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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47 views

Can I increase the no of operating hours of a battery without increasing its capacity?

Setup Let's say I have a 12V / 1Ah battery pack. A device that consumes 0.1Ah will run for 10 hours. When the battery drops to 8V, the voltage will be insufficient and the device won't work anymore. ...
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0answers
36 views

Protection Circuit Module for 18650 Li-Ion Pack

I'm planning to build a 7.4V battery pack to power my bike light. My current battery has died as it was left for a long time. It has 4 x 18650 cells in 2s2p configuration. All cell voltages are now ...
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0answers
33 views

GPS tracking for valuables [on hold]

What type of specific engineer is used to develop a micro gps or similar tracking device?
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2answers
86 views

Making my 18650 30kW Battery array

I put this in the comments of my last question but I realised that might not get many eyeballs so I will ask it here. I have have been thinking of making a battery using 18650's. the battery ...
2
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2answers
73 views

Creating a large 18650 Array

I am looking for some help with wiring for a large battery array using 18650 lithium ion batteries. Ok so I am looking at going solar and lead-acid batteries are too low overall capacity and their ...
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3answers
60 views

Wiring Emergency Stop button to disconnect two independent circuits

I am trying to use one emergency stop switch to disable two batteries that function in independent circuits. My circuit diagram is attached below. A motor controller connects to each of the exposed ...
2
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1answer
92 views

How to get 5V 4A from two 5V 2A chargers

I have two 5V 2A chargers. I want to get 5v 4A. Can I connect both in parallel like this?: simulate this circuit – Schematic created using CircuitLab Can I do it? Because in parallel ...
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1answer
48 views

12V 345 Amp lawn mower battery to a 12V 10 amp motor?

I have a 12v scissor jack that is meant to plug in to a car cigarette lighter, which I believe is around 10 amps. However, I want to hook this jack directly up to a 12V battery, which is rated at ...
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0answers
15 views

Battery Discharge Circuit

I'm looking to build a low-current (1~5mA) discharge circuit for some small LiIon batteries. I need the discharge current rate and the discharge voltage limit to be adjustable. I would also like to ...
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2answers
48 views

Can I estimate a cell capacity (mAh) with the amperage and the time of work?

I'm trying to know the capacity of each cell of a bank power, the finality is to replace them: 6x3.7V cells, 12.35V fully charged. (tested with multimeter) step-up circuit 12v -> 19v (efficiency: ...
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1answer
41 views

DC motor speed control: 12VDC 700mA fan motor powered by 7.2Ah sealed lead-acid battery

I am using a 7.2 Ampere-hour Sealed Lead Acid Battery to power a 12V DC motor which is driving a fan, and I need to understand ...
0
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2answers
58 views

Figuring out battery life from amp draw?

I decided to take apart one of those cheap handheld fans. It takes 2AA Alkaline batteries. I wanted to hook it up to an arduino as a way to get into electronics, and I wanted to know what kind of ...
0
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1answer
74 views

Replace Li-Po Packs

I have this battery with it's own charge/discharge circuit. There are 5V out and 19V. The total capacity is 42000mAh @ 5V with 6 cells inside. (4.11V/4.12V each, fully charged). I don't know the ...
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4answers
68 views

Use GPIO to disable voltage divider

I'm using a voltage divider to read the battery level of a wireless sensor platform using STM32L151. I'm shooting to use 20k for R1 and 10k for R2, to be under the 50k limit of the MCU's ADC ...
0
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3answers
63 views

How to calculate voltage in an open resistor circuit

I have an open circuit that looks like this: I can measure the voltage at these points using a voltmeter: A -> D: 4.65V (the batteries) B -> D: 4.3V C -> D: 4.23V Say I did not have a ...
2
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1answer
42 views

How to monitor voltage and charge status in USB battery pack

What's the easiest, least intrusive way to monitor voltage, charging status, and remaining charge of a USB battery pack? Battery packs and charging circuits for mobile projects can be complicated and ...
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1answer
42 views

What is the effect of pulsed discharge on watt hour (Wh) efficiency of lead-acid batteries?

When discharging a (lead-acid) battery you see a voltage increase (volts rise) as soon as the discharge is paused. source: http://uu.diva-portal.org/smash/get/diva2:461718/FULLTEXT01 In the quest ...
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2answers
40 views

external battery claimed iPhone 6 charges versus my calculated charges mAh vs Wh and voltage step down confusion

I did a charge on this page and could not find the answer I was looking for. Perhaps it was over my head, or perhaps I was using the wrong search terms, so here goes nothing: I am trying to ...
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2answers
46 views

Recommended approach to create a lead acid battery level circuit

I want to build a battery level indicator circuit for a 12 V sealed lead acid battery. The battery indicator circuit will have two functions: It will power 4 LEDs to show the level of the battery ...
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3answers
140 views

Battery versus Supercapacitor

I recently read an article (http://www.eejournal.com/archives/articles/20130506-batteries/) that seemed to indicate that "supercapacitors" are starting to approach the energy densities of batteries ...
0
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1answer
101 views

How to increase watts ? out of 12 volt?

I am making a project, a DIY so please co-operate I don't know much about electronics the overall project needs some electric combinations... I have a rechargeable fan with built-in battery but I am ...
1
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1answer
43 views

Is voltage same till end , using dc battery ?

I want to find the remaining charge of 12v dc battery . I am confused in voltage and current , either voltage remains same till battery power get finish ? ( I mean if a battery is 12 volt and is ...
0
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1answer
68 views

Makeshift way to drain a battery?

I have a 3.8V mobile-phone battery that I need to discharge. However I don't have any electrical components (say led) with me. What is a crude way to do this using household items?
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2answers
47 views

Constand output voltage from batteries / rechargable batteries

I'm trying to make myself a battery pack for my DSLR camera. The original battery of the camera has 7.2 V and 1200 mAh. I've also bought a coupler ( a dummy batterie for external DC input ) which ...
0
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1answer
32 views

DC Motors Power Supply Connection

I am currently working on a project using Arduino UNO and two 3 volts DC motors. I chose a 9 V Goldtop battery to power my Arduino. The two motors draw voltage through the 3.3 V pin in the Arduino. ...
2
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4answers
375 views

Do I need a resistor between the microcontroller and the battery? [duplicate]

I'm doing a university assignment and I need some advice. Do I need a resistor between the 9V power source and the microcontroller that uses 5.5V and 1mA? Also between a gyroscope sensor that uses 3V ...
2
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1answer
137 views

Terminal voltage of DC battery

It is said that measuring the terminal voltage of DC battery directly with a voltmeter, it can give misleading values and it is always advisable to take such readings while the battery is connected in ...
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1answer
44 views

Variable Current Lead Acid Battery Charging

I'm designing a solar controller in order to charge SLA batteries. I did some research on dedicated ICs that act as controllers, and found that most implement some sort of MPPT, in order to extract ...
0
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2answers
122 views

brief explanation of Ohm's law

How can I calculate ideal values of current for both short and open circuits by using Ohm's law. Further more usually said that it is not advisable to connect DC batteries of different voltages in ...
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1answer
23 views

2600mAh Battery Charging Time

I've spent a very long time trying to work this out, but some websites seem to conflict the information - or I'm completely missing the point. I have a rechargeable battery: 2600mAh 4.2V max charge ...
0
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1answer
121 views

RPI with power supply alternating between Li-ion battery pack and DC 5V

I have a Raspberry Pi model B+ and I've been trying to design a solution so that I can switch power supply without having to shutdown. The idea is this: I have 2 li-ion 18650 batteries with ...
0
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1answer
59 views

Substitute a Li-ion Polymer Battery with AA(A)s

My headset broke a few days ago, but the circuit board still functions properly. I want to see if I can re-use it by soldering two 3.5mm female plugs to it, so I can use it with any speaker or ...
0
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1answer
40 views

Switching and protecting batteries from external power supplies

my device can work from external power source as well as from two AA batteries, so voltage in this case is 3V, but external supply is 5v. I need to protect my circuit and power supplies in case of ...
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1answer
31 views

estimating battery discharge current approximately from ac load current

I would like to know that if we have a data logger installed at a site and the logger measured the constant load current of 10 A from the Grid(Single phase@ 230 v) during a certain time say 10 am. ...
1
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1answer
57 views

Significance of Vf terminal in Li-Ion Battery

i was going through some propriety schematics that i can't post the battery used in the schematic is a li-ion battery of 3.8V/2.1Ah/ from samsung, which gives out three pins ...
0
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1answer
20 views

Max Voltage of Electrical Stimulator for Cardiac Tissue Bioreactor

I'm designing a bioreactor that will electrically and mechanically stimulate cells in media in an incubator. I'm using monophasic, square waveforms and have a max stimulation level of 12V/cm, else ...
1
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1answer
75 views

How are cell failures handled in large lithium battery packs?

In a large battery pack of lithium-based cells for an electric vehicle or grid storage system, how are failed cells handled? Answers to another question indicate these cells are usually hardwired in ...
2
votes
1answer
46 views

Li-Ion battery over discharge protection

I'm designing a Li-Ion battery charger circuit with a bq24702 chip. I will use it with two Li-Ion batteries connected in series. In order to protect the batteries from over discharging, I have to ...
0
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1answer
73 views

Designing E-Cig, need some help with the schematic and components [closed]

So I'm in the process of gathering all the parts needed for an e-cig (vaporizer). Will be using a Lithium, 3.7V nominal battery, heating up a coil that will be somewhere between 1 ohm and 2 ohms (this ...
3
votes
1answer
240 views

Purpose of this diode on this circuit?

I have this circuit and I do not understand the purpose of the diode connected to the ground. This is a Bluetooth device (works at 3.3v) that has a 4x 18650 battery pack and a USB charger. When you ...
2
votes
3answers
141 views

CR1632 (3v) vs. Two AA's

Kind of a newbie at this, so forgive me if this is a stupid question. I've disassembled a small lifeline alert pendant transmitter that normally runs on a CR1632, can I replace it with two AA's? Are ...
1
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1answer
48 views

Battery voltage compatibility [closed]

The original Li-ion battery in my camera has a voltage rating of 7v. Can an aftermarket battery with a 7.4v rating be safely used in my camera?
1
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1answer
62 views

Selecting the right battery type and capacity

Have a machine in mind which is intended to be portable (hence weight and dimensions is a constraint), has a miniature refrigerant compressor (like those of Aspen) plus a blower of nominal wattage. ...
2
votes
1answer
180 views

What is this Externally-Triggered Fuse?

In the datasheet for an overvoltage protector (TI BQ771815) there is a device I don't recognize: It is used in the datasheet as a fuse which can be opened by an external signal from the overvoltage ...
0
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1answer
61 views

Is this SSR design recommended?

I want a hard power switch for some battery-powered BLDC motors, but the currents (5A, up to 20A transients) and voltages (up to 60V) limit the kinds of switches I can use. Because I want some small ...
0
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0answers
18 views

What is the relative mass of a LiPo cathode?

Relative to the mass of a LiPo battery cell, how much is the mass of the cathode? That is, what is the percentage-mass of a LiPo battery's cathode?
0
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1answer
41 views

How to estimate motor current under load

How do you estimate the average current under a typical load of a brushed DC motor? I'm trying to size the right motor, motor driver and battery to propel a small two-wheeled platform using this ...
0
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2answers
47 views

Li-Ion 26650 battery holder

I'm going to use 26650 Li-Ion batterys with a suitable battery charger IC in my hardware. I'm looking for an adequete battery holder for two 26650 batterys like this for AA batterys. But I find only ...
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2answers
56 views

Charging a bank of lead-acid batteries in paralel

I have a lead-acid battery similar to the one in the picture (mine is 15Ah) and I also have a spare car battery (50Ah). Is it safe, or a good idea to put them both in paralel to achieve a bigger ...
0
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1answer
43 views

Supply voltage of LM741 with Virtual Ground

I'm looking for a way to feed LM741 with a battery. I found this example that uses the TLE2425 to create a virtual ground of 2.5V (in the original example was used opamp TLC272): I simulated this ...