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

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Rest time for testing lipo cells

My university's student electric racing team has to test a large number (250) of lipo cells before using them in our electric car. Our testing methodology will be approximately like this: ...
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2answers
57 views

How do you tell if a Li-ion battery has a protection circuit?

I bought a li-ion battery off of ebay. The listing claims that the battery has a protection circuit, but a week later, the battery didn't cut out or anything. With a multimeter, it is reading 10V when ...
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61 views

Would this Li+ flashlight circuit be considered safe?

I recently got an inexpensive (~$4 USD) Li+ 18650-powered flashlight from banggood.com, one of my favorite sources for inexpensive Chinese electronics to tear down and hack for fun :) I wanted to ...
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63 views

DIY Powerpack 18650 4s3p 14.8V charging

I plan to make a portable audio system with 4 speakers and a subwoofer which are driven by a 12v TDA2030A 2.1 Amplifier. Everything is already packed in a small enclosure (approx. 30x15x30cm) and ...
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2answers
49 views

charging circuit for Lithium Ion Battery [closed]

I am going to prepare a 12v battery using 3 18650 Lithium Ion batteries in series. As i am new to these batteries, i read some articles about it. But I'm not clear in charging it. Suggest me the ...
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1answer
319 views

What protection circuits do laptop batteries come with?

I am currently using an old lithium-ion laptop battery pack for my portable sound system. The battery seems to work pretty well for its age. I simply hooked up a cable to the positive and negative ...
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1answer
51 views

DIY battery Pack Cell amperage difference

I have individually tested the capacity of ten 18650 batteries with my iCharger 4010. My question is, how much ampacity difference is ok when packing them in parallel ? The following are the readings ...
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26 views

Switch (safely!) between running/charging status with li-ion batteries (18650) in series

I am building a solar robot/car which is going to be solar charged (or alternatively usb, I can't detach batteries to charge with an external charger). I am using inexpensive parts such as TP4056 ...
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2answers
49 views

Can I convert L-ion battery backup to supercapacitor?

I have a RAID card in my home server and the battery went dead. It's a lithium ion chemistry with the circuits to tell the RAID card miscellaneous information. I could buy another L-Ion battery to ...
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1answer
69 views

Many-year-old laptop batteries: safe in my closet? For how long? [duplicate]

I have laptop batteries that are a few years old and lost their charges, but which I've still kept "just in case"*. However, I've heard that letting them lose all of their charges can be dangerous. ...
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1answer
34 views

Power to tool vs duration of larger ah batteries

I have a Milwaukee M18 Fuel 18v LI ion cordless impact wrench. It came with a 18v 2.0 ah 27 Wh battery pack. They also sell a 18v 5.0 ah battery pack among others. When reading online some people ...
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15 views

Safely managing charge of 4s27p configuration

I have qty 108 brand new CJ (brand) FST 18650 2000 mah cells (3.6V nominal, 2.9V min). The goal is a peak 600W charge & discharge pack with 800 Whr. The topology will be 4s (14.4V). Each cell ...
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1answer
97 views

How deleterious is topping-off my Li-ion batteries (phone/laptop) every time they drop to 90%?

I have read recently that frequent top-off charging of my personal electronics is hard on the batteries. Specifically, Li-ion batteries in recent model smart phones and laptops will show significant ...
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2answers
51 views

Why MCP73871 lithium battery charger IC takes so long?

I'm working on a Microchip IC: MCP73871, a very small linear charger for lithium-based batteries. It has very nifty feature: a load-sharing system that gives priority to the load over the battery in ...
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1answer
42 views

Understanding Li-ion Battery(ICR18650-26H)

I trying to use a Li-ion Battery in my project. ICR18650-26H is suitable for my project(GPS data logger) I think. I am having hard time understanding one particular parameter in the specification ...
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3answers
59 views

Looking an IC chip to charge cell phone [duplicate]

I have a DC voltage source (between 5 and 10V) from which I want to charge cell phone with a USB cable. I believe that using a LM317 or similar IC for charging cell phones is not a good idea as most ...
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1answer
59 views

5 volt small UPS design (review request)

I'm designing small 5 volts UPS that would allow me to run on battery or 5V source. If source is unavailable, step-up module takes power from battery. If this 5V source is restored, then this source ...
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0answers
36 views

How to connect capacitors to SIM800C gsm module [duplicate]

I am powering a SIM800C from a 3.7V Li-ion battery. If the battery charge drop below 85% (it still has 4.1V measured without load), the module keeps restarting during startup. This probably happens ...
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1answer
26 views

Re-attaching Tablet Lithium Ion Battery With DC Power Pigtails

Complete electrical newbie here. Please forgive my ignorance. I have a tablet that gets "circuit locked" or something. It refuses to detect the charged battery. It seems to charge the battery, but ...
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2answers
79 views

Should you plug your device in more frequently and wear out the MicroUSB port, or let the Li-Ion battery drain more and wear out the cells? [closed]

I would like to know what advice to give the consumer about how often they should charge the device. I read in this answer (and various other places on the net) that MicroUSB ports are rated for ...
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0answers
51 views

Lithium Polymer battery puff sensing

I have an IoT application which requires > 20,000 mAh of battery capacity. This can either come from a single cell or a number of cells connected in parallel. The device is going to remain unattended ...
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0answers
51 views

Transzorb for MCP73831 USB LiIon Charger?

The datasheet of MCP73831 (a small LiIon charger device) recommends a transzorb on the USB power input (VDD) for input over voltage protection. See Section 6.1.1.2. Absolute maximum ratings for VDD ...
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1answer
129 views

How many battery cells in a smartphone?

Are most batteries built into smartphones (e.g. iPhone) single cell batteries? If so, why might that be?
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1answer
42 views

Peltier and Portable Litium Ion Battery [closed]

I am designing a portable rechargeable heat flask using peltier module at what specifications I should choose my power supply?? I am actually going for rechargeable lithium Ion battery with 12 volt ...
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1answer
72 views

Why do Lithium Ion batteries self discharge?

I've seen some questions about loss of capacity due to internal resistance and oxidation of plates. I've also learned that these batteries have protection circuits. But I'm curious about Self ...
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1answer
172 views

TP4056 Lithium Charger Module issue

Im having an issue with TP4056 Lithium Charger Module. Connected the battery 3.7v 150mah battery. When charging the red led is on but it never shuts off and no charge state is reached even after 1-2h ...
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1answer
64 views

Separating lithium ion cells for charging

I have a large set of circuits to make using Lithium Ion cells for power. The circuit requires ~12V, which is easily achieved by stacking three cells in series, but the charging circuits I've ...
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2answers
69 views

What is the valid capacity ranges of Lithium Ion 18650 batteries?

I'm seeing wildly varying capacities that are seemingly fake on 18650 cells, such as these "9,800 mAh" ones on eBay, but are ~$1 / cell. However, 'genuine' cells from Panasonic and similar name ...
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2answers
174 views

How to connect old 18650 different capacity cells as a 2S2P pack?

recently I've opened up a laptop battery pack and got 6 18650 cells and 2 of them were 0V and other 4 had 3.75V. so i fully charged them with a Imax b6 charger and discharged them at 1.0A to 3V and ...
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1answer
57 views

Discharge Characteristics of Lithium Ion Battery

I am doing a simple experiment to analyse the discharge characteristics of a Lithium Ion battery to see how long it takes to discharge. I have a 12V 4000mAh battery. Once charged, using a voltmeter I ...
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3answers
547 views

Is draining a Li-Ion to 2.5v harmful to the battery?

I am running one of my projects from two 2000mAh Lithium Ion batteries wired in parallel I decided to let the battery run until it died, just once, to see how long it would last. It lasted 25.9 ...
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1answer
55 views

What's going to be more efficient, buck from series or boost from parallel?

I've found many similar questions, and hate to ask something so similar, but my goal is to get usb power (4A continuous) from 4 18650 Li-Ion cells. I'm debating putting them in parallel and using a ...
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4answers
593 views

Running 3.3V MCU from LIR2032 Lithium-ion button cell

Background I wish to power my circuit with a Lithium-ion battery LIR2032 (around 40 mAh capacity). These batteries have a voltage that goes from 4.2V to 3V typically during their discharge cycle. My ...
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3answers
55 views

power micro controller with 7.4V 400mah battery

I want o control a servo with a micro controller and I need more torque so I chose a 7.4V battery. Power my micro controller requires only 3.3V and obvious if I try to power it straight from this ...
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2answers
75 views

optimal mAH 18650 cell required for laptop

Good day I will be replacing my laptop batteries with 18650's, however my question is as follows. Stats : Battery pack = 6 cell (18650 type Li-ion battery) Time : +/- 3-5 Hours if memory serves. ...
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2answers
55 views

Get Li-Ion battery capacity from discharge time (constant load)

I would like to ask if there is some easy enough way to calculate Li-Ion battery capacity if I measure the discharge time with constant load (not constant current!). I have made a "discharger" using ...
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2answers
66 views

Replace Li-Ion battery with buck converter?

I have a remote control for a GoPro camera. The remote runs off a 3.7 v li-ion battery. The remote draws about 100 mA. I want to extend its usability by supplying 12 v power. The camera cable takes ...
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82 views

Li-ion swappable 18650 in parallel - preventing mixing charged&discharged cells

I'm designing a device that has 6 18650 elements (all parallel) in holders, made so that the end user will be able to pop out the batteries when they're discharged and plug in a set of new batteries. ...
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1answer
149 views

li-ion balancing with zener diodes

Would there be any potential problems with the below implementation of a rudimentary li-ion balancing/(overcharge protection) circuit? Would a resistor need to be in series with the zeners? ...
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1answer
59 views

How to calculate how much current can lithium battery provide?

I need to know how much current can produce battery below? And how to increse current and voltage with 2 batteries like this below? Here are some details: ...
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1answer
203 views

Questions about Li-ion battery charger and battery monitor chips

I want to build a system powered by 14.8v Li-po battery pack or mains power (selectable power path). When the mains adapter is connected, the battery will be charged and the system will be powered ...
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1answer
31 views

Using other Lithium based batteries

My question pertains to different types of the Li-ion batteries currently available. ...
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1answer
187 views

Is it possible to use a MOSFET for Li-ion reverse polarity protection when protecting a charger?

I've made a simple charger out of 4 TP4056 modules and 4 18650 sockets. These modules have overcharge, undercharge and overcurrent protection included, but I also want to know how simple it would be ...
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55 views

Balancing lithium iron phosphate / Charge in parallel and discharge in series

I'm trying to make my current project charge with a more convenient barrel connector charger. This also means I want to keep the charger as small as possible. So the packs are wired in parallel to ...
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1answer
90 views

4s2p lithium ion battery charging from USB

I am newby in electronics. I planning to design a 4s2p (3.7 V, 3000mAh) li-ion battery pack and a charger. I want to use TI BQ series (BQ24618) ICs for charging. I know we can charge battery pack ...
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1answer
119 views

Overcharge Lithium-Ion when using charge controller + Arduino Load

I'm trying to determine if I need to rethink my circuit for a solar + Li-Ion powered Arduino. Basically a solar powered module with 3.7V Li-Ion backup for night / clouds (to be charged during the ...
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583 views

How plausible is the claim about a 200 kW battery solution?

Following this question posted on Aviation:SE: Does the ARCA hoverboard violate known limits on small-diameter electric fans? which is related to a hovering board described on the vendor site: ...
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1answer
54 views

Two voltage regulators on same circuit

Would it work if I have a lithium ion battery that's connected to a voltage regulator that's connect to a Raspberry PI then another voltage regulator to a display?
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1answer
85 views

Paralel charging two Lithium Polymer batteries on a MP3 player Colorfly C4

Is it a good idea to replace a built in lithium polymer battery rated: 3.7 V, 2000 mah with TWO x brand new 3.7 V, 1800 mah ...
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1answer
139 views

Selecting a battery for a DIY project

I am building myself a laptop (for fun, I know it doesn't make economical sense ;) ). I have now come to the problem of implementing a lithium battery for it. It will have to power the SBC and the ...