Questions tagged [battery-charging]

Please specify the battery type in your question. Include chemistry (e.g. lead-acid), voltage, number of cells and how they are connected (series or parallel), capacity (in A·h or W·h).

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89
votes
5answers
238k views

Why are there 3 pins on some batteries?

Lots of new batteries (for mobile devices, MP3 players, etc) have connectors with 3 pins. I would like to know what is the purpose of this and how should I use these three pins? They are usually ...
28
votes
4answers
137k views

How to measure capacity of a Lithium-ion battery

I bought a Lithium-ion battery for a camera (much cheaper than the brand replacement but non unreasonably cheap compared to AAA Li-Ion batteries with similar charge). I however have doubts that it has ...
26
votes
3answers
4k views

Why do batteries recover after a load is removed?

I carry a small 2-AA flashlight, and a few times, I have accidentally left it on in my holder. Each time it dies completely, so that no light is emitted, but if I turn it back off and wait for a few ...
24
votes
8answers
37k views

How do USB charging and “smart” charging ports (e.g. Anker's PowerIQ) work?

Software engineer with a hobbyist understanding of EE here. I've noticed lately lots of claims from producers of USB battery packs that their ports are "smart" and "identify the device" to "deliver ...
20
votes
3answers
9k views

Lithium Battery Protection Circuit - Why are there two MOSFETs in series, reversed?

I was studying a battery protection chip and reference circuit (below) commonly used in cell phone Li-ion batteries, and am confused by the two MOSFETs in series on the negative terminal EB-. ...
20
votes
2answers
28k views

Some advice on charging circuit used in simple UPS

I have looked around for some way of having a 5 volt power supply that acts like a UPS. Basically want to use a micro usb connector for +5 have a battery and li-ion or other charging circuit that ...
18
votes
4answers
4k views

Is temperature the only battery charging speed limitation?

Charging too quickly can cause the battery to blow up due to heat. But what if I cool the battery down? Can I charge as fast as I want, provided that I cool it down sufficiently? Can I enforce ...
17
votes
1answer
23k views

Why charging Li-Ion batteries in cold temperatures would harm them?

Accordingly to what I've found in several sources (user's manual of electronic devices, various forums, e.t.c.) I shouldn't charge my Li-Ion batteries in cold temperatures because this would harm them....
17
votes
2answers
9k views

Why battery chargers take a pair of batteries and not one?

I have a number of AA- and AAA-sized NiMH rechargeable batteries ('accumulators'). All the chargers I encountered allow to charge 2 (4, 6, 8,..) such batteries at a time, but never a single battery. ...
16
votes
6answers
58k views

Is it possible to revive a dead battery by passing a high voltage through it?

I have an almost dead laptop battery and read in this forum that "The problem with most of the broken batterys is that they are exhaustive discharged. the trick to solve this is to give them ...
16
votes
2answers
4k views

Can I safely trickle charge a 24v garage actuator battery with a pair of 12v solar panels?

I have a Hormann Promatic Akku Garage door actuator, since my garage doesn't have mains electricity. Generally speaking I'm very impressed with how well it works. Unfortunately while it lasts around ...
16
votes
5answers
77k views

Powering laptop from 12V sources without inverter

This question has two parts: 1) How inefficient is it to boost 12V to 120V and then back to 12V as in using a traditional car power inverter to power a laptop (i.e. the 12V car battery power is ...
16
votes
5answers
49k views

How long does it take to recharge a car battery after starting?

Assuming a typical lead-acid, 12 V car battery (typically at 13 V or so fully charged), and that it takes roughly 500 A over 3 seconds to start an engine, how long will it take to recharge the battery ...
16
votes
6answers
43k views

Combining and Charging multiple Lithium Ion Battery Cells (3.6 V or 3.7 Volts)

1] Voltage: 3.6V or 3.7V Are all 18650 lithium ion battery cells 3.6 or 3.7 voltsor or are there different voltage Lithium Ion cells in the market as well? 2] Possible Voltage Shortage? Do all 3.6/3....
16
votes
2answers
4k views

How fast can a Li-Ion battery be charged?

So far I've seen many Li-Ion battery chargers that do the full charge in about 1,5 hours or more. There're also NiMH battery chargers that claim they charge a NiMH battery in 15 minutes and then the ...
14
votes
4answers
3k views

Battery chargers that can recharge disposable batteries. How do they work and are they safe?

A few years ago a product called SecondWind appeared, which claimed that it could recharge disposable batteries. To a layman like me that sounded like a great idea, but does such a product really work,...
14
votes
3answers
21k views

Understanding Two MOSFET with sources connected

I am having problem understanding how this MOSFET configuration (used in battery charger) works? In this slide, what does it mean "blocking voltages in both directions while allowing ...
14
votes
2answers
4k views

LiPo vs. NiMH for kid's toy

I've been researching here and on google regarding potential battery technologies for a toy that I want to make for my kids. I was hoping to get others' perspectives on this, keeping in mind that ...
13
votes
3answers
16k views

Measure Lithium ion battery voltage (thus remaining capacity)

What I am working with: I am running my self-made Arduino board (in the sense that I use the Arduino bootloader and code editor) at 3.3V, and powered from a Lithium ion battery, which is USB-charged ...
13
votes
4answers
14k views

Is it okay to keep a mobile phone connected to its charger, 24 hours a day, 7 days a week?

I want to ensure that a mobile phone is always charged, without requiring manual intervention: e.g. disconnecting/reconnecting the charger, switching the charger on/off, et cetera). One idea would be ...
12
votes
3answers
5k views

Takes days to charge phone from 10W solar panel

I bought a small 10 W solar panel which is rated to deliver 570 mA at its peak, according to the specifications: Power: 10 Watt Max. Voltage: 18 Volt Max. Current (Imp) : 570 mA So I bought a step-...
12
votes
3answers
6k views

Extra negative battery cable when charging outside car?

If you go to: http://www.battery-chargers.com/charging_instructions.htm ...Under "Operating Instructions" part "B: Charging battery outside of vehicle", it says you have to attach an extra jumper ...
12
votes
3answers
15k views

Low current battery monitoring

I want to run a micro-controller from a 1S lipo through a 3V linear regulator. I need to measure the battery voltage however. The problem with using a voltage divider is that it would drain the ...
12
votes
5answers
10k views

Parallel charging of lipo batteries, maximum voltage difference?

There are numerous products that enable lipo batteries to be charged in parallel. Most sources are clear on voltage and capacity requirements, which follow pretty directly from basic circuit ...
11
votes
2answers
15k views

Floating multiple sealed lead acid batteries in parallel

I know with multiple lead-acid batteries you should really charge them separately so that one battery doesn't try and charge another and waste power. But that holds true for the main charging process....
11
votes
5answers
21k views

Charging lead acid batteries in series

I recently bought 2 12V lead acid batteries (AGM type) for my mobile music needs where I need 24V, so I discharge them in series. At the moment I charge both batteries separately, which is a bit ...
11
votes
2answers
4k views

Does TI's LiFePO4 CV-free fast charge method reduce cell lifetime?

TI claim that you can charge LiFePO4 cells by CC (constant current) charging as usual but to a higher than usual voltage (eg 3.7V rather than the usual 3.6V for LiFePO4) and then step transition to a ...
11
votes
3answers
28k views

how can I try to revive this AGM deep-cycle battery which started to perform dramatically below specifications?

I have a AGM deep-cycle battery, 150 Ah, 12V: Banner "Stand By Bull" SBV12-150. 12V150AhC20. Up until recently it was working quite OK, I was able many times, for many months, to drain about 170 mA ...
10
votes
2answers
26k views

Can I charge a 12v sealed lead acid with an old wall-wart (not made for charging)?

Will it hurt the battery? If I left it overnight would I run the risk of "exploding" the battery? I have a 7Ah SLA battery that I need to charge, but I don't have a charger and I don't want rake out ...
10
votes
4answers
12k views

How is fully charging a Li-Ion battery in 35 minutes possible?

I happen to own a power drill/driver that runs on a Li-Ion battery and ships with a charger that charges it fully in 35 minutes and claims to charge it to 70% in 15 minutes. According to answers to ...
10
votes
3answers
2k views

Is there any sense in this technique for charging Li-Ion batteries?

This is a replication of this question on Android SE. I feel that it is in fact an electrical engineering question, since it covers batteries behavior in details. Basically there's a claim that the ...
10
votes
6answers
36k views

How to autoregulate a TP4056 for maximum solar power extraction

I'm using a solar panel (6V - 600mA at peak power) to charge a Li-Ion (3.7V) battery using a TP4065. The TP4065 I'm using has this configuration: Where the value of the resistor Rprog determines the ...
10
votes
1answer
1k views

Intelligently Charging and Profiling Lithium Polymer Battery Packs

Lithium Polymer battery packs are widely used in Radio Controlled (RC) airplanes among other things for their charge/weight advantages. These packs typically consist of X series cells and Y parallel ...
10
votes
2answers
397 views

Before storage why should a Lithium Polymer battery be charged up to only 40-60%

While storing a Lithium Polymer battery cell or a device with a Lithium Polymer battery why should we make sure to discharge the battery to 40-60% (and only then put it to storage)? What happens if ...
9
votes
5answers
2k views

Battery balancing circuit

I am facing the following problem. I need to power my device (RC airplane) with 2 separate battery packs 12 V each in order to extend the capacity. Connecting them in series will not work, as the ...
9
votes
5answers
5k views

How much can I overcharge a 4.35V LiPo?

I'm building a charger for a set of LiPo cells. My circuit needs to make sure they get fully charged to their maximum level of 4.35V. At the same time, the circuit should protect the cells from ...
9
votes
3answers
1k views

NiMh or LiPo batteries for unattended charging/usage

I'm in the planning stage of a summer project: A WiFi controlled robot for remotely monitoring a shore home. The robot will consist of a 4-wheel platform (4 motors, 1 A stall current each, 7 V), ...
9
votes
3answers
5k views

How deep should we discharge lithium batteries to maximise their lifetime?

Recently I posted an answer mentioning the very classic "lithium batteries like partial discharges, so design your system for limited depth of discharge". But then I wondered: with partial discharges, ...
9
votes
2answers
65k views

How can I safely charge multiple deep cycle batteries simultaneously?

I work at a car auction and we use deep cycle marine batteries with booster cables attached to hand trucks to wheel around the lot for boosting cars. I've been told by our battery distributor the ...
9
votes
4answers
58k views

Voltage input for charging NiMH Batteries

I have 12 AAA NiMH batteries(1000mAH and 1.2V per battery) and I want to know what is the optimum voltage for charging them. I am using a simple Constant Current charger(LM317 and 68 Ohm Resistor(R in ...
9
votes
3answers
21k 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 ...
9
votes
2answers
967 views

Properly charging and discharging Lithium cells during battery testing?

I'm working on some software that automates charging and discharging battery cells to generate discharge curves. I have a few concerns about properly charging and discharging of lithium-ion / lithium-...
9
votes
2answers
5k views

“Breaking-in” lithium polymer batteries:Is there any research on that?

Well I just got new batteries for my RC glider and I'm thinking about what to do with its battery. For those who aren't in the RC hobby the story goes something like this: New kid buys a battery and ...
9
votes
3answers
67k views

What is the meaning of a battery's “cycle life?”

I started to read about batteries, I am interested in lithium batteries, I found a description regarding the stability and capacity/weight, but I read some unclear descriptions like "cycle." What ...
9
votes
3answers
33k views

Is there way to construct an 18650 battery pack with built-in balance charging? Or is balancing not very necessary?

This is my first post here. Err, I'm a DIY enthusiast especially in electronics. I'm actually building a portable Playstation 2 Slim with an IPS display, so that it would look like a Wii U controller....
8
votes
3answers
6k views

Why some phones need a 5V charger although the battery needs 3.7V only?

I've many mobile (smart phone) chargers. The output of them is 5 volts but the battery needs 3.7v only. Why is it better to make a 5v charger then convert the 5v to 3.7v ? Why don't we just make a 3....
8
votes
7answers
38k views

How do I design a 2A or more power supply for my consumer USB devices?

I understand that many of my consumer devices charged by USB ports can charge at higher rates than 0.5A. However, in testing, I've found they don't consume more than this. Test Setup I have a power ...
8
votes
6answers
4k views

How can a smartphone's extended battery be same size as the original battery?

I know this is kind of a basic question, there might be a few ways to answer it... Recently I found out there is a slim extended battery which has the same size as OEM battery (I mean really same ...
8
votes
3answers
40k views

Extending the backup runtime of a UPS with an external car battery

I'm looking for a simple/inexpensive way to have a longer power backup time. My fist thought was putting 2 cheap UPSes in parallel. But I quickly found it's not that simple. You would need another ...
8
votes
4answers
12k views

Are 4xAA DIY Gadget Chargers Safe?

I've found some Do-it-yourself guides to making a 4-AA battery gadget charger, which are basically four AA batteries connected to a cut up usb cable: http://robotification.com/2007/09/15/diy-usb-...