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

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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 ...
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2answers
43 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 ...
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2answers
49 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 ...
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0answers
44 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 ...
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2answers
44 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 ...
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0answers
27 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 ...
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2answers
31 views

Charging 4 protected li-ion batteries in series

I have bougth 4 protectected li-ion batteries from e-bay ...
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2answers
44 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 ...
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1answer
56 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 ...
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0answers
92 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 ...
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2answers
95 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 ...
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1answer
44 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 ...
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1answer
83 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
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1answer
66 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 ...
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2answers
60 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 ...
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1answer
77 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 ...
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3answers
96 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 ...
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5answers
99 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 ...
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2answers
126 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 ...
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1answer
74 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
111 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 ...
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1answer
76 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 ...
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1answer
46 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 ...
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1answer
119 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, ...
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2answers
77 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 ...
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2answers
144 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 ...
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3answers
360 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
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1answer
131 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 ...
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1answer
100 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 ...
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0answers
92 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 ...
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3answers
204 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 ...
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3answers
121 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): ...
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2answers
106 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 ...
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1answer
181 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 ...
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1answer
107 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 ...
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1answer
92 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 ...
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2answers
333 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: ...
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1answer
130 views

Cheap and easy way to power MCU from Li-Ion, and keep it powered during charging

What is the cheap and easy way of powering MCU from Li-Ion battery, with automatic 3.3V regulator disconnect while charging, to properly charge the battery? I've came up with something like this: Is ...
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2answers
198 views

Charging Li-ion batteries in series

Recently, I bought a DC 12300, a 12V battery with high capacity 3000mAh and I got a charger 12.6V and 500mA output. First thing I did when I got the battery, I measured its voltage and it was 2V. ...
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2answers
144 views

Wrong behavior li-ion battery charger

I followed this tutorial to build a li-ion battery charger circuit, I made two circuits (the last one better than the first), but any of them works as expected. Schematics (I copied from the page ...
0
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1answer
47 views

Li-Ion Charging - Constant Voltage Stage

The charging curve for Li-Ion batteries (explained here) has a final constant voltage stage where the charge voltage plateaus and the charge controller slowly shuts off the current until it reaches ...
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1answer
271 views

Arduino and N mosfet lithium battery charging/discharging measuring capacity

I need an Arduino based lithium battery tester that uses N channel Mosfets to switch On charging from and external power source and discharging through a 2 Ohm resistor. I have no issues with either ...
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2answers
128 views

Charging li-ion batteries with protection circuit

If i'm using a protection circuit like this one: http://www.batteryspace.com/pcbfor148vli-ionbatterypack5alimitwithfuelguagesocket.aspx and 4, 3.7v li-ion batteries. Can I use a simple 16.8v dc ...
0
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1answer
280 views

SIM908 Li-Ion charging with 6V solar panel

So, I want to know if I can hook up a 6V 2 watt solar panel to the Vchg pin on a SIM908 gsm/gps module and trickle charge my 6Ah LiPo battery that way. A little background... So, I have completed ...
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1answer
90 views

What is the maximum voltage of a Lithium Ion Battery

My question is about the maximum charge voltage of a Lithium-Ion cell. I have charged my battery pack with 8.4V (the maximum voltage). The pack is a Samsung ICR18650-26F. The pack has a smart ...
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1answer
126 views

Dual smart battery design and PCB layout

I have a system that is powered by a 7.4V Lithium-Ion battery. The system, which is a combination of processor module and sensors, draws a varying amount of current at varying voltages (5V, 12V, -12V, ...
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2answers
88 views

Can I use lithium coin cell battery CR2320 for discharging about 80 mA at 3 V?

I need to use a coin cell battery as a source for supplying 3.0 V at about 70-80 mA for about 2 hr per day. The coin cell battery I want to use, its spec sheet doesn't tell me much about what I want ...
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1answer
124 views

charging 10Ah li-ion batteries in parallel

i'm trying to charge a 5Ah single cell li-ion battery using bq24090 charger controller (up to 1A fast charge current) in parallel with a current boosting circuit. Overall controller should supply fast ...
0
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1answer
125 views

Can I connect directly a 3.7V 18650 li-ion battery to a mobile (cellphone)? [closed]

If I remove the 3.7V battery from my mobile, is it possible to connect to the battery +/- terminals a 3.7V li-ion 18650 battery?
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1answer
103 views

Are there any high energy density (i.e. zinc-air or lithium-manganese dioxide) batteries without high internal resistance?

For my wild life camera, I want a small cell that can provide 0.5W for 8 hours or more. It doesn't seems rechargeable lithium ion batteries have that energy density. I don't mind if the cell is ...