Tagged Questions

2
votes
2answers
123 views

Why do batteries in series add up voltage?

This question will probably sound easy to most of you, but to me, it is still a kind of magic :) Taking in account all I know until know, I guess a battery has two sides: one that "emits" electrons ...
4
votes
1answer
361 views

Can I connect my laptop that runs on 18.5V directly to a 12V battery?

I have days of electricity outages here (due to war!!!) and I need to use my laptop. The thing is, it runs off 18.5V 3.5A (AC adapter output), so it is expecting 18.5V, what will happen if I connect ...
-1
votes
2answers
114 views

Is it possible to amplify a sine voltage by a factor of 190? [closed]

I would like to amplify a sinusoidal wave (-1.23V to +1.23V) to a wave between -230V and +230V. I am planning to use a 12V@8.1Ah battery as my Vcc source. My question, Is this idea possible? If it ...
1
vote
1answer
271 views

Can you damage an iPhone by charging it using a (homemade) solar panel?

I found a guide online that shows how to make a solar phone charger (in a bottle), and I thought I'd try it out, but I'm worried about damaging my iPhone 4 (for a school project). (If anyone's ...
-6
votes
2answers
150 views

Battery with most mAh that outputs between 1 and 1.5v? [closed]

I am looking for a rechargeable battery between 1 and 1.5 volts that can provide this voltage for the longest amount of time (most mAh). Any suggestions? Thanks.
-1
votes
4answers
86 views

Conversion of voltage of battery [closed]

I have 9 volts battery. What resistance do I need to have 5 volts. And how to calculate?
1
vote
1answer
187 views

Simple circuit Voltage regulator question?

I am trying to build a simple circuit that takes a 9v battery through a voltage regulator that outputs 1.5v across a load resistor . The load will be just a piece of metal that gets heated up. My ...
1
vote
1answer
121 views

Getting a higher voltage from a battery than specified

This may be a totally stupid question, but say I have a battery that supplies power at 7.5 V. Is there any way to boost its voltage to provide 9 V? I know you can step down voltages in many ways ...
6
votes
2answers
104 views

AA cells depletion

Currently I have two AA cells in series powering a 3.0v bus line for my application.Recently I am finding that one of these AA cells gets completely dead before the other. What could be the possible ...
5
votes
1answer
231 views

If my battery charger says 160mA on the back, what does that mean to my 1800mAh batteries?

I'm sorry if this is a horrible place to ask such a question. I just stumbled upon here from google. So I have this battery charger that DOES NOT indicate when a battery is fully charged (stupid ...
0
votes
1answer
147 views

Battery monitor gauge for embedded development

For one of our upcoming projects, we have a battery pack consisting of 12 Energizer L91(Lithium /Iron disulphide AA Battery). We divide this battery pack into three sets of 2 ,5 and 5. In order to ...
2
votes
2answers
131 views

Increase resolution of voltage divider

I have a lead-acid battery on which I am using a voltage divider to measure the remaining charge. Its my understanding that an example battery could discharge from 100-0% over say 10.5V - 12V. ...
0
votes
1answer
190 views

SPICE Modeling voltage during battery discharge

I am trying to create a spice model of a battery discharging into an LED. I would like to model the charge remaining (Ah) throughout the discharge and as I understand it this can be acheived by ...
4
votes
1answer
187 views

What's a good estimate on how low an alkaline battery voltage can be to still make the battery useful?

Here's a YT video by Duracell about how many batteries declared dead and sent to recycling still have some usable energy. In the beginning of the video there's a sequence where they have a row of ...
2
votes
1answer
273 views

Battery Power for RC Car

I'm working on a school group project which involves setting up a remote controlled car with a BeagleBone, webcam, WiFi module and a powered usb hub. To handle the mechanical side, we bought a cheap ...
1
vote
1answer
159 views

Connecting arduino to power another device

I have an arduino board which I want to use to give power to a device which uses two 1.5V batteries. I think I have to remove the batteries from the device and control the power supply via arduino, ...
2
votes
2answers
482 views

3.7 Volt external battery to charge a another 3.7 Volt Phone Battery?

I would like to know if a 3.7 V external Battery would be able to charge a phone battery of the same voltage. From my understanding, the batteries would charge each other until the charge in both the ...
3
votes
1answer
218 views

Battery in parallel with main power source

I have a system that is powered by a main voltage supply and I want to connect it to a battery for backup, in case of power outage. I need to know what would happen if I connect the system with the ...
5
votes
1answer
346 views

Laptop power supplies - why the spectrum of voltages and connectors?

Why do are laptops designed with different Voltage input requirements? Is this just a power requirement consideration, or something more technical? Maybe the lithium battery requirements? (And - for ...
0
votes
1answer
77 views

which battery will supply the load?

I have connected 14V supply terminal from alternator to 12V battery terminal and has taken the load across these terminals . But the load is operating still in 12V, and when measured across the ...
1
vote
1answer
475 views

How to calculate consumed energy effects on battery voltage?

I have 2 3,6V batteries. I want to send a SMS when voltage drops down to 3,4V. I ve chosen a voltage detector which has a 3,4V threshold. What I am trying to figure out is how long does it take the ...
2
votes
2answers
194 views

How to best estimate power consumption for a system?

I'm not an engineer, I'm a software guy getting into hardware - so bear with my ignorance! I'm in the process of building a system with many components (e.g. a computer, many sensors, a few motors, a ...
1
vote
1answer
131 views

dying battery, increasing resistance

this is a graph of v-i relationship of a battery (not ideal one since it has internal resistance) as you can see, the slope is 1/R, so as time passes by, R increases, therefore, the slope ...
1
vote
0answers
488 views

Arduino Mega run on 2 AA batteries? [closed]

I am completely new to electronics and I have a question. I read that the Arduino Mega runs on 5V and that a supply of 6-12V is recommended for stable operation of the board. So what if I wanted to ...
6
votes
2answers
435 views

How does a battery recharge?

Alright, I should probably know this, but I don't. For a school project, I need to be able to charge a 12v battery from an alternator. What I am stuck on is the method of how batteries (generally ...
1
vote
1answer
202 views

How to provide stable power to RF receiver when operating on small batteries with blinking LEDs

I have a very simple circuit design (simple to keep cost low) consiting of a super-regenerative (or super-heterodyne) RF receiver, a Microchip PIC and 3 LEDs. These are powered on 3 or 4 AG13 ...
2
votes
1answer
610 views

19v Charger with 14.4v Battery: What exactly can I expect?

Long story short: I have to replace the charger AND battery on my ASUS U53F-BBL5 laptop due to a combination of lost original charger and Best Buy can't read a laptop's model number for the correct ...
2
votes
1answer
1k views

Why is there risk of overvoltage when jump-starting a vehicle?

Ford Focus C-Max manual describes jump-starting procedure as follows: shut off everything, connect the jump cables, start the donor vehicle engine and let it run for a while, turn the ignition key on ...
2
votes
1answer
450 views

Battery charging questions Parallel charging and battery balancing of LiPos

I'm having a long discussion on an RC board regarding LiPo parallel charging. The basic crux is that my understanding of how charging works is something like this: Charger Line voltage of x(8.4v in ...
5
votes
2answers
526 views

Can 12V Batteries be made to act as a ±12V power source?

I am an undergraduate electrical engineering student, and as a final project for one of my classes I made a speaker system which could play music connected through a 3mm cable. The system was powered ...
7
votes
4answers
1k views

Least expensive way to boost DC voltage

What would be the least expensive way to boost a DC voltage? The aim is to convert 1.2 V/1.5 V (from an AA/AAA cell) to 3.3 V to power a small 8-bit microprocessor, like Atmel ...
1
vote
1answer
132 views

Safe operating area for different types of battery chemistry?

I'm trying to find the safe operating area for various types of batteries; in particular I need minimum and maximum termination voltages, although information on temperature / power / current is also ...
2
votes
1answer
474 views

Can I use a 220V incadescent bulb to drain a 12V battery?

I'm about to replace the batteries of my UPS. For safety, I'd like to drain the old batteries completely before disposing, but I don't have a large 12v load at my disposal. Can I wire it to a 220V ...
1
vote
3answers
161 views

Connect a 8 V motor to a 16 V battery

I am hacking a vacuum cleaner robot by trying to control the motors with an Arduino. I have then two 8V motors, each one needing from 50mA (when the wheel is turning free) to more than 1A (when the ...
5
votes
3answers
171 views

Close enough for voltages?

I want to extend the use of a camera. The camera currently uses a special li-ion 3.7V 1000 mAh battery. I could grab a couple of those batteries, wire them up in parallel, and that'd work just fine. ...
2
votes
3answers
166 views

How to I determine/ interpret values of autoranging multimter

I have an autoranging multimeter and many AA batteries.... how do I interpret the readings when deciding to keep or discard AA (1.5 volt) batteries?
6
votes
2answers
1k views

PIC voltage measurement

I am running a battery powered device, and would like my microcontroller (PIC) to report on the supply voltage. This is so I can determine how many batteries is used in the supply, and also the state ...
6
votes
3answers
1k views

Wide voltage supply for PIC microcontroller

I am looking to power a PIC microcontroller with a supply voltage that ranges from 4.5V to 18V. This will be a battery powered device so I would like to conserve power, ie. linear regulators like the ...