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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Battery Management Controller

I designed a wearable with a 3.7V Li-Po battery (381018). Everything worked good at the begining and now after 6 months I realize some circuits are not charging anymore. For what I understood when I ...
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46 views

Help understanding secondary cells discharge curve

This is what I've understood about the process of discharging of a secondary cell. If I have a rechargeable cell, full charged, and I make it discharge at a certain constant current, let's say 1A, I ...
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Non inverting DC-DC converter that makes fix 4V from a decreasing voltage from 4,2V to 2,8V? [closed]

Is it possible to make a a non inverting DC-DC converter that makes a fix 4V from a Li-ion battery's voltage. I need about 1,5A. The input voltage starts from 4,2V and decreasing to 2,8V as the ...
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47 views

How does battery protection ICs sense current

I have a hard time grasping a concept when it comes to a particular type of battery protection ICs (which protects from overcharge/under-discharge and over-current). One example is the BQ2973 from TI, ...
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1answer
27 views

Connecting breadboards with different batteries to a single switch

I have three different breadboards with ten LEDs & resistors connected in parallel. All three are powered by a 9v battery. I was wondering if there would be a way to wire all three batteries to a ...
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65 views

How to build a small LED assembly?

I'm building a custom model of the AT-ST from The Mandalorian: I have the model almost done and I thought it would be really cool to add actual lighting to it. The model is about 6" (16cm) tall, but ...
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1answer
39 views

Do DeWalt charging safety features reside in a dewalt charger or a dewalt battery? [closed]

This is a cordless battery of the the type I mean, a DeWalt flexvolt: https://images.app.goo.gl/zKHBsvBnT4ViMJL56 This is the kind of charger I'm talking about: https://images.app.goo.gl/...
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19 views

Can we use DC-DC Buck convert installed 3.8v battery to power Phone continuously?

I have a Windows tablet whose battery is dead and I want to convert it to without battery to use as a digital photo frame. Table dead battery is 3.8V Can I use DC-DC Buck convert (DC-DC converter ...
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1answer
43 views

Choosing a resistor for balancing lead acid batteries

I have a solar-panel-and-battery kit with a built-in inverter and what not built into the battery box. (Goal Zero Yeti 400) The battery box has Anderson Powerpole connectors for chaining it to ...
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3answers
62 views

How to drop 5v regular phone charger voltage to 3.7v to run a device, which use 3.7v output battery before

I have Motorola Moto 360 2st edition smartwatch and watch original battery is dead. I have converted smartwatch into table watch in DIY wooden block and added 18650 3.7v battery instead and now its ...
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4answers
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How much of the loss of battery capacity in higher currents is caused by its internal heating?

For example this page give this data for one AA battery: 0.5A : 1.84Ah 1A : 1.411Ah 2A : 1.18Ah Is it mainly b/c of the internal heating?
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Powering 9VDC from battery

I've got a Roland TD-11 drum module that I want to power from a battery. I only need to power it for 2 hours at a time. Can I please have some recommendations how to achieve this? SPECS: Output ...
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78 views

Benefits of square vs. triangular/hexagonal packing of cylindrical battery cells

A triangular or hexagonal packing (depending on your preference of terminology) of circles has a packing density of \$ \pi\sqrt3/6\$ \$ \approx\$ 91% (see here at Wolfram Mathworld, for example), ...
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60 views

How long will my x 2 23a 12v battery last running a 300mah camera?

I’ve brought some WiFi cameras to run in bird boxes but the battery life on them aren’t very good at all. I’ve tried running them from battery power banks but they switch off after the cameras have ...
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2S 18650 Li-ion battery pack conundrum

I recently bought a remote control toy for my son which included 2 2S battery packs, with a single SM-3P plug, and a corresponding USB charger as shown here. Initially, the car worked fine, though ...
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1answer
45 views

What is the distance I can put between a 20watt solar panel and a controller and still have enough current to make it work

I purchased a 20 watt solar panel to be mounted to the hardtop of my boat to charge my batteries. The directions say put the controller within five feet of the batteries and the solar panel can be up ...
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Jeita compliance for discharge?

I know there is a Jeita compliance charging scheme for charging batteries. But is there such certification for discharging them in the function of temperature? The following is an image of the Jeita ...
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1answer
68 views

Help me with a 4S1P for vacuum cleaner please [closed]

I'm new here, and this is my first time trying to fix my Ilife V7S pro vacuum cleaner battery. The original battery is this: I want to replace the 4 18650 with my INR18650-25R daweikala I have seen ...
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2answers
70 views

Connecting a light to a battery

my son and I are working through this book called The Thomas Edison Book of Easy and Incredible Experiments. We are stuck on the first experiment where you make a switch to connect a battery to a ...
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1answer
75 views

Why is there a lead (Pb) warning on extra heavy duty batteries? [closed]

I have some batteries labelled as Extra Heavy Duty with a picture of a trashcan and the letters Pb for lead, and an x over the trashcan which I believe means not to discard in the trash. The batteries ...
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0answers
45 views

li-ion battery protection circuit [closed]

My goal: To operate a cellphone using a bench power supply in place of the cellphone's Li-ion battery. To this end, I removed the battery from the phone and de-soldered the anode and cathode posts ...
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3answers
75 views

Thoughts on storing electricity in water vapor [closed]

for an engineering class I had to create an electrical energy storage device and I began thinking about thunderstorms (I think it was a cloudy day) and how they create lighting. I know it's not ...
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46 views

Charge a car battery from 14V 20A Max - how to limit current?

Could anyone point me in the direction how I would make a circuit to charge a large car battery from an alternator (say 12.5 to 14.5v) depending upon state of charge of the main battery, but it needs ...
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51 views

Limit current when charging a battery?

So I am trying to charge a 12V 1.3Ah lead-acid battery(actually they are two 6V batteries in series). Now I have a power supply which says 12V 500mA but actually outputs more like 21V.. No idea why.. ...
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1answer
63 views

Raspberry Pi UPS circuit review request + improvements

Based on this question I created the following circuit: Since I made some (component) changes, first I would like to have a validation of the circuit for long-term usage (and some improvements). ...
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1answer
71 views

How to discharge batteries using bench PSU?

I've heard that if you can have negative current in PSU, you can use that to discharge batteries. Is this true? If yes, how to design/modify a linear bench PSU (which have transformer with several ...
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42 views

Equivalent circuit of lithium battery

I am trying to figure out what the equivalent circuit is for a Lithium battery. You know, the buttoncell battery (NOT a lithium ion battery). But everything i find is about de lithium ion battery (...
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2answers
69 views

How are series connected batteries of different voltages (or even same voltages) charged “equally”?

I am trying to understand conceptually, how a series bank of batteries is charged "uniformly". Let's take the example of of six 6V AGM batteries for a 36V golf cart. The charger is 36V nominal but ...
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0answers
28 views

Sony NP-F battery terminal connector

I'm looking to repair some electronic equipment and am scratching my head why the part I need is so hard to identify. I recently had a bad connector on an Aputure Tri-8s LED light (Brand new out of ...
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1answer
51 views

How long will a 32v 15A (500Wh) e-bike battery last outputting at 5V 1A?

I hope it's okay to ask this here My e-bike has a Lithium Ion battery (32 Volts, 15 Amps), and it has a USB-A output, marked as 5V and 1A, I have 3 questions: How long will this battery last while ...
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1answer
57 views

Li Ion computer battery puncture

[![enter image description here][1]][1]I accidentally punctured just the very first (pouch?) layer on my MacBook lithium ion battery. A smell came out of it but the battery still works fine and holds ...
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ntc half stack V (oltage?)

could somebody assist pls? im experimenting with battery pack for my cordless chainsaw blackanddecker 36v gkc3630l20 h1 36v. i created 36v battery pack from lifepo4 batteries instead of liion. it ...
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1answer
30 views

18650 battery pack. Current distribution

I'm creating a 20s6p li-ion pack from 18650 cells. Here is the design I am are using 8 by 0.2mm nickel strips rated for 6.5A. With 6 parallel branches that's 6*6.5 = around 40Amps. But since we ...
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1answer
30 views

How to keep a stable output voltage from changing input voltage

I'm learning about solar panels and bought a 6V panel and a 3.7V Li-Ion battery as well as a solar battery charger, all from adafruit. I also got a boost converter thinking that the output of the ...
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1answer
39 views

9V 1A adapter and 2*3.7V battery IRF9630 produce sound and gets very hot 9V battery not (metal detector)?

I am not an expert at electronics.I am trying to build a pulse induction metal detector. I have this circuit from that Book I am using it with stm 32 blue pill but I have to stabilize the 9v supply ...
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1answer
43 views

How can I roughly estimate the load in this case?

A DC device operates with three industrial AA batteries meaning 1.5V times three = 4.5V. Besides that I only know that the approximate operating time is is 4 hours. Is that possible to estimate the ...
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28 views

Is it safe to have two batteries in series on a solar panel system with 14.22v and 14.46v?

I have two batteries in series plugged to a solar panel system. In parallel they used to balance each other perfectly. But now i'm trying to have a 24v system and I have them in series. They ...
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1answer
64 views

Charging a Li-ion battery with a Buck Convertor & ATmega8 [closed]

I'm trying to charge a 7.4 V Li-Ion battery following the CC/CV protocol and have a few questions. I want to use an SMPS from my old laptop that can provide 20 V/3.25 A and feed that to a buck ...
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1answer
77 views

Ambiguous labels for AA battery insertion

I have a consumer device that accepts two AA batteries. The battery chamber is designed such that the batteries are inserted from open end of the chamber rather than the side (i.e. along the axis of ...
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1answer
46 views

Lithium ion Battery

What is the difference between lithium ion battery internal resistance and internal impedance? Are both same, if not which is greater ? How these values will be measured and how they help to analyze ...
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0answers
37 views

14.8V LiPo Battery Protection

Disclaimer: This is my very first time I have to work with batteries so I have basically no idea whatsoever. I need to protect a 14.8V LiPo Battery from overcharging/overdischarging. I have looked up ...
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1answer
55 views

Where to fuse high voltage batteries connected in series?

I have modules of cells in series each with 48V. I wonder where is the right place to fuse the modules in series. (The current to trip the fuse is the same on every point). Version 1: simulate ...
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0answers
44 views

HowTo create an accurate constant-current dummy load using immersion heaters controlled by Arduino?

Given: variable sized nominal 3.2V LI/LFP battery cells, from little 18650 / 26650 cylindrical A123s up to large prismatics from CALB / Winston etc. the desire to capacity-test them off grid (no ...
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1answer
142 views

Current calculations

Emergency lighting solution Continuing from the previous post above. Firstly I know how to calculate current in a DC situation. However, since I am using an inverter that produces 220V at its output ...
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2answers
83 views

What plug type is this?

I recently bought some LiPo battery packs from Ali, Now im trying to figure out what type of plug it has! Anyone knows the answer? Would be awesome.
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26 views

Low power LiPo cell ADC with an nMOS switch and a resistor or capacitor divider circuit?

This is my first question on this platform and am looking for advice on doing a very low power LiPo battery measurement for a wearable device. My current circuit looks like this: (See image below) ...
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2answers
34 views

PWM disables charging battery after heavy load on inverter

I have 2 batteries 12V 80Ah deep cycle lead in series for a 24V system. I connected an invertor directly to the battery pack. I have ~600W (~44V) of solar panels connected to the PWM charge ...
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0answers
100 views

How to active limit the current from a DC source

I have a source with variable power output during the time because it is shared with another devices and this source has not enough power to feed my load (a battery charger for a 1 cell 4.2V lipo) so ...
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2answers
45 views

Charging current/voltage for lipo batteries

I have a 500mah 1S lipo battery. I wanted to charge it with my lab bench power supply. Easy, I thought: I want to charge at 2C (which is 1A) so I simply set my power supply to 4.20V and 1A limit and ...
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2answers
56 views

How long can i run this appliance? [closed]

How long could I run a 115 Vac window unit on a 12v 200Ah battery (using a 700W inverter from a 400W solar panel and assuming 100% efficiency)? Thanks!

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