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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2
votes
2answers
524 views

How much energy can this battery store?

I have a 16 V lithium battery with 60 Ah. How much energy can this battery store? My home specifications are: 220 V mains and I have a contracted power of 6.9 kVA.
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2answers
5k views

How fast can a Li-Ion battery be charged?

So far I've seen many Li-Ion battery chargers that do the full charge in about 1,5 hours or more. There're also NiMH battery chargers that claim they charge a NiMH battery in 15 minutes and then the ...
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2answers
1k views

charging a lead acid battery

(n00b question) I have a small (6 cell regular bike) leadacid battery and want to charge it via solar sheet of 15V - 0.3A. the voltage solar sheet changes and in cloudy day goes below 10V. does the ...
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2answers
2k views

How should I wire two batteries to make my mobile DVD player work longer?

I have a plain old mobile DVD player (Apex model PDVD-937). It runs on a single rechargeable battery supplying 1600mAh at 7.4V. I would like to augment it so that it can work for a longer period of ...
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3answers
1k views

Get 12 volt power supply from Dell Laptop

Is there any way to get a 12V supply out of my dell inspiron 9400 laptop? I have an external 2.4Ghz video receiver which I want to power from my laptop without using a separate battery. Could I just ...
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2answers
41k views

Can non-rechargeable batteries be used in place of rechargeable ones?

I am aware that attempting to charge a non-rechargeable battery is a terrible idea, and I have no intention of doing so. But supposing that, in a pinch, I needed to use non-rechargeable batteries in a ...
2
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3answers
3k views

Battery circuit power drain

Bit of a newbie question here... I want to build a battery powered LED light for use outdoors. So basically needs to be pretty bright and last a while. If I have battery rated like this: ...
3
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3answers
21k views

Building a large lead acid battery?

I am building a large water tank. I'm thinking to convert it into a big lead-acid battery. I am interested if exists a formula that could calculate how much will be the capacity of that battery, ...
2
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2answers
285 views

What rechargeable battery is suitable for severe frost (−10 Celsius and below)?

Suppose I want a rechargeable battery for a hybrid electric vehicle like Toyota Prius - one that can power the vehicle traction motor at low speeds. The vehicle would have to operate in a region where ...
2
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2answers
214 views

Low voltage 2 channel stereo analog switch

I am looking for a ultra low voltage 2 ch stereo analog switch. I have two headphone audio sources that I need to switch between. It is very important that the chip can run of a 1.2v rechargeable cell ...
4
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3answers
1k views

How does the size of a reservoir capacitor affect battery life?

I have a circuit, powered by a 9V alkaline, where a solenoid is actuated via a MOSFET. I have a large reservoir capacitor (4700uF electrolytic) on the high side of the solenoid. I was wondering how ...
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7answers
27k 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 ...
2
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1answer
2k 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
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1answer
2k views

How am I able to jump my car when I ground one of the jumpers?

Electrically, when I think of jumping my car, I visually see basically putting a stronger voltage source in parallel with a weaker voltage source (see http://imgur.com/qz8jX). However, on every car ...
1
vote
1answer
436 views

When charging mobile decices using an external battery is DC > USB more efficient than AC > USB?

I bought a "jumpstart" battery that has a built in power inverter to support both AC and DC ports. I have it for a project but also want to use it for charging my mobile devices occasionally. I do ...
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1answer
168 views

Circuitry for Running Many Small Motors

I'm creating a simple vibration mat for a child which will be triggered by a force sensor. I'm not trying to do anything complex (like changing frequency of vibration) - simply an on/off circuit. What ...
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2answers
2k views

Have I got these simple power calculations right? (for battery consumption)

Lets say an ideal AA battery I have provides 2.0 Watt hours. It could be different, just a quick search for this example. My very simple load is the battery connected to a 5mm LED. The LED has a ...
2
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1answer
595 views

POE Battery Survey Toolkit

I want to try my hand at producing a POE battery power supply for use with an access point [AP] for site surveying purposes. My solution is an 11.1v LiPo 3s pack and charger fro a remote control car ...
12
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1answer
938 views

How to power a widget, while the li-ion battery is charging?

I am in need of a way to charge a 3.7V li-ion cell (probably an 18650 type) from a 4.5V - 20V input. That's not a problem, there are plenty of (switching) battery chargers around with that kind of ...
2
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2answers
5k views

Use a lithium ion battery from a laptop, for a small project?

Now laptop batteries are very expensive, however I have a slightly beefy Dell Inspiron 1525 laptop with a half year old battery that works fine. Other than complete depletion, of which I have heard ...
4
votes
1answer
15k views

What power motor should be used to power a Segway-like device

I am planning on building a personal transportation device which will either be a skateboard with a motor etc or a Segway-like device. I will have two wheels and must be capable of getting me to move ...
12
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5answers
11k views

Parallel charging of lipo batteries, maximum voltage difference?

There are numerous products that enable lipo batteries to be charged in parallel. Most sources are clear on voltage and capacity requirements, which follow pretty directly from basic circuit ...
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2answers
64k views

Adding mAh when wiring battery cells in series?

When combining battery cells in series, the voltages of the cells are added to get the voltage of the final circuit. Do the mAh add up, or stay the same? For example, suppose you have two 3.7V cells,...
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3answers
336 views

Would any current flow when batteries and resistors are set up like this?

What would the current flow be through the 1 ohm resistor? They are constant voltage sources, not batteries.
6
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2answers
779 views

Can batteries be wave soldered?

Common sense says that you don't wave solder batteries, because the wave would short them for seconds. Yet in this appnote I read Primary lithium cells may be wave soldered as long as the cell ...
6
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1answer
2k 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 ...
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4answers
10k views

Charging 3 AAs in series

I'm currently repairing a project built by someone else and want to avoid tinkering with it as much as possible. I am looking to recharge 3 AA NiMH batteries (at 1.2v each), that are in series. I ...
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2answers
7k views

What is the white powdery stuff that leaks out of a battery if I accidentally submerge it in water?

Does it mean that the battery has exploded? I often see the white powdery stuff when I see "battery disposal" boxes in public areas
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3answers
2k views

Deciding between 7.4V and 11.1V power

Suppose I had a unit that could accept DC power between 6 and 14 volts, and the choice of using either a 7.4V 1000 mAh or 11.1V 1000 mAh battery. Do either of these choices offer a clear advantage? ...
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1answer
3k views

how to run 12V x 2 battery inverter in (12V x 2)+(12V x 2)?

apologies if i can't ask this in this stack. My 24V sine inverter runs on 12V x 2 lead acid old batteries (left with ~50% capacity). I want to buy two new leadacid batteries but still try to ...
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2answers
1k views

AA Battery Level

I am building a system with 4x AA batteries. (3V output) I like to understand the battery level for the system. I cannot control which battery people use (li-ion vs alkaline) or quality of the ...
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3answers
2k views

AA Battery charger and re-chargeable battery

I have a Canon digital camera that requires a 3.2V battery. I'm trying to figure out what would be the impact if i use a re-chargeable battery that has 1.2V capacity. For a similar reason, I need to ...
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2answers
10k views

How can I disassemble an iPhone 4 battery without damaging it?

I would like to measure the power consumption of an iPhone 4 using a source/measurement unit. On other devices I am able to connect the SMU directly to the +/- battery terminals, using tape to ...
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3answers
1k views

Is there a limit to the number of kilo-watt hours an AAA (or AA) battery can hold?

Or in other words, is there a limit to total battery capacity? Is the limit a physical one or is it an economical one?
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8answers
63k views

Do batteries lose voltage as they're used up?

V = IR Resistance stays same, and I know as a fact that I (or current) decreases (my stuff runs slower on old batteries). So could a 9 Volt battery turn into a 1.5 volt one?
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2answers
619 views

corroded battery on old calculator

I am attempting to revive an old HP-41CV calculator. Everything works, but one of the leads on the battery pack is corroded. Is there a quick fix, or will I have to figure out how to replace it?
4
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3answers
3k views

How can I avoid voltage spikes when connecting/disconnecting a 12v battery?

I have a computer that runs on 12v from two parallel lead acid batteries. I need to be able to swap the battery banks for fresh ones every now and then without ever losing power to my equipment. I ...
28
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4answers
140k views

How to measure capacity of a Lithium-ion battery

I bought a Lithium-ion battery for a camera (much cheaper than the brand replacement but non unreasonably cheap compared to AAA Li-Ion batteries with similar charge). I however have doubts that it has ...
5
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4answers
14k views

How do I calculate the self discharge rate of a lead acid battery?

Okay, like the title suggests, I need a method of calculating self discharge rates of Lead-Acid batteries. Here's the catch: I varied the electrolyte which the batteries were using, replacing ...
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2answers
1k views

microcontroller low battery indicator

I am powering a board and circuit with a 9V battery (those alkaline ones). And I would like to read the 9V battery to keep track of how much power it has left. I have read that I can do this with a ...
2
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1answer
205 views

R/C BEC with a 12v lead acid

Pretty much all BECs (Battery Eliminator Circuit) are rated to work fine with 12v input but I haven't seen any that mentions lead acid batteries. Almost all datasheets for BEC regulators have write ...
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3answers
353 views

Charging marine battery while powering equipment

I've got a quite delicate setup with a PC and some other minor equipment such as a microcontroller connected to a large 100Ah sealed (AGM) 12v lead acid battery. I need to be able to run my equipment ...
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1answer
3k views

Increase the capacity of a 12v battery bank by adding new batteries

We have two 12v marine batteries connected in parallel – they power some LED lights and a small inverter used to charge a laptop and the odd camera battery. The marine starter batteries are about 2 ...
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2answers
3k views

Charge 3x AAA from USB

I'm trying to charge 3 NiMH/NiCd AAA cells from USB. I've already got an atmega32u4, so I can use that to read battery voltage and stop when battery reaches 4.2V. I'm not sure about the capacity, but ...
4
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3answers
1k views

Battery for reliable field sensor with low temperature conditions

I'm designing a frost alarm for farmers. The basic idea is that the farmer puts a sensor somewhere in his field. This sensor reports the temperature every 10 minutes to a base station with a wireless ...
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4answers
9k views

Why are more powerful tools using higher voltage?

AFAIK each of the world leading cordless power tools manufacturers produces several "product lines" of cordless power tools with different voltages. For example, Bosch currently produces tools with Li-...
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2answers
8k views

What are the tolerances for the maximum current a battery can supply?

After a lot of research and experimentation I have come to learn that the sentence "This is a 1.5V, 2800mAh battery" is entirely a lie. (i.e., the potential difference between the terminals of a ...
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1answer
387 views

I am thinking of designing an electric car and am wondering about the best way to drive the wheels

I'm thinking of a light cart - barely enough room for one person and the batteries. What do you think would give me the best battery life? I am thinking a (brushless?) motor with the input voltage ...
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2answers
193 views

How realistic would charging batteries with inductive power transmission be?

I've read articles on inductive charging and related stuff on Wikipedia and now I wonder - what if I wanted to develop a battery (also a matching charger and the battery compartment) with completely ...
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2answers
348 views

Electromagnet force

If connect a battery to an electromagnet, would the magnetic force be equal stronger or weaker if I used a battery with a capacity of 5000V and 0.5A (2500Watt) or 0.5V and 5000A? Or will it be ...