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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46 views

Calculate battery duration [duplicate]

Maybe this is a trivial question, but I am struggling with it for a while. I have an alkaline AA battery which is consuming 80mA for 8 seconds each 30 minutes. I need to calculate how many days it ...
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120 views

battery backup switching

I am working on an appliance project in which I have been tasked with the design of the power supply. The project specifications hold that from a 230v 50Hz wall supply two voltage rails of 5v (for ...
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3answers
225 views

Is everything OK with this circuit?

Coming from this question, I decided to have some changes. So my case is I have an LED with this description: Dimensions (diameter x height): 20 x 8 mm Operating voltage: 3,4-3,6 V Rated current: 700 ...
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3answers
238 views

Can I replace a battery with a source of the same voltage but different capacity (mAh)?

I have a device that has a bad battery and I am trying to find a suitable replacement. There are no replacement batteries for the device so I am trying to put something together myself. The original ...
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1answer
179 views

Lead acid battery charging current dosent become zero

Here I am charging a 6V 4.5Ah lead acid battery by using a 8V-10V LM317 input supply for the circuit. I'm using the BD139 transistor to cut off and a 6.8V zener diode. As the battery voltage reaches ...
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2answers
80 views

SLA battery constantly being charged and used

I have a 12V 7Ah SLA battery with a smart battery charger for SLA batteries with the maximal output of 0.8A. I would like to use the battery to charge an Arduino board with few other things (at most ...
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2answers
127 views

How can I power mobile devices from my 36v or 48v battery safely? [closed]

I want to buy a rear rack battery for my bike, but not for powering the bike. Instead, I want to power other things, such as an action camera+gimbal, a mobile phone charger, grip warmers, lights etc ...
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3answers
114 views

How to find out which end of a dead battery is the anode, and its voltage [closed]

The battery pack for an old rc car I played with as a kid, has died. Salt crystals everywhere, smells like vinegar. The pack consists of 8 batteries of AA-size connected in series. The red markers ...
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1answer
194 views

Which DC-DC converter for a uController

I want to power a uC project (uC is a STM32, supposed to be powered with 3.3V) over a LiPo battery. Since LiPo's output ranges from 4.2 volts to 3.7 volts, I feel unsure whether to use a step-down or ...
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1answer
91 views

9v battery voltage goes down very low when connected, but shoots back up when it is disconnected?

Whenever I leave a 9v battery connected to my circuit (simple circuit connected to a motion sensor) It goes down to about 3.3v, but when I disconnect it again, it will slowly go back up to about 8v. ...
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1answer
1k views

Excessive voltage drop from LiPo battery

I am using a 750mAh 25C 3.7v LiPo battery for a custom electronics project which currently draws ~1.5 amps, far below the rated operating current of (0.75 * 25 = ) 18.75 amps. However, at the battery ...
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0answers
25 views

Dedicated li-ion step up drivers

I have a design which will include the optional use case of boosting up to 7V from a li-ion battery. I can't seem to find any drivers dedicated to li-ion for this? There seem to be a few buck boost ...
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1answer
980 views

Lithium ion battery protection IC not able to drive MOSFET

I have integrated the TP4056 charger design into my PCB. The problem is that when I connect the battery at the battery terminals, I am not able to get the voltage at its output pin. The circuit can be ...
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3answers
4k views

Running 12V PC Fan with 9V Battery

i got an old PC fan which according to its label runs at 12V drawing 0.14Amps. I would like to run this with a 9V Battery so that it doesnt go too fast. Does this make sense? How long would the fan ...
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2answers
95 views

Solar powered water pump - need some advice

I am completely new to elecrical engineering, but I want to give it a shot and am really interested in learning more details about how all of it works. I've had an advanced physics course in high ...
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2answers
136 views

Why is it recommended to not use a device while charging? How does it harm the battery or the device?

I was planning on getting the new VR headset from Oculus, dubbed Oculus GO. The battery life of that thing is roughly 3 hours max. So, during long VR sessions, powering the headset via a power bank ...
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3answers
141 views

Will battery last longer with larger capacity but lower efficiency (high V through LDO) or vice versa?

Given a simple circuit of a draw around 28mA (when supplied 3.3v). I'm trying to maximize run time on a battery, but working with what I've got on hand... I have the following batteries: 5000mAh 3S ...
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2answers
321 views

Is it safe to connect a small solar panel to a lead acid with only a diode?

Is my setup safe? I'm connecting two 7.2v 100ma solar panels in parallel using two 1N5817 then to a to 6v lead acid battery with a Constant Voltage Charge of 7.3-7.4v for cycle use.I can't use a MPPT ...
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2answers
86 views

Safe assumption for AA and C battery current draw

I have 5 LED candles with built-in timers, but they eat batteries, so I'm hoping to use an AC adapter to power them instead. They are all different with some using AA batteries and others using C ...
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1answer
2k views

Replacement of li po battery with li ion battery [duplicate]

Is it possible to replace a battery for headphones? I would like to replace a 052030 li po battery with a Nokia BL-5C Lithium Ion battery. The li po battery is rated at 130 mAh with 3.7v. The Lithium ...
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1answer
298 views

Could I replace headphones NIMH battery with Lithium Ion phone battery of the same voltage?

Is it possible to replace a battery for headphones? I would like to replace a 052030 li po battery with a Nokia BL-5C Lithium Ion battery. The li po battery is rated at 130 mAh with 3.7v. The Lithium ...
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1answer
258 views

Parallel lipo batteries with mcp73831 charger IC

After reading this very informative blog about load sharing while charging batteries, I'm planning on using an MCP73831 in the same configuration as detailed by the blog for use in a project I'm ...
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1answer
99 views

Connecting a Lithium battery directly to the GSM module

I have a GSM module (M66 from Quectel) and a single cell Lithium battery,Based on Datasheet module operated in the 3.3 ~ 4.6 V and as I know battery deliver 3.7 ~ 4.2 V based on it's sate of charge....
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3answers
428 views

XBee power supply design using a Li-Po 3.7V battery

I'm currently designing the power supply for a device which uses XBee PRO S2C as a medium of communication. We are using a Lipo battery 3.7V 3500 mAh battery and TP4056 based battery charger. The ...
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1answer
60 views

Possibility of series connected LIPO batteries for running stepper motor

I have project where I am using a motor driver DM860A2 to run NEMA 34 85 kg-cm stepper motor. Currently I have used a transformer to supply 48V AC during testing. I have with me four 2200 mah 11.1V ...
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2answers
56 views

How to calculate the required battery capacity for audio system

I'm converting audio speaker to run on batteries. the speaker is Stagg SMS 8p - RMS 90W, peak power consumption 200W which is consistent with 1A fuse for 220V. Say I go with 12V battery - peak ...
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1answer
134 views

Oscilloscope differential measurement for battery powered circuit using single probe

I want to measure the voltage across a resistor in my circuit. The circuit is battery powered. I don't want to use the two probe method and calculate A-B to get the results. Can I use one probe to ...
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1answer
72 views

How to calculate 18650 battery use time?

I am currently powering my mini fan using a normal power bank (the one used for smartphone) which is 5V, 2A output and can last for around 6-7 hours. If I power my fan using two 18650 3.7V 2300mAh (...
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1answer
60 views

Battery to AC conversion voltage question

I am converting a device that uses 2 [C] size batteries (1.5V) to use a transformer in an AC outlet. I understand that the transformer rating should output 3 volts. However.... I only found a 3.2 ...
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1answer
252 views

ON/OFF push button circuit with battery under voltage protection

I have put together the push button circuit explained in TI's SCEA048B application report with an under voltage protection using TI's LMS33460 chip. I ended up with the circuit attached. The idea is ...
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1answer
324 views

Not enough power going through IRLZ44, activated by Arduino

I've a 9v battery and I'm trying to get 9v through my IRLZ44, to power an solenoid. It's a seperate system from my arduino who's sending a 5v signal to the IRLZ44 in order to activate it. For some ...
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0answers
15 views

Where can I get informations about smartphones battery datasheet?

I'm hardly trying to find the datasheets and I still got nothing :(, what I was try to find is like Asus battery for Zenfone 4 Model: C11P1404 datasheet. Please for your kindness tell me where can I ...
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1answer
36 views

Hooking up a battery to a BLE beacon

I am looking to add a battery to this BLE beacon with as few parts as possible. In their product's datasheet they include a section on an example schematic for adding a battery (included below). My ...
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2answers
147 views

Battery reads 5V but can't power a 5V sensor?

I have a circuit set up similar to that shown bellow which allows readings to be taken from an infrared sensor (MLX90614) using an Adafruit Feather HUZZAH ESP8266. This works fine when the battery ...
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1answer
52 views

How can software give an accurate estimation of remaining usage time for a worn battery?

I understand that the system can read the current voltage and determine battery remaining percentage from that. Say, if a Li-ion battery in a mobile phone is at 4.3V, it's likely the battery is full. ...
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1answer
224 views

Control the output current of battery

I used DC-DC to get 3.3V supply from my battery with 3.6V capacity. I used large battery (connected number of cells in parallel) for long term operation of device (81Ah). So my questions are: -> I ...
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5answers
429 views

Using battery to operate a DC load

FOLKS, am a learner. This is the problem am trying to get around. what would happen if I use a 200amp 12V battery to run a dc standing fan of say 2amp power draw or a piano of same rating or any ...
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3answers
125 views

Can 2 9v batteries heat an electric range heating element

For an experiment I am trying to power the heating element in the link attached. http://www.appliancepartspros.com/frigidaire-range-surface-element-316442300-ap4356466.html My goal is to power it ...
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1answer
59 views

Speedcontrol for a 14.4V DC 20A motor

So, for a small home-made engineering project I have cannibalized a 14.4 V DC 20 A motor from a Bosch battery powered screwdriver/powerdrill to spin a flywheel. I'm still using the trigger (...
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1answer
196 views

0-1А adjustable current source IC for dimming battery powered LED [closed]

I'd like to build an adjustable current source for battery-powered LED lamp to dim it so I can adjust its brightness for reading while using it. It is originally powered by 4V 0.75А PSU but consumes ...
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0answers
264 views

Does mixing and matching battery capacities result in a bottleneck when wired in series?

I want to make a 12V battery pack to run an Nvidia Jetson TK1 for an afternoon. I am new to using batteries and was wondering - will mixing smaller capacity lithium ion batteries with larger capacity ...
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1answer
83 views

+ and - 12 V power supply with 12v Batteries, How to make a ground rail with both batteries

I'm new to electronics. I want to make a battery supply to power an OPT301M {photodiode with integrated op amp} and an ADTL082 dual {op amp IC} in order to attempt to reduce noise in the circuit. I ...
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1answer
397 views

Higher brightness LED with bigger resistor to save battery life

I need to run three LEDs for indoor indication purposes and want them to be around 500 - 1000 MCD. I will run them off batteries and I'm wondering if there is anything I can do to increase battery ...
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1answer
125 views

Battery power to DC mains power [closed]

First time posting here :) Hope someone can help. I have a wireless Yale home alarm system and the external siren is chewing through batteries in no time and is expensive to keep replacing them. I ...
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1answer
105 views

What DC motor controller will work for a small toy train? [closed]

I'm thinking about modifying a battery-powered toy train to use a higher voltage battery so the toy can go faster. Like this: https://youtu.be/qK-IVIllOBY?t=30 The 9V battery has a nice form factor ...
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1answer
64 views

lithium ion battery in series discharging question

Trying to connect 4 12V 5Ah lithium ion batteries in series to make 48V 5Ah source. If my circuit is running on lower amps than 5, lets say 1A. Is the batteries going to be fully discharge in 5 ...
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1answer
86 views

Latching control via active-high battery supply / regulator shutdown pin?

I'm looking to supply an MCU (3.3 V) from battery via voltage regulator: a pushbutton should enable the supply, the MCU then should keep the supply enabled until it wants to shut itself down. But the ...
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1answer
193 views

Precise low power millisecond timer

Any suggestions on a low-power programmable timer that does something like the following (to wake up a microcontroller)?: Shortest delay I need is about 10ms. Highest delay I would like is a few ...
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1answer
58 views

Understanding battery capacity with solenoid application

I am working on early stage of product design and was hoping I could get some guidance/ help. My product will use between 12 and 15 individual, small (less than 1" diameter) rotational, self-...
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1answer
223 views

Need to run a mobile robot on batteries

I made a 4wd mobile robot with an 4 DoF robotic arm on it and currently in process of designing a power board for my robot. I would like get a detailed road map on designing a power board for the ...