The process of removing energy from a store, such as a capacitor or battery. Stores may be parasitic, resulting in rapid spontaneous accidental discharge, as in a static shock.

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40 views

How will unmatched lithium-ion cells in parallel react?

We are stocking a portable power pack for USB charging. We tested them when they first arrived and found no issues but after 3 months we tested some of the remaining stock and found about 50% of them ...
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0answers
36 views

Li-SoCl2 battery state of charge

I'm developing a data logger powered by Li-SoCl2 (http://www.100y.com.tw/pdf_file/02-SAFT-LS33600.pdf) battery and I have no idea on how to overcome the problem of estimating the residual charge of ...
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1answer
66 views

Why is there heavy oscillation in my capacitor discharge circuit and is there anyway to fix it?

I have the following capacitor discharge circuit: simulate this circuit – Schematic created using CircuitLab When solving for the voltage across the primary and secondary inductors, I ...
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2answers
358 views

What is a safe max. discharge rate for a 12V lead acid battery?

I've got a 12V 2.4Ah lead acid battery which I plan to connect a water pump to. I've looked at various pumps, but the one I'm most interested in draws 2.2A. I'm not so interested in how long the ...
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2answers
105 views

Where does power in my laptop go when I disconnect the battery? [closed]

I have a laptop which, when put to sleep, sometimes enters a state of limbo, from which it can be neither turned off nor on, and the only solution is to disconnect the battery, reattach it, and turn ...
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1answer
48 views

Flash Bulb battery depletion

Extremely simple question for you. Probably beneath all of you to answer apologies for that. My camera's flash is rated in Watt seconds. My battery is rated in mAh . If my battery can output 1000 ...
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0answers
80 views

Corona discharge of a ring

As far as I know corona discharge usually happens when there is high electric field or when the object that stores charges has sharp points. Would corona discharge still happen if we used a circle ...
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1answer
42 views

Mobile Battery Charge

I just wanted to ask whether it is possible to voluntarily discharge a mobile phone's battery and transfer it onto another battery?
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2answers
62 views

PKZ 1023 Battery

Does anyone happen to know the manufacturer's specs for the PKZ-1023 model battery? All I know right now, is that is that it is NI-MH, 9.6V, and 1000mAh. I was hoping to find a chart of discharge ...
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1answer
49 views

Lead Acid max discharge rate?

I am building a flashlight using a large(ish) 35W HID headlamp from a car, and I'm having troubles choosing a good battery technology. The inverter draws about 3.5A - 4A at 12V, tested on a large ...
2
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1answer
103 views

Discharging electrolytic capacitors

I believe that capacitors are safe to discharge through a short, if the voltage is not high enough to cause a dangerous spark; and the energy stored in the capacitor (E = V × Q = V² × C, if I'm not ...
2
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1answer
46 views

Gas Discharge V-Q Lissajous

I've been investigating non-thermal plasmas, specifically dielectric barrier discharges, where two electrodes, at a potential difference of several kilovolts, are separated by a dielectric and a gas ...
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38 views

Current Return Path for Plasma Experiment

I'm planning to use an old non-GFI neon transformer to produce plasma for some research I'm conducting. However, the neon transformer is center-tapped which complicates diagnostics (such as ground ...
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1answer
84 views

How to calculate Li-Po battery discharge time?

I want to calculate the time for a Li-Po battery (7.4 V, 2200 mAh, 30 C) to discharge. Battery powers up an embedded device, that requires 5 V, 147 mA. For this reason, I use a voltage regulator, in ...
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1answer
88 views

Removing neon transformer center tap?

I have recently acquired an old neon transformer (rated 12kV) for conducting some low temperature plasma experiments. It is the mid-point grounded style with a center tap on the secondary coil. I had ...
2
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1answer
166 views

How exactly does a capacitor discharge its charge?

When an empty (discharged) capacitor is connected to a battery, it slowly charges up as one plate fills up with electrons, while the other plate has electrons drawn away from it towards the positive ...
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2answers
37 views

Internal resitance of a battery and SOC related?

How do you find remaining SOC of a battery, say 12V 100 Ah? Is it possible by monitoring internal resistance of the battery? Or is there any better way (logic wise) used in industries? I'm using an 8 ...
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2answers
152 views

What makes a device intrinsically safe?

I work in possibly gas filled environments. As such safety recommendations are that I don't use my cell phone, camera and computer while touring around these areas that explosive gas may be present. ...
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1answer
71 views

Maximum load current that is still indistinguishable from battery self-discharge

I am designing an electronic device that will be powered by a battery, and I am trying to keep my device's current draw in standby to a minimum. Specifically, I would like to keep the current just low ...
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2answers
1k views

What is 1C charge/discharge rate in battery instruction manual?

Instruction manuals and discussions mention battery charge and discharge rates in terms of "1C", "2C" and so on, without giving an indication of what "C" is. I presume it is not a Coulomb. What is ...
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1answer
123 views

Why discharging static to laptop's VGA ground is more disruptive over a pencil then directly?

When I touch a laptop's corner, USB or VGA port ground with finger, the resulting spark seems not to affect anything. However I've just tried touching the VGA port's outer ground with a pencil ...
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2answers
175 views

How to calculate time for NiMH batteries to discharge?

I want to use 4 battery cells AA NiMH (or NiCd) 1.2 V, 2600 mAh in order to power up circuit that requires 5 V, 300 mA. I know that fully charged NiMH can provide 1.35 V each, which means 5.4 V in ...
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3answers
269 views

Why charging time is same and discharge time is different for two inputs in dual slope integrating ADC?

For different input voltages in dual slope ADC, charging time remains same but discharge is proportional to the magnitude of the input voltage. How it works in that way ? Charging time is independent ...
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0answers
82 views

Discharge limit on a 12V 9800mAh Lithium-ion Battery

I am running a 12V solar system that powers a 5050 LED light bar of 7.4W. Powered by a 25W mono PV and has a total 12V storage of: 1x 6800mAh 1x 9800mAh (Lithium-ion batteries in series) The ...
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2answers
61 views

Grounding a conducting object

Is it possible to trap some electricity in the object even though the object is grounded? For example if we ground a conducting sphere over a resistor, will all electricity leave the sphere once it's ...
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1answer
138 views

Capacitor discharge math discrepancy

I'm trying to cross check mathematically the mA being discharged from a .33uF capacitor which is charged to about 1200V by a circuit which is provided 37W of power to it. I do it three ways. 1) ...
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1answer
134 views

Safely discharging large value capacitor without blowing it up

This is related to my previous question. I have this circuit in which I discharge the capacitor by turning ON M2. The ON resistance of the MOSFET I have in mind (the picture shows the wrong MOSFET in ...
3
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1answer
262 views

Discharge curve of a LiPo battery

What is the mathematical formula to calculate the voltage of a (typical) LiPo battery as a function of it's charge, current flowing and external temperature?
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1answer
231 views

How to measure battery charge and depletion over time

When using my various electronic devices, they always seem to know how much charge is left in the battery. They also know when the battery is completely charged. Not exactly sure how this is ...
2
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1answer
125 views

Preventing Arc Discharge

I am repairing some ozone generators and one of them has a tower with a discharge path I can't seem to get rid of. Back in the heyday of television, my dad ran a side (hobby) business repairing bw ...
2
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1answer
122 views

Static electricity discharge, what gets transfered?

Ive been studying Maxwell equations at school and I solved several excercises regarding electrostatic fields, however I still have some very basic unanswered questions: When a non conductive object ...
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1answer
548 views

How to Calculate the charge/discharge power of a battery?

I need to measure the discharge power of a battery in general. At the end i want the maximum charge/discharge power as a function of the state of charge(SOC). So i need a curve that looks like the ...
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1answer
198 views

Can leaving rechargeable batteries in the unplugged charger for a few weeks cause batteries to lose their charge?

Is it okay to leave rechargeable batteries in charger even if it's not plugged in?
3
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1answer
377 views

How to detect low battery of a lead-acid battery?

I've heard that discharging a lead-acid battery to 0% is bad and wears it out. I have a 10Ah 12v lead-acid battery, is there a circuit to tell me when the battery is low?
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2answers
2k views

How do I determine the maximum amp output of a battery pack?

How can I determine the maximum amp output of a battery pack? Some background: I've got a 5-AA battery pack hooked up to a microcontroller and some continuous rotation servos, but there's current ...
3
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4answers
480 views

Sawtooth generator not working - transistor wont discharge my capacitor

I have been trying to build a sawtooth generator using current source which linearly charges my capacitor and a comparator which was supposed to discharge my capacitor, instead it doesn't. Here is the ...
2
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4answers
5k views

Circuit to safely power-down Raspberry Pi

I want to use a Raspberry Pi as an XBMC server in the car. The XBMC docs say that you should always use the shutdown command before disconnecting the power. I don't want to have to (tell my wife to) ...
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1answer
218 views

LiPo discharge circuit doesn't work

A friend of mine gave me this circuit to discharge a 3V7, 5000mAh single-cell LiPoly accu: simulate this circuit – Schematic created using CircuitLab The zener is to make sure that the ...
2
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1answer
861 views

Constant current battery discharge

I'm simulating NiMH cell discharge from 1.5V to 1.0V. The circuit I drew is supposed to draw a constant current from the battery. I simulate a DC Sweep in circuit lab but somehow the current draw ...
3
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1answer
295 views

Why is this capacitor not discharging?

I am trying to implement a delay mechanism out of passive components. The digital input in this case is a PIC input pin. The operation is as follows. The capacitor is pre-charged to 5v, and then the ...
2
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2answers
159 views

Need help designing a custom box

I am doing a hobby project and I don't know much about engineering; therefore I decided to ask pros. I have a 12v electric device that runs on Car battery only and I need to make it work if there is ...
2
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1answer
163 views

LSD NiMH cells that provide reasonable capacity even in subfreezing temperatures

Sanyo claims that 2000 mAh Eneloop LSD AA NiMH batteries provide about 1400 mAh at -10 °C (-15 °F). I wonder if only Eneloops provide reasonable capacity in the cold, or if the competition does too. ...
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1answer
2k views

Calculating resistance given capacitance and charge over time

Given the seconds \$t\$ it takes a capacitor (with farads \$C\$) to discharge from 5 volts (\$V_0\$) to 0 volts (\$V_t\$), how do you calculate the effective ohms of resistance R in a circuit? Based ...
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3answers
887 views

Automatically discharging capacitor [closed]

Say I have a capacitor of 100uF connected to 2Volts battery supply (In real circuit, this will be a solar panel exposed in the sun)... After some time, the capacitor will be charged fully with a ...
-1
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1answer
335 views

Capacitor discharge after charge

I have this circuit for charging a capacitor: What I need is a circuit for discharging the capacitor after 'V' (the voltage across the 100 µF capacitor) has reached the maximum value of 2V. I ...
4
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1answer
908 views

What's a good estimate on how low an alkaline battery voltage can be to still make the battery useful?

Here's a YT video by Duracell about how many batteries declared dead and sent to recycling still have some usable energy. In the beginning of the video there's a sequence where they have a row of ...
4
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2answers
2k views

Making a lithium polymer circuit

I want to create a circuit that will power my Raspberry Pi using Lithium Polymer. My knowledge of LiPo is rather low and I believe they can get dangerous if used incorrectly so I turn here. THe ...
7
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1answer
588 views

Constant power discharge of a non-ideal capacitor

My employer sells boost converters to hold up motor drives during power loss. These boost converters are fed from capacitor banks. In order to size these banks correctly, we need to take their ...
2
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1answer
5k views

What's the max discharge (in “C”) of a Pb-acid and LiFePO4 (lithium iron phosphate)?

I know that lead acid batteries can handle massive loads, and they are even used to power houses with solar panels, but what is the maximum safe discharge for one of these? I've done some Googling ...
8
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4answers
10k views

At what voltage is a NiMH battery empty?

I have a battery pack of NiMH batteries. It is ten cells with 1.2V, 4000mAh each, put together in series. So rated voltage is 12V. After charging, i.e. when the charging device says that it is ...