Questions tagged [cell-battery]

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Microstrip on FPC board

Do anyone know, what is the strange track on FPC board on image below? My guess is, it is something like a microstrip track. The image is for a FPC board, that measure cell voltage of batteries.
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Ultra low power 1 digit LCD [closed]

I have a very weak power supply (Fuel cell) and I would like to connect it to power a 7 segment LCD. The reason I am connecting the LCD is to use it as an indicator to see the increase and decrease in ...
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2 answers
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Li-ion End of life

What will be the reason for reduced capacity of Li-ion cell at End of life? What will be the nature of voltage at EOL with respect to BOL? Will it be still reaching something like 3.65 or 3.7?
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2 votes
3 answers
547 views

Wire resistivity / heat generation

How to calculate the volts/amps of a battery which is connected to a simple wire for heat generation? That is, how to use: known wire length, diameter/area, resistivity to calculate the required volts/...
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2 answers
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How can I characterize this voltage source?

This is my first attempt at trying to characterize a voltage source. The voltage source is a 99.8% magnesium rod (10mm diam., 160mm in length) its length wrapped by paper 1mm in thickness then its ...
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What is most effecient cathode material for fuel cells?

I am a beginner working with fuel cells. In my lab two main cathodes (electrodes) are used : 1- Silver Oxide Ag2O 2- Platinum on Carbon Powder (Air cathode) I would like to upgrade to a better cathode....
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-1 votes
3 answers
129 views

Why can't electrons move in an open circuit?

According to answers I saw on net "how electrons flow in a circuit with help of potential difference". I got answers like: A battery is basically just a chemical reaction. At the negative (...
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1 vote
1 answer
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Lithium Ion Cell Precharge

The IC I am using is: STNS01. As I read, charging Lithium ion cells consists of three phases: Precharge ("conditioning" on other articles) phase -> Approximately 10% or 20% of fast charge ...
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2 votes
1 answer
108 views

CMOS coin battery drained out in 5min even without the BIOS IC

I have a high-end motherboard (Asus WS Z390 Pro) out of warranty. My bios looses its settings everytime cut-off the power. I found out something is draining the battery way too fast. I decided to ...
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How to design DC bus bars for batteries?

What factors should we consider for designing bus bars for cell terminals? Suppose I have LFP battery pack made up of 9 cells in series each having maximum of 3C discharge rate and a nominal capacity ...
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Li-ion battery 2 in parallel or 2 in series - Capacity vs voltage, which one will give more battery life?

My circuit needs 3.3 volt, and I have 2 options with a Li-ion battery pack. Option 1: I can put 2 cells in series and get approximately 4.4 to 6V (7.4 volt mean) and then using buck converter reduce ...
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1 answer
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Battery voltage measurement using ADC problem

I want to measure the open circuit voltage of an electrochemical battery using an ADC and an Arduino. I need to use the ADC in differential reading mode (A0 por positive and A1 for negative). ...
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1 answer
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Is it okay to assemble Li-ion cells all in line (series and parallel)?

Could there be some practical issues when operating a lithium-ion battery pack that consists of cells all in one line? (for instance, at a +/- series connection, individual cells within the first ...
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2 votes
1 answer
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Why does the emf depends on the material of the electrodes? Why is the emf independent of the distance between electrodes and amount of electrolyte?

Concise Physics mentions that: The emf (electromotive force)of a cell depends on 1) the material of the electrodes and 2)the electrolytes used in the cell.However it is independent of the a)the shape ...
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1 vote
1 answer
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Converting a range on high side to a range on low side for very precise voltage sensing in ultra low power application

I have an ultra low power design running on CR2032 where it is critical to monitor precisely the current usage and the primary cell voltage during dev. So I added a second MCU dedicated to ...
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1 vote
1 answer
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2.7-4.2 V Li-Ion battery to 5 V 5 A converter [closed]

I have a 2.7-4.2 V Li-Ion battery. I want to convert this battery to boost 5 V-5 A power supply for a short time usage. I know there are lots of ICs to convert these values but I need advice for which ...
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What can be possible reason for explosion and fire in battery pack built with 3S Li-Ios BMS

I recently made some 12v battery back using regular 3S Li-Ion BMS and 18650 cells. Unfortunately, 3 of them EXPLODED and one even caught fire on site. The BMS I used was almost exactly like this but ...
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Having battery cells in parallel does increase autonomy ? (My load is a constant power load. DC/DC)

I have 4 AA alkaline cells and I'm trying to figure out which is the best cell configuration to achieve maximum autonomy with constant power load. I understand that if your load is a constant current ...
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1 vote
1 answer
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Use multiple board Arduino to read cell voltage batteries series

As title, I have 3 batteries connected in series composed by 7 cell each. I have several Arduino nano and I want to use one on each battery pack to measure all cells voltage. Then they will be queried ...
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3 answers
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Is an Ideal Diode necessary for BMS?

I'm designing a battery pack that's on the order of 10s5p. Each 10s stack has its own BMS, with high side driven FETs for charge and discharge. This is based on the Texas Instruments reference design, ...
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1 answer
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How does carbon paste (graphite) interact with other conductors?

I am running a half-cell battery configuration. I am using carbon paste (graphite) as a trace (jumper) because my solution contains bio-materials and carbon is bio-friendly. The carbon paste is coated ...
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Is it okay to double wrap 18650 cells?

I’ve got some salvaged 18650 cells here that I’m looking to sell. Most have perfectly intact wraps/sleeves, but some have small nicks showing bare metal that I’d like to fix. I want to rewrap these ...
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Hybrid charger and NVDC charger

I have some questions about the battery chargers. Here are my questions, 1.) Could someone explain the Narrow Voltage DC charger, I try to google it, but I am still very confused. 2.) In what ...
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4 votes
3 answers
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How can I improve the accuracy of my voltage divider?

I am designing low-cost SoC (State of Charge) evaluation software for a LiFePo4 battery cell at zero current (actually only a low current due to auto discharge). For this peculiar application, low ...
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2 answers
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What causes undervoltage cell in a lithium ion battery pack 48v100ah? [closed]

The lithium ion battery is composed of 15 cells. It has a battery management system. When I check the battery using the BMS app there is 1 undervoltage cell but the other 14 cells are normal. What ...
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Battery Cells Voltage Measurement

I'm using LM324 Q-op amp as a differential amplifier for measuring the voltages of 19-cell battery pack in series which happens to be 1.5 volt for each and the differential amplifier gain ratio is 1:1 ...
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1 vote
2 answers
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What would be the best way to power a 200W motor?

I'm trying to build my own battery pack as part of an electric scooter project I'm working on. The motor I have is 200W 24V and is rated at 11 A. I've explored using six 18650 Lithium ion cells for ...
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Battery made of Li-ion cells assembly

Do you see any issue (feasability, safery, ...) about assembling a battery pack with 10 Li-ion 3.7V 2600mAh cells (put in parallel) having their own individual protection circuits (overcharge and over ...
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1 answer
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Very Noob Question: How to connect Seeeduino Xiao to CR2032 battery holder with switch?

I am planning on soldering together a seeeduino xiao along with an adafruit 20mm Coin Cell Breakout w/On-Off Switch for use in a portable trinket to inject code. Problem is, I've never really done ...
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Parallel light failed to work, one light get's blow other remains good. How to get it working?

I'm using a mobile battery (4V) to power the two (each takes 3.0V) light in parallel since series circuit won't work with one battery. After connecting the wire, for a short time it did work. Then one ...
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If a watch battery that has not been used for 7 years gets reinstalled and is new, what are the chances of it working? [closed]

I have a watch last used in 2014 with a new watch cell battery. However, the cell lost good contact with the watch connectors. Would the battery still be good upon reinstallation with a good ...
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18650 12P2S Charging with BMS and Charge Control Module

I have a quick question on charging options for a 12S2P 18650 Li-Ion pack made of Samsung INR18650-35E cells. I have a pack built using a 12S balancing charging BMS (https://www.ebay.com/itm/...
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1 vote
1 answer
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AP9211 Battery Protection Circuit, Datasheet suggests shorting the negative terminal of the Battery to ground

Question I used to use the Chinese DW01A as a protection circuit for prototyping. The initial prototype worked and I have to switch to a western chip now. For this I have chosen AP9211 because it is ...
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3 answers
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What is the technically right thing: the function of a battery cell in a battery in a phone is to maintain certain voltage or provide certain current?

I need to write the precise functions of an individual battery cell in a li-ion battery of a laptop. I am not sure whether one of the functions should be to provide voltage or provide variable current....
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2 votes
2 answers
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Nominal voltage of a battery

How is the nominal voltage of a battery determined? A NiMH cell's usable voltage ranges between around 1.4-1.0V and the nominal voltage is quite in the middle of that at 1.2V. Similarly, the nominal ...
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Dividing current between inverter and relay

I want to make DIY ATS. My power supply is from 120Ah 12V battery. I have a 12V to 220 inverter and a relay circuit. My problem is the inverter doesn't supply 220V when it is in parallel with the ...
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1 answer
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What cell voltage should I use to charge a 2S 7.4 V LiPo battery? [closed]

My battery charger asks for a cell voltage. To charge to full, should this be set to 7.4 V or is the 7.4 V split between the two cells? If you know of any good resourses to look at on batteries that ...
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Cell matching by capacity and resistance

When matching li-ion cells in a battery pack how do you use both the cell's resistance AND capacity? I've seen sources mentioning that each parallel group should have about the same capacity, and that ...
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1 answer
183 views

How can I build a power bank which charges to 16.8V and outputs 12V?

I am working on a battery build project to drive a small 12V electric motor (7A max current draw), and so far I have gotten this far: I will use Li-ion 18650 cells in a 4S6P configuration I will wire ...
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What's the name of this battery connector?

Been trying to find this "battery bridge" as a spare part to old virtual pets. It's like cell battery connector, but it's individual part connecting two cell batteries (LR44), which has ...
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Does Sony NP-F type (generic) batteries have any over discharge protection circuitry inside?

I use these Sony NP-F550 or NP-F570 Li-PO generic batteries (8.4V) for video light and for powering my DIY projects. I've read you shouldn't discharge a 8.4V Li-ion (it's a double 3.7V cell inside the ...
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1 vote
3 answers
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Can I use a single AAA battery to power a motor?

Can I use a single AAA battery which has 1.5V and 700mAh to run a stepper motor which has operating voltage 3.1V and draws 1.2A/phase? If, yes then how many minutes will it run? Someone briefly ...
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0 votes
1 answer
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Primary Battery and DC Power Switch

I have designed the below circuit to automatically switch between a primary cell (3v) battery, and if available, an external DC power supply (~3.3v). Since the cell is a primary cell, it needs to be ...
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18650 Cell boost converter to 4.8v (not 5v)

I have a torch in which 3 AAA cells are put in (1.6 (new AAA) * 3 =4.8v). The problem is these are not long lasting and i have to change them after few days. What i am looking for is a rechargeable ...
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stack/ladder n- mosfets

I need to drive n-mosfets to switch on/off resistors in parallel with Lion cells. Each cell+mosfet is in a series - 50 cells. It looks much like a BMS except it NOT a BMS, but a cell test system. See ...
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-2 votes
1 answer
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What is wrong with one of the cells in my 4-cell laptop battery? How can I make it better?

History My laptop battery has shown less and less capacity. So I got a new battery (LA04) in Jun 2018, with a warranty of 6 months. After about 8 months, the new battery also showed problems. It went ...
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How many 18650 cells in series for 48V Li-Ion pack

I'm looking at the Samsung 35e and trying to build a 48V pack. I'm trying to figure out how many I should put in series to get 48V. I'm assuming I use the nominal voltage to spec that (3.6V/cell)? ...
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0 votes
1 answer
460 views

Dashed and Solid Line Signs on a Battery

What is the meaning of the solid and dashed line on a battery or charger? I will give two examples below and the first one is a 4-cell battery and it says "7.6V [dotted/dashed line] 54.4 Whr 7150 ...
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3 votes
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Blinking fishing lure, best way to save this design?

Background I ordered 10 PCBs with a design for a blinking fishing lure (it's a hobby project.) I have discovered I made a mistake when I designed it and wanted to see if anyone has any ideas how to ...
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2 votes
1 answer
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Shortcircuit protection using transistors

I'm designing a short-circuit protection circuit for x2 AA battery (3V) and I'd like some tips from the community on how can I make it a low power mode circuit. When V_out is short cirtcuited, the ...
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