). Why is this not the case with normal (nonrechargeable) batteries ? I tried to google the question but found no answer.
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Function to describe alkaline battery voltage under constant current / load

Introduction Commonly used alkaline batteries (Duracell etc) have a pretty interesting discharge curve. For example, an AA duracell has the following voltage characteristics under constant load, and constant…
geometrikal
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Integrating battery and battery charger with my project - I never want to remove batteries from this device for charging, how do I do that?

(I used to design and build electronics - HiFi, automation, digital systems up to and including CPU-based controllers - so I have a good understanding of the basics. I just stopped being involved in the field about 15 years ago, so my knowledge of…
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