Batteries Definition and 464 Threads

  1. J

    Same load one or three batteries

    I am drawing 12 volts at 1/2 amp for 6 hours a day off of one 12 volt car battery battery which is powered by a 2 amp solar charger voltage goes to almost 14 volts when charging I then added two more car batteries voltage is under 13 volts when charging with the same load is it better to use...
  2. M

    Chemical Batteries (Car Batteries)

    Why does the effectiveness of a car battery seem to drop off rather sharply when the voltage gets a bit below 12? I would think it would be more or less a linear decay of current ( I = V/R etc). Thus one would think that the current generated would be proportional to the voltage but anyone...
  3. Femme_physics

    Connecting 4 Batteries for 24V: Case A vs Case B

    Given are 4 batteries whose value for each is 12 volts. Connect all 4 batteries in such a way so you can get a general voltage o 24Volts http://img208.imageshack.us/img208/4452/kasht.jpg Case#A is my original solution My classmate asked me why not case#B...I think it also possible...
  4. A

    Solving 2 Questions on Circuit Analysis: PD Across 3 Ohm & EMF of Batteries

    Homework Statement I have two questions. Both questions are in the picture below. Dont mind my workings lol http://img163.imageshack.us/img163/5680/scanpic0001qe.jpg Ans to the 1st qn: C The potential difference across the 3ohm resistor is zero. Thus, it can be considered that the 4ohm and...
  5. johann1301

    Circuit with 2 batteries when one has a reversed polarity

    What happens if you take let's say a 12 volt battery and connect it to a lightbulb(not LED). Well... the lightbulb lights up obviously! But then connect a 6 voltage battery also(in series), but with reversed polarity (against the current that is). What happens then? Will there be a shortage...
  6. L

    Leaky alkaline batteries - did I clean up enough?

    Hi everyone, I was cleaning up my computer room/office today, and I found a plastic bag on a shelf with 4 AAAs inside that had white corrosion all over them. I did some Googling and I am guessing the leakage was likely potassium hydroxide. The batteries must have been about 10 years old...
  7. H

    When do batteries drain more quickly?

    Will a battery (for eg AA 1.5V) drain out faster when connected to 5 similar bulbs in parallel as compared to only 2 bulbs in parallel? What I really want to know is that when we connect MORE bulbs parallel to a battery, does the battery have to do some extra work for managing more number of...
  8. M

    PEM Fuel Cells vs Batteries: Understanding the Difference

    hi I've got to do a project for college and need some direction I want to know a few things more so if you can help let me know. some of the things include (if you could answer any it would be useful): why can't we make a longer electric current to harness all the electricity produced in a...
  9. L

    Question about battery amp hours

    Question about battery amp hours Hello, A particular manufacturer has two Lithium-ion batteries available for use in a cordless tool. One battery is rated at 2.4 amp hours, and the other is rated at 1.5 amp hours. Given that both batteries are brand new and fully charged, is the...
  10. T

    Batteries in Parallel and series

    Homework Statement You are given two circuits with two batteries of emf "E" and internal resistance R1 each. Circuit A has the batteries connected in series with a resistor of resistance R2, and circuit B has the batteries connected in parallel to an equivalent resistor. Note that the symbol...
  11. H

    How Electric potential and potential difference work in batteries

    How is electric potential manipulated in batteries? Why do some batteries have a rating of 1.5v and others have ratings of 1.25v? I'm not looking for the answer of "its the materials used in the chemical reaction" because I know that.WHAT DO THESE MATERIALS DO DIFFERENTLY TO THE PHYSICS OF THE...
  12. R

    Converting a toy that runs on batteries to wall power

    In a desperate search to find a bubbly little icon for my aquarium, I came up disappointed and learned that nothing I grew up with was available anymore because it contained lead based paint. The disappointment quickly transformed into a challenge that got me excited. I was looking at a...
  13. C

    A kirchoff's law question with multiple batteries

    Homework Statement To find the voltage at the 5 ohms resistor. Homework Equations V=IR Kirchoff's first and second law The Attempt at a Solution The attempt was simply too long I ended up with a voltage of 6.5V on the 5 ohm resistor... Please help me, I have been stuck in this...
  14. P

    Constant Current in Batteries? How?

    I do not know the exact electrochemical reactions which make a battery work, but I understand that the essential anatomy of a battery is a cathode and an anode separated by an electrolyte, and the anode absorbs electrons. When the battery is connected to a wire, the electrons move from the anode...
  15. P

    How do I properly charge a VRLA battery?

    hello, pozdrav my question is about Valve Regulated Lead Acid battery. may i charge it only with "float" voltage (cca 2,25 Vpc) or do i have to "boost" it (2,4 Vpc) sometimes? if my battery gets discharged to 20% can i recharge it only with "float" voltage? i have capacity cca 150Ah...
  16. V

    How Cell Phone Batteries Calculate Remaining Charge

    I do not know to which section this question belongs correctly. The question is : How does our cellphone calculates or knows the percentage of battery left?
  17. R

    Eneloop batteries unable to charge phone?

    Dear Experts i have 4 new eneloop AA batteries in series making 5.5v , all fully charged. I connect this to samsung note battery level at 75%. Phone detects charging. 10 mins later, status quo. Not sure why? Thanks for reading. Best regards Ramone
  18. A

    Why does voltage increase when batteries are connected in series?

    Hey! I am looking into how batteries work but I can't understand why -- from a chemical perspective -- voltage increases when they are connected in series. Let's say we have two identical batteries: battery 1 at the bottom and battery 2 on top, connected in series. The negative bottom end...
  19. A

    3 batteries, 5 resistors using KCL & KVL

    Homework Statement 1. Using Kirchhoff’s Laws, find all the currents flowing in the circuit. 2. Hence, determine the voltage across each resistor and show that all loops comply with KVL Homework Equations KVL and KCL The Attempt at a Solution Please see the pictures...
  20. S

    Circuit With Three Batteries Two Resistors

    In the above circuit: V1 = 12.00 V V2 = 6.00 V V3 = 3.00 V R1 = 220.0 R3 = 270.0 Because of the direction of the batteries, a student looking at the above circuit makes this guess for the direction of current across resistors R1 and R3. Is the student...
  21. A

    Internal Resistance problem when batteries are connected in opposition

    A simple circuit with 2 batteries and a resistor connected in series. The positive terminals are connected to each other via a 4.5 resistor. Their emfs and internal resistances are below. What is the resultant emf? battery 1: ε=6V r=1Ω battery 2: ε=24V r=0.5Ω resistor connecting...
  22. V

    Powering my xbox with batteries

    I need to do a project for my electricity/magnetism class, and I thought about making several copper/zinc batteries to power my xbox360. Suppose I get huge strips of copper and zinc and put them in a fish tank full of salt water. How many volts do you think I could get out of this? Is there a...
  23. C

    Circuit help? with two batteries and resistors

    Homework Statement If R3 = 14Ω: a. What is the current out of the 24 V battery? b. What is the voltage drop across the R3 resistor? c. What is the power dissipated by the 12 Ω resistor? Homework Equations I=V/R V=V(R3/Rtotal) P=I2R The Attempt at a Solution Answers...
  24. W

    Voltage Drop in Weak Batteries: Exploring the Equations

    Relevant equations: V = I*R ε = I*(R+r) Then, V = {ε/(R+r)}*r V = potential difference, ε = electromotive force, R = resistance of external load resistor, r = internal resistance of the battery. So say the external load resistor's resistance is a constant for two batteries of the...
  25. K

    Circuit with 2 Batteries and 6 Resistors

    Homework Statement A circuit is constructed with six resistors and two batteries as shown. The battery voltages are V1 = 18 V and V2 = 12 V. The positive terminals are indicated with a + sign, The values for the resistors are: R1 = R5 = 56 Ω, R2 = R6 = 157 Ω R3 = 118 Ω, and R4 = 97 Ω. The...
  26. E

    Mass Loss in Batteries: Debunking a Myth

    I just want to confirm an error I have seen on another website about discharging of batteries. The poster suggested that the mass of a battery decreases because matter is being converted into energy according to the equation E=mc2 as the battery discharges. They said that because c is so large...
  27. J

    Extremely high energy density batteries?

    Are there articles written on exotic, ultimate batteries? I'm not referring to those for hybrid cars, but those that have energy densities up to that of nuclear fuels or higher. Rather than batteries that operate via chemical oxidation and reduction, is there a theoretical type of battery...
  28. R

    Batteries and Radiation: Exploring the Kinetic and Electromagnetic Theories

    Why don't batteries give off a significant amount of electromagnetic radiation and lose their charge quickly? I was thinking about kinetic theory and electromagnetic theory, and it seems that the ions in the battery ought to be accelerating quite a bit since they are in constant motion and...
  29. R

    How Do Kirchhoff's Rules Determine Currents in a Dual Battery Circuit?

    Homework Statement Use Kirchhoff's rules to determine the currents flowing through the two batteries in the following circuit: http://img217.imageshack.us/img217/2779/circt.jpg Homework Equations Kirchhoff's junction rule and loop rule. The Attempt at a Solution The correct...
  30. S

    How Do Capacitors Charge in a Circuit with Multiple Batteries?

    Homework Statement Three capacitors C1–C3, all initially uncharged, are placed in the circuit show above. The capacitances are C1=15.2 μF, C2=9.8 μF, C3=4.4 μF, and the battery voltages are V1=20 V, V2=20 V, V3=5 V. What is the magnitude q1 of the charge on capacitor C1 once equilibrium...
  31. T

    Help- using NiMh batteries for high load applications (150A peak)

    Greetings, I’m constructing a machine that involves a linear actuator powered by a 12vdc motor. My linear actuator has a foot that crushes an aluminum soda can until the motor’s torque maxes out and it stalls. The machine is intermittent duty at about 6 seconds of use every 3 minutes. My machine...
  32. S

    Batteries and Internal resistance

    A 6.0 V battery has an internal resistance r. The measured voltage (emf of the battery) is 6.0 V. When connected to a resistor R the terminal voltage is 5.9 V and the current is 0.18 A. I managed to get a) What is the internal resistance r of the battery? 0.556 ohm as well as b) What is...
  33. wukunlin

    Recharge My Batteries: Strategies to Regain Focus

    For the last couple of years there is always a fuzzy feeling in my head. Most of my attentions span is gone. Just typing this short post took over an hour in fact while I was looking at a bunch of other web pages at the same time. I remembered in the final year in high school I was able to...
  34. C

    Batteries, resistors, find the currents

    Homework Statement Two batteries and three resistors are connected as shown in the figure Determine the magnitude of the current that flows through 6V battery when the switch is closed. Homework Equations V = IR, Kirchhoff's rules (junction, loop). The Attempt at a Solution...
  35. I

    How Does Current Flow in a Circuit with Bulbs in Series and Parallel?

    Homework Statement Imagine a simple circuit loop with a battery and two bulbs connected in series. I'm having trouble with the voltage of them, where are the + and - poles on the bulbs? At first I simply told myself that the current flows (using the passive convention) from plus to minus...
  36. I_am_learning

    What is the impact of long-term storage on sealed lead acid batteries?

    I am offered Sealed Lead acid batteries at heavy discount (half the price) at local Sale. But they were manufactured some 5 years back. How much damage does long storage do to them? They have never been touched. Just bought 5 years back, and stored.
  37. S

    Voltage Increases When Connecting Multiple Batteries

    Hello, why when I connect 2 or more battery in series the voltage at the extremes of batterys will be the sum of single batteries voltages? what happen phisically? how the electrons of second battery go to the positive pole if they must pass from the first battery? Thanks!
  38. B

    Calculating the EMF of batteries

    Hi all, I'm a total noob when it comes to chemistry, and would need your help to understand the calculation of EMF for batteries. I have a couple of questions about the calculation for Zinc-Carbon batteries in Wikipedia: http://en.wikipedia.org/wiki/Zinc%E2%80%93carbon_battery I can't...
  39. R

    Positive and Negative 5v from 2 AA Batteries

    I'm designing a portable device running off of 2 AA batteries that requires positive both positive and negative 5v power at the same time. What is the best/cheapest way to achieve this?
  40. S

    Energy storage alternatives to batteries?

    I was pondering our reliance on and the limitations of todays electrical batteries. It seems to me (uneducated member of the public) that while technology continues to develop with an impressive momentum our energy storage methods struggle to fuel these ever evolving technologies effectively...
  41. M

    Wind Physics and Gravity Batteries

    At the current rate of oil consumption, the world will run out of it in twenty years. The Netherlands is investing somewhat into wind energy since that's one of the few renewable resources around in our country. Now the obvious problem with wind energy is that it is unreliable, so people are...
  42. M

    Charging Batteries: Can iPhones Share Power?

    Hi, Does anyone know if (in theory) it would be possible to link two iPhones together by a small cable and share power between the two? i.e if the battery is flat on one and full on the other is it possible for one of the phones to "give" power to the other? The process of how much you share...
  43. D

    Car Batteries, and how they're connected

    This is an automotive-related question, but I’m sure any of you guys can answer it. The car battery is a significant part that supplies lots of power to various components of the car. I always thought that the battery would be connected to various connectors in order to supply the power...
  44. L

    How Does Electric Current Flow Through a Resistor in a Parallel Battery Circuit?

    Homework Statement Two parallel connected batteries with internal electrical resistances R1 and R2 are connected with a resistance R of 5 ohm. Which electric current flows through R. Homework Equations U=I*R U= voltage R= resistance I= electric current The Attempt at a...
  45. X

    5000 watt 120V generator to charge 10 12V Automotive batteries

    5000 watt 3600 rpm 120V generator to charge 10 12V Automotive batteries. Will this work? Less or more batteries? Im wanting to put together an electric car. If i use the items above (which is what I have laying around) What size motor would best for longevity, speed ? HP? RPM? AMPs?
  46. T

    Battery Series Powering GPS Device: Safe?

    I have a 36 Volt golf cart using 6 - 6 Volt batteries in series. If I add a circuit by connecting an automotive accessory plug to opposite poles of two adjacent batteries, will I get a 12 Volt circuit to be used to power a gps device, and is there any danger to the device?
  47. P

    How do batteries maintain charge

    I recently realized that I actually have no idea why batteries need the two terminals connected in order for electricity to flow from the anode to the cathode. After all, if electricity flows when the two terminals are connected, since there is an electrolyte solution between the two, electrons...
  48. J

    Batteries: voltages when in series, parallel, and combination?

    Question involving the voltage when batteries are connected in different ways? What is the voltage across six 1.5 V batteries when they are connected a) in series b) in parallel, c) three in parallel with one another and this combination wired in series with the remaining three? I'm not sure...
  49. P

    How discharging and recharging batteries effects lifetime

    i saw in car batteries in electric vehicles one can get more cycles (discharging them and recharging them) if one does not discharge it all the way. ie, its better to charge often even when it does not need them. but i had heard that for my phone battery it was better leave it charge all the way...
  50. Drakkith

    Batteries and Capacitors in Series

    I was looking up some information on series and parallel circuits, and a question popped in my head. I know that hooking up batteries and capacitors in series will give you a voltage equal to the sum of all the voltages in each component, but I was wondering why it does that?
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