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

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Charging Li-Ion cells

I have 6 18650 Li-Ion cell from a very old Dell laptop. Unfortunately I could not find any info about them from their markings. They were connected as 3S2P with a total of 11.1V and 4700mAh. ...
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60 views

I want my cellphone battery to remain useful for five years; please advise me on how to achieve such a feat [migrated]

I own an Android smartphone with a lithium-ion battery. I want its installed rechargeable battery to remain at least somewhat useful for five years, if possible. (Other people aren't so careful; ...
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1answer
27 views

Charging circuit for a small capacity (13 mAh) li-ion battery

I got my hands on some of Panasonic's new "pin-type" li-ion batteries – the CG-320. However, I have never had to charge a battery with such a low capacity (13 mAh). Are there charge management ICs out ...
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29 views

Battery testing depth of discharge vs cycles

I am currently investigating the relationship between the depth of discharge of a lithium battery, the number of cycles and capacity lost. I know from literature that the lower to DOD (%) the more ...
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0answers
24 views

Can't MCP73871 directly power a load?

I'm looking at lady ada's PowerBoost which uses both a MCP73871 and a TPS61090. Why is the TPS61090 needed? Can't the MCP73871 directly power the load? If I'm reading it correctly, the design doesn't ...
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1answer
21 views

Load regulation and battery charging

With the MCP73871, the load regulation is 0.08%. Does that mean it expects the battery voltage to increase strictly monotonically? That is, if the device consumes 2000mA at 5V (around 3000mA at 3.7V) ...
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2answers
70 views

Lithium Ion battery charging

Its just a simple Question Lets Say, I have 4 x Lithium Batteries each 6800mah capacity and Lithium Battery Charger IC BQ24618 from texas instruments. Will I be able to charge these batteries ...
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53 views

How to get constant 12v power from a Lithium Ion jump pack

I'm building a backpack portable microclimate system. I have a PowerAll PBJS12000R Rosso Red/Black Portable Power Bank and Car Jump Starter (got it cheap on ebay). I want to get constant 12v power to ...
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1answer
35 views

How to connect Li-ion batteries with thermistor pin in parallel?

I have a Li-ion charger with 3 contacts: (+) (-) and (TH), based on TP4056 chip. I also have several batteries with corresponding contacts, and the charger does a good job charging them. Now I would ...
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46 views

Replace battery with empty/short circuit?

I have a device (Garmin nuvi 765) that can run on external power but which also won't fully boot unless a (reasonably functional, it seems) internal battery is installed. The battery in it has died ...
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1answer
66 views

Lithium battery basics [closed]

I have a few things that I don't get about this battery . In our product, when we connect the lithium battery 3.7V charged, things work, but when it's discharged, ...
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1answer
95 views

Determine SOC of a Li-Ion Battery

My question is how to measure the SOC (State Of Charge) of a Li-Ion Battery. Now i know it is a very common question and i can google it. So i did google it and read about all the techniques for e.g ...
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9 views

Question about Solar Panel and Lithium charging board

I have a 6V 4.5W solar panel which I would like to use to charge my Lithium-Ion batteries. The battery chargin board accepts 4.5-5.5V. Would it still be safe to use it with 6V? If not, should I just ...
2
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1answer
57 views

How do you protect a Li-ion / Li-polymer battery from over-dishcharge?

I'm setting up a power regulation system for a lithium polymer battery, but I'm aware that my LDO will continue to draw current from the battery even after it's fallen below an acceptable level of ...
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1answer
75 views

Reverse polarity protection for LiPo

I'm looking at using the S-8261 for reverse polarity protection. On page 24, it reads R2.. Select a resistance as large as possible to prevent large current when a charger is connected in ...
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2answers
52 views

Arduino remove power if battery voltage is too low

I want to power my Arduino using a Lithium-Ion battery. When the battery is below 3.0V, the power to the Arduino should be disconnected, and when it rises high enough again is should be reconnected ...
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1answer
65 views

Potential safety hazard? [closed]

Suppose one uses a poor 18650 (low quality and without a datasheet) to charge a phone and the phone tries to draw 3A-4A (2A @5V) from it. Would this be hazardous even with a protection circuit built ...
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2answers
172 views

How come 2 MOSFET chips are needed in protection circuits?

Like those here, the protection boards have at least 2 MOSFET chip (AO8814). Does anyone know why so many (4 fets) are needed?
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1answer
47 views

Implementing protection circuitry for a single cell [closed]

I'm hoping to embed a protection circuit for a single 18650 in my device's circuit. No over-charge protection is needed since it won't allow charging - so only protection against over-discharge, ...
1
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0answers
38 views

Could a lipo/18650 overheat during discharge?

Suppose a cheapish lipo/18650 has a typical protection circuit in place, which, e.g., shuts off the battery when voltage gets too low, shuts off the battery when the current exceeds 4A, and prevents ...
1
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1answer
26 views

What's a reasonable threshold for UVLO?

I see that the TPS61093 UVLO is triggered at 1.55V. However, this boost converter has a threshold of 2.6V. Is 1.55V a bit too low for lipo? If so, how come the TPS61093 is designed this way? Thanks
2
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2answers
155 views

How come 18650 Li-ion cells aren't meant to be sold loose?

I've heard that 18650 Li-ion cells aren't meant to be sold loose. They're meant to be built into packs and the "good" manufacturers won't actually sell them for any other purpose. FWIW, there's the ...
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1answer
57 views

Charge Lithium-Ion batteries using a solar panel in parallel

I want to charge some Lithium-Ion batteries using a solar panel with this loading circuit found on ebay here. Apparently it works fine with just one Li-Ion battery, but I would like to extend the ...
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0answers
52 views

Poor man's Li-Ion fuel gauge

I am developing a portable, battery-operated device that needs a coarse form of fuel-gauging: just being able to differentiate between close to full charge, medium charge and low charge would be ...
0
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1answer
72 views

Materials required to convert NiMH rechargeable 24V/6Ah circuit (20 C-cell) to Li-Ion rechargeable circuit

Below is a picture of a battery shell for a NiMH circuit for a power assist wheelchair battery. I'm taking a guess that each of the 20 batteries is 1.2V because the entire circuit is 24V. These are ...
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2answers
32 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 ...
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1answer
67 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 ...
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2answers
95 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
38 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 ...
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1answer
62 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
64 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 ...
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2answers
431 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 - ...
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1answer
49 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 ...
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0answers
35 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
38 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 ...
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2answers
59 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 ...
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1answer
54 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 ...
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0answers
87 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 ...
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2answers
176 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 ...
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2answers
50 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
89 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
73 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
142 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
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1answer
40 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
49 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
93 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
124 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
222 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
118 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
94 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 ...