batteries

  1. 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...
  2. 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...
  3. 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...
  4. 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...
  5. 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...
  6. 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...
  7. 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...
  8. 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...
  9. 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...
  10. 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
  11. 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
  12. 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...
  13. 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...
  14. 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...
  15. P

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

    1. Homework Statement Find currents I1 and I2 in the following circuit: 2. 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...
  16. 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...
  17. 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...
  18. 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...
  19. 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...
  20. 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.
  21. 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...
  22. 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...
  23. 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...
  24. JordanHood

    Maximum power from a battery with source resistance

    1. Homework Statement A 5V battery rated at 1800mAh has a soucre resistance of 10 Ohms. What is the maximum power that can be extracted from the battery? 2. Homework Equations 3. The Attempt at a Solution I understand that had the battery not had any source resistance then the power out...
  25. C

    Desulfation of batteries

    What are the methods of dissolving sulfate crystals that form on the lead plates in a lead/acid battery?
  26. C

    What happens when we connect 2 batteries + with +, - with -?

    1. Homework Statement Batteries are connected together with their + and - poles. 2. Homework Equations 3. The Attempt at a Solution I quess that nothing happens because there is no change in potential difference.
  27. Nader AbdlGhani

    Maximum Current Intensity

    1. Homework Statement How can I get the maximum Current Intensity by connecting 72 cells to a 3 Ohm resistor each cell has a potential difference of 1.5 Volt and internal resistance of 1 Ohm Please don't tell me to connect them all in parallel or all in series as in parallel the potential...
  28. J

    Emulating car battery output through home power?

    I'm setting up an amplifier which is intended for use in a car, and I'm not using it in one. I'm trying to power it through a typical DC 250 volt wall outlet. What kind of transformer should I use? (I'm also trying to power a car stereo with it as well)
  29. ryanuser

    How to store electrical energy?

    Hello I made a little wind turbine so when it is directed at wind it turns and generates electricity as I can see the outcoming voltage on voltmeter. My question is how can I store its energy? Can I use a rechargable battery and let it run out, then stick copper wires at each sides of it coming...
  30. O

    How to hook up a 12-24v system to a battery pack

    I'm working on a very similar issue to the one shown below https://www.physicsforums.com/threads/linking-battery-packs-to-change-voltages-and-how-to-charge.514002/ I've found some batteries that should do the job. i need to keep them fairly small, and the length of charge doesn't matter too...
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