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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52 views

Why is it that current pass from charger to battery while both of them have the same voltage?

Why is it that the charger stops charging when the battery is full? I answered myself that the battery is like a variable resistor and when it empty the resistor is low and when it full of energy ...
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0answers
40 views

How to design a circuit checking if 12V car battery is charging?

I have a small solar power charging module and load balancer, that takes input from a solar panel, has connectors for a car battery (12V) and output terminals. These things are pretty common on thing ...
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1answer
33 views

24v vs 48v solar inverter

I have 4 batteries of 150AH each. Earlier these were connected as series to 48v solar inverter of 3000 Watts, now as that old inverter is dead and I need to replace it with new one. I want to know ...
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1answer
43 views

Practicality of using different types of battery cells to avoid DC-to-DC conversion

One problem with solar systems is the need for high-efficiency DC-DC converters. For example, if lead-acid 12V storage batteries are used, then the user is faced with the problem of down converting ...
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1answer
23 views

How to connect both a bluetooth receiver and a amplifier to the same power input?

Dear users of this forum, I am new to this so I apologize in advance for any rookie mistakes. I am building a portable speaker of which I connected the speakers and the amp already. I am looking for ...
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3answers
76 views

Get -50V to 50V range from battery output

I have the following problem: on the system which is battery-powered(4S1P Li-ion battery, 14.8V) I need to create outputs from -50V to 50V. The system has microcontroller on-board. I am baffled on ...
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1answer
65 views

Low voltage drop regulators?

I am building a battery backup system for a dc appliance that runs on 6v. I have a 6v sealed lead acid battery to serve as the backup source. However i read that a lead acid battery at full charge ...
1
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1answer
74 views

Ni-MH battery voltage [duplicate]

I have a battery pack of 8 Ni-MH 2400 mAh cells connected to a load that draws ~700 mAh (a Raspberry Pi Zero, display, WiFi dongle, USB hub, and a wireless keyboard dongle). I want to add a led that ...
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0answers
37 views

Relation between battery cell capacity & internal resistance

I'm trying to design a large battery pack, that should provide a given amount of power, with a reasonable amount of heat dissipations. To do so, I have three degrees of freedom: indidividual cell ...
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2answers
61 views

Help powering an old heater control board im trying to reprogram

Not photo of my specific board. I got 3 old universal controller board's , I'm attempting to reprogram them to learn hardware hacking. But i not quiet sure what would be the best method of powering ...
0
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3answers
64 views

Does LiPo4 battery amperage output increase as voltage decreases from 4.2V to 3.57? I'm trying to size up a diode [on hold]

I'm trying to determine the max amp output of a battery pack that has 28 cells in it. To be more specific towards what I'm doing: I'm trying to size up a diode for the charge port; the battery charges ...
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1answer
80 views

Lithium-ion battery Internal resistance myth

I am making a battery tester, lithium ion battery for particular. and I want to measure the internal resistance, but after testing few cells, I am skeptical for my results, since most of them, new or ...
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1answer
83 views

Why 12v batteries but not 110/240 corresponding with the mains?

I have a basic curiosity question while I trying to learn/figure electrical "things" while I trying to size my UPS. I know that an UPS will convert power from mains (240v in my case) into 12v battery ...
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2answers
67 views

What's the C rating for NiMH batteries? [duplicate]

On most hobby Li-ion packs there is a prominently displayed C rating (typically 20 - 35), which tells you how many amps you can draw from it, in a multiple of the capacity. I have never seen a C ...
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1answer
36 views

(External Battery) If i have Portable Charger that has a capacity of 50,000 mAh and

4 ports with 2 amps, 2 amps, 1 amp, and 1 amp that can charge 4 phones respectively. How long will the battery continue to charge these phones, assuming they are pulling the largest load possible? ...
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0answers
38 views

Can a power bank be customized to give output of 3 and 4 amps instead of 1 and 2.1 amps? [closed]

I would like to know if in any case a power bank could be designed/customized that could be easily charged with normal micro usb charger 5v DC , that could give out the power in 3 and 4 amps instead ...
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0answers
15 views

Sanyo 92P1131 Lenovo battery voltage [closed]

So I've got a new battery for my good old Thinkpad. It's not genuine tho. On Linux 4.4, it says that the voltage at 25% is 12.2xxV, but on the Battery it is written that it is 10.8V nominal voltage. ...
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0answers
28 views

why the BMS gets hot on a 24v 18650 battery pack

I built a 24v battery pack for e-biking using a BMS I found on ebay here is the link: http://www.ebay.com/itm/131574426689?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT I'm using ...
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3answers
140 views

How many amps can a car battery supply?

Googling this hasn't given me much information. I've heard numbers ranging from 30A to 300A. My question isn't how many amps a car battery does supply in normal operation, it's how many amps I ...
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3answers
69 views

Multiple source Smartphone charger pack

I am in no means a electrical engineer or student but i dabble. I have a project to make a BIG smartphone charger using multiple 1800mAH batteries. you can choose which cell to use and charge via a ...
2
votes
1answer
71 views

Flat coil inside rechargable lithium battery

Take a look at this de-labeled smartphone Lithium-Ion battery: What is the coil used for? Possibilities I thought of: Wireless charging - unlikely because the outer metal foil would screen the ...
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1answer
83 views

mAh and Wh ratings not matching with voltage of device

I was under the impression that Wh = Ah * V I have a 20000mAh battery charging device for my phone but am confused about the information provided by it on the side. It claims to have a 5V output (3....
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0answers
50 views

An SoC pulling the power source voltage

I'm trying to power a SoC with a battery as in the figure below. The SoC in question is the WeMos, based on the ESP-8226. simulate this circuit – Schematic created using CircuitLab When ...
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1answer
30 views

Standard/Specification for regular alkaline batteries

Where can one find the standard specification for regular alkaline AAA, AA, C and D batteries? I mean, I know that different suppliers must have different battery capacity/property but there must be ...
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2answers
49 views

High current draw at start up of DC motor. How to understand if the battery can withstand it?

Suppose I have a solar powered plant like this one below: simulate this circuit – Schematic created using CircuitLab The solar panel charges the batteries and, when needed, the power is ...
0
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1answer
38 views

How to make inverse switch with bc547?

I want to make a circuit where the power to mcu switches from mains transformer to dc battery when when mains power is not available. The basic concept is to use a transistor to stay open circuit to ...
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1answer
58 views

CR2032 alternative for higher current [closed]

I'm designing a small battery powered circuit which will draw around 50mA for a millisecond every couple of seconds. I was planning on using a CR2032 coin cell but have recently learned that a coin ...
0
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1answer
52 views

The battery voltage and current relation

While a battery is discharging ,its voltage is decreasing , what happens to the the current? Does it decrease ,increase ,or stay constant?
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0answers
20 views

battery charger

is it be advisable to connect two deep cycle batteries from the same brand(both 12V 52AH and 55AH). will a 3AH difference affect my system?,should i want to make a 24V volts series connection. The ...
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0answers
35 views

What is a good melting point for a lithium battery contact fuse?

Tesla uses a fuse on every battery for their cars, and many fusible alloys melt from 50 to 90 degrees. because the fuse is welded onto the battery it wouldn't matter what the fuse current was, you ...
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0answers
22 views

Usb battery charging

I am designing a system which has a mcu (with usb peripheral). The whole system is powered by a 18650 Li ion battery. Now, imagine I am charging the battery by plugging the usb to a computer usb ...
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0answers
12 views

Why do I connect the positive and the negative to the battery on a boat? [migrated]

My trolling motor for my boat has a black and a red connection. The red goes to the positive on the 12 volt battery. The black goes to the negative on the 12 volt battery. Could I connect the black ...
1
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3answers
89 views

Does a helicopter battery drain when it is “off” but attached to a battery hot bus?

I'm reading about the DC Power System for a civilian helicopter. It shows the following diagram for when the battery is off: However, it shows that the ...
0
votes
1answer
34 views

Detect battery/cell's charge

I am building a portable device with Raspberry Pi and powered by 3 AAA batteries in series. I am trying to create a battery indicator with a LED: Green = Full power Orange = Half power Red = Low ...
1
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1answer
27 views

Inequal discharge across battery cell

I am looking into building my own battery management system, and I am beginning to understand the concerns of overcharging/discharging, overheating, and equal use of each of the cells. I am planning ...
0
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1answer
42 views

Two 12 volt batteries lowering reaches power

I just added an extra deep cycle 12 volt battery to my camper. I used half inch 15ft (or so) wire to connect the positive to the older batterys positive and the same for the negative. My older ...
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1answer
51 views

Can I put a 4500 mAh 18650 li-ion battery on a 2600 mAh powerbank?

I recently bought a mobile phone powerbank without realising that the battery wasn't included on the kit. So now I need to buy a 18650 li-ion battery and I found one that has 4500 mAh. Can I put the ...
0
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0answers
30 views

How to charge a Tablet Lithium ion Battery outside the tablet (not connect to it)?

I would like to know what is the pinout of this battery (cf. the image) and to know how I can charge it outside the tablet (not connect to the tablet). Can we charge any kind of Tablet lithium ion ...
1
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1answer
37 views

What happens when wire touches only negative battery terminal?

Might be more of a physics question, but what happens when you connect a wire only to the negative (or positive) terminal of a battery, in terms of electron movement? Do electrons flow in/out of the ...
0
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2answers
107 views

Alternatives to USB connector to supply 5V for charging battery on small circuit

I am looking for a way to get power in my recharging circuit, since my device uses a battery. The problem is the USB cable: the connector is soldered on the PCB, but with the stress of plug and ...
1
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0answers
59 views

Start a dead battery car with a power/USB charger [migrated]

today my car couldn't start beacuse of dead battery. The battery is not old, I simply left my dash cam attached for a few days without using the car... I'm alone at home and my car is in a difficult ...
2
votes
2answers
49 views

Battery to battery charging - Ah vs Wh

Assuming you have these two batteries: Battery A: 12V, 15 Ah = 180 Wh Battery B: 5V, 20 Ah = 100 Wh Can you use battery A to fully charge battery B? Battery A has less capacity (with respect to ...
0
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0answers
42 views

Battery volts and amps for 100W LED

I am interested in building a flashlight by following this tutorial, but I only want to build a 1 LED flashlight, not 10 LEDs. It suggests using 2 batteries to supply 1000 Watts. Meaning that 1 ...
0
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0answers
60 views

Is it bad to put 3.7V on 3V mice? [migrated]

I have mouse that take two AAA batteris, so it take 3V. Is it OK put one 10440 of 3.7V and one spacer instead?
0
votes
1answer
22 views

Recommended BMS for 18650 lition 7S 24V Battery Pack

I want to build a 24v 7S 3.7-4.2 18650 lion pack. My concern is the parameters my BMS should have to keep in balance all the 7 cells, not over charge them or over discharge them. cells from laptops: ...
0
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2answers
45 views

GoPro Hero 2 Battery Elliminator? (3.7v versus 5v)

I have an old GoPro Hero 2 who's external USB plug has failed, and I have no way of powering it externally. I need to run this GoPro using an external wired power source (available over a 5v USB). ...
0
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0answers
41 views

What features should be look for when evaluating USB batteries for all day use in a commercial setting [closed]

What features should be looked for when evaluating USB batteries for all day use in a commercial setting? My employer has supplied me with one battery I would like to have a second. What features ...
4
votes
1answer
182 views

Why are 3.8V lithium-ion batteries used in mobile devices, rather than 3.6V or 3.7V batteries?

I've noticed an odd trend in the lithium-ion batteries used in smartphones and tablets: rather than the 3.6V or 3.7V per cell typical of most Li-ion batteries in other types of consumer devices, they ...
2
votes
2answers
120 views

Why do power banks have such a limited amperage vs. 18650 battery packs?

I ordered an LED light that ships without a power supply and has an USB connector to connect one. I thought I'd just buy some power bank subsequently to power the device, but then I realized that all ...
0
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0answers
42 views

How to Recognize a Battery's Technology [duplicate]

Given a battery of unknown chemistry and unknown origin, how to I tell it's a rechargeable alkaline manganese, NiMH or NiCd battery by looking at its electrical or physical properties, eg. maybe they ...