Questions tagged [battery-operated]

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
votes
3answers
4k views

Why do batteries recover after a load is removed?

I carry a small 2-AA flashlight, and a few times, I have accidentally left it on in my holder. Each time it dies completely, so that no light is emitted, but if I turn it back off and wait for a few ...
20
votes
6answers
7k views

Can I disable a battery powered device by reversing half of its batteries?

When I have a device that is powered by two batteries, can I disable it by turning one battery around? For illustration, the purpose is to leave batteries in the device for storage, but it does not ...
20
votes
7answers
4k views

Why do batteries in consumer electronics get used unevenly?

When changing the batteries of kids toys, remote controls, etc., I test the batteries and have noticed that they drain differently. One will be dead and the other is still in the green. Why does this ...
17
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5answers
14k views

How to solder wires on Li-ion cell phone batteries?

I am making a obstacle avoiding robot and wanted to power it with mobile phone batteries. But wondering how to solder wires on battery correctly for no inconvenience. p.s. I am a new arduino ...
16
votes
3answers
14k views

Lithium Coin Cell CR2032 battery specifications

I am using a CR2032 battery module to operate a BLE 4.1 module. The BLE radio for communication takes around 3.5ma to 5ma of current. But when I look at the datasheet of the battery (https://cdn-shop....
16
votes
1answer
7k 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?
16
votes
2answers
34k 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 = resistor, ...
14
votes
2answers
4k views

LiPo vs. NiMH for kid's toy

I've been researching here and on google regarding potential battery technologies for a toy that I want to make for my kids. I was hoping to get others' perspectives on this, keeping in mind that ...
13
votes
4answers
3k views

Does it matter if a fuse is connected to the negative or positive terminal of a battery?

I am currently going through the conundrum of where to place a fuse in my DC battery-powered circuit to protect the circuit components and the DC battery. I've been googling for a definitive answer, ...
11
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2answers
2k views

How much current can lead acid batteries safely supply?

I have a motor I wish to drive with an 18V lead acid battery. The motor can draw quite a lot of current when stalling and I am worried of overdischarging the lead acid battery. Unlike LiPo batteries ...
10
votes
6answers
4k views

Possible battery solutions for 1000mAh capacity and >10 year life?

I'm looking into the possibility of running a wireless sensor node for up to 10 years on a single battery. I think the average current draw is likely to be around 70uA, with the peak current draw ...
9
votes
10answers
3k views

Would a 7805 5 V regulator drain a 9 V battery?

Doing some DIY as a hobby, I'm making a small humidity-temperature radio sensor. An ATmega328 is reading from a DHT11 sensor and then transmitting data to a Raspberry Pi by an STX882 radio ...
8
votes
1answer
7k views

Rechargable power for arduino

What is the best way to provide rechargable power for an arduino based portable device? So far I've found the following options: 1: Use removable batteries and include an external charger with my ...
7
votes
5answers
2k views

Using DC voltage instead of AC to supply SMPS

Situation: You have a battery pack with voltage of 300V. You have some appliances designed for 250V AC. These appliances have SMPS inside. Claim: Instead of using DC to AC inverter, you can use DC ...
7
votes
4answers
6k 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 ...
7
votes
1answer
450 views

6x UV-leds in parallel turning on and off when they should be on all the time

I have 6x UV-leds in parallel driven by a 6V source. The problem I have is that they glow for a little while, then they are completely off for a little while, then glows and then they are off ...
7
votes
3answers
1k views

A separate MCU to cutoff LiPo on low voltage?

I'm designing a project that is going to work on a flying quadcopter. It features an ATmega328P MCU in the main 5V circuit, and is powered by a small (<500 mAh) 1-cell LiPo battery. I want to ...
6
votes
5answers
12k views

simple, energy efficient circuit to make single IR LED blink

I'm using a 850nm IR LED (spec sheet), and in order to extend my battery life, I'd like to make the LED blink (UF 1.9 V, IF 100 mA). I found a couple of links 1, 2, 3 but they either a) require two ...
6
votes
1answer
12k views

switch between battery and usb power no microcontroller circuit

Following an earlier question about how to switch between battery and USB power, I would love to implement the TC2014 LDO as suggested by Russell McMahon. That way I could switch between 4AA ...
6
votes
3answers
6k views

Regulating AA to 5V and achieving high efficiency

I'm trying to regulate a single AA battery to 5V for charging a USB device. I know even at perfect efficiency, it won't provide much juice (1.5v * 1500 / 5v). But what is the expected efficiency for ...
6
votes
2answers
551 views

Fake a panasonic battery to revive camera to copy photos from internal memory

Got this camera from a friend, battery door broken, no cables, no battery. There are some important photo's on this camera that I want to copy from internal memory to SD card. We first want to try ...
6
votes
1answer
1k views

If I turn a AA around will it drain or damage electronics?

I have an Apple Bluetooth keyboard. The thing turns on all the time when I put it in my backpack. This is bad because it blocks the soft keyboard on my phone. It runs on 2 AA batteries. Lately, I ...
6
votes
3answers
572 views

Design Question: Precision Current Source

I am attempting to design a voltage-controlled bidirectional current source that will drive an inductive load. The current source needs a range of 100uA to 200mA, and it needs to work with precision ...
5
votes
5answers
6k views

Coin Cell Battery for Arduino/Microcontroller

Excuse the lack of electrical engineering knowledge but I have an Arduino Uno microcontroller that I want to power with a coin cell battery. The project will have 6 LED lights that will flash for a ...
5
votes
3answers
2k 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, ...
5
votes
2answers
767 views

5 year run time on small battery

I am working on a project that checks a sensor every 12 hours and reports the status via cellular modem to our server .. Power consumption is less than 1mA during sleep mode and spikes to 900mA ...
5
votes
4answers
13k views

Options for getting 3.3v @ 220mA from small batteries

I have a system running at 3.3v requiring 70mA at most times and 220mA at peaks (roughly 20% of the time). I'd like to find a way to power this from coin cell batteries or other small portable source. ...
5
votes
2answers
2k views

Why does this CO detector forbid the use of lithium batteries?

I have several Kidde KN-COB-LP2 CO detectors installed in my house. They look like this: They operate on standard AA-size alkaline batteries, and typically last several years on such batteries. The ...
5
votes
2answers
915 views

Detect if connected battery is rechargeable

The device I am building can be powered by USB or 3xAAA batteries. While connected to the USB, the device will charge the batteries. But before charging the batteries, the device needs to make sure ...
5
votes
1answer
942 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 ...
5
votes
3answers
1k 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 ...
5
votes
1answer
1k views

Coin Cell Battery Safety?

I'm working on a wearable project that is really space constrained. Originally, I had planned to use a Li-Ion battery, but I opted out of it because the person wearing it won't be able to take the ...
5
votes
1answer
2k views

How good is the advice to run the car headlights before starting the car in cold weather?

I'll do my best to formulate this as a purely electrical problem so that it isn't claimed to be belonging to Vehicle Maintenance SE. We have a lead-acid starter battery (not a deep cycle fashion) ...
5
votes
2answers
136 views

Efficiently sensing the voltage of a battery pack

I'm looking to sense the voltage of a battery pack that is powering a device by the device. Depending the the level of the pack (2 cell LiPo 1200mAh) the device will change it's behavior. As the pack ...
5
votes
2answers
610 views

Battery powered sensor node power down circuit

I am using the BQ24079T to control power for a wireless, battery powered sensor node. The MCU will operate in one of two modes: periodic sample mode where it takes sensor readings and then sleeps, or ...
4
votes
2answers
1k views

Atmel SAM E70 (ATSAME70Q21, Cortex-M7) battery backup

I'm building a USB-powered demo board with the Atmel SAM E70 controller, and a single hurdle I'm facing is the battery-powered operation. I intend to use a simple 3V coin cell battery as a backup ...
4
votes
5answers
1k views

Does CW or SSB consume more power?

CW pumps out the full carrier but has a better SNR. On the other hand SSB suppresses the carrier, and one side-band but this suppression demands additional circuitry. There are probably additional ...
4
votes
3answers
1k views

On— off— on— off timer circuit

I want to make a circuit to do something that is relatively simple but I need to find the optimal way to do it in order to take as little current as possible. Here is what I want to do: When a ...
4
votes
2answers
523 views

battery lifetime with self discharge

I want to calculate the lifetime of a battery operated device. Without self discharge of the battery, it is easy to calculate the lifetime, it's just the battery capacity \$Q\$ (given in mAh) divided ...
4
votes
3answers
2k 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 ...
4
votes
1answer
136 views

Do high and low side labels on bidirectional logic level converters matter?

Logic level converters like this one from Sparkfun have high side and low side labels on them. Now i have an application where I think I need to shift logic levels but the high side and the low side ...
4
votes
1answer
822 views

Battery powered device hardware design tips

I'm working on a prototype product(Wifi motion sensor) that will be powered from a battery source, it has a mega328(arduino bootloader, with sleep mode on and wake on interrupt,and WDT in case it ...
4
votes
1answer
5k views

Automating music box with electric motor

I recently purchased a DIY music box kit from a website which I will not link to here. If you watch this video you can see that it has a serious design flaw: it has a tiny hand-crank, and it's thus ...
4
votes
1answer
474 views

Beaglebone Black Power Switch Detection

I've looked around and found a bit of information regarding attaching a 3.7V lithium battery to the BBB (Beaglebone Black) but I haven't found an exact answer to what I am looking for. I understand ...
4
votes
2answers
1k views

Active 433Mhz RF tag battery life question

I am exploring the world of RTLS system and trying to produce one on my own. I chose 433Mhz frequency for its penetration capabilities and I produced a PCB mounting CC430 TI family MCU-transceiver, ...
3
votes
3answers
2k views

Best way to reduce battery consumption for LED device?

I'm building a device that needs to "light up" to indicate status to the user. I of course want to use LEDs to light the device up, but I'm worried about battery consumption since I would like it to ...
3
votes
2answers
5k views

Using MOSFET to turn on/off a sensor controlled by ESP8266

I want to power an MCU (ESP8266, 3.3V) and an ultrasonic sensor (HC-SR04, requires >= 3.7V) using AA batteries. By using an efficient LDO (MCP1700T-3302E) and spending much time in deep sleep mode, ...
3
votes
2answers
4k 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 ...
3
votes
1answer
628 views

Boost with LDO?

I'm working on a project that requires 3.3V from a pair of double AAs. I had thought that LDOs were always buck and if you needed boost you had to use a switching regulator. While doing some ...
3
votes
2answers
893 views

Power switch for a dive computer

I am creating an open source dive computer (www.diydivecomputer.com) and I am having a little bit of a problem trying to figure out how to power the device on and off. The problem is that the device ...