Battery Definition and 1000 Threads

Hi PF! Does anyone recommend where to purchase a new battery for my MacBook Pro 13" Retina Late 2013? I was thinking here https://www.ifixit.com/Store/Mac/MacBook-Pro-13-Inch-Retina-Late-2013-Mid-2014-Battery/IF123-053-1 but I wasn't sure if I should buy from Apple directly or if there are...

Hello, I am trying to solve an issue which occurs when two robots with different static charges make contact. It has been some time since my Physics classes and I have some ideas that are only partly making sense to me. I need to minimize the effect that a static shock is having on a small...

Recently i bought a laptop with my friend. So, i went home charged it fully and begun to use it. However, my friend informed me that Acer recommends users to charge and deplete battery up to 3times.https://sg.answers.acer.com/app/answers/detail/a_id/27666 I was confused over this. Shouldn't...

Let's say you have a circuit connected to a 15 volt battery. If current travels from the negative terminal of a 15 volt battery to the positive terminal, the voltage is said to rise 15 volts. I believe this is right, but correct me if I'm wrong. Assuming that is right, then does that mean that...

There is this debate in car audio forums of this question whether it is better to connect your amp ground to the frame of the car or the battery.. basically they haven't came to a conclusion so I was curious what you guys think... Basically what I mean is that when you hook up an amp in the...

How does it work? I mean I know all the stuff, there is difference in potential and the charges flows, my question is, does the negative terminal of the batteries suck charges or the charges flowing to the negative terminal are flowing because they are pushed by the charges induced on the plate...

Homework Statement [/B] A 12 Volt lead-acid car battery, engineered for "up to 500 or more charge/discharge cycles," has a rating of 330.0 Ampere-hours. It sells for $ 262.00. Part B: The battery has a mass of 32.7 kg. What total mass of such batteries would be required to deliver the same...

Hi Guys. I am trying to charge my scooter's battery which is : 12 volts 2.3ah The battery currently has around 3 volts. I am charging it with an adapter : 12 volts 2.0ah Can you help me how long would it take to charge and is it safe for me.. Thanks.

Hello, I'm trying to teach myself ...still learning...but I'm stumbling. I have a 15W solar panel whose output is 5V and 2.1A. I wish to charge a 12V battery (98Wh/8800mAh), but am unsure how to do this calculation as approximate time it would take (Assume sunny days - I know it's an...

Is it possible to charge a 7.4V 850mAh lipo battery on a 10V 4mA power source? Inquiring minds want to know. Thanks everyone!

Hello, I am curious if this has been done, or would even be worthwhile. The idea would be to use a generator at the pedal and conduct the electricity directly to a wheel motor with no power storage. This would eliminate gears and a chain. Does anyone know what the approximate efficiency of...

If a battery run a current by making the positive charge at one end and negative charge at the other end, in other words by making an electric field inside the wire, then we should expect to have larger currents when the wire is straight rather than bent. In the straight form, the electric field...

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...

Hi Guys! I'm new in this forum and I'm a greenkeeper, it means that you can ask me everything about grass, flowers and trees but I have ZERO knowledge in electrical systems. This is why I'm asking here if someone with good patience and really helpful can help an ignorant gardener with some...

Somehow I've never really known how to tell if a battery is bad without simply using it and seeing if the device it is powering doesn't work, an experiment that can get tricky trying to isolate a singe battery in a device that uses multiple battery cells. I figure that it is some combination of...

Sometimes when my TV remote doesn't work, I've tried removing the battery and replacing it (the same battery), and it works again. How does this work?

Hello, I made powerbank for my bicycle to charge my phone while I ride it. I am using one 4400 mah Li Ion battery. I was wandering If it is possible to charge the battery with less than 1 amp and not constant current? Because, generator I have on my bike produces 3W and it varies as I change...

Hello, I am made a powerbank myself with li ion battery. I used boost converter and everything is fine, charging my phone. But the li ion battery and my boost converter is getting really hot while charging my phone.The battery capacity is 4400mah. I don't know the reason for such temperature...

We created a 5x5 seawater battery system to test voltages across multiple pHs and concentrations of NaCl. Concentration ranges go from 0g/L to 32g/L (near saturation) and the pHs range from 3 to 11. We used copper and magnesium electrodes to test the voltages in each cell and got some results we...

greetings, here I found a Simulink model on mathswork, I want to replace the battery with a fuel cell, so I'm stuck at the level of the energy management block. here is the link of the model: https://www.mathworks.com/matlabcentral/fileexchange/28441-hybrid-electric-vehicle-model-in-simulink...

Hello I have a circuit. When I power the circuit with a power supply, the power supply reads 5V and 0.025A. This gives me the P=IV=0.125W. Is this the same as 0.125W per second? I want to power this circuit with a Li-Ion battery that is rated 5V and 3200mAh. How long will my battery run...

Homework Statement A standard D cell can supply 10mA at 1.5 volts for about 300 hours. An alkaline D cell can do about the same. Assume - 2 - that the chemistry of the batteries will produce the same amount of energy and will maintain the same EMF regardless of the current drawn from the...

I've got two monitors I am trying to power with a battery. They accept 19V @ 1.3A each, and I'll have them in parallel off a single battery, so they'll need 19V @ 2.3A from the battery. I'm looking at http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=56845. The specifications...

The battery post is moving up and down. It doesn't seem to want to come all the way out. Will the battery still perform properly or is it damaged? Can it be repaired? Pictures attached.Thanks in advance.

Hi All! I am a Dutch university student and I have an assignment to make a Search & Rescue Robot. Because we have to work with a budget, we have decided to make our own batteries (using AA penlights). Now while calculating the required capacity of the battery pack, I encountered some...

My Huawei Y6 2 With a 5.5" HD LCD screen has a Kirin 620 CPU with 2gb RAM and 3000 mili ampear battery. The battery percentage dropped from 80% to 50% after 2 HOURS and 18 minutes of web browsing on chrome. Is this unusual? The phone is very new, bought it last month brand new. Please help. The...

Hello, I am building a power bank myself and want to set put detector that determines the voltage level and indicates it in LED (4 LED are planned to be used). I know how to make it with transistors and op amp. But I was wandering if there is any IC chip that does it? Thank you, Akmalidin Alimov

Homework Statement The battery in the circuit below has EMF 5.4 V and drives a current of 0.30 A through a lamp. The voltmeter reading is 4.8 V. Explain why the voltmeter reading is less than the EMF of the cell. Calculate values for (a) the internal resistance of the battery, and (b) the...

Hi, I am a university student in the Netherlands and I just got the assignment of building a robot on a budget. Because of this budget I would like to make the battery pack that powers the 2 servo motors and 2 electric motors myself. I did some research and found out it would be best to...

Homework Statement Hi everybody! I am struggling with an old exam problem, could someone maybe help me out to figure it out? Here is how it goes: A rod with resistance ##R = 0.1 \Omega## lays over two parallel tracks (resistance ##\approx 0 \Omega##, ##l=10##cm). A battery is connected...

Hello Ads say a gyroboard with the battery 48V 4.4AH, and the motor 700 Wt will run for 2 hours at the speed of 20km/h ! But - simple physics - will not the motor drawing about 10-15 Amp exhaust the battery in just some 20 minutes !? Do ads lie ?

Hi guys! For a school experiment we are supposed to connect a 9v battery to a 180 ohm resistor and multimeter and calculate how long it take to die at different temperatures . does anyone know how can i do this using a formula? I will need it in my report. Thanks for the help! :)

Hello, I have seen a video online that shows how a LED can be lit using a single lemon without using a copper and a zinc nail. They simply stick the LED into the lemon. What does that work? I know the lemon contains the electrolyte but don't we always need to dissimilar metals for the battery...

Hi all, I am reading some materials on electrical parameters of a AA battery which give 1.5V and about 2000mAh. As my understanding, the 2000mAh means it will produce 2A if we keep taking current from the battery for an hour. 2A is huge current for human being. I wonder why it won't hurt the...

Homework Statement Homework Equations no equations The Attempt at a Solution I know that we will have an equal current flowing through bulbs 1 and 2 when we connect them in parallel in accordance with kirchhoffs voltage law which says that the voltage drops around both paths must be equal...

Hello, I have a bit of an issue and can't figure out how to find out the answer. I want to understand how to find out what battery I would need if I want to scrap the diesel generator I have and go for a battery bank. I have a 1250 kVA rated generator. PF is 0.85, Rated voltage is 400V, rated...

Hi, I plan to make a simple 12v-battery trickle charger wind turbine that I will put on the roof of my garage and connect to my jetski to keep it topped off during winter when my solar panel is performing poorly. I have a 24v Motor I will use and will use a bicylce wheel for the "blades". I was...

I can't get my head around question about energy consumption, energy supply and run-time. I think I forgot (Im sure I forgot) something in my equation. I am trying to find a way to calculate for how long could UPS supply my PC I don't know why I can't find Amp-hours of UPC on it but let's assume...

Homework Statement See attachment for the question and the picture Homework Equations Pe= E x Is Is = V/R The Attempt at a Solution I figured that in order to find the power delivered by the source, I would have to use the equation: Pe= E x Is. E is already given to me.. 60. That means I just...

Homework Statement In a household, the wife reads a book that uses a light bulb that has a resistance of 100Ω and is connected to a 100 V line while the husband watches a TV that draws 100 W of power. They do these actives for 200 mins. Power comes from a wind generator that charges batteries...

(Look at the level above) If you have a battery which is made by two plates having opposite charges ( constant E-Field), But outsidethe electric field doesn't cancel out. (The same applies to capacitors) not infinite So the question is why doesn't an electron get affected by a really huge...

Homework Statement I'm currently doing a mini project as an assignment in my engineering course. I tried replicating the coin battery, where I stack a piece of cardboard soaked in black vinegar (couldn't find white vinegar), a piece of aluminium foil, then a 20 sen coin (Malaysian...

First, the electric/Coulomb force set up by a battery across its terminal is conservative, and its potential is given by the well-known V. I also understand the conventional usage of emf is as a voltage potential. However, a battery does more than just set up the electric field and its...

If I attach a battery to two parallel plates to create an electric field between the plates, will the electric field last for the lifetime of the battery?

This has been confusing me a lot lately. I built a type of battery derived from a solar cell that outputs a constant voltage of 0.5 Volts. My original plan was to work out a method to boost this voltage to around 1V to power a joule thief and light an LED using a capacitor charged by the cell...

Homework Statement A battery with an emf of 60 V and an internal resistance (r) is connected to a 10 ohm external resistance. The power lost inside the battery is 50w. The same battery is then connected to a 4.0 ohm resistance. The power loss is 200w. What is the internal resistance of the...

Hello, I am a Telecommunications student who does not have a lot clue about cars.Does a car charges up its battery when it moves? What power supply is used for lighting in car, the battery? So if car charges the battery when it moves, why sometimes external/additional charging of battery is vital ?

I have a still unwired pump at the end of a new drain outside my house. The startup current required of the pump is significantly higher than the steady state current required. If I put a UPS between the pump (the pump has a standard 110V plug) and the outlet, will this reduce the max...

I have four 125 ah batteries powering a 6000 watt inverter. The inverter is supposed to have a no load draw of 2 amps. I have a 12 amp 120volt Ac load. How long should I be able to operate before drawing my batteries to 50%

Now, to be honest, I can comfortably light it with TWO piece of wires and not ONE. So , was it a trick question? Technically, those are havard grads. Please weigh in.