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

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2
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3answers
69 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
62 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
62 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
40 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 ...
-1
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1answer
47 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
61 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
40 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
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1answer
115 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
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2answers
64 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
79 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
votes
3answers
161 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
78 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
73 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
votes
0answers
74 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
144 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
59 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
votes
2answers
55 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
vote
1answer
110 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
75 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
86 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
145 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: ...
0
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1answer
102 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 ...
0
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2answers
135 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. ...
0
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2answers
105 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
44 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 ...
1
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1answer
218 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 ...
0
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2answers
96 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
votes
1answer
177 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 ...
0
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1answer
77 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 ...
3
votes
1answer
101 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, ...
0
votes
2answers
80 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 ...
0
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1answer
92 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
votes
1answer
100 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?
1
vote
1answer
96 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 ...
0
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0answers
60 views

Power with Battery + 1wire to i2C

I'm creating a project with Raspberry PI B+ where I will get energy from a truck (12~27v) or/and a solar power (6v 5.6w) to charge a battery and keep the device running until the battery finishes or ...
0
votes
1answer
54 views

Effects of C Rating on Battery Life

A polymer lithium ion battery is rated at 3.7v, 6600mAh and a maximum discharge current is specified at 3.3A. I take it this means the battery can be discharged at 3.3A and last for two hours since ...
1
vote
1answer
80 views

How will unmatched lithium-ion cells in parallel react?

We are stocking a portable power pack for USB charging. We tested them when they first arrived and found no issues but after 3 months we tested some of the remaining stock and found about 50% of them ...
0
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0answers
88 views

Disabling a LiPO balancer when not charging

I'm looking at building a solar MPPT charger / balancer based on combining two designs (I'm not confident enough in my hobbyist skills / ability to not burn the house down to design the whole thing ...
0
votes
1answer
75 views

Drain Li-Ion battery by connecting USB +5V and GND

I have a sportswatch which can be connected to a PC via USB for downloading the training information, upgrading the firmware, etc. I have used those features for a year on weekly basis, but since ...
0
votes
1answer
910 views

3 Cell Series Li-ION charging with TP4056

I've searched my situation but cannot find my exact answer, I am trying to make 3S Li-Ion battery charger with 3 TP4056 Charger Module. TP4056 Module 1A 5V one cell battery charger i thought if i use ...
1
vote
1answer
100 views

Why are 5 Volt 7-8 Amps chargers not available for charging phones quickly? [closed]

Available phone s chargers have either 0.5, 1, 2 Amps rating depending on the batteries (varied capacity) used. Why is it that 7, 8 Amps chargers are not available ? if the limitation is in the ...
1
vote
1answer
60 views

Can I wire 6V power packs in series and still use them as individual power sources?

I have 4 x 1Ah Lithium Ion battery packs. These I have two systems, one operates at 5V (usb) and the other requires 20v - 24v. I'm wondering can I power both the 5v system and the 20v system by using ...
4
votes
1answer
571 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
votes
0answers
65 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 ...
1
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2answers
635 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 ...
2
votes
2answers
129 views

Implementation of coulomb counting

How do I implement coulomb counting algorithm ? Once I read the current using a ADC , what processing do I do ? say for 10ms load draws 1mA, next 5ms it draws 7mA. So am I supposed to just add the ...
3
votes
3answers
227 views

Connecting a higher-current power supply to a lithium-ion charger will damage the battery. Why?

I am not asking how the battery gets damaged, because that answer is straightfoward. What I am asking is why lithium-ion chargers allow batteries to be damaged by excessive charge current in the ...
1
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1answer
2k 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 ...
0
votes
2answers
68 views

USB li-ion charger with usb output

I would like to power my robot with li-ion batteries. The logic is 5V so I thought about something like this http://www.powerstream.com/n-charger.htm. This does exactly what I want - it is charged ...
0
votes
1answer
109 views

How can I regulate the voltage of a Li-ion battery with the least drop out voltage?

I have a one of these: descriptions: full charge voltage : 4.2V cut off discharge voltage : 2.75V capacity : 4000mAh size : 18650 And I want to get 3.3V from it. but the problem is I can't use ...