Read about batteries | 44 Discussions | Page 1

  1. narayan821

    Does DC or AC work best for charging most industrial batteries?

    I have a source of electricity that's alternating but at variable frequencies. So an asynchronous alternating current of sorts if you will. Can industrial rechargeable batteries be charged like this efficiently? Or would DC current work best? Or normal AC?
  2. Kaushik

    B Intuition about electromotive force (EMF)

    My understanding of emf Let us consider 2 parallel plates with charges (opp. but equal in magnitude) stored on it. When we connect both the plates from the outer side, the electrons from the lower potential (i.e., negatively charged plate) moves to the higher potential (positively charged plate)...
  3. P

    I Difficult Series Battery Problem

    Modern batteries use double-sided anode and cathodes for greater energy density. Series wiring of batteries is typically accomplished by connecting the anode of one cell to the cathode of another. However, can series be accomplished by stacking double-sided anode and cathode alternatingly with...
  4. Stonestreecty

    I How do I know the lithium content of a lithium-ion battery?

    Power bank is common for our daily life, especially for our smart phone, which always a lithium-ion battery. Taking airplane is easy at our daily life, but there are restrictions on lithium content for air travel, thus air travelers ask the question "How much lithium in a battery am I allowed to...
  5. W

    I Electrons @ battery negative terminal

    Does the negative terminal of a battery have a negative charge due to having a surplus of electrons? If so, then why do the surplus electrons from the negative terminal of the battery not discharge to the human body or earth (which have a neutral charge) when touched?....thereby causing the...
  6. SchroedingersLion

    Batteries: Is the current a diffusion current?

    Greetings, I realized that I don't understand a fundamental fact of common Li-ion batteries. During the charging process, electrons are forcefully extracted from the cathode and pushed into the anode. Charge balance then yields a flow of positive Li ions from the cathode to the anode (through...
  7. S

    Battery Charge and Discharge Time Calculations

    I am performing some calculations but struck with confusion whether I am doing it correct or wrong due to contradictions of these calculations on different calculators websites. I hope here someone will help me with the validation of my calculations. Battery Capacity = 150 Ah Battery...
  8. M

    I Would a giant orbital gravity battery be a good future power source?

    Gravity batteries intrigue me. We are starting to develop them now. We currently are able to drop cement blocks and harness the energy that the kinetic energy releases. We are considering them as an alternative energy source to help the environment. Here’s a link for those unfamiliar with it...
  9. P

    I Would a charged lithium battery combust more energetically?

    Conceptually this question makes sense to me I know a overcharged lithium battery will became unstable however with identical batteries except a different level of charge what would the properties of their combustion be? In depth conceptual, and mechanical explanations are always appreciated as...
  10. Brett Anthony

    Batteries in Parallel, One Reverses Polarity

    So, some time after getting a new car the batteries on my FOB died. So I went in and replaced them, two CR2016's was all that was needed (on top of each other in parallel). No more than a month later I noticed the battery felt like it was dying already (light not as strong, delay on the actions...
  11. R

    Could you create a battery powered plane?

    After watching a video on YouTube, I recently became interested in the dynamics and physic's of why we aren't using electrical powered planes instead of burning thousands of fossil fuels every day. After doing a bit of my own research, I found the problem. When we increase the weight, we have to...
  12. J

    Observed battery set discharge unbalance

    I previously posted the below as a footnote on one my posts on the Mechanical Engineering Forum and it was suggested I start this thread on the subject here. "PS On a general note about battery replacements. On my field GPS I use rechargeable batteries and always test them before recharging...
  13. C

    How to calculate the accurate capacity of a battery?

    I'm trying to figure out how to calculate how much energy is stored in a battery between certain voltages. I know capacity is traditionally calculated by multiplying amps drawn by nominal voltage by time, but this seems like an approximation because voltage decreases as the battery is...
  14. L

    Energy Systems and Optimal Control -- combining energy storage systems like flywheels and batteries

    I'm currently working on combining energy storage systems like flywheels and batteries to balance consumption/regeneration. I've been looking at using an optimal control scheme so that a cost function can be tailored to our wishes. I'm curious about what other people in this field have been...
  15. A

    Are the terminals of a Battery neutral?

    So I've been learning how batteries work. What I learned is that a battery consists of 2 pieces of metal both with different electronegativities. These metals react with an electrolyte. One metal (called the anode) is oxidized and has its electrons removed, leaving behind a positive ion which...
  16. A

    I How do Batteries Work?

    So I understand in a battery that an anode (such as zinc) and a cathode (such as carbon) are separated by an electrolyte. I also understand that the electrons want to flow into the cathode, but can't get to them, so as soon as a conductor connects the two terminals, current can flow. However...
  17. T

    B In batteries, does stored energy vary with battery voltage?

    Hi For a 1200 watt tool, there are 20, 40 and 60 volt batteries, and in the case of a 2 amp hour (7200 Coulomb) battery, using energy = charge x voltage gives different values of stored energy for each of the three batteries, which are 144000, 288000 and 432000 Joules. Is this correct? Thanks
  18. M

    Can rechargable Li-ion batteries be rebuilt?

    After so many cycles, rechargeable Li-ion batteries powering electric cars go bad. This I know. I am wondering what goes bad? Is it the electrolyte, the electrodes, or both? And in general, could it be possible to take these degraded battery components and fix them? Thanks in Advance! Mike
  19. J

    How much energy is stored in compressed air?

    Hi all, My name is Jesse and I love renewable energy and finding ways of beating coal. Right now Solar Photovoltaic energy competes with coal in sunny areas during the day, but at night, you need to store the energy from solar and it's not worth it due to the cost of storage mechanisms (might...
  20. Mzzed

    Simple Battery Misunderstanding

    If a small voltage - say 1V, is applied to the negative terminal of a 1.5V alkaline battery (although I don't think the type of battery matters?) will this create a current between the 1V and the negative terminal until the charges are somehow balanced? If not, what will this situation do to the...
  21. D

    Engineering Chemical vs Mechanical Engineering

    I am a high school senior caught between these two fields. they both seem very exciting and I am not sure which would be better suited for my interests. In high school, my favorite subjects have been Physics, Chemistry, and Computer Science. I am interested in working to develop: -more...
  22. P

    Find currents I1 and I2 in a 3-loop, 2-battery circuit

    Homework Statement Find currents I1 and I2 in the following circuit: Homework Equations I know I have to use Kirchoff's loop rule but I am not sure of the current going through the 5 ohm and 8 ohm resistors, is it just I1 and I2 respectively? Also do I incorporate the large loop at the...
  23. S

    A Physical Understanding of Kirchhoff's Laws

    < Mentor Note -- thread moved to the EE forum from the Homework forums since it is a more general set of questions > So, we are going into Kirchhoff's Laws in class, and my entire understanding of circuits, which took me a while to form, is again falling apart. A physical understanding is...
  24. T

    Batteries connected in parallel - Amps won´t add up?

    Batteries are connected in parallel. Multimeter shows: 1,5V AND... "0.12A" regardless of battery number. Volts stay the same but should not Amps add up in parallel? "0.12A" with 4, 5 or 6 batteries... Details: Amps measured correctly by closing the circuit with multimeter probes (bulb lights...
  25. G

    B Please help me understand how a battery works

    There is an explanation of how a battery works that says that in a battery circuit, the electrons do a complete loop and, given enough time, they can return to their starting point. This theory says that when the electrons arrive in the positive terminal and they lost all of their potential...
  26. A

    I Help with Experiment on Batteries

    Hi guys!! I am currently having Physics Internal Assessment in my school and I want to do an experiment to calculate the different times it takes for a 9V cell to to discharge (reach a 0.1V) in different temperatures. The problem I am having right now is to efficiently discharge my cell. How can...
  27. cyril joel

    Dc motor

    Hello i am abeginer i have to connect a 12v dc motor can i connect it to two 9v batteries in series meabs a total output of 18V.
  28. P

    Charging of a battery

    A battery has an Emf 6 Volts. It is completely discharged. It is charged by maintaining a potential difference of 9 Volts across it. If the internal resistance of the discharged battery is 10 ohms, find the current through the battery, just after the connections are made. My textbook says that...
  29. P

    How to shut off Led on buck converter

    I am using a buck converter with a battery pack, for a usb charger. The issue is, is that the buck converter I have ( http://www.ebay.com/itm/DC-Converter-Step-Down-Buck-Module-7V-24V-to-5V-3A-5V-usb-output-power-adapt-/261030150117?hash=item3cc69bffe5:g:Q3UAAMXQTT9R0Qos ) has a led on it, which...
  30. S

    Charging a battery from a fluctuating, unpredictable source (pedal-powered dynamo)

    So I want to charge a battery from a pedal-powered dynamo, and use that to power my PC, my screen, and pretty much everything else in my home office. This whole thing is a little project to improve my own health while I'm working; I'm not here expecting to make major miracle savings on the...
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