Questions tagged [charger]

A device which controls the voltage and current being delivered to a capacitor or battery.

Filter by
Sorted by
Tagged with
54
votes
3answers
73k views

What is the ideal way to handle data pins D+ and D- on a USB power adapter to be compatible with fast charging on devices?

I have found that many USB wall chargers use a resistive voltage divider to set the D+ and D- pins to a specific voltage, usually between 2 and 3 volts. Other USB wall chargers short the D+ and D- ...
22
votes
2answers
1k views

Solution for adapting to USB current draw limits?

Summary: I'm setting up a USB-powered Li-ion charging circuit and would of course like to draw the maximum charge current possible situationally -- but also want to ensure I don't violate the USB ...
18
votes
4answers
12k views

Cellphone charger has no transformer?

I opened up a really tiny mobile phone charger I have, to see how it is designed. The entire "charger" is integrated into a small 2-pin mains plug, 1 x 1.25 x 0.5 inch, that has an USB socket for the ...
17
votes
3answers
86k views

Using a 12V battery while simultaneously charging via solar panel

I have a couple of 12v batteries that I'd like to use to power a cooling apparatus while camping for several days. I also have a 15W solar panel I'd like to use to top-off the battery. Can I use the ...
13
votes
5answers
11k views

How does a USB 2.0 Wall Charger negotiate current output?

I'm trying to use a mobile phone charger for my projects, and want a high current output. I have read this, however my measurements show something else. Here is a link to the Battery Charging ...
12
votes
5answers
20k views

Converting and Stabilizing output voltage of a dynamo hub

Preface - I don't know much about electronics :P I have ordered a Shimano dynamo hub for my bicycle. I have done a little homework and here are my findings about it: The output of the above ...
12
votes
1answer
984 views

How to power a widget, while the li-ion battery is charging?

I am in need of a way to charge a 3.7V li-ion cell (probably an 18650 type) from a 4.5V - 20V input. That's not a problem, there are plenty of (switching) battery chargers around with that kind of ...
10
votes
6answers
41k 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 ...
9
votes
5answers
3k 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
1answer
13k views

How does a battery balance and protection circuit work?

I am building a 4S LiPo battery pack that I would like to incorporate in a portable speaker project and I need to make sure the batteries will never require maintenance beside replacing them ...
9
votes
1answer
12k views

Why is earth pin absent in phone chargers plugs but present in laptop ac plugs?

Both mobile phones and laptop get dc voltage from ac source for charging.These chargers have transformer for isolation and rectifier + filter if i am not wrong.I guess the amount of output dc and ...
8
votes
3answers
7k 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
2answers
15k views

Why are these USB data lines conned to pull-up resistors?

I recently got a car lighter to USB adapter which I planned to use to charge my mobile phone. Unfortunately, the phone won't charge (and I know that the phone is capable of charging over USB port), so ...
8
votes
3answers
641 views

Name of component on output side cable of a DC power adapter?

What is the name of this component (circled in red) of a charger? What are the uses of this component?
8
votes
2answers
18k views

How can I use two TP4056 with two li-ion batteries, but single load?

I have two TP4056 modules (with protection circuit), which I am using to charge two batteries respectively, off a single power line. The modules are the ones that have charge output (B+/B-), and ...
8
votes
2answers
509 views

What is the purpose of these forks?

I have disassembled a phone charger today and I have found some interesting feature that I do not understand, I have marked it on the picture. Left side of this structure is connected to P1, that is ...
8
votes
2answers
355 views

Wireless Power Transfer for a toothbrush

The general idea is to charge a cordless toothbrush from 12V DC, instead of the mains. I have used a simple circuit that I more or less lifted from a Linear AppNote/Demo manual (DC1969). I would like ...
7
votes
4answers
699 views

Why ship a low power charger with an overkill thick cable?

Today I saw a Sony camera charger that claimed to provide 8.4V/1.7A output but had a cable going to the device being powered with 18AWG (0.824mm2) cross-section and insulation rated at 300V (yeap, ...
7
votes
2answers
2k views

How do snap-on induction charging systems not interfere with device functioning

There's a variety of snap-on wireless charging solutions on the market. For example, this one includes a charging mat and a plastic case that is put onto iPhone. I suppose the winding is in the ...
6
votes
4answers
4k views

Why doesn't my computer USB port break when I plug in a 2A device?

For typical AC to DC power adapters, I understand that the device draws the current it needs from the adapter. If it pulls more than the adapter can supply, this can cause overheating and lead to ...
6
votes
1answer
10k views

What is the function of “Picture tube charger”?

There is a bizzare device called picture tube charger or CRT-Charger. Here I attach the some diagrams of it from a circuit-book. Now, what is its function? what changes it create inside the CRT? ...
6
votes
4answers
21k views

Building a USB charger for camping

I was looking into building a battery powered USB charger for camping. It occurred to me that car chargers are pre-built and run off 12 V. If I made a battery pack out of 8x 1.5 V batteries in series ...
6
votes
2answers
4k views

Critique of my Data logger's Power circuit design

I am laying out my first full device, a fairly simple sensor-data logger, with these specs in mind: I'm running microcontroller and sensor @ 3.3V, with load varying from 10 mA to 400 mA device will ...
6
votes
4answers
4k views

When using a Laptop, is it desirable to keep it charged from the Mains all the time?

While using laptop I usually plug in my Laptop charger (i.e., from Mains power). What is more effective - to keep Laptop plugged in at all times when possible, or some other approach (e.g., running ...
5
votes
6answers
18k views

How to charge Laptop Li-ion Battery cells manualy?

I have received some Li-ion batteries which were originally used in Asus A2 Laptop battery original one and I would like to know if it is possible to charge each cells independently with some device ...
5
votes
3answers
887 views

How to make a voltage multiplier of 1.075

I have an 80v power supply that's rated to put out 18 amps, and I'm planning on using it to charge an 80v battery pack. Unfortunately the pack's charge voltage is 86v, so what I'm wandering about is ...
5
votes
3answers
4k views

Charging phone battery with a lower voltage, coming from a bike charger?

Since travel by bike a lot, and use my phone very often during those trips, I tried designing a USB phone bikecharger that would use my bike-dynamo that also powers my lamp. Yesterday, I did my ...
5
votes
2answers
18k views

What might cause audible noise in an inductive charging system?

I have a pair of Qi-compatible wireless charging pads, and I've noticed that when a device is charging, the pad will emit a quiet but noticeable squeal in a relatively high frequency range. Perhaps it'...
5
votes
3answers
1k views

Why AC supply is rectified first before stepping voltage down?

I have opened one of my phone chargers and was trying to understand how it works.. I found IC MB6F just at AC input which came out to be a bridge rectifier. My question is why AC is first rectified ...
5
votes
2answers
1k views

Detect if connected battery is rechargeable

The device I am building can be powered by USB or 3xAAA batteries. While connected to the USB, the device will charge the batteries. But before charging the batteries, the device needs to make sure ...
5
votes
3answers
7k 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 ...
5
votes
3answers
10k views

Supercap charging circuit for RTC backup on STM32

I'm asking for a reliable/simple/cheap circuit for the VBAT section of a STM32 design, powered at VDD=3.3V, that will safeguard the built-in RTC (based on 32768 Hz Xtall) for like 10 days. Based on ...
5
votes
1answer
11k views

Can I recharge batteries with a normal AC to DC transformer? [duplicate]

Possible Duplicate: Charging 3 AAs in series My batteries charger is not working, but I have an AC to DC transformer that can output different voltages. If I connect two 1.5v (rechargeable) ...
5
votes
1answer
4k views

Dirt cheap NiCad charger

So sharptooth has a question up for creating cheap charger units that uses battery packs to charge a phone: Is designing and producing a dirt cheap charger really that hard? My question is the other ...
5
votes
2answers
3k views

PWM Solar Battery Charger for 192V battery

I bought a solar controller for my 192V solar system that did not work as advertised (instead of MPPT, works with ON-OFF cycles - Chinese ripoff - but that is offtopic).I want to redesign the control ...
5
votes
2answers
702 views

Hacking wall wart as a USB charging station

I would like to modify an old power supply to have a USB A female adapter so that I could use it to charge any device. I plan to split out the power lines from an adapter that is: Input: 100-240V - 1....
5
votes
1answer
3k views

Parallel charge a serial pack, LiFePO4

I have an idea that I am trying to explore. I use 48V headway cell packs to power my various electric bicycle projects. Trying to balance charge a 16s pack can be a problem. I had the idea of using ...
4
votes
4answers
2k views

How do cheap phone chargers charge li-ion batteries?

I read about li-ion battery charging and it requires monitoring for the voltage and current, How does those extremely cheap phone chargers do that? Or Is it just an adapter and the charging circuitry ...
4
votes
3answers
3k views

Charging phone battery with a high current source

I am working on a project which the goal is using some android tablets to show pieces of video file to form a multiscreen. One electronic problem that I have faced is: The tablets should be always on....
4
votes
2answers
4k views

Building an inverter to charge various devices

With all the power outages being caused by Hurricane Irene, I thought it might be useful to have an inverter that I could charge my cell phone with. Plug in battery power on one end, cell phone on ...
4
votes
2answers
732 views

Lithium Ion prolonged lifespan

According to the Battery University, charging a Li-ion cell to just 3.92v is the optimal voltage to avoid stress and lithium plating. Problem is, nearly all consumer chargers focus on going to 4.2v ...
4
votes
5answers
673 views

Detecting HI-Z state of charge controller

I have been building a Li-Ion charge controller with MCP73831. The STAT pin has 3 states as shown below: The circuit I come up so far is this: Is there a way to detect the HI-Z state with another ...
4
votes
1answer
14k views

Is a solar panel clamped to a battery a drain on the battery at night time?

I noticed that in the night time (dark) the voltage measurement on the battery was lower than in the day time (sun), measured with my voltmeter. I'm new to electricity, but that made me assume it had ...
4
votes
1answer
1k views

Can someone clarify how to charge a battery without an off-the-shelf battery charger?

I am a college sophomore studying EE, I am currently working on making a simple battery charger circuit for an integrated device. The device has 3 Li-Ion batteries in series for my motors, and a ...
4
votes
1answer
20k views

How to determine the total number of charges a portable charger can supply for a phone?

According to can a 3000mAh portable charger charge a 1500mAh battery?, it was mentioned that a 3000mAh Portable charger can only charge a 1500mAh phone's battery 1.33334 times. So, how do we determine ...
4
votes
2answers
1k views

How to lay out a schematic for review? Please critique

So, because I haven't posted a schematic for review before, I have no idea how to do it. Apparently, my previous attempt was poor. I got some actionable feedback, but I'm looking for more! I would be ...
4
votes
2answers
2k views

Is using a 50Hz rated battery charger at 60Hz safe? [closed]

What would happen if I used a battery charger rated for 230VAC 50Hz input here in USA where we use 60 Hz? Would it be ok? What side effects may happen because of the mismatch in input frequency with ...
4
votes
2answers
576 views

Verify this charging circuit

This is the circuit I have designed. I want to be sure whether I have designed it properly or not. Here is the Purpose: I am trying to power a Network device 24 hours which requires 9v (600ma). I have ...
4
votes
1answer
14k views

Can a more powerful charger burn something? [duplicate]

I am told that I must use 5V, 1A charger to charge power bank. If I will use 5V, 2A charger then will it burn power bank? Is that possible? \$I = V / R\$ Charger give constant voltage and current ...
4
votes
1answer
5k views

Smart charging circuit for NiMH battery pack

I want to build a solar powered charger for a niMh battery pack to run a microcontroller. What are the fundamentals of building a smart circuit that will not overcharge the battery and will also allow ...

1
2 3 4 5
15