Involving or pertaining to a circuit or device that is intended to be operated with cells or batteries (as opposed to mains power, for example).

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26 views

Switching between power supplies with supply dominance selection

Following an earlier question Switching between power supplies - USB dominant After doing some more research with the given answers and after seeing switch between battery and usb power no ...
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1answer
3k views

Why do smoke detectors run off 9v batteries?

Is there a component that requires a higher voltage? Wouldn't they last longer on AA/AAA batteries?
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1answer
32 views

What are the main considerations for a battery operated project [closed]

I just wanted to know what are the major considerations to be taken into account while designing a battery operated project. What are the major optimizations to be done in order to improve battery ...
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3answers
722 views

Simple, efficient “breathing” LED circuit

I'm currently working on a small circuit, which I intend on running off a CR2032. The intent is to have the circuit last at least 2 weeks (the longer the better), pulsing a green LED every 3 seconds, ...
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72 views

Dual redundant 1.5V battery power system?

I'm trying to build an efficient way to connect two 1.5V alkaline batteries in a redundant configuration for my circuit. I only want one battery to be supplying power to the circuit at any given time. ...
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2answers
71 views

Beaglebone black gets shutdown signal when I move rc motors

I have a beaglebone black that I tucked inside an rc truck. I removed the radio control chip. Everywhere it had 3.9 volt logic I put in a 3.3v gpio control from the beaglebone. It works great I'm ...
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1answer
56 views

Nimh battery for Electric Bike

I've come into an electric bike that currently has a nimh, 24v, 20cell battery pack. On the pack as well it says 8000mah. The previuos owner has misplaced the original charger :( The bike has been ...
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1answer
64 views

Can I use arduino to feed this circuit instead of an external power source?

I am following this tutorial to connect the output from my guitar with arduino. I'm wondering: is it possible not to use the batteries, and to feed the circuit with the 5V output pin provided by ...
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2answers
77 views

What does current draw mean for the [closed]

Does this mean that the battery only outputs current equal to the amount of current draw? I always thought that batteries outputted a constant output, but apparently after some research I found this ...
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3answers
153 views

Boost Converter Problems

I'm having trouble with a boost converter I made: it outputs 1.2V with no load and 2.4 with one. I expect to draw 0.25 Amps MAX with Roughly 0.2 Amps continuous. My battery pack is 2P2S NiMH with the ...
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1answer
120 views

Reverse current protection for a battery operated circuit

I'm planning a hobby project with the following characteristics 3.3V circuit, battery operated (by regulating standard AAA batteries) Most of the time in "sleep" mode, so I need very small quiescent ...
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1answer
60 views

How to detect the power source when multiple power sources are available?

I have very little background in electronics, I'm from software background. I'm interested to design a system in which there is an 8-bit micro-controller which should get powered from two different ...
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1answer
150 views

DC 5V USB to replace AAA-battery source: down converter

I have a portable lithium battery-powered speaker which takes auxiliary sound input from a single AAA-battery powered pocket radio. The speaker includes a USB port for charging source devices: I ...
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0answers
60 views

Adaptation of LVD (Low Voltage Disconnect) circuit

I'm trying to build a Low Voltage Disconnect circuit with ultra-low power consumption. A quick search on the forum returned a few threads related to LVD, but my question concerns a specific circuit ...
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1answer
24 views

Mixing battery sizes [closed]

Apologies if this is the wrong Stack. I suspect this is a bit of a lowest-common-denominator question. I've got a cheap little Christmas tree covered in blue festive lights that takes 3 size-C ...
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2answers
82 views

About battery capacity and regulation

For a portable application, I would be using a single 3.7V 2600mAh li-ion cell. The circuit requires 2.5V to 5V to function with the current requirement being 100mA. So obviously a voltage regulator ...
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2answers
119 views

How to Check Rechargeable Battery NiMH Status with Microcontroller?

I created a device, based on an Arduino Uno, which runs on 6 rechargeable NiMH batteries. Now I would like to add a check, if the batteries have enough power left, to warn with a signal when the ...
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1answer
38 views

Any Protection Required for Rechargeable Battery Powered Device?

I created a device which is powered with 6 NiMH AA rechargeable batteries. The device uses between 10-100mA current. It is nothing special about it, there are some foil and electrolyte capacitors from ...
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1answer
83 views

Understanding Battery rating

I need clarification regarding the rating of the battery shown in the below figure. I know battery ratings are given in Ah(Ampere-hour), but here it is given A/s. The picture is from "Linden's ...
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4answers
138 views

Convert a device that is powered by a 12V 2 amp ac-to-dc SMPS to a battery powered device

I have looked up my requirements in all possible sources (Google, StackExchange, DiY boards, etc.) but I have not been able to find a clear answer to my problem. What I have is a device that needs ...
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0answers
79 views

Power micro LED's from 5 Volt USB

simulate this circuit – Schematic created using CircuitLab I'm working with this set of LED's: Link here: 30 Ft Led wire I measured the draw for the entire string at about 170 ...
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1answer
64 views

Microcontroller self-shutdown with MAX682

I have read How to implement a soft power switch controllable by microcontroller? and am wondering if something similar would be possible with a MAX682. What I want, is a device that is turned on by ...
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1answer
59 views

Difference in self discharge rate between Lithium iron phosphate battery vs Lithium Polymer Battery

What is the difference in self discharge rate between lithium iron phosphate battery and lithium polymer battery? I have a remote application in which the self discharge rate matters a lot.
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2answers
116 views

Capacitor leakage and design for low energy battery powered devices

For the design of a portable battery operated device, I have some power circuitry which requires a DC-DC converter and some other regulators, battery charger IC etc. While in the process of ...
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3answers
206 views

Boost regulator from 3V to 14V; then two LDO to make a +5/-5 power supply?

I am designing a mixed signal circuit and I need +5/-5 dual supply for my opamps. Could the following configuration work, else what are my alternatives? ...
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4answers
323 views

Battery-Operated Mobile Charger

I want to build a mobile charger that is battery operated and found this diagram. At first glance, this diagram looks kinda simple and I thought that this won't work. I'm a newbie on making this kind ...
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2answers
140 views

How to actuate 24V solenoids from 3.6V batteries

I want to build a battery-powered device that actuates a 24 V solenoid when a button is pressed. How could I power it from a 18650-sized lithium-ion cell? It should work down to about 3 V, when it's ...
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1answer
63 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 ...
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0answers
44 views

Battery backed RAM for access by the OS

I apologize if this is the wrong place to ask this (just let me know where to go, if that's the case). I want to know if anyone has an idea how to set up battery backed RAM, like in an old S/NES ...
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3answers
188 views

How to keep circuit powered when battery disconnected for short time

In an assembly, I'm using spring loaded pins to connect a battery to a circuit board. It's possible from dropping the assembly that power may become disconnected for milliseconds at a time from the ...
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1answer
97 views

How create a low-voltage boost (~4v to 5v)

I am looking for a circuit that will go from a Li battery that has a voltage between 3.6v and 4.3v up to 5v - and I have seen similar questions such as this and this, but those just recommend ...
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2answers
115 views

Toggle battery powered LEDs

I am helping to build a costume prop that has four LEDs lights on it (1 white and 3 amber). This device is worn on the wrist, so space for power is limited- a 9V battery or something that will fit in ...
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0answers
114 views

L293D causing motors to move slowly

I'm modifying an RC car to use bluetooth. I use the L293D chip, and when I connect the motor to the chip, the car barely moves. If I connect the 9V battery directly to the motor, it moves the car ...
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1answer
50 views

Lengthen charge times with batteries

Would replacing a 3.7v 1000mAh lithium ion battery with a 3.7v 5000mAh lithium ion batter make my projects last longer between charges?
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1answer
108 views

Finding the right battery?

I have a 5v circuit that's running on a 3.7v 1000mAh battery. I got it changing just right and the circuit is running fine but it doesn't last as long as I want it too. So how can I find the right ...
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2answers
2k views

How does this mosquito zapper circuit work?

For the purpose of learning, I have tear down a small mosquito zapper racket. I am now trying to understand how the circuit is working (which goal is to produce high voltage). (yellow = ...
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1answer
399 views

nRF24L01+ RX in pulsed operation to save power?

I'm considering building a handheld radio receiver based on an nRF24L01+ and an ATtiny chip. It needs to receive "continuously", to receive a control signal that might operate some attached LEDs or ...
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1answer
198 views

How does the nRF24L01+ performance degrade with supply voltage?

I'm looking at building a small handheld unit based on an nRF24L01+ in PRX mode. It needs to be able to receive "continuously" to receive control signals that would cause an attached Atmel ATtiny to ...
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2answers
754 views

How to get 12v 5amps battery setup for LED strip

I'm building an LED lightbox but I really want to avoid using a power supply/cable so I'm trying to figure out a way to do it with batteries. The strip I'm using is ...
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1answer
220 views

Arduino Battery Over-Discharge Protection (O-DP)

I am getting an Arduino Uno soon, and am planning to run off a 8-cell NiMH battery pack (through the power jack). Assuming a .9V cut-off per cell, that'll mean a 7.2 cut-off voltage. How would I wire ...
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2answers
315 views

RF Wakeup - Battling power consumption

I am currently using two nRF24L01+ (2.4 GHz RF transceivers) together with two AVRs to create a keyless entry system. My problem is battery lifetime when using a CR2032 battery to power the key. The ...
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2answers
123 views

Alternatives to relay/contactors in DC circuits

I wanted to switch a 60Vdc line to ON/OFF using a 60Vdc controlling signal for some kind of a feedback system (yes both are 60Vdc). Presently I have two options visible: Solid State 60Vdc input ...
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1answer
113 views

On button press, use battery if no power is provided via USB

I'm making a binary clock that is normally powered using USB 5V. I already have a battery (CR2032) for the RTC chip. So I want to also use this battery to power the board, when a button is pressed ...
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3answers
252 views

Using timer to power on/off a high current circuit

I'm working on a Arduino project that takes measurements from the environment and sends them to a remote server over WiFi. The circuit should be battery powered and I've measured that what I have at ...
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2answers
224 views

How do I use an adjustable LDO regulator to power devices with USB that usually use AA/AAA batteries (or should I)?

I want to use USB to power devices designed to work with one, two, or three AA/AAA batteries. Three seems to be the trickiest, because it involves dropping the voltage only ~0.5 V from 5±0.25 V to 4.5 ...
3
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1answer
105 views

What is this most efficient way to power a high powered 6 V and a low powered 12 V device from a battery?

I'm looking to power two devices (two amplifiers, an Akai - EIE Pro and a Behringer - MICROAMP HA400) from a battery source (a big 12 or 6 V sealed lead-acid battery). Unfortunately they require ...
3
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1answer
119 views

Backward measurement of AVcc against reference voltage connected to ADC input

what you think about ADC backward measuring supply voltage in microcontroller? It looks interesting for battery-powered devices. The idea is: Connect constant voltage (some voltage reference IC) to ...
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0answers
56 views

BMS: Comparator using TLV1702

I was asked by my boss to develop a system to manage an automatic door battery system. The goal is for when, for example, the power goes out, you get home and want to open your garage door, with this ...
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1answer
2k views

LED needs a minimum current or minimum voltage to operate in forward bias

I want to wire up an IR LED on a battery. I've seen many tutorials telling me that I should add a resistor, but none says what resistor to use to maximize battery life. So a 680ohm resistor will do ...
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2answers
124 views

How can I regulate a 5V battery?

I am trying to use this 5V RAVPower battery pack to drive some electronics and a high-current load: ...