Questions regarding Li-ion batteries (Lithium-ion), including proper charging and usage.

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2answers
29 views

Use a li-ion battery at two different voltages

I scavenged a li-ion battery from a broken laptop. It is made of 6 Samsung ICR18650 cells (3.75V 2800mAh), parallels two by two so that the total pack is in fact the sum of 3 cells at 3.75V, so 11.25V ...
-1
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1answer
52 views

Battery holder for protected 18650 battery [closed]

When placing a 18650 Li-Ion rechargeable battery in its battery holder, everything is fine. The problem is with protected 18650 Li-Ion battery. There are protection circuits attached into them and ...
0
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2answers
68 views

Li-Ion battery charging as simple as possible

I have read articles here and there about charging Li-Ion batteries. Most of them try to solve the problem of maximizing capacity and also maximizing cycles. The most recommended method is charging ...
0
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1answer
32 views

When to use Battery Fuel gauge

I am designing a measuring instrument powered by a Li ion Cell, I need to display remaining battery capacity on it, so I was wondering what is good or lets say widely used method. Should I use full ...
0
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1answer
45 views

Buck converter charge battery control output voltage

I have a buck converter charging 8 series of Li-Ion batteries ( 8 x 4.2 voltage of charging) with a source of 36 V. I am using this schematic (from here): I know that for a resistive load, the ...
0
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1answer
31 views

How to attain a topping charge for a lead-acid battery?

Charging a lead-acid battery involves three stages: CC, CV, and Float. I have a charge controller which charges my battery at CC to the float voltage. I would like to add a device that would charge ...
3
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2answers
153 views

Hazards of puncturing lithium-ion batteries?

I was doing some electronics repairs, and accidentally punctured a small (mobile phone capacity) lithium-ion cell battery with a metal spudger. At first, I hadn't realised I punctured the batteries - ...
1
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1answer
36 views

MCP73844 Li-Ion charger

I am using a MCP73844 dual cell Li-Ion charge management controller to charge a pair of LIR2032 cells, which are rated at 45mAh. I have breadboarded the circuit according to the schematic in the ...
0
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0answers
30 views

Does the battery protection circuitry work automatically within this Li-Ion charger IC (STNS01)?

I want to use the STNS01 Li-Ion Charger/LDO regulator in my circuit for its protection circuitry including overcurrent, overdischarge, overcharge, and over temperature circuitry. However, I can't ...
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0answers
23 views

Li battery series charging voltage for balance board

I am looking for some boards that will charge/protect 4 li batteries in series, such as this: http://www.newegg.com/Product/Product.aspx?Item=9SIA7BF2K19148 and am not sure as to what voltage I ...
-1
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2answers
57 views

How to thoroughly and meaningfully test a smartphone battery?

A bit of background: my girlfriend's smartphone lately has picked up the habit of turning off while the battery is still at about 35%-40%, or so the system says. For anyone around here who is not knee ...
0
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1answer
36 views

Powering LEDs + a Controller with Lithium Ion Batteries

I am trying to build a portable project with some form of RGB LED (probably APA102) and a controller such as a Raspberry Pi. I am trying to figure out what is required to safely power both the LEDs ...
0
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0answers
46 views

Li-ion powerbank UPS + DC boost converter

I have a philips cordless landline phone and its power rating mentioned in its OEM ac-dc adapter says output of 6v 500mA. the problem is that in my place we have intermittent power failure, and since ...
0
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2answers
98 views

Can I convert my 3.7 volt lithium ion batteries into a usb charging power bank?

I have several high capacity 3.7 volt Li-ion batteries. How might I convert them into a USB charger for my phone? I'm not interested in the most elegant solution, or if this would be less financially ...
1
vote
2answers
47 views

Is it possible to have a charging unit and output unit connected to a battery at the same time?

I am very new to DIY and electronics stuff, so please excuse myself having little knowledge about this stuff. Here is what I am trying to do: Assuming I have both things (The Converter with USB ...
1
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2answers
67 views

How can the SparkFun Lipo USB charger power other devices at the same time as charging?

How is this SparkFun charger capable of charging a LiPo at the same time as powering other devices? The Set up would look like this: This is what the schematic looks like. Basically, my confusion ...
0
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0answers
52 views

Li-ion Rechargeable Battery maximum pulse charging current

Having a Li-ion Rechargeable Battery, giving a smoothe 1.9A current (nominal average current) requires me to have high inductance in buck filter or in my battery balancing system. Instead I can use a ...
0
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2answers
70 views

Solar Cell to DC-DC converter to Li-Ion charing module, is the DC-DC converter necessary?

I have the following components: 1W Solar Cell (5V at 200mA): http://www.ebay.ca/itm/291435192356 DC-DC Converter (2.5V Vin_min, set to 5V Vout): http://www.ebay.ca/itm/200983543561 5V Lithium Ion ...
0
votes
1answer
35 views

Is slowly charging a battery extending the lifetime? -why

Is slowly charging (like usb: 500mA) a battery of a cellphone/ tablet/ notebook increasing the overall lifetime of the battery itself? If yes: why is it ? Why do LiIon batteries lose capacity over ...
-1
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2answers
41 views

Charging 4 protected li-ion batteries in series

I have bougth 4 protectected li-ion batteries from e-bay ...
1
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2answers
60 views

How to detect remaining capacity in a Lithium-ion battery?

I need my device to have multiple power sources, and connect to different power supplies depending on power availability. Each power source is a different rechargeable, Lithium-ion battery like this ...
0
votes
1answer
79 views

How to turn-on laptop's battery pack after replacing cells? [closed]

After a few years of use, my battery pack finally died. The laptop doesn't even detect or try to charge the pack anymore. So I replaced the cells in the pack for new ones, but that didn't make it to ...
0
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0answers
146 views

Protection Circuit Module for 18650 Li-Ion Pack

I'm planning to build a 7.4V battery pack to power my bike light. My current battery has died as it was left for a long time. It has 4 x 18650 cells in 2s2p configuration. All cell voltages are now ...
1
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2answers
103 views

If Li-Ion battery is deeply discharged, is it harmful for it to remain in this state unused?

It is well known that Li-Ion batteries should not be deep discharged. But sometimes they do discharge deeply. Is it OK for the device to remain in such state for a long time (and recharge again only ...
0
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1answer
65 views

USB powered Switch Mode Li-ion Charger

I want to design a Switch Mode Li-ion charger which uses 5V as input and charges a single cell Li-ion cell. I am referring this AppNote On page 4 they have given the equation to find inductor value ...
1
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1answer
100 views

How are cell failures handled in large lithium battery packs?

In a large battery pack of lithium-based cells for an electric vehicle or grid storage system, how are failed cells handled? Answers to another question indicate these cells are usually hardwired in ...
2
votes
1answer
104 views

Li-Ion battery over discharge protection

I'm designing a Li-Ion battery charger circuit with a bq24702 chip. I will use it with two Li-Ion batteries connected in series. In order to protect the batteries from over discharging, I have to ...
0
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2answers
81 views

Li-Ion 26650 battery holder

I'm going to use 26650 Li-Ion batterys with a suitable battery charger IC in my hardware. I'm looking for an adequete battery holder for two 26650 batterys like this for AA batterys. But I find only ...
2
votes
1answer
92 views

Directly Power STM32 from Lithium Battery

I'm putting together a wireless sensor node and it's running a STM32L051 which can run at a 1.65-3.6v range. I've also got an RFM69HW radio onboard which can run at 1.8-3.6 (2.4-3.6 for full power ...
2
votes
3answers
109 views

How to gauge safety of cheap Lipo batteries?

I see a ton of cheap 12V lipo batteries for sale on Ebay, but other than the mAh rating, I can't find any info or datasheets on how to safely operate them. I'm looking for a good battery to power a ...
0
votes
5answers
135 views

Reducing the voltage drop on a simple comparator driving a MOSFET to avoid LiIon overdischarge

I would like to use a LiIon cell recovered from an old laptop to power my bike light (a bulb one, 2.4W 6V). I thought about using an opamp controlling a MOSFET to avoid overdischarge (MOSFET ON for ...
1
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2answers
200 views

How to efficiently boost a low voltage high current input to a high voltage low current output

I have a 3.7V 6600 mAh lithium-ion battery that I'd like to use to power some small 6V motors that only require 500 mA. However, I need the battery supply to last as long as possible (which is why I'm ...
0
votes
1answer
105 views

How to calculate lithium-ion battery energy density

According to this battery comparison sheet, lithium-ion batteries should have an energy density around 110-160 Wh/kg. Wikipedia cites it may be around 100–265 Wh/kg, although it refers to it as ...
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1answer
165 views

TA/USB battery charging

Apologize if the question seems silly, searched for the answers on google but couldn't get an answer, so please manage to help. I am studying detailed charging process of a smartphone ...
1
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1answer
96 views

How to design a Lithium-Ion battery pack?

I have a project that I am working on that requires the use of a rechargeable battery pack. The major issue I have is that the battery pack needs to be as slim as possible. So far all I could find are ...
0
votes
1answer
49 views

Run multiple charging circuits on the same battery [closed]

I've recently purchased a set of 3.7V 1A Li-Ion charging circuits available HERE and was wondering if i could charge the same battery using multiples of these to get a quicker charge. Is there any ...
0
votes
1answer
121 views

What's the name for this connector?

Recently bought 3.7mAH li-ion batteries on ebay (it's labelled for use with RC toys, but I'm using it for DIY projects). Will need to buy the female adapter. Here are some pics: EDIT: Well then, ...
1
vote
2answers
85 views

Will back emf damage a lithium ion battery?

I am prototyping a battery-operated toy containing a couple of motors - these motors are driven by a pair of h-bridges which are controlled by a micro controller. I'm running this whole thing from a ...
1
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2answers
209 views

Voltage drop when measuring battery capacity

I'm trying to build a battery capacity tester for Li-ion batteries. I made this schematic using Arduino: While bush button is not triggered arduino only shows battery voltage on Serial & when ...
0
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3answers
534 views

Replacing 18650 cells in laptop battery with greater capacity ones

My laptop battery died and I can't find a replacement (old laptop) so I'm going to need to replace myself the 18650 cells it has. It is an 8-cell battery (a series of 4 banks of 2), making the whole ...
0
votes
1answer
152 views

Li-Ion charging ic with 5V input and battery voltage between 3.9V and 3.6V [closed]

I am currently in search for a battery charging ic that has a variable output voltage (so that I can set it to 3.6V to 3.9V) or a fixed range, similar to what I would like to have. But why would I ...
1
vote
1answer
122 views

How to prevent DC motor from dropping voltage of supply when switching on

I have a circuit which uses an ATtiny85 output to a transistor (S9013), which will trigger a relay that controls a motor. The reason for the transistor to relay is because I do not have a transistor ...
0
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0answers
98 views

Building a UPS for Raspberry-Pi

I am trying to build a 5V/2A uninterrupted power supply (UPS) for my rPi B+ using LM7805 and some phone batteries (3.8V/0.5A and 3.7V/2A) or any of the 6 pcs 18650 batteries (3.7V/2A) that I have ...
0
votes
3answers
256 views

Relay not switching correctly, controlled from ATtiny85, output to motor

I have an ATtiny85 switching an NPN transistor, which will in turn switch on a relay that will run a motor. Everything is run off a 3.7V 18650 Li-Ion battery, but I have since moved over to a variable ...
0
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3answers
185 views

ATtiny85 to control a relay, which will turn on and off a motor

I am trying trying to control a 5V relay (SRD-05VDC-SL-C) with the ATtiny85. I have a simple sketch uploaded (Blink without Delay example): ...
0
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2answers
123 views

Low voltage cutoff circuit

I'm powering an attiny45 from a lithium ion battery; using these batteries the voltage cannot get below 3volts or it will damage the cell. How should I go about cutting the voltage out? Software, or ...
1
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1answer
291 views

Charging li-ion cell using constant-voltage only

Introduction Various resources [1] [2] state that the optimal method of charging a li-ion cell -- such as one found in a mobile phone -- is to charge at a constant current (usually <1C) until a ...
0
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1answer
131 views

Using LM2577 boost converter to charge the 2S lithium ion battery with an input of 15W at 5V

I am trying to design a Lithium ion battery charger that can charge a 2S battery. The input power will be 15W at 5V. I am thinking of using LM2577 boost converter to efficiently step the input up to ...
0
votes
1answer
95 views

280LM Led Headlamp needs FCC certificate?

Do I need FCC certification for my 280LM Led Headlamp with 1800MAH Lithium battery which is rechargeable only via USB? More details: Watts out: 3W Lithium-ion Cells: 103450 Energy Content:1800Mah ...
0
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2answers
547 views

Do I need a balance charger if i use a Protection Circuit Module for Li-ion batteries?

I'm looking into making a battery pack for a portable speaker system. If I use one of these: ...