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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Shape Memory Metal framed sail

I am working on a costume prop that utilizes a triangular cut sheet of emergency blanket spined with a single 12" long, .04" dia piece of nitinol wire that has a transistion temp of 115deg F. My plan ...
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1answer
21 views

Difference between Lithium Polymer batteries of varying capacity and cell amount

I was looking to purchase a LiPo batteries online for a side project. Upon shopping around, and reading up on LiPo batteries, I have a fair understanding on what the numbers/letters on the battery ...
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0answers
45 views

Is there any A23 Battery as a rechargeable battery? [on hold]

I need to buy an A23 rechargeable battery. When I tried to search it on Amazon, there was no option to select a rechargeable property! But I found an expensive A23 Battery called a "Energizer A23 ...
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0answers
29 views

AGM Batteries: Comparison of Auto to Marine

Research (links go through to the actual product descriptions, for those who read specs): Diehard AGM Auto Group 34 775 CCA: $153 Diehard AGM "Marine" Group 34 880 CCA: $250 West Marine house brand ...
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2answers
77 views

Low noise voltage regulation

I have a circuit which currently runs off of either a 12VDC wall wart adapter, or it falls back to a 9V battery if the wall wart adapter is not connected. My circuit currently uses a chip which ...
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3answers
64 views

Low battery level circuit - Changing “trigger” level

I am re-creating a simple low-battery level circuit that turns on a low-power LED to indicate that the battery needs to be changed. The circuit is shown below. There are two things I would like to ...
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0answers
52 views

Which would be the safest battery type for a wearable electronics?

Which battery chemistry is most suitable for a wearable electronic gadget like a wrist band? I wanted to consider safety, and potential power (mAh etc)? I know there are the new "flexable" batteries, ...
3
votes
3answers
422 views

Automatically switching from 9V battery to DC wall adapter on insertion

I have a simple circuit that runs off of a 9V battery. I'm re-designing it so that it can also run off of an external 12V DC source (ie: a wall adapter). I want to design the circuit so that if both ...
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0answers
24 views

Li-SoCl2 battery state of charge

I'm developing a data logger powered by Li-SoCl2 (http://www.100y.com.tw/pdf_file/02-SAFT-LS33600.pdf) battery and I have no idea on how to overcome the problem of estimating the residual charge of ...
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1answer
53 views

How big should battery be to power two strips of led for few hours?

I have an idea for halloween costume for upcoming Halloween. It will involve building two small sets of infinity mirrors. I am completely new to the electrical engineering. The infinity mirrors ...
3
votes
2answers
313 views

What is a safe max. discharge rate for a 12V lead acid battery?

I've got a 12V 2.4Ah lead acid battery which I plan to connect a water pump to. I've looked at various pumps, but the one I'm most interested in draws 2.2A. I'm not so interested in how long the ...
2
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2answers
95 views

Battery Charging Circuit - NiCd

I am designing a battery charging circuit for an in circuit NiCd battery (used on a RC car). From my research I understand that I need to charge using a constant current source, and for fast charging ...
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2answers
786 views

Why don't we get shocked when we touch a car?

According to this answer to a question about car batteries: [...] so the entire chassis is an extension of the minus terminal of the battery. If this is the case, I would expect that you'd get ...
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1answer
44 views

How to charge an iPad for maximum battery efficiency [closed]

iPhone chargers provide 5W of energy while iPad chargers provide 10W of energy. If you plug an iPad in an iPhone charger it will charge slower than normal. Also, there are many computers which provide ...
0
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0answers
22 views

Battery gas gauge for coin cell battery [closed]

I've tried searching for battery gas/fuel gauge ICs for coin-cell batteries and I haven't been able to find any. Does anyone know of any dedicated battery gas gauge ICs that can be used to measure a ...
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3answers
63 views

Figuring resistor wattage and value

I have a remote controlled airplane that I am putting LED lights on. The power supply is a lithium polymer battery that is rated at 22.2 volts and 4000 miliamps. I have an LED that is rated between ...
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votes
2answers
100 views

Where does power in my laptop go when I disconnect the battery? [closed]

I have a laptop which, when put to sleep, sometimes enters a state of limbo, from which it can be neither turned off nor on, and the only solution is to disconnect the battery, reattach it, and turn ...
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3answers
86 views

How long would an original gameboy last on a modern lithium battery? [closed]

The original Gameboy was famous for it's battery life on 4AA batteries. My HTC One smartphone can last about as long as the GB did back in the 80s. So how long would an original gameboy last if ...
0
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1answer
39 views

LiFePo4 2 Cell Series Charging with MCP73223

I want to make a charger for two LiFePo4 cells in series. As I'm aware, charging cells in series may be problematic, due to slight differences on each cells, that may charge one and not the other, ...
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1answer
92 views

Is it okay to put a solar cell and battery into resin?

I was thinking about making a simple circuit with LED, solar cell and battery and put it in resin mold to make it weather proof. I wonder is there anything wrong (chemically) with putting a battery ...
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3answers
124 views

Are control systems and motors typically driven from the same source in robotics projects?

My control system is a simple microcontroller between 3.3V and 5V, but the stepper motors I require are 12V. I have ordered a 14.8V battery that I intend on regulating down to 12V to drive the motors, ...
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2answers
32 views

Battery Chargers - What properties to look for [closed]

What electrical properties should you look for when choosing a charger for either your cell phone, laptop etc, I am referring to Li-Ion batteries more specifically. Some people say you need to look ...
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1answer
47 views

Flash Bulb battery depletion

Extremely simple question for you. Probably beneath all of you to answer apologies for that. My camera's flash is rated in Watt seconds. My battery is rated in mAh . If my battery can output 1000 ...
4
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2answers
141 views

What are the use of these diodes?

I have a circuit diagram which is for a circuit used for testing batteries under a load, only one of the batteries can be tested at a time and I was just wondering what the point of the diodes in the ...
0
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1answer
61 views

NiMH battery charger using discrete elements

Below is a schematic of NiMh battery charger that must automatically switch off charging current when battery is fully charged. I am aware that the main part of this scheme is current source, build ...
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2answers
64 views

Looking for efficient battery supply to power 3.3V circuit

I have been searching everywhere for the best way to power my circuit and I can't find straight forward information. My circuit needs 3.3V and the maximum current it draws is 50mA. It will run at ...
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1answer
56 views

Issue charging a 12V battery using solar charger

I bought a 12V solar charger for vehicle batteries, because I am usually using wall chargers and I wanted to give green technology a try. When I connect the solar charger to my battery, it shows 10V, ...
3
votes
1answer
57 views

What can be the consequences of charging a lead-acid battery with an excessive voltage?

In my field-operating device I use a simple PWM step-down to charge a 6V 3.9Ah lead-acid battery from a 5W solar cell with a voltage of 7.2V. Unfortunately the DC regulator got damaged today and the ...
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2answers
43 views

nexus 7 battery repurposing [closed]

I have just broken my nexus 7 and I was about to salvage the battery. I was thinking of using it maybe to power my raspi or arduino. My main question is how do I charge it? I was thinking of cutting ...
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2answers
57 views

Can my 3.2V LiFePo4 battery power my cell phone through the cell phone's micro USB port? [closed]

I have a large LiFePo4 battery cell made by Headway (model 40152S 15AH single CELL, 3.2v). I'd like to use it to power my Samsung Galaxy S3 phone. On the original phone battery it says that it is a ...
0
votes
1answer
55 views

Power supply for Raspberry Pi

Before you tell me that the question has already been asked, only similar things have been asked. I need to power a Raspberry Pi with some electrical equipment attached to it. The Pi needs to run ...
1
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1answer
56 views

Minimum AWG of a battery wire

I have a 3.7V one-cell polymer battery 350mAh 25C. It's linked to a board over a 50mm wire. What would be a good AWG diameter to ensure a maximum voltage drop inferior to 2%?
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1answer
83 views

How to figure out battery life of audio amplifier?

I have a design of an audio amplifier. It has some special features but basically it takes in an audio signal does some filtering, and amplifies it through a class D amplifier chip. The chip says it ...
0
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1answer
54 views

my UPS (uninterruptible power supply) has a 12V 4.5AH battery, will a 12V 7.2AH battery work as well? [closed]

I have a UPS with a flat battery that needs replaced which says 12V 4.5AH on its label but online the cheapest and most common type of battery I'm finding is 12V 7.2AH...will this work or do I have to ...
0
votes
1answer
71 views

Why does my DIY “solar panel circuit” show battery voltage and not solar panel voltage? [duplicate]

I have six solar panels but each are different from one another. The first is 4.5V. The second is 6V. And the last four are all equal up to 6V. It all adds up to 16.5V in series or on a good sunny ...
0
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3answers
124 views

Why do most batteries or circuits use a 12V supply?

I have seen most of the circuit using 12V supply, is there any reason behind this? Is there any reason to choose 12V in all systems like battery-powered devices?
3
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1answer
78 views

How long can I run my camera off this battery?

I have Ultramax NP7-12 12v 7ah specifications here: http://www.batterymasters.co.uk/ProductDocs/SLAUMXNP7-12-TECH.pdf My camera consumes 1.25 watts per hour and runs at 7.8 volts but can run between ...
4
votes
1answer
537 views

How can a micro controller turn off itself by closing the VCC line when battery is low?

My board has a Li-ion battery with the capacity of 4000mAh and maximum voltage of 4.25V and minimum voltage of 3.25V . This means that the battery voltage shouldn't get lower than 3.25V. When the ...
0
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1answer
112 views

Is there any problem with soldering a charged battery?

I have a project in mind that amounts to little more than rebuilding a broken eGo-T (electronic cigarette). The battery when I took the busted eGo-T apart had quite a kick and I got a minor burn from ...
0
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1answer
32 views

Detecting battery module AVR removal

I am working on a module (based on ATTiny) that will be plugged and unplugged onto a MCU systems. This MCU system powers up the ATtiny module and when this module is removed, the MCU system has to ...
2
votes
2answers
130 views

Why “bury” lead acid batteries in the ground?

I've heard once from a person who had installed stand alone systems in rural villages in the third world, that ideally batteries should be placed in a hole in the ground, even though it rarely ...
1
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1answer
51 views

Will 2 600mAh batteries give me the same usage level as one 1200mAh? [duplicate]

I am considering obtaining a pair (2) 3.2V AA Lithium Phosphate batteries rated at 600mAh for a project that needs to operate at 3.7v/1.8ohm at peak times and next to nothing the rest. Obviously the ...
0
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2answers
69 views

Do batteries have a delay when adjusting to a new load?

So I am creating a battery voltage measure, and it takes a reading both when the battery is in open circuit, and when it is loaded with a 100mA constant current. I have set it up and the reading is ...
0
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1answer
63 views

How much/fast is a battery allowed to degrade? [closed]

My friend's Macbook Air battery has degraded almost 21% in just over 2 years. This made me wonder how much a battery is "allowed" to degrade over time. Is 21% in 800 days a lot? Or does it seem like a ...
1
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1answer
92 views

What do you use to connect simple battery holders?

I'm sorry for this very rudimentary question, I'm completely new to this hobby. I need to have a ~30V power source and I want to buy 22 AA batteries and connect them in a series. I intend to use ...
2
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2answers
137 views

What are the voltages noted next to the C-rates?

I am looking at a brochure/datasheet for some lead acid batteries, Hoppecke deep cycle gel, OPzV (link to brochure). Below you see two snippets from it: I have some problems understanding the ...
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0answers
36 views

Electric vehicle battery balancing

I need to choose a method for my project in for active balancing of Li-Ion batteries for EV application. I read a paper for this purpose: "A Review of Passive and Active Battery Balancing based on ...
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2answers
158 views

Converting 28VDC -> 14VDC at around 200A How do you pull that off with that kind of current?

Current boat has 110AC air conditioners and some small appliances but the rest of the systems are on 12VDC. Genset ate a jellyfish and has to be replaced, so I'm working out options to upgrade/change ...
2
votes
1answer
45 views

Hoover batteries, sensors and charging

I have a battery for a robot hoover (aka vacuum cleaner) (Ni-MH) that seems to be on the blink (very low run time). I'm trying to understand how it works in case I can do anything to fix it or if I ...
2
votes
3answers
246 views

How to combine batteries in series and parallel

I need to combine S*P number of batteries (same types) to get S times the voltage and P times the capacity. Which of the following combination is better? Is there any difference? _