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
99 views

Capacitor Bank Design for Electric Vehicle

Good day all, I'm toying with the idea of using a small supercapacitor bank to buffer short bursts for acceleration/regen of an electric vehicle (likely an e-bike). It seems wasteful to put a ...
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2answers
91 views

What is the peak current for CR, LIR and AA batteries?

I'm working on a project that requires low energy consumption. In standby mode, it will consume about 11uA. However, when it starts working (it will transmit data in RF), the current goes up to 121mA. ...
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2answers
49 views

Proper voltages from same source

I'm building a small electromobile. I was planning on using a car alternator as the motor, however I'm now looking into buying a 48V 500W BLDC motor. The problem is I'm not really sure how to manage ...
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1answer
69 views

How to wire a normally open switch to a recoil start engine with no external battery?

I am making an engine toggle switch for a recoil-start engine using two switches wired in series for safety. The engine will shut off only when two "kill" cables on the front have been connected. In ...
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1answer
56 views

Help Identifying Parts of a Battery Management Board

I am currently way over my head in a personal project to design and create a 5 cell battery protection system. I'm fairly confident that I've correctly cloned the cell balancing section (section C) of ...
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1answer
41 views

Battery consumption for four N20 motors [closed]

Hi everyone Electrical newbie here. I wanted to use N20 motors with metal gear box for a 4WD smart car project. There are different RPM version of N20 like 200 rpm, 300 rpm and 500 rpm. If I choose ...
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1answer
121 views

Is there a good way to test your schematic before buying the parts and building it?

I'm trying to design a BMS that can handle 12 cells, be powered either with a isolated dc-dc converter or the batteries themselves and uses active balancing, but I'm not sure if my design will work:
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3answers
68 views

Switching between battery and external power sources with reverse polarity protection

In my design, I will use AA batteries to power the electronics board. As a requirement, also it should accept the power from external power supply (12V) - The board should automatically switch from ...
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1answer
38 views

Working out the safe continuous discharge current for a lead acid battery

I have a Numax DC25MF 12v lead acid battery with a quoted capacity of 95Ah (C20) What is the continuous safe discharge current for the battery? By 'continuous' I mean a few hours without a break, and ...
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2answers
87 views

Advice for using 60 watt peltiers? Is 12V 3A enough to get the job done?

The weather right now is so bad and hot! A friend of mine runs a mobile stream and his phone refuses to charge when it is hot. His stream crashes because he can't charge his phone or it overheats. Not ...
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0answers
62 views

Battery Monitoring IC communication via SPI

I am trying to use Max14921(Battery monitoring system) to measure voltages of 16 cells of a battery pack. I have used stm32f103c8t6 as mcu. The problem is that I could never communicate with IC. I ...
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0answers
52 views

How do portable batteries with AC outlets handle the ground pin/wire?

There are many portable batteries ("power stations") that have AC outlet(s) with – what looks like – a dummy ground pin. From what I can find in their manuals, it doesn't seem like these devices are ...
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1answer
98 views

Is is safe to let my PWM charge my 12V battery at 14.8V?

I have a 12V battery linked to my solar panels. In the middle I have a PWM charge controller, that is configured by default to charge the battery if Voltage if lower than 14.8. At night, battery ...
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0answers
39 views

Is it possible to somehow revive an AGM battery, that quickly loose voltage when used?

I have a GLP 120-12 AGM battery, this thing to be exact: https://glpower.eu/produkt/glp-120-12/ It's a 120 amps batter, and it is about 26 months old. All of a sudden, I noticed that the battery is ...
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1answer
29 views

Two power sources into appliance (12Vdc)

I am creating powering board for LED strips inside the cacti glass house. It consume 12V DC around 2 amps. I would like to power them up from battery (charged by solar, lead-acid battery 20Ah), but if ...
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1answer
90 views

Charging 3P pack of 18650 batteries using a single TP4056, and protection standards

For a project at uni, I'm trying to learn to work with 18650s and TP4056s. One of the tasks is to be able to USB-charge three 18650s (Panasonic NCR, 3350 mAh each) in parallel, whilst also being able ...
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5answers
152 views

When you connect two batteries in series, why doesn't the middle short?

When you connect two batteries in series, why doesn't the middle short? The connection between the positive terminal on one battery and the negative terminal on the other battery has no load, so ...
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1answer
66 views

How to generate heat using a battery and a wire

If i connect the positive and the negative terminal of the battery with a wire, the wire will turn red and generate heat.This creates a short circuit.This can damage or explode the battery?Is there ...
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7answers
1k views

How do batteries connected in parallel give more current than batteries connected in series?

Let's say we have three 1V batteries and we're connecting them to a 1Ω resistor. Connected in series, the voltage is 3V and since the resistance is 1Ω, that means that from Ohm's law, the current ...
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2answers
66 views

What is the energy density of voltaic piles?

I heard voltaic piles have very small power but long lifetimes so I was wondering what their energy density per unit volume and energy density per unit mass is. If specifying a type of voltaic pile ...
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3answers
120 views

What power adapter do I need to charge a 7.2V 4000mAh battery that I made? [closed]

I made a Ni-CD 7.2V 4000mAh battery. What power adapter do I need to charge it? How many volts and how many amperes should the adapter output? Each battery cell is 1.2 volts. I have a 9V 500mA ...
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0answers
20 views

How to use SPI serial interface with ATSAMD21G18?

Like the title suggests, I have a ATSAMD21G18 microcontroller that I want to interface with a LTC6803-4 chip, but I'm not sure how to set up the SPI bus on the microcontroller, and the datasheet ...
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1answer
62 views

STM32F437 UART doesn't work at 3.6V~4.2V(lithium battery)

led is on but UART doesn't work when using lithium battery. stm32f437 UART can work at 5V(power supply). ...
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1answer
78 views

Noise in portable power supply to guitar effects pedals [closed]

I am constructing a battery powered power supply for a guitar effects pedal board. There are 5 pedals and I am using a phone charging battery and a boost converter to supply 9V (centre negative) to ...
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1answer
66 views

Sense Resistor in Battery Charging Circuit

I have a 3 18650 in parallel Li-ion battery pack and wish to use the LTC4162 as the charger and LTC2944 and the level indicator. I am unsure as to who to wire them to effectively use both. I noticed ...
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1answer
38 views

Voltage regulator STBY & OFF - whats the difference?

I am looking at MAX883 voltage regulator and from the documentation is not very clear whats the difference. It says this about pin OFF: In this mode, the pass transistor, control circuit, ...
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1answer
78 views

How to solder the 4-pin battery connector back to phone's motherboard?

One wickedly hot day the battery of my old Nexus 4 swelled up. I use that phone as Android development platform, so most of the time it was plugged into the computer for USB debugging. It's been ...
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0answers
50 views

Li battery charger reference voltage problem

schematic datasheet I have designed a battery charging circuit for a lithium ion battery.When i connect a battery the charging IC seems to do nothing. Only when i use a multimeter probe to measure ...
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2answers
38 views

Batteries connection for 3 wheel e-bike

Goodday. I need info on this. If i connect say 3 x 12 volt 28amp batteries in parallel to increase the amp hour that makes it a big 12 volt battery and then connect 2 x 24 volt but lower in amps ...
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0answers
47 views

24-60V Precharge schematic critique

I'm looking to design a soft-start precharge circuit for starting up circuits with substantial input capacitance (~1.5J @ 24V). The main requirements are: 24-60V compatible Constant current pre-...
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3answers
60 views

How to monitor the voltage of a bunch of batteries using Arduino?

Ive got about 36 batteries that all stay between 2.8v and 3.6v, and I want to be able to accurately monitor the voltage(and therefor the state of charge) of all of them using an Arduino Nano, the two ...
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2answers
31 views

Counting pulses in low power device

I have a mechanical water flowmeter with reed switch output and I connect it to my low power, battery powered device to count pulses. The reed switch is connected to my device via a 15 m long cable ...
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2answers
94 views

Raspberry Pi Zero 12V Battery backup to 5V - do I need the resistor?

I found this diagram on the internet which seems to divide the voltage down to 5V and still be able to deliver 1A with the 7805 just like I want. It will use a 12V lead acid battery and a 12V IN ...
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2answers
155 views

Lithium ion (Li-ion) vs. Lithium thionyl chloride (LTC) battery?

I need some consultation on which battery of the two to use for the GPS trackers I'm designing. My trackers wakeup when there's movement only so they're not on all the time and they have low power ...
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1answer
58 views

How can I limit the current drawn by a Li-Ion battery pack BMS?

I have a Li-Ion battery pack made with twelve 18650 in a 3S4P configuration, using an off the self Battery Management System (rated for 25A), that I purchased on aliexpress. I tried to charge it using ...
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1answer
52 views

Reading a low voltage signal from a battery connected to a transformer

So currently I am trying to read the current draw from a battery that is being run through a transformer to generate an arc to light a gas burner. I have a roughly 1 ohm piece of wire that I am ...
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0answers
42 views

Voltage step up module and if I am using it correctly

I am making a "simple" bluetooth speaker and have followed instructions from a Youtube video on how to assemble the components I have bought. However... I am finding that the rechargeable li-po ...
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0answers
35 views

Connecting a 12v router to a 12v battery [duplicate]

can I connect a 12v router directly to a 12v battery which normally will be at 13-14v (because most of the time it’ll be charging)? The router is a TP LINK Archer MR200 rated at 12V 1A
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1answer
78 views

Can anyone help me identify this component from an old rechargeable battery pack? [closed]

I was given an old, maybe 10 years, battery drill, it had seen almost no use, but, unsurprisingly, the battery pack would not charge. I took the pack apart and several of the cells were obviously ...
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3answers
128 views

How to block reverse current from battery to charger (DC-buck CC/CV module)?

The set-up For a project, I have a set-up where the power to the main load comes from either a AC-DC adapter input (24V) or a battery pack (12V to 16.8V - 4S4P 18650 Li-ion cells). The battery pack ...
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0answers
34 views

Changing between usb power and battery power using P-Channel MOSFETs and a CMOS Invertor

I am trying to switch between USB power and a single cell lipo using two mosfets. Would the circuit below be ideal or is there a more efficient/reliable way to do this? When the USB is connected the ...
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1answer
27 views

BMS for 2S Lipos

I have 2 lipo batteries in series, each has a built in protection circuit and these specifications: Voltage: 3.7 Vcc Capacity: 1000 mAh Maximum discharge rate: 2100 mA I need to charge them, but I ...
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0answers
35 views

12V Lithium Ion Polymer Battery

I am trying to develop a product that requires a 12 V portable rechargeable battery that can output at least 2 A. Since conventional LiPo battery runs only on 3.7 nominal voltage, is it advisable to ...
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2answers
55 views

Unknown Battery Connector [closed]

Hi, this is a standard 260mAh 3.7V battery. I've seen this on several listings on eBay, Aliexpress however nobody says what this connector is. In particular I'm looking for the receptacle part of ...
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1answer
50 views

Bypassing battery cell with transistors

Is it possible to create the schematic below with transistors in any way? As I see it, there is no voltage difference between j1 & j2, so a transistor connected the normal way would not work. ...
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4answers
161 views

How would you wire small computer to run on both batteries and AC power? [closed]

I'm trying to use a motherboard (Mac mini 2018 model) for a project that will require it to be able to run off batteries. The project is essentially building a custom laptop using the Mac mini mobo ...
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1answer
30 views

Power switch: leaving battery connected at one terminal

Just wondering if there is any real-world practical difference between a power switch that disconnects both terminals of a battery vs a switch that just disconnects one terminal. Are there any ...
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1answer
21 views

MAX856 Low-Battery Indicator Question

the MAX856 says it has a low-battery indicaitor. My setup has a single 3.7v nominal LiPo pouch and I want it to trigger the low-battery at 3.4V. Datasheet: https://datasheets.maximintegrated.com/en/...
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0answers
62 views

Reducing Current?

Having a problem with my EV a converted Fiat 500. The conversion is made with part from companies that dont exist any more, so it is hard to get information about them. The car have two batterybanks ...
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1answer
39 views

Custom charger with solar cell

I want to make kind of autonomous power supply for my RPi. So that I am planning to use 12V solar cell and batteries for this project. Also I will use Arduino to controll all of this stuff - to ...