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
55 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 ...
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0answers
16 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 ...
0
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2answers
36 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
59 views

5 volt via USB to 3 volt battery [on hold]

I'm really new to electronics and I'm trying to build a simple circuit, I want to power a 3V Lithium rechargeable battery using the computer 5V USB. How can I drop the 5V to 3V? EDIT: The battery ...
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1answer
52 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, ...
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0answers
45 views

Should I keep my notebook connected to the AC adapter all the time or “excercise” the battery for long lasting battery life [on hold]

I have a Dell 7537 and I want to keep the battery in good shape. I have not found a clear answer as to how I should treat the battery. Most of the time I use my notebook indoors and connected to an ...
3
votes
1answer
46 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
41 views

nexus 7 battery repurposing [on hold]

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
49 views

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

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
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1answer
48 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 ...
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1answer
54 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
82 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 ...
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0answers
40 views

How do I design a wave generator to produce a sine wave of 1.5 Vpp, 13 - 20 Hz? [closed]

How to design a wave generator to produce a sine wave of 1.5 Vpp, 13 - 20 Hz? I need to make a battery to produce above specified wave with a DC input of 12 V, 2A. Thanks in advance!
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1answer
48 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
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1answer
67 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
120 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?
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1answer
77 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
533 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 ...
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1answer
110 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
128 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 ...
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1answer
47 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 ...
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2answers
68 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 ...
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1answer
61 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 ...
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1answer
91 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
votes
2answers
135 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
30 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
151 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
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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
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3answers
240 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? _
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2answers
48 views

Amp hours (9 Ah vs 8.5 Ah) [closed]

I'm trying to replace two Data Safe NPX-35, 12V, 8.5Ah SLA batteries. When I called support to figure out what to order (before pulling the actual batteries out) they said that any 12V 9Ah SLA would ...
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1answer
78 views

Will this be able to run 24/7? [closed]

I'm trying to find out if I can run an appliance of mine can off the grid, completely on solar power and a battery. The appliance uses 4.91 amps and uses 110 volts on the power cord. The solar panel ...
1
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1answer
75 views

Battery power in the home: Fire Safety

I would like to use 12v LED tape powered by an 8 x AA battery holder and switched with a motion sensor. This will be connected in my home 24/7, so I would like to know what precautions (if any) I ...
1
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1answer
50 views

18650 Li-ion cells for the laptop battery: with protection circuit or not?

My laptop battery died and I've took it apart to replace the cells inside. Do I have to buy new cells with protection circuit or without it? Googling the existing cells part number LGABC11865, I've ...
1
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3answers
70 views

Calculating energy in battery

Let's imagine a regular deep cycle gel lead-acid battery from the building market. Capacity: 100Ah Nominal voltage: 12V Is it really correct to say that the energy in the battery is 100Ah*12V = ...
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2answers
57 views

Recharging dissimilar batteries

I have a lot of Eneloop batteries and am very happy with them. However, many of my devices, annoyingly take an odd number of batteries, but the Eneloop charger only charges in pairs. How bad is it ...
2
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1answer
117 views

Does the ground line in a DC circuit carries current?

I'm confused a little bit about whether or not a DC return line carries any current. the reason is that in our design we have 2 batteries 24V and 8V, they supply ~4A and ~2A respectively to different ...
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0answers
48 views

Interesting observation about different 'low battery voltages'

I have an old Nokia phone battery which is rated at 3.7V, 1500 mAh Lithium Polymer. I noticed that when the the battery died it measured around 3.8V (off load voltage) and on the other hand I have ...
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2answers
59 views

How to handle / dispose of spent lithium primary cells [closed]

Disclaimer: This is a material safety question and not electrical. But it is electrical engineers who generally decide which type of battery to use when designing a system and other electrical ...
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0answers
21 views

Internal volts in arduino for percent battery [migrated]

I'm working on a small project that is creating me a headache. I know arduimo (ATmega 328P .... etc. ..) has an internal voltage source code millivolts, but I would like to know how the full source ...
0
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1answer
64 views

555 timer flashing led circuit

I just have a question about this simple circuit or example: http://www.555-timer-circuits.com/flashing-led.html. I just don't get 1) why do they use 9V battery to power a single red LED light. 2) why ...
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1answer
388 views

Using an AC Fan on DC Battery

I have a 30wp solar panel which charges a 28amp 12 V dc battery. Can I use an ac fan (with less power) on that battery? I am newbie to electronics.
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0answers
58 views

Understanding the output of /sys/class/power_supply/BAT0/uevent [migrated]

Ubuntu shows the remaining battery time on my desktop as ~2 hours. I was trying to arrive at this same value from /sys/class/power_supply/BAT0/uevent. The output ...
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2answers
81 views

Heat output element

I'm building a little quiz game in Arduino and I already have it displaying a multiple choice question and people can answer by pressing pushbuttons. But anyways now I wanted to know if it's possible ...
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2answers
168 views

How does a battery figure out how many amps to send to an electronic circuit?

How does a battery only send the amps amount the device needs, and not more?
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3answers
135 views

Rate my Rasberry Pi UPS

I've made simple schematic for a UPS for Raspberry Pi. It contains a 12V Lead Acid Battery (40Ah), 5V LM7805 regulator and some capacitors. I'm supposing max 1.2A load from Raspi. Should I add ...
0
votes
1answer
51 views

12V UPS power supply and battery [closed]

I'd like to use a Tripp Lite PR40 as a backup 12V UPS by connecting it to a battery before a couple motors in parallel. The battery is 125AH deep cycle AGM. Can I do this? The manual says that the ...
0
votes
3answers
91 views

Ok to use one of the two 12V batteries of a 24V system?

Coach bus with a 24V system of 2x12V 120Ah batteries for aux load. I need 12V for IT stuff. Is it ok to take it from a single battery or is it a bad idea? Right now I have a crappy 12V->24V converter ...
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4answers
113 views

Using a BJT to enhance battery life

I have a little project going on, that involves turning on and off a led strip. The led strip specs : 5M Led SMD 600 Lights LED : 3528 SMD 600 Lights, 5m : 120 LED / m According to this site, it ...
0
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1answer
116 views

Charging Li-ion batteries in parallel

I wanted some opinion on my set up here, just to make sure I got the basics right. I have a Li-ion battery charging circuit based on the MCP73113. This is designed to be a single-cell battery ...