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155

This page has a good answer: "it depends" The answer is: YES and NO, it depends on the situation. Having a battery fully charged and the laptop plugged in is not harmful, because as soon as the charge level reaches 100% the battery stops receiving charging energy and this energy is bypassed directly to the power supply system of the ...


26

Yes, it is absolutely safe to charge a device with a charger that has more current capacity than needed. Ohm's law tells us the relation between current, voltage, and resistance: I = V / R (current = voltage / resistance) Since the voltage is held constant (5V), the only factor that determines current draw is the load (another ...


20

You're asking the wrong question. You don't plug USB devices into wall sockets: wall outlets provide alternating current (aka AC), and computer devices, including USB, run on direct current (aka DC). What you do plug into the wall is a power supply of some kind -- a switched-mode power supply (for desktop and server computers) or a wall-wart (for laptops ...


18

Note that the USB Specification somewhere says that devices that are only connected but haven't "authorized" yet may only drain 100 mA instead of the usual 500 mA. It could be that your USB Hub simply does not supply the full 500 mA if it isn't connected to a PC, to be in line with the standard. Wall chargers ignore that as they aren't USB devices but ...


18

From a view point of your battery's health you should keep the laptop plugged into the wall and unplug the battery from the laptop. Not because of over charging or whatever, but because of the heat generated by the laptop. By removing the battery it will be cooler, which is good for the battery. If you were to unplug the laptop from the wall, you would ...


17

For lithium-ion, it is actually now considered bad practice to completely drain the battery before recharging. NiCd and NiMH batteries need this to be done to minimize their so called "memory effect" - not so for Lithium Ion. In fact, it will actually be harmful for Li-Ion batteries. I quote you this paragraph from this link A lithium-ion battery ...


16

NiCd and Nickel Hydride batteries need occasional deep discharging. Lithium batteries do not suffer from the same issue - and deep discharging can damage them. This article discusses the subject in more depth.


15

This is not a defect or a problem. Your battery firmware or software driver is probably configured to forego charging when the battery is very near to 100%, to save on charge cycles. Rechargeable batteries have a limited lifespan, and repeated charging can shorten it. Charging the battery also heats it up, which can shorten its lifespan. The firmware is ...


11

Check: Transform a USB hub into the ultimate DIY gadget charger I'm talking about a standard USB hub--those little accessories that multiply one of your PC's USB ports by a factor of four, five, six, or even seven. I took a spare seven-porter--the Belkin F5U701 ($20)--plugged its included AC adapter into a nearby wall outlet, and started loading it up ...


11

Apple makes their power adapters (cables) so that they will work worldwide (100-240V 50-60Hz) which means that you only need an adapter (plug) and not a converter. Apple sells a kit with the interchangable plugs for each country, but this isn't necessary and you can use any standard adapter. Have another another look at the power adapter from Apple. Are you ...


10

Applying power to a USB port while the computer is powered off sounds like a method of damaging something. To charge the computer, you need a direct connection to the battery. A USB port won't give you that. The 5V which comes out of the USB is (more or less) carefully regulated by electronics. Electronics doesn't work backwards.


10

I have an EEE PC with an additional charger which I can use inside my car. It plugs into the cigarette lighter thingie that seems to be standard in every car. When on the move, it does allow me to charge my laptop that way. Very practical. But charging through an USB port is only possible at one side of the USB connection, not on both sides. Basically, the ...


10

Shorter answer. Fairly simple question, do USB 2.0 devices charge quicker if they are plugged into a USB 3.0 port rather than a USB 2.0 one. I’m not asking about a specific device I have, I just mean in general. Yes, no and maybe is the answer. While you are asking this question as a general, non-device specific question, the reality is it’s ...


9

Generally no. Most phones will only charge at 500mA (about half of what a DC charger for a modern smartphone outputs) if it detects it is a USB port. The official standard sets USB 2.0 current levels at 500mA and 3.0 at 950mA. It is not uncommon for USB ports to support 1A or higher though, especially on laptops. The problem lies with the phones. Some ...


9

This all depends on the type of material the battery is made out of. Each battery material has different ideal characteristics. Look on your battery label and determine the type of battery it is. (i.e. lithium-ion (Li-ion), nickel-metal hydride (NiMH), nickel-cadmium battery (NiCd), etc. Once you determine which type of battery it is simply google the ...


9

Having just paid over £100 to have the the power board inside my daughter's Inspiron replaced and had the explanation confirmed by the Dell engineer, here is what happens: The power connector consists of 3 pins, 2 are power and earth, the 3rd is a signal line to identify the PSU as a compatible (Dell) unit. If the Laptop does not get the signal, it does ...


7

I'm aware of no computer that can be charged using the USB port. The capacity of a USB connection is only up to 500 mA (milli-Amperes) at 5 volts, or 2.5 Watts per powered port. This is not sufficient to actually run a typical laptop these days. Its worthy to note that USB1.1 ports only 100mA. (Source: our host Jeff Atwood's blog.) In principle you might ...


7

I find it impossible to believe that USB cable can't supply enough current for a device and that for power supply use length of SUB cable can matter. Here's some reasoning why: I'll cite USB specification 2.0. It says that the minimum cable which may be used for USB is AWG 24 cable. If we say that the device has 10% voltage tolerance, it'll need at least ...


7

Sony PS3 AC adaptor I have found it! The amazing PS3 adaptor does the job. It is a full USB host and will charge any USB standards compliant device under the sun! Details After spending weeks going through dozens of generic and not so generic wall to USB power adapters, some of which work with some devices, and some that work with others, the PS3 adaptor ...


7

Based on this article: Use partial-discharge cycles Avoid charging to 100% capacity: why don't you unplug the charger now and then? Or try that software : http://fruitjuiceapp.com/ (Note: I haven't tried it myself...) Limit the battery temperature: make sure your laptop is well vented, and do not forget your laptop in your car during the summer. Do not ...


6

As long the adapter has 5 volt output (which is the usb-standard) you could not damage your device. However, some devices won't charge with those adapters.


6

Computer ports can be Fried if a device uses more than 500mA , chargers range from ~500mA to some higher than 2A. The devices itself use a 5V input, but the amount of current they can need to run (even) or get a charge going, or a fast charge going, is more than the normal computer port can handle usually. Take a device that is designed to power or charge ...


6

How many USB power sources do you have? Do you have a multimeter? Do you have laptop's original power source available or at least its detailed picture? How good are you with soldering iron? What's your budget and most importantly, do you have a plug which goes into your laptop's power port? Also, how much USB extension cables and hubs do you have? I'm ...


6

Your AC power at the house is not "clean" either. I have done this with several laptops without issue, you just need to be sure the wattage output of the inverter is more than enough for the AC adapter.


6

I think a less complicated solution would be charging your phone through an outlet by using the included charging adapter or a powered USB hub. That way you don't have an entire computer running just to charge your iPhone. I am currently waiting to receive my pre-order on 3 TruePower UCS Power Outlet with USB ports so I can plug devices in at night without ...


6

There is another possibility aside from an intentional limit to protect the battery. Laptops often (I can confirm for some Dell and HP models) have a specific signal from the charger, which informs the laptop of the charger's maximum capacity. Sometimes, the wire that carries the signal or the corresponding part of the socket is damaged, and the laptop can ...


6

Your computer's charger and the computer itself will prevent overcharging of the battery. Depending on how your computer's manufacturer set it up, you may actually see it stop charging after 95% or 98%, but most will show it going to 100% and still say charging, even though it is actually running off of the charger but not adding power to the battery. ...


5

In general there is no problem charging your mobile phone over the USB interface of your laptop. Read: ExtremeTech: How USB charging works, or how to avoid blowing up your smartphone I think a usual safety measure is to avoid placing things like passive USB hubs between the laptop and the mobile phone -- particularly, avoid connecting multiple devices on ...


5

I've been trying to find an answer to the question at the top of this page, and so far have not found anyone who has actually measured things. Lots of people say "should" and "might" and "generally" but there is no actual answer. Having the equipment to do so, I did so. I measured the voltage and current coming from my USB power source (more on that ...


5

Your battery could be faulty, and at that age, its certainly under warranty. However, before you find your local service center for the laptop, you should probably try caliberating the battery. If you have the usual thinkpad power control application, its there - otherwise, it seems you can do it from something called one key optimiser. If caliberation ...



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