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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3answers
118 views

Why does TTL work with 5V, when there's no 5V battery?

It's a noob question, but every circuit I make uses 5V: 74LS uses 5V, ATMEGA328 uses 5V and so on. But in reality, everybody's designing circuits and shove a voltage regulator with 9V or 12V power ...
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3answers
54 views

How do I keep my constant current source constant?

So I am trying to created a current source that will be used to drain a battery at specific time intervals for a specified duration. simulate this circuit – Schematic created using ...
1
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1answer
37 views

How to keep rarely-used Li-Ion batteries functional?

I have many gadgets around the house that I don't use often, recently I notice that a battery failed on an Mp3 player not used for a year. The battery now has a life of 1 minute from the original 5-7 ...
2
votes
1answer
84 views

Charging 10 1.2V nicd batteries

I have 10 x 1.2V Sanyo NiCd batteries. They are connected in series. I would like to charge them. The thing is, I don't have a charger. I looked up chargers and they are all quite expensive(I live in ...
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2answers
55 views

Battery Polarity

I was bored at work, and remember when i was little, putting batteries in the wrong way would stop the object from functioning, then decided to try reversing the polarity of the batteries in my torch, ...
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0answers
35 views

How to keep the output of motor constant by using secondary battery? [on hold]

In our project,we need the piston working efficiently with the help of the motor power.But actually the problem is that the efficiency of the motor decreases with the charging in the battery.so we ...
0
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0answers
47 views

Which type of power supply to equalize SLA battery?

I have some 6V SLA batteries wired in parallel and am wanting to apply a 7.5V (2.5V * 3 cells) equalization charge for a couple of hours. The problem is I'm trying to figure out which type of power ...
0
votes
1answer
55 views

What size/kind of diode to use for a lawn tractor charging circuit [on hold]

I have a lawn tractor which is not charging properly. I only see 25-28 V AC out of the engine to charge the battery. I can't seem to locate where the diode or rectifier is. When this fails, is it ...
4
votes
1answer
100 views

How power system is designed for extreme small system, such as google contact lens?

I just read this news and got very curious: http://www.takepart.com/article/2014/07/23/goodbye-finger-pricking-how-googles-smart-contact-lens-really-helps-diabetics Google is designing "Google ...
0
votes
2answers
90 views

How to calculate battery life with a given load?

I am not very good at electricity things so any help anyone could give me would be fantastic. Here goes: I have a battery (for power tools); it is 18v and 1500 mAh (imagine DC). I'm trying to get it ...
4
votes
2answers
287 views

Battery Ampere-hour rating vs Battery Amps (not an experienced user)

I have almost no experience whatsoever with the technical's of electronics so this is probably a very easy question for someone who does... Do you know if a battery with a 200Ah rating can put out ...
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votes
2answers
60 views

Converting a 9v Battery powered Device to a 9v dc power supply [duplicate]

I have an old Vivanco MX300 mixer which runs of a 9v battery. I have it in the same place and it's an inconvenience having it run by batteries. Could I use an old AC/DC adapter that would supply 9v ...
2
votes
1answer
111 views

Measuring Remaining Battery Life

I am working on a project testing alkaline batteries and need a way to quickly measure remaining battery life. I would like to be able to estimate mA-h remaining in the battery. If I measure mA-h over ...
0
votes
1answer
51 views

Good volts and amps but phone still charging slowly

I am really new to the EE game and am still tinkering. I have built my own portable DC power source similar to a Minty Boost from scratch and plugged it into the USB port of my Galaxy S3 and it ...
0
votes
1answer
44 views

Charge/Discharge efficiency rate of a lead-acid battery

What is charge/discharge efficiency rate of a lead-acid battery and how can I calculate it? Lateral question: Is there any relations between lead-acid battery efficiency calculated via dissipated ...
0
votes
0answers
23 views

What depth of discharge does 0% on a UPS correspond to? [closed]

When a UPS like an APC Smart-UPS shows 0% charge remaining, does it mean the deep-cycle batteries are completely discharged or that they're at 20%?
0
votes
1answer
64 views

Isolating polarities on a series wired battery bank

Can anyone, with 100% certainty (that means you know what you are talking about) tell me how to "isolate" the positive from the negative posts electrically in one direction so I have a true 'positive' ...
0
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1answer
40 views

Lengthen charge times with batteries

Would replacing a 3.7v 1000mAh lithium ion battery with a 3.7v 5000mAh lithium ion batter make my projects last longer between charges?
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2answers
75 views

How to power my datalogger?

I am building GPS datalogger. It will consist of Arduino Pro Mini 3.3V, GPS module - GY-GPS6MV2 (GPS Ublox NEO-6M) (bypassing 3.3V regulator) or Skylab SKM53 (MT3329). Data will be written to SPI ...
2
votes
2answers
99 views

Do cell phone batteries contain protection circuits?

I have tens of old cell phone batteries lying around and I want to try to make use of them. I've googled around for the answer, but haven't able to come across anything consistent. LiPo batteries ...
5
votes
4answers
2k views

Storing batteries in a refrigerator

The electro-chemical reaction is more favorable at higher temperatures. Consequently, when it is warmer, the batteries will perform better. This is also evident from practice: old batteries do not ...
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4answers
78 views

30A power connector

I've never really used power connectors before. I am working on a project and saw there are power connectors in it. We had some issues and changed the manufactured power connector to a 30A power ...
2
votes
4answers
217 views

Need help explaining this circuit and how it is dimensioned and designed

I'm working on a project to school where I'm designing a battery charger with battery status indicator, and I found this circuit online: but to include it in the project, I must explain how it ...
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votes
1answer
51 views

Replacing CR2032 batteries with AAs to power bathroom scales

My digital bathroom scales take 2 CR2032 batteries that I seem to have to replace all the time. Can I simply replace them with 4 AA (or AAA) batteries (assuming I can find room) or do I need to ...
0
votes
3answers
88 views

preventing blown fuses in simple circuit

I am trying to prevent blowing fuses in a simple circuit: that consists of a battery(12V), fuse, and 2 lights(50W). There are no switches; the lights are connected and disconnected from the live ...
0
votes
1answer
44 views

Battery setup for LED headlamp

I am a keen fisherman and always looking for new projects to work on in my spare time. My latest pet project is that I'm looking to increase the capacity of the batteries that power my 3W cree LED ...
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1answer
63 views

LVD solution with low power indication

I power my 3.3V circuit with step-up power converter. Input to the converter should be from two Ni-MH 1.2V batteries or alternatively from two 1.5V alkaline batteries. I need to indicate low battery ...
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votes
3answers
82 views

Batteries in parallel

What will happen if 2 or more ideal batteries with different emfs are connected in parallel across a resistor? Just curious to know what folk around here think..
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1answer
61 views

How to calculate Li-Po battery discharge time?

I want to calculate the time for a Li-Po battery (7.4 V, 2200 mAh, 30 C) to discharge. Battery powers up an embedded device, that requires 5 V, 147 mA. For this reason, I use a voltage regulator, in ...
0
votes
1answer
53 views

Battery pack for DSLR coupler

I am planning to make a battery pack, by using rechargable batteries, that i can use to power my DC-coupler for my DSLR camera. (Ref. Image) On my original camera battery it says 7.4V 1.2A but i ...
0
votes
1answer
45 views

Modifying a chip on a bought voltage measurer

I have bought a battery checker for my RC LiPo battery packs. The battery checker can measure and alarm at low voltages between 2.7 and 3.8 volts, however with LiPo batteries, the interesting range is ...
0
votes
1answer
52 views

Proper resistor for simple circuit

I have a potentially stupid question, but I have no idea how to handle the problem. I want to use 9V battery with a diode that requires 5V. So I need a resistor. How do I find the resistance if (as ...
0
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2answers
75 views

Finding batteries to make a stable 12 V battery-power supply

I want to make a stable 12 V battery-power supply for RPi and LED matrix. Schematic is something like: ...
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2answers
96 views

Sensor scraped from a pc battery pack

I scraped some battery cells off two old pc battery packs. In both packs there were a sensor but I can't figure out what kind of sensor it is. Can someone explain what kind of sensor these are? I have ...
0
votes
1answer
49 views

Battery supplying different voltage

I 'm trying to build a portable device running on battery. It needs power at 2 different voltage: 3v and 4.5v Is doing something like this a good idea ? if so, what type of diode should be used ...
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2answers
53 views

Can I embed this charger in a project?

I have been attempting to create a portable arduino gaming system. While I have tried normal 'AA' or 'AAA' batteries, they are too large, so have decided to use a lipo battery. I now have this, but I ...
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votes
1answer
58 views

Charging battery using computer power supply?

I have new 600W ATX computer power supply unit. I have wired green and black together to make power supply turn on when plugged in. I wanted to charge my 12VDC empty battery, without dealing damage to ...
2
votes
1answer
65 views

What will happen on regulator as battery gets depleted?

I want to make a 5V-power source with four 1.5V-AA batteries. I think it can be done easily with 7805 regulator. What I am concerning is the case that batteries are getting depleted as time goes by. ...
0
votes
1answer
62 views

TLV431 as direct replacement of zener?

The answer here suggests using strings of suitable zener diodes to drop the cell-voltages of a battery stack down, to measure the individual voltages by standard (that is non-high voltage) ADCs. The ...
1
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4answers
94 views

Will voltage or current determine a diode drop for this battery charging circuit?

I am using a li-ion battery charger IC that regulates an output to 4.2V. I have a schottky diode in series with the output that then connects to the battery. How do I determine the voltage drop? If ...
-1
votes
1answer
73 views

What do B+ and C+ mean on the wires of a Lifepo4 battery pack?

I bought this Lifepo4 battery pack. It came with its own charger. The seller told me the charger can be connected directly to the battery. There are 4 cables coming out of the battery: C+, C-, B+ and ...
0
votes
1answer
68 views

How can I modify the charging circuit of the solar powered system using super-capacitor with or without battery (diagram is attached)?

I 'm working on a device which according to the below diagram, has a solar panel witch gives at most 10v voltage and 30mA current (average 9v and 20mA) and also it has a 6v lead acid dry battery with ...
0
votes
2answers
79 views

What's the correct way to solder wires on that (LiPo) battery's terminals?

I need to solder a wire on each of the terminals on the battery shown below. They are approx. 15mm large. Should I solder the wires, of use some sort of clamp? It looks like the terminals are made of ...
1
vote
1answer
60 views

Efficient power utilization by MPPT battery charger

I am designing an MPPT solar charge controller to get more efficiency out of my system. At the moment I am at the conceptual stage and I have some questions about MPPT battery charging in general. ...
3
votes
1answer
482 views

What is the purpose of a battery on a GPS receiver?

My GPS receiver has a small MS621FE battery: Any ideas what might be the purpose of a battery on a GPS receiver?
1
vote
2answers
94 views

Battery Voltage Sensing Circuit (Voltage divider, buffer)

I've been trying to figure out a quick and easy circuit for sensing a battery's voltage, then translating that voltage to an 0-5v signal that could be read by a microcontroller like an Arduino. My ...
2
votes
1answer
201 views

Can a low current (low power) solar panel charge a battery?

I have a solar panel that provides max 7V and average 5.5V under the sun. But it cannot produce enough current even for a little 3V DC motor. Can this solar panel charge a 3V battery? Or maybe two 3V ...
1
vote
3answers
199 views

Simple low voltage disconnect circuit for Arduino

Preface: Under impression to need a low voltage cut out, to prevent 2x AA NIMH rechargeable battery from being drained too now, and damaging them. (right??) In deployment this circuit will commonly ...
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2answers
78 views

AAA batteries solar charging help needed

I have a project running on 2 regular AAA batteries, I'd like to convert it to NiMH or NiCd rechargable batteries using solar power. I wanna use a panel like this: ...
2
votes
5answers
202 views

How is time of supplied real time clock module maintained without battery?

I am thinking about purchasing this RTC ( real time clock ) module. Since this particular item comes supplied without a battery, I wonder how the time is being kept running in the chip since it's ...