Questions tagged [batteries]

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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2answers
45 views

Small battery for multiple small charges

What are small batteries that can put up with lots of small charges? I get that you can't have everything in a design, so I get that it will be heavy or expensive. Imagine a RC car with some photo-...
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1answer
77 views

Will my DIY powerbank be safe? It will be charged using laptop chargers

I want to build a DIY power bank that can be powered using most types of laptop chargers. I do not have any background except personal interest and lots of videos and documents read online. I need ...
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3answers
56 views

Battery charging voltage additive?

I've got a 18.5 volt battery made up of 5 3.7 volt cells (Li-Ion). For charging the datasheet for the single cells says the battery requires .5 volts more, to counteract the internal resistance, I ...
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5answers
147 views

Can commercial 9v batteries deliver 2 amps?

Are these commonly used, cheapish batteries able to deliver 2 Amps of current continiously and safely? I know that assuming 200mAh capacity the battery will be dead in 6 minutes or so. Example ...
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2answers
91 views

Using 18650 batteries to power TV during power outage [on hold]

I have a ton of 18650 batteries. As a fun project, mostly to learn. I would like to build a battery pack with these batteries, and power my TV when there is an outage. Can I just match the AC 120 V ~ ...
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2answers
67 views

Current delivered by the vehicle alternator

I have a vehicle alternator with following parameters: 14V, 140A. In parallel to this alternator is connected 14.4V vehicle lead acid battery. The alternator is used as a power source for a load which ...
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1answer
52 views

Zener diode conduction

Why doesn't the zener diode conduct even while the battery is being charged at a higher voltage than 6.8v? I assume that to charge a battery the charging voltage has to be more than the batteries ...
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2answers
28 views

Effect on mAh of connecting 2 batteries in series

Two batteries, each at 1000 mAh let's say, connecting them in series will not result in a 2000mAh capacity, right?
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1answer
31 views

Help needed configuring battery bank out of smaller cells

Due to availability and not practicality, I am attempting to build an as large as possible battery bank from 16 AH AGM batteries. The end goal is a large system that is charged with a solar system ...
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3answers
568 views

How much energy is stored in a AA battery when its voltage has dropped to 1.2V?

The general question is how useful it is to use weak batteries with a boost converter - say, boosting 3AA of 1V each to 5V? According to this image it seems that only 5% of the energy is left when ...
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0answers
27 views

Help about MCP73831-2 charger management chip

I designed a circuit with a battery charger using MCP73831-2, this is the circuit i used After testing it for about 4h i ended with a swollen battery My question is what can cause this problem ? and ...
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1answer
66 views

Meaning of battery name

I'm currently working on making a battery I salvaged from a mowing robot usable. It doesn't have a datasheet or anything, since it was made specifically for the robot and wasn't intended for consumers....
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0answers
29 views

Switching between two power sources (LiPo cells) [duplicate]

I'm building a circuit with a 2S or 3S LiPo as power supply. If a 2S LiPo is connected the circuit should be powered with 2S (7,2V). If a 3S LiPo is connected the circuit should be powered with the ...
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1answer
30 views

lithium 72v(2x 36v series) charging with double 36v charger For ebike project

Edit1: Voltage is wrong but here basic wiring diagram for paralel to series Changeover switch a diagram i found on internet closest to what i want i want to series 2 36v battery pack i know to ...
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1answer
35 views

Battery with alternative power supply

I have a circuit that can use a 9V battery for power, but also want to alternatively connect to a power supply (usually higher that 9V) without taking out the battery. Is it OK to just connect the ...
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1answer
40 views

Battery connector and wire ampacity

I’m considering using a JST ACH connector with my LiPo, but I don’t understand whether the current rating on the data sheet is for aggregate or for each wire individually (which is my guess since they ...
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2answers
99 views

Power a 12V 30A (instantaneous) load. Possible with 18650 cells?

(novice) Hi, I'm driving a 12V load for ~1s second very infrequently, at a draw of about 30A. The load isn't particularly voltage-sensitive. Total mAh isn't that important. I have a supply of ...
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3answers
54 views

Buck converter source current draw

I'm doing some calculations for a system that is going to use a few buck converters. I need to make sure that the battery will be able to feed enough current but I'm not 100% certain how power on the ...
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1answer
88 views

how to increase output current (5V Output, 1.5V input Switch Boost Converter) [on hold]

I designed a small boost converter with discrete transistors, and now I need to increase the output current. The output is 30ma/5V but I need more than 70ma. How can I improve the circuit? R5 is load....
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3answers
48 views

Adding different voltage battery to same circuit

I have 9 volt battery to get 5 volt using step down converter. I want to enable the step down using a timer IC max input voltage 6 volt. I will use 3.7 v battery for this. So my question is: Can I ...
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1answer
30 views

Should I charge an in-series 6-pack of Li-ion batteries at 4.2v 1A or 25v 1A?

I have a 6-pack of 18650 Li-Ion cells connected in series, so it gives around 22v dc output. To charge a single Li-Ion cell I need a 4.2v 1-1.5A charger, simple stuff. But to charge the whole 6-pack, ...
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0answers
55 views

How to prevent voltage droop when discharging a battery?

This is quite an open question, so apologies in advance if you would rather schematics and the like, if you really think this would help I can provide them My problem: boosting from 2x AA Li ...
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0answers
29 views

R-Pin on 4-Pin battery?

I am currently salvaging parts from a husqvarna automower 305 to use in later projects. Among the parts is a variation of this battery: https://www.amazon.de/Green-Werkzeug-Husqvarna-Automower-...
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Present information in coulomb counter in Windows/Linux

I'm making my own mini laptop using the innards of a compute stick clone. One thing that has me confused is how I should interface the battery monitoring to Windows in order to show it in the standard ...
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1answer
45 views

How to measure dry cell charge level

I'm trying to measure dry cell charge level. I'm using 6V/4Ah/20Hr dry cell battery. In my system there are atmega32a and 6 seven segment display; how can I measure the charge level of this battery?
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1answer
43 views

P channel mosfet as a switch on logic level

I'm quite confused about the p channel mosfet as a switch. I saw designs with zener diodes, other mosfets or BJTs but these seem overcomplicated. I have many P channel mosfets from broken chargers (...
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1answer
44 views

How to get started with battery replacement in a bluetooth speaker? [closed]

I have a bluetooth speaker with a faulty battery (this model). I'd like to replace it but I have very limited experience with this kind of repair work. To get started, I'd like to identify what type ...
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2answers
67 views

How to calculate a lithium-ion battery's discharge time at a specific load?

How do i calculate the discharge time for an lithium-ion battery at a specific load? Let's say i have a lithium-ion battery with a nominal voltage of 3.7 V, a cut off voltage of 3.0 V and a nominal ...
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0answers
19 views

BMS with same charge and discharge port

I needed a BMS for my 2S 3.2V Lipo4 (powered by a solar panel), I ended up finding this: https://www.aliexpress.com/item/32739763914.html However, same charge and discharge ports caused me to ask ...
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2answers
50 views

Battery mAh and device operation

If a small signal electronic load is designed for normal operation by using say 1.2 V 630 mAh battery and if the same battery is replaced with say 600 mAh or say 700 mAh rating battery, does it affect ...
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0answers
14 views

designing Step Up Converter G5177 for battery project

I need to use the typical design offered in the datasheet of the G5177c Designing Step Up Converter for a mini battery-powered project. I bought a PCB with the circuit already built, but I would like ...
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1answer
42 views

Battery heating issue

In my project, we are using Li-Polymer batteries. We have LCD and high-power components which will generate heat. We have an enclosure in which battery and LCD and other hardware will be fitted. We ...
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2answers
136 views

Why are there 2 connectors on li-ion batteries

I'm looking at just about any assembled li-ion battery pack for sale and they all have 2 connectors coming out (4 wires total) and I'm wondering why is that?
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1answer
27 views

Power 3V EL wire inverter with DC adapter

For a project I have 20 pieces of EL wire that each have their own 3V (2xAA) inverter. Now I think it's a complete waste and hassle to replace the batteries every so many hours, so I wanted to try and ...
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1answer
57 views

Can I work 30 of these Solenoid Valves from a battery?

The (30) solenoid valves are 12v, all identical, each controlled by a relay and are rated at 6.2 watts of power consumption. They will all be turned on simultaneously and turned off separately. This ...
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1answer
38 views

Identical li-ion packs in parallel

I'm looking for a 1kWh battery at 36V, something around 30Ah should be fine. Browsing popular sites I see that the lower end starts at about $400 which is a bit over what I'd like to pay. I stumbled ...
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1answer
76 views

Options for replacing a broken charger when dealer no longer sells these [closed]

First post on this exchange, please do not delete it as a "request for shopping recommendation", this is close to, but not intended as one of those. We have a Trimble DiNi 22 which runs fine, but we ...
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1answer
60 views

Can I use USB to power a flashlight that runs on 3*AAA or 1*18650 battery? [closed]

I am thinking of buying this UV flashlight. It runs on either 1 18650 battery (4.2v) or 3 AAA batteries (4.5v). Since the flashlight can already take 4.5v, will it be safe to run on 5v USB? I found ...
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1answer
120 views

Identify dead component in notebook battery

Battery name is GARDA31, based on bq29330 and bq8030. Most probably I killed it myself when soldering by shorting terminals with solder wire :( Controller is alive (communicates through SMbus), but ...
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2answers
53 views

Maximum power/current for a battery?

I'm learning electronics and found this question below, which is exactly what I've been questioning myself. But there was no good answer there, so maybe someone here can help. Original question: ...
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0answers
27 views

How long could 4 series connected 18650 Li-ion batteries be used to produce a constant 14V 3A supply from a 14V 2Hz pulse train, before failing?

How does switching from charging to discharging at high amperage affect the battery life? The batteries would be fed by the 2Hz pulse train whenever they were supplying power, so they would always be ...
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0answers
44 views

Li-Po battery unable to power 12v device

I would first like to say I have no background in electronics, so my question is probably an easy answer, and my lack of knowledge is preventing me from finding the solution. The Story: I am an ...
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1answer
51 views

How to limit maximum voltage when it's 0.1V too high and the device controller complains?

I built a retrofit Li-Ion battery pack for a scooter that originally ran on two 12V SLA batteries in series. I measured the voltage of the original SLA charger during the CV phase and it measured 29....
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1answer
34 views

How to choose the correct fuse in a double paralled battery supply system?

Suppose I have the following system: simulate this circuit – Schematic created using CircuitLab As you can see we have: Two 500V battery with an estimated 500mohm average internal resistance. ...
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0answers
45 views

Protecting IC from voltage spikes

I'm currently designing a PCB with a boosted audio amplifier. It is powered with a single li-ion cell with 3000mAh capacity. According to the datasheet of the audio amplifier, it is recommended to add ...
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3answers
67 views

What would happen if I connect a battery which has lower voltage than output of battery charger

At this moment I'm building a charger for Li-ion battery based on constant current, constant voltage method. I have used IC LT3741 to build a charger. The specs of my charger: 8,4 V, 2A But I dont ...
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1answer
72 views

How to power a device using a USB port instead of AA batteries?

I have a device that uses 3 AA batteries and I would like to power it from a USB port instead. As I understand I will have to use resistors but I have no idea on which ones. I have found the ...
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0answers
35 views

Low voltage cut off on 10s battery? GPS tracker on e-bike

I'm trying to put a GPS tracker in my e-bike battery so that it is hidden and always powered on. It accepts up to 100V so that's no problem but if i directly connect it to the cells it will ruin my ...
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1answer
88 views

Are lithium ion batteries damaged by strong magnets?

I'm wondering if it is okay to put a lithium ion battery directly next to a strong permanent magnet. Would this affect the functioning of the battery? Can it lead to early failure? In the worst ...
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2answers
82 views

Can batteries shrink physically in size?

A few days ago I took apart my laptop,an HP BC000nq, with the intention of adding a new 4GB RAM module but I found something intriguing.The battery surface was carved with deep cavities between each ...