An electric battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy

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Small battery with good current supply

I'm looking for some way of using a display that can be read at night but found out that the available options spend allot more mA's than the rest of my circuit. Is there some kind of small battery ...
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1answer
22 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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2answers
47 views

Can a 9v battery be substituted with an array of LiIon 3.7v?

I use some audio devices (mixers and effect boxes) that literally drains out my 9v cells (specially the rechargeable). I'm thinking on doing arrays of LiIon batteries (rated at 3.7v-4000mAh each), ...
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4answers
1k views

Is my phone battery better / more capacitative than my laptop battery?

When we go out and look for phones, the first thing I do I always look at the battery capacity, usually 2000 mAh, 3000, up to 10000 mAh for a (external?) battery. Looking at laptop batteries, they ...
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1answer
27 views

Sharing negative terminal (“ground”) between 2 LiPo batteries and UBECs / paralleling 2S LiPo packs

One of my projects require a hefty amount of amperage - and as such I want to use 2 LiPo 2S batteries, in parallel. In addition, I am regulating the voltage using multiple DC-DC step down converters ...
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1answer
33 views

how much time it will take to fully charge a 48 V 35 Amp hr battery using a 100 V DC dynamo running at an average speed of 20 km/hr

The above mentioned dynamo is being used in an e bike. i have tried to go through many sites but didn't get a proper answer.
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2answers
31 views

running time for an e bike on a fully charged battery

how much time a battery(48 V 35 Amp hr) can drive an electric cycle(weighing 80 kg) powered by a 150 Watts permanent magnet DC motor at an average speed of 20 km/hr.
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1answer
68 views

Battery chargers that can recharge disposable batteries. How do they work and are they safe?

A few years ago a product called SecondWind appeared, which claimed that it could recharge disposable batteries. To a layman like me that sounded like a great idea, but does such a product really ...
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2answers
56 views

How to power a Arduino Yun with a 6V battery?

I would like to power my Arduino Yun board with the following battery: Arduino Yun has a VIN pin that represents the input voltage to the Arduino board. The official documentation says: Unlike ...
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2answers
78 views

Designing effective usage time from 12v car battery

Need a little power design help: I have a project I'm working on where I have measured that I will use approximately 14.4Ah over 24 hours. This is quite the load for a small timelapse setup where I ...
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3answers
128 views

Can I use one battery to power up two circuits?

I 'm planning to use a zinc–carbon 9 V battery to power up two circuits (the one that battery belongs and one more). I 'm thinking of using a breadboard in order to achieve this. The second circuit ...
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0answers
22 views

Czech RF10 Battery Help [closed]

Need some help. I purchased a Czech RF-10 radio which has a battery box with Five Ni-MH "D" cells inside.. (see prc68.com) I would like to know how to recharge these batteries. Can I use a universal ...
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3answers
49 views

Calculating battery time giving its capacity and load

I am referring to the airplane shown here. The battery is said to have 640 Whr capacity (actually this is the discharge rate), the load being a 2700 W motor. Then the endurance is giving as 110 ...
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1answer
54 views

Charging 7.4V Li-Ion battery

I'm making a battery out of two 3.75V Li-Ion cells to go into a speaker system that powers an amplifier. I was wondering on the PCM, how many volts would be max to charge these cells? The cells I have ...
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1answer
117 views

How to make a battery draining circuit?

I have an air soft gun battery that needs to be completely before charging it because the charger does not have overcharge protection. Basically I have to time charging it. I would like to make a ...
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4answers
74 views

Replacing adapter with batteries?

I have some device with ac/dc adapter [9v, 500mA], and I want to replace the adapter with batteries. If I used [6 * 1.5v] battries, is that acceptable? do I have to worry about the max current of the ...
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2answers
80 views

Overcoming voltage drop in a battery

I want to use this battery for my Arduino Uno: ...
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1answer
39 views

Battery Voltage is not as it should be when connected to ckt

I brought 6F22 9V battery. One's output voltage became nearly 6 volt after some use.But when I connect it with a MCU ckt , It gives only 3.37V as output ( voltage tested directly from the battery's ...
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1answer
36 views

Measuring smartphone's battery State-of-Charge during charging

I'm designing a mobile device that uses a Li-Ion battery. It is required to indicate to the user the State-of-Charge of the battery, similar to how it's done in smartphones. At first I considered ...
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3answers
130 views

Help my off grid solar system is driving me mad

Please can someone help me with this problem I'm having with my solar system? Ok I have 7 × 190w 24v panels wired in parallel, Coming down to a 80A MPPT charge controler which automatically selects ...
3
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1answer
68 views

What type of eye protection should you use with a battery tab welder?

There are a ton of youtube videos and websites about how to make a DIY battery tab welder - however none of them seem to have any information on what type of eye protection to use. I know that some ...
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1answer
39 views

Electric car charge depletion time? [closed]

I'm assuming these batteries are similar to or exactly like a capacitor? Also is there an equation to determine the charge decay rate based on usage and/or the time it stays still? If i wanted to make ...
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3answers
144 views

How to drive optocoupler with BJT properly [schematics]

Recently I asked a question about optocoupler: Shematics: optocoupler controls a transistor and doesn't work as expected I have one more question related to the topic. PWM input comes from the ...
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6answers
306 views

Is there any physical device called current source?

I have seen both current source and voltage source in many electrical circuits (in paper). When it comes real hardware battery can be considered as a voltage source. Then what is a current source ? ...
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1answer
38 views

Low Current Battery Montior Detail Question

I'm trying to design a circuit that will be running from a battery. I'm currently working on the part that detects the voltage and came across this question (and answers) here: It made pretty good ...
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1answer
52 views

High-current monitoring circuit

I have the following circuitry: Battery Supply => Current Monitoring Circuitry => DC Motors Battery Supply: 4AA NiMH batteries - 4*1.2V (1.5mAh * 4) Current Monitoring Circuitry: Max 4378 chip ...
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1answer
52 views

Charging 2 Li-Ion Batteries via a single charger

I'm currently building a portable USB charger. It uses 2 Li-ion batteries in series connected to a USB port via a 5V regulated buck converter. While a single Li-ion battery would suffice for most ...
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5answers
148 views

How to Choose a Battery

I would like to start off by saying I have little actual experience in electronics, so bare with me, and for all I know I could be way in over my head. Anyway... I was thinking of making a ...
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1answer
83 views

Can batteries be charged and discharged at the same time? And do they wear down faster when doing so? [duplicate]

Imagine batteries connected to a charge controller and a load at the same time. When the load asks for power, and the charge controller delivers power, there are three possible situations: P_in > ...
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2answers
80 views

What is the maximum safe voltage for 1.5V and 3.7V gadgets of consumer electronics?

I know that most electronics for 1xAA battery accept at least 1.1-2V and for li-ion 3.5-4.3V. But what is probable safe maximum? Can I use li-ion with 20ohm resistor or even without it for supply 1xAA ...
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1answer
78 views

Li-ion battery choose question

I am new to this forum and I hope you can help me with this. I want to build a small circuit that will have: an ATXMEGA ucontroler that uses all of its 5 USART and one bluetooth module. This circuit ...
2
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2answers
80 views

What is “current rating” in a battery implied by?

How battery limits current to the maximum level that is indicated in its specification? If V/R value is greater than maximum current rating then current through the device will be V/R or maximum ...
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2answers
99 views

Is it possible to run a photodiode plus op amp on a 3V battery?

Naive question here. I've been toying around with the idea of making a simple light meter. From what I've read, photodiodes generally offer the best sensitivity and accuracy (as compared to ...
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1answer
91 views

Designing an ultra-thin battery holder (CR2016)

We are designing a miniature electronic device and run into an issue. The suitable battery holders we were able to find are 2.6 mm thick. But the battery is just 1.6 mm thick. It is a huge difference ...
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1answer
80 views

Mysterious voltage drop then slows climbs back up when powered off

Ive built a simple circuit on some strip board, just a motor and a micro controller and LED and powered by 6 AAA batteries. The motor takes its power straight from the battery and the micro and LED go ...
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2answers
145 views

How to adjust output current on a buck converter?

I 'm planing to use a zinc–carbon 9 V battery to power up: the circuit that battery belongs to BeagleBoard-xM I 'm thinking of using a breadboard, in order to power up both circuits. ...
2
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2answers
123 views

How to power up BeagleBoard-xM using batteries?

I 'm looking for a battery solution to power up BeagleBoard-xM. Until now, I used a 5 V, 3.2 A AC/DC power supply adapter (2.1 mm barrel plug). I 'm thinking of using a 4 x 1.2 NiMH AA battery pack ...
2
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1answer
74 views

why do rechargeable batteries fail so horribly in high drain environments?

I've tried nicads and nimhs in flashlights and they always end up leaking. I know how spikes and memory work in such batteries, but why do such high drain applications cause such catastrophic ...
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2answers
70 views

Charging lead acid (car) batteries with a common ground

I have three identical lead acid batteries. All three batteries are on a common ground since they power different components on a same circuit. I have three independent "intelligent" chargers whose ...
3
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3answers
148 views

Li-Ion battery questions

After putting battery in freezer overnight (in ziplock bag to avoid moisture (according to sites battery loses >20% Capacity in >3 months to a year) Does the rapid heating up cause by turning phone on ...
0
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3answers
122 views

Sanyo battery: what 430MH stands for?

I have a SANYO NI-MH battery from my Oral-B toothbrush. I reads 430MH. Now I'm curious what does 430MH stand for? Im thinking its probably nickel–metal hydride if ...
2
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2answers
98 views

How to choose what voltage power supply to use?

I'd like to build a keyboard emulator, and I've found three links that detail the process: 1, 2, 3. Here's the rough circuit: The thing is, across the various articles I've read, people are using ...
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1answer
63 views

Prevent full startup when only battery backup applied

I have an ATMega328 running firmware that goes to sleep when main 5V power is removed and runs on a 3V backup battery instead. While in sleep, the watchdog timer wakes it up occasionally to keep a ...
0
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1answer
40 views

How does the battery and power adapter interfaced in the laptop?

How is the typical laptop's battery (multi-cell Li-Ion) and external power interfaced ? What all components go into designing that circuit ? The required behavior is: When power cable is connected ...
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1answer
39 views

GSM module working when powered by laptop via USB but keeps restarting when powered by battery

I am using a sim900 module in the following link and I connect it to my laptop using USB to TTL converter and the module works properly. But, when I connect the same module to 9V DC battery the module ...
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1answer
92 views

Connect batteries with different voltage in series

simulate this circuit – Schematic created using CircuitLab I have two 9V batteries connected together in series. I also have a battery connected in parallel with total voltage of 6V and ...
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1answer
33 views

Need to know battery configuration for a 250 watts inverter [closed]

I have a 12 Volt inverter which have ability to produce 250 W output. I would like to purchase a battery for this. can any one tell me the configuration of battery ? eg: Minimum AH
2
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2answers
105 views

How to detect how much battery power is drawn?

I'm programming a small device using a microcontroller. I'd like to optimize it to use less battery. How can I detect how much power uses over time as I run it through some tests? Based on the ...
2
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3answers
442 views

What to plug in first to usb charger when charging: wall outlet or cell phone and why? [closed]

I asked this question on Physics StackExchange but was advised to ask it here. When I charge me cell phone or notebook or whatever device what should I plug in first? Should I at first plug in usb ...
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2answers
77 views

What to plug in first to usb charger when charging: wall outlet or cell phone and why? [duplicate]

When I charge me cell phone or notebook or whatever what should I plug in first? Should I at first plug in usb charger to the AC wall outlet and only then to the cell phone or vice versa ? What are ...