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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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55 views

Power use question for a trail camera

I am trying to calculate how long that a trail camera can be deployed before the batteries run out. The trail camera in question is a Reconyx HyperFire 2. Here is a useful review of the trail camera ...
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60 views

Can I extrapolate battery power by a brief observation?

Part of the research we are conducting requires us to estimate how detrimental our proposed algorithm to the battery life of the wearables. To do so, I opted to simply charge the wearable to 100% and ...
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685 views

Many questions about charging a lead acid battery

Well, I have a 12V 9AH SLA Battery, and I use a 7815 + a diode in series to charge it, (I really wanted to build a charger using the L200 or the LM317 but I couldn't find any of those in my city). So, ...
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72 views

Lithium battery performance in cold temperatures powering BLE Beacon

I am working on a project that requires the use of BLE Beacons in very low-temperature environments, on average -15°C but on occasion as low as -25°C. We are currently trialling a brand of BLE Beacon ...
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29 views

Advice for a Solar Charger and Battery Project

I am a high school robotics teacher (no formal engineering training) and I am taking a group of students to Kenya this summer to work with high school students there. The organization we are ...
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23 views

Context of Li-Ion MnO2 “Cell Configuration” Specification

My application supports variable pack configurations: 4S4P, 4S6P and 4S8P. Each one obviously uses a different BMS profile, and other minor changes such as charge/discharge MOSFET and fuse selections....
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285 views

DIY 4S Li-Ion battery pack

I am in need of some help designing my battery pack. I have a few concerns, mostly around charging. My plans consist of using a microUSB boost converter to bring the voltage to 16.8V for charging. ...
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99 views

How can I size the current ripple of a DC-DC converter for lithium batteries

I am designing a bidirectional DC-DC converter to charge and discharge batteries on a DC bus. The power of this converter is 50 kW and the average current in the inductor (the same as that on the ...
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139 views

How separators prevent electrons from passing through

Separators (polymers) in batteries keep electrons from passing through but they let ions through. How do they do that if electrons are smaller than ions? Can we imagine it as a kind of 3D wire mesh ...
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314 views

Lead-Acid Battery Desulfation Circuit Design:

I'm seeking ideas for making a pulsing lead-acid desulfation circuit design. Several circuit designs are available via Google image search, however, I'm hoping to get some help here to design a ...
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1k views

UL Testing for low voltage battery powered devices

Is UL Testing needed for a 3.6 V battery powered device that is totally enclosed in ABS platstic with no electrical terminals outside?
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30 views

Protecting Copper Anode in 12V DC System

Getting to grips with cathodic protection here. If someone had a 12, 24 or 48VDC system, say solar PV and batteries, and the battery negative is earthed, this means the earth is the cathode, and the ...
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38 views

help building 6S2P balanced Li-Ion battery pack

I'm trying to build a 6S2P balanced Li-Ion battery pack for a quadcopter using LG 18650 HG2 cells with pre-soldered nickel strips (1st image) so that I won't solder directly on the cell's terminals. ...
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31 views

Usability of a deeply discharged Li-ion batteries

I have a question about Li-ion batteries. About three years back I bought two Sony VTC 5 batteries for my vape. They are rated as 2500 mAh 30 A. But I quit smoking about a year ago and I left these ...
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33 views

Sense resistors in system-side Li-Ion charger/gauge circuit

I'm working on designing a charger and fuel gauge circuit for a premade 3S3P Li-Ion battery pack. The battery pack has basic protection circuits onborad (over/undervoltage and a PTC) and only the pack ...
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26 views

Battery Powered System and Input Capacitance

I have a battery powered system in which the battery is connected to a buck/boost converter to derive 3.3V from two or three AA batteries. The regulator I'm using is a TI TPS63050, and it has a power ...
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51 views

How to disconnect 3.7V battery when USB is connected (boost)

I am developing a circuit which enables me to charge a lithium battery and boost the output voltage up to 5V for a microcontroller. My boost converter is the MT3608, and the charging circuit is the ...
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34 views

Powering refrigerator using solar inverter

I have got a 3 kVA (2400 watt) solar hybrid inverter (pure sine wave) which is connected to a 1280 watt PV array and 2 x 12 volt 150 Ah batteries. It is supposed to switch to utility mode if the ...
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55 views

Ultra low power battery

I am currently in the middle of a project and I am quite unsure of what type of battery and battery charger I should be using. To be honest I have never worked with battery or battery charger yet. In ...
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23 views

Responsible Battery Reserve Capacity and Low voltage?

It's been asked here, but looking for clarity. How bad is it to undervoltage a 12-volt lead-acid battery? SLI automotive starter batteries list RC (reserve capacity), but I think this a usable ...
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60 views

Charge a 12V marine/boat battery with AC

need to build a diode bridge to recharge a battery (car/boat type) from a boat engine that gives 12V AC. I thought of doing something like this: simulate this circuit – Schematic created using ...
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16 views

floating solar battery charger

Hello!. I am mounting a solar charge controller. with floating voltage !. the schematic illustrated is as follows. A voltage of 27.6V is introduced, which passes through 3 diodes of 10 Amperes. along ...
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109 views

Replacing 18650 Cells in a laptop Battery

Is it possible to reconstruct a battery of a laptop with better quality 18650 Cells than that are used by the OEM Manufacturers. eg i have a MSI ge62 6qf with rubbed off LG cells so i cant tell what ...
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43 views

How to consider lifecycle in PV power smoothing?

I am planning to size Battery for Solar PV system by smoothing the PV output. Capacity size can be obtained by looking at Max charge/discharge needed to smooth the fluctuation. This should make able ...
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45 views

Is current draw the same when powering a device directly from batteries or from a dc-buck converter?

I’m having a strange problem here: When I use two AAA batteries to supply a small slave flash, it charges in 10 seconds, with 1.4A instant draw for the first second and smoothly reducing current draw ...
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38 views

battery life of rechargeable lithium battery

I am trying to determine the life of a lithium rechargeable battery (approximation) before a complete replacement is required. From Panasonic's datasheet, I see that at avg. 10% discharge, it is rated ...
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128 views

Is there a theoretical performance limit for Lithium Ion batteries?

Is there a theoretical performance limit for Lithium Ion batteries? I'd like to compare energy density of Petroleum Products based upon what limits can be obtained from stored energy in Lithium Ion. I'...
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63 views

Voltage drops after connecting two batteries in parallel

I have two batteries 12V GEL 130Ah, each charged to 14.4V. After connecting them together in parallel, the voltage drops gradually and equalizes at 12.99V. (I use 10mm^2 short cables to connect them ...
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191 views

Tp4056 overcharging

I have combined five 18650 cells in parallel and i am charging them using a single tp4056 circuit . The problem i am facing is that the module keeps on charging. I had to stop the charging manually at ...
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203 views

Battery Backup with Monitoring, Low Voltage Cut Off with Hysteresis and Auto Power Recovery

As an overview of what I am trying to achieve. I want to create a circuit that will trickle charge 8 x NiCd batteries (2200mAH) so that in the event of an “occasional” power loss my 5v circuit is ...
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0answers
258 views

Li-ion charging circuit

I have a project that I want to power with a single cell lithium ion battery, which is to be charged from a USB plug (but not from a laptop or computer, rather from a wall supply like a phone charger)....
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28 views

Buying used Lithium Ion Battery

I'm setting up a hybrid solar system and was looking into batteries. There is a local guy selling Aggison 48V Lithium Ion batteries that he claims are "slightly used". How do I check the usage on the ...
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170 views

high voltage multiplexer for battery cell monitoring

I'm working on a battery management solution with 50.4V battery (36 cells in series with 1.4V a single cell voltage) for automotive application. i'm planning on using multiplexer and differential ...
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64 views

Can changes be performed to IEC 62133 certified batteries?

The vendor I contacted asked me about changing the length of the leads, removing the connector and adding a NTC thermistor to the protection circuitry of the battery pack (IE-C62133 certified). ...
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69 views

Acceptable voltage difference between two batteries connecting them in parallel

Although the answer might be easy, I am a newbie and want to ask before burning my house down. I've seen a lot of battery packs tutorials. Now I have to use my knowledge to connect two 7S packs in ...
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114 views

My BLDC motor is stuttering and I have no idea why

I'm driving 2 BLDC motors with two ESCs, the motors and the ESCs are powered by an external LiPo battery and the Arduino is powered via usb. The motors work with pulses between 1000 and 2000 ...
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53 views

Precision battery voltage meter, Auto adjustment by R-2R

For a more precise measurement of a battery voltage I'd like to apply auto adjustment. The input voltage ranges from 2.5V-4.2V (single cell) to 20V-72V (module). At the moment the input voltage is ...
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34 views

Can lipo and Lithium-ion batteries be used together?

Lithium ion batteries have high specific energy and lipo have high c rating (high power). Is it possible to put lipo and lithium-ion batteries in parallel if they are at the same voltage and ...
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290 views

Connecting new and old 18650 in parallel

Now before everyone start saying how bad or dangerous it is to connect used and new 18650 Li-Ion Cells together - I would like to keep it technical and fact based. I (like many others) have many used ...
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315 views

LM3914 schematic values

I'm trying to study an electronic schema based on a LM3914 but I can not find the same threshold voltage, can you help me? Source of the schematic ...
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0answers
380 views

Li-Ion battery modification to charge with Ni-MH charger

First of all, I have to say I know "Li-Ion batteries can not charge with NiMH charging". So this question about li-Ion battery modification. 1. I found a battery from China that consists of 2 serial ...
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147 views

LTC4417 Power path converter not working

I am fairly new to pcb design and I am having trouble understanding why my PCB is not working. I am using a LTC4417 power path converter and a IRF7324 power mosfet to turn on an embedded system with a ...
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0answers
59 views

Designing Battery Power System For Robotics

I'm building a mobile robotics project for a class and I'm trying to figure out how to (or even if its necessary) to design a nice battery power system for it. I sort of wanted to learn how to build a ...
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91 views

Battery life and negative current

I am working on a battery powered project. With a multimeter I've been measuring current on the "positive" side of a module and observe 5μA. However I thought to measure the "negative" side and was ...
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405 views

Ultra low power arduino wireless sensor : care of battery discharge

I'm prototyping a ultra low power wireless sensor. To consume less I run a arduino mini pro at 1.8V at 8MHz with sleep 99% of time. The power comes from a LIR2032 coin and the 1.8V is generated from a ...
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0answers
113 views

Self-charging robot safety considerations

I have made a 3S5P (18650 Sanyo NCR18650GA 3500mAh with 10A discharge rate) battery pack (about 220 watt hours when fully charged) for a robot. I'm using a BMS with balance (supports up to 60A ...
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0answers
400 views

Output voltage of powerbank circuit is the same as the battery voltage

I'm trying to use this small (and awesome?) unit as a boost/step-up converter for my project. I need to give my ESP8266 12-E NodeMCU a 5v input from a 18650 battery. Since this powerbank already had ...
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0answers
99 views

Source voltage and capacitance

Does changing the source voltage (i.e. voltage of the battery) affect how long it takes for a capacitor to charge in a circuit? Am I right in saying that since the capacitor charges until it reaches ...
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38 views

High-Current Shutoff Protection on a Robot

I'm working on a robot that uses a total of four motors for its movement. Each are rated for 2A stall, and the battery has a high enough discharge capability to run all of them at full, and then some. ...
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126 views

Can I control the charge of a Cell-Phone with a 555 Timer and a Transistor?

I want to charge my phone in a controllable manner, using a 555 and a Mosfet transistor. The 555 is a countdown timer that gives an output (pin 3) of 5V for 1 minute, and then remains at 0V until an ...