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On February 13, 2019, Geoff Matthews wrote:
I have two sets of bluetooth headphones each with a USB C port on their battery cases, if I go C to C from my laptop (lenovo with thunderbolt 3) or my multi port charger (anker USB-C PD) or my larger battery pack (also Ankter USB-C PD) neither of them charge. If I use the Laptop USB C power supply they do charge Why is this?
On December 24, 2018, Nick Bernardo wrote:
grateful for this site an all of the experts here! I'm looking to make a device that charges an 18650 battery and an Ipad Pro at the same time through a single port (magcharging/usb). Can anyone give me any advice or help point me in the right direction? Will I need a custom PCB for this? I’m very appreciative of any information and help. Thanks.
On August 27, 2018, Andre Van den Wyngaert wrote:
to NK: your player and old charger are for 3V, so the 5V you apply now can be too high and might damage the player. You can add 2 pcs 1N4001 diodes (very cheap) in series. They will reduce the 5V with 0.7V each, so that leaves 3.6V. 'In series" means you need to cut the red wire inside the USB cable and solder the diodes in between: wire - diode - diode - wire, all in a row. The diodes only allow current in one way, so if you mount them the wrong way it simply won't work; no harm done. Mount them the other way then. White line on the diode means current out; other side is current in. regards, Andre
On August 27, 2018, Andre Van den Wyngaert wrote:
to Dean: you need 5V on each USB connector. The phones will take care of the current they will draw. If you don't connect anything to the data lines in the USB connectors, the currents for each phone will never be higher than 500mA. You can make one 12V-to-5V converter, and then simply put all USB connectors in parallel. That will work. If there are 4, you need to take care that your 12-to-5 converter can deliver 2000mA. A switchmode converter will do that, and will give you 90% efficiency or more. (2000mA at 5V = 10 watts; this will draw 926 mA from 12V if efficiency is 90%). A cheaper way is to use low-cost linear "7805"-type regulators. They can handle 1 amp. They have an input pin for +12V, a ground pin, and a +5V output pin. In that case I would use one per USB port. If the current is 500mA at the USB port, it is also 500mA from the 12V battery, since it is a linear regulator. That means the regulator itself will dissipate 500mA x (12V-5V) = 3.5 watts and it will get too hot if not screwed against a heat sink. The metal mounting tab on an 7805 is ground, so you can all screw them side by side without isolation on a piece of metal or a nice heat sink. Good luck! Andre
On August 27, 2018, Andre Van den Wyngaert wrote:
to Arthur: Since your solar panel delivers 5V (USB) and your lead battery is 12V, it won't work. You would need a small step-up circuit to increase the 5V to 13.8V. Then you connect the battery, and it will trickle charge and you can keep it connected forever. Only watch out that no current is drawn when it is dark. Andre
On July 13, 2018, manny ares wrote:
Did you answer NK's question of June 1, 2018? If so can you please send me a copy?
On July 11, 2018, Arthur wrote:
I’ve done a few solar installations in my RV and have a spare 21 watt solar panel with USB out for charging small devices. I’ve also got a small 2 amp water pump. I’ve used the pump to water plants by attaching to a 12volt 18ah Bicycle battery. So...I’m thinking...using the 21 watt panel...plug in a usb to alligator clip connector to the 12 Volt 8 ah battery to trickle charge it. I use the pump/battery system for maybe an hour to no more than 2 hours a week. Is there something I’m missing other than charge controller. Thinking controller not needed as it’s a trickle charge that I can keep track with multimeter and unplug. My big question is would this setup deliver a trickle charge to the battery or am I missing something?
On June 5, 2018, Dean wrote:
Hi I am building a USB loading station for 4 smartphones that is indirectly powered by a solar panel through a 12V lead battery. For the lead battery, I have a battery charge controller, that keeps the voltage for charging at the right current with build in protections. But from the lead battery trough usb ports to the smartphones i have some trouble designing the right configuration. Because how can i control the amperage/voltage through the usb to be the right, and what is the right amperage (1000mA and then it will be tuned down further by the smartphone? or 0.3C sow 600mA?) . And does every usb then needs its own regulator? or can you build them in series (what if one is only in operation?) I cant find any standard components for this like the 12V charge controllerSo what type of USB port should I use to charge the mobile devices?. Thanks in advance.
On June 1, 2018, NK wrote:
I'm trying to power/charge a minidisc player using USB rather than using the old power adapter that came with it (which is broken). The original power adapter provided an output to the minidisc player of 3V at 500mA. I have found a mini barrel to USB cable which fits the minidisc player and plugging it in appears to work however I'm concerned I may be doing damage to the player since my understanding is that USB is only capable of providing a minimum of 4.5V. Unfortunately I can't find any documentation for the minidisc player which highlights the tolerances. I'm very grateful for any advice. Thanks.
On January 5, 2018, ej wrote:
Thanks for this site! I've searched multiple places but can't find the answer to my following questions: when charging a device (phone or tablet) via USB sleep and charge (plugging the device into a desktop or laptop), does the power come from the desktop or laptop's battery, or does the power come from the power outlet? Obviously, if the laptop is NOT plugged into an outlet, then it must run by battery, which means the phone or tablet being charged is drawing power from the laptop's battery. What if the laptop (or desktop) is plugged in? The answer to these questions have important implications for a laptop's battery life because if USB charging uses laptop BATTERY power even if the laptop is plugged in, then the laptop battery life will eventually decrease. I like USB sleep and charge because it seems like a more gentle method of charging, but if it 1. uses the same amount of power as plugging my phone or tablet directly into the wall (does anyone know the answer to this??) and 2. causes a computer or laptop battery to work harder and eventually shorten their battery lives, then is USB sleep and charge a gentle method of charging? Or should it be avoided? Thanks!
On October 8, 2017, Juan wrote:
Andrew, when you charge your phone with a charger or through the USB port of your computer, the phone through a voltage control circuit is responsible for powering the battery, thus controlling the current and voltage that the battery needs, a Once the battery is charged at 100 this circuit cuts off the voltage supply so there is no overcharge in the battery. regards
On July 26, 2017, Gokul wrote:
I need to charge my power bank (13,000mah) how long it will take by using my accer laptop USB port I need to know pls reply me via Gmail, Bcas my charger got failure I can't use my charger after this
On May 29, 2017, Matt wrote:
I have looked everywhere for an answer to my problem but unfortunately have been unable to find one. I have an electric bike with a micro usb port on the display. This micro usb port puts out 1 amp at 5 volts, but I have been unable to find a cable that can transfer more than 500mA to my iPhone. I need the full 1 amp for it to charge. Please help me if you can, you can email me at firstname.lastname@example.org Thank you, Matt
On April 7, 2017, Prodigit wrote:
Hi Robbie. You have to check battery fluid levels. If the levels are good, chances are your battery is ruined. You need to change lead acid batteries every 2 years or so. If you think it'll still work, then just buy a car battery trickle charger. They go on Amazon from like $10-15.
On April 7, 2017, robbie wrote:
hi i have a 12 volt k-cell sealed lead, rechargeable battery that is dead and i would like to make a charger for it. or possibly might have one but i have no idea what im looking for. or what exactly would charge it fully. any help would be appreciated. thank you .
On March 27, 2017, Andrew wrote:
Hi, If I'm charging a phone via a computer's USB port, does the computer's USB port know when to stop charging (by sensing battery voltage) or will it always supply 5VDC regardless of what the battery percentage is? How does the phone stop charging? I just want to know if it's the phone that switches to trickle charging or the USB port that does the switching. Thanks
On March 4, 2017, Silas wrote:
Hi, I have 3.7 V , 520 mah recharable battery for RC toys...when i connect it with the usb cable and charge it the lead light from usb does not go off ( after more than 80 minutes also ) required duration ...when tbe battery is placed in toys it does not work ? tried jump stating the battery with 12V dc adapter..still it does not work ? the volts in it is too low ...it it possible to fix the battery ? Please guide.... thanks
On March 2, 2017, vicky wrote:
I have constructed a small solar charger with output 5V, max 1000mA. While charging a power bank (li-ion, 3,7V), it delivers 4,65V and max 750mA. Am I damaging its battery? The charging current is VARIABLE - because of moving clouds etc. from 40mA to 750mA. Is it OK?
On October 8, 2016, ProDigit wrote:
Make some article about using a 5V USB plug to extend laptop battery life. I have the EEEPC901, and my battery life is about 6 hours. I know by connecting a hub to it, that powers an external harddrive, or printer, I can supply power via an external port. However the laptop (or netbook) by itself without apparatus attached, does currently not benefit from connecting to a 5V USB charger port. I want to see if my 6 hours could possibly be extended to maybe 7hrs, by providing a constant 5V 500mAh to the laptop, relieving it from some power demands (eg: wifi, SD Card, bluetooth, audio jack, or screen. The CPU might decide to drop providing voltage to the USB port, since the voltage is higher than usual (maybe 5.1V from the charger), essentially perhaps telling the voltage controllers to cut USB power completely as the external USB charging voltage might provide enough to relieve 1 USB bus/hub. The math behind this? The battery connected is a 19V, 6000mAh battery. This equates to about 96Wh, spread over 6 hours that's 16W usage (each hour). The charging voltage and current are: 5V, 500mAh gives 2.5W. 2.5W added to 16W = 18.5W, should extend the battery to: 6 * 18.5 / 16 = 6.9hrs. I know that the laptop probably won't get the full 2.5W benefit, but perhaps it gets a percentage of the supplied power, and extends a bit more. In worst case scenario, the provided USB voltage is lower than the laptop, and the laptop would be providing the charger with power. In this case it would drain. But most of the times, a laptop in power saving mode, should have a lower voltage on the USB port, than an AC charger port. Any comment on this?
On September 6, 2016, Nicholas MacNaughtan wrote:
HI I have a PCB board that requires a Mini USB for power, however i was wondering if i could use some wires and connect a Micro USB instead also the Mini USB has 2 rows of pins 3 on the first row and 2 on the second I can't find a diagram showing what these connections are please help quite new to this. regards Nick
On August 23, 2016, JHANE wrote:
I wonder because my Globe wifi was damaged. Its not charging anymore through Honda City 2016 model. I used dual USB cord socket. I went to Globe center to check my battery but my battery was okay. We used another Globe wifi but the problem still happened. Upon charging to dual USB port my wifi didn't work anymore. Even I try to charge to another power supply, I can't use my wifi anymore. Please help how can I solve the problem.
On June 2, 2016, Lyn wrote:
I'm looking at buying an mp3 player but I won't often have access to a computer to charge the mp3 via a computer USB. Is it OK to use an USB that is plugged into the mains power of a house? (I'm obviously a novice, your information is good for those who know a lot more than me).
On May 26, 2016, Abdul Rauf wrote:
Hi, I am using Iphone 5, i got a situation with its charging. Whenever i charge the phone with usb 2.0 it charges smoothly even when screen is off. But whenever i charge the cell with either 1A charging adapter or 2A, it stops charging when the screen goes off. It only charges as long as screen is kept on. I even replaced the battery but the problem still exists. While charging with adapter and screen is off it starts discharging after sometime. Any ideas whats the problem and how to overcome this?
On May 13, 2016, prem thapa wrote:
I appreciate a lot for this great article. But i am confused about USB charging. How can we make the current flow from 5V USB to a battery bank which can supply 5V to peripheral(s) ? is there any logic/technique which can make current flow from 5V to 5V ? dont we need a small voltage difference to make current flow ? i guess current flows from higher potential to lower potential. please, anyone give me some idea.
On February 21, 2016, Laura wrote:
Great article! It helps me a lot especially the clear context about USB charging and standards. What makes me surprised is that you keep information updated and even including USB type C and Power Delivery in this "Battery-central" blog. It's amazing and thanks a lot.
On November 18, 2015, paul wrote:
Since ATX power supply can provide 5V line with higher current than 0.5A, would it be safe to splice a ATX molex cable with a micro-USB and use that to charge a high-demand phone/tablet?
On October 10, 2015, Larry Becque wrote:
Take a look at the article at http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries The voltage limit is very critical which is why charging circuits use both CC CV techniques. Over-voltage will either cause the battery to explode, catch fire or shorten its life.
On October 9, 2015, Jon wrote:
I´m sorry, I search through BU chapters and articles and found many pieces of useful information. No need to answer my former questions... I´ve never seen so professional and accessible web like BatteryUniversity so far, thank you for it!
On October 8, 2015, Jon wrote:
I need to clarify - now I´m using LM2596 circuit without the CC CV ability - this type: http://www.ebay.com/itm/LM2596-DC-Adjustable-Step-Down-Power-Module-LED-Voltmeter-USB-2-54mm-Needle-/161025990411?hash=item257de59f0b So the whole solar charger is a solar array 10V/1000mA and this LM2596 step down regulator with voltage regulated to 5,0V.
On October 8, 2015, Jon wrote:
Larry, thanks for your response. Do I understand it right that for charging a li-ion battery I need this CC CV circuit and the LM2596 circuit I´m using now is suitable only for DIRECT powering other devices? And still - am I harming the battery by charging it without CC CV module at 4,65V - 5,0V? And how? What´s happening inside the battery while it is getting harmed when incorrectly charging? Well - I haven´t read all the articles on batteryuniversity so fat, if it´s there, please just tell me and I´ll look it up...
On October 7, 2015, Larry Becque wrote:
Jon, There needs to be a CCCV (constant current, constant voltage) battery charging circuit between the USB port and the battery being charged. This will limit the voltage to no more them 4.2V during the end of charging. Same thing with the solar charger. Take a look at: http://www.ebay.com/itm/5A-Lithium-Charger-Step-down-5A-5V-32V-0-8V-30V-Power-Supply-Module-LED-Drive-/141249782084?pt=LH_DefaultDomain_0&hash=item20e324a144
On October 6, 2015, Jon wrote:
1) Well but the li-ion battery has a "Charge limited volts" specification at 4,2V +- 0,05V. If USB ports have output 5,0V and cca 350mV are losses, it is still cca 4,65V. This is not a problem for the smartphone battery although it has a 4,2V limitation? 2) I have constructed a small solar charger with output 5V, max 1000mA. While charging a power bank (li-ion, 3,7V), it delivers 4,65V and max 750mA. Am I damaging its battery? The charging current is VARIABLE - because of moving clouds etc. from 40mA to 750mA. Is it OK?
On September 10, 2015, Drake wrote:
Great article! I was just browsing and looking through some usb port related reviews coz a friend was convincing me to buy one of these USB Sockets. Has anyone here tried one of these? My friend bought it from here http://usbsockets.com.au/ . What do you guys think?
On June 10, 2015, Rana G wrote:
i have phone 3gs mere paas iska charger nahi hai siraf iski aik lead hai jo kay laptop se bht slowww charge ho rahi hai tofrndzz kiya koi mujhay bataae gak me laptop k usb port ka vault barhane kliye kiya karu thanx plz reply.....
On June 1, 2015, PeteTy wrote:
Orlin: some devices dont have charger/maintainers/conditioners ie plug it in to charger if charges to full then turns OFF my kindle charges from the 2a charger in about 2 hrs or 4 hrs from usb port the led goes from yellow to green now if you go back in a week or month the led is still green... but if you unplug it at turn it on its obvious it NOT a full charge plug it back in and the light is yellow it turns green again when it reaches "full" charge it will remain green until its unplugged a week, a month or year later later and the battery may run down enough so it cant be recharged (Li-Ion)
On June 1, 2015, PeteTy wrote:
Larry the answer is yes IF both the usb and the device working are functional "For-Phone-MP3-4-/400896416020?var=670439291743&_trksid=p2056016.l4276 The first time I used the car charger to charge it started smoking heavily within a few minutes." the older12v to 5v regulators are usually shunt based (ie 7805) these can fail to a short and get the full 14.2 volts to the device you are trying to charge. if the car battery cable is loose and the car is running, you may get far higher than that 15V at the cigar lighter the new regulators are commonly switch / chopper based ie on/ off 5/12 which only dissipate heat from the ir drop in the switch but both ways can fail to a short. giving the full 12v nominal voltage the cigarette lighter is fused at 40a nominal 14V or so and can set most anything on fire especially a 5V device some of the european/american power adapters for 220V to 120v use a diode to change 220vac to 120v dc that will run ac devices that are NOT transformer based a transformer look like a dead short to a dc source... an induction motor is also a direct short on dc most small hand tools are dc motors with brushes (universal motors) true dc motors the poles are solid iron rather than laminated any source of electric power that is properly wired and fused is made to keep the house wiring from setting the 2x4 studs on fire if they run over current
On May 31, 2015, Larry Becque wrote:
This article mentions “Can I cause damage by plugging my device into a USB charger that delivers more current than 500mA and 900mA? The answer is no." While theoretically this statement may be correct, I have a practical example that disproves this. I have been using a 2.1A rated USB car charger to charge my phone for months. http://www.harborfreight.com/universal-usb-car-adapter-61546.html It charges much faster than another that I had with a lower 500mA rating. No problems charging the phone at all. Then I bought two USB power banks which are rated 2A for charging input and 2.1A output. http://www.ebay.com/itm/5V-2-1A-USB-Power-Bank-Case-Kit-4X-18650-Battery-Charger-DIY-Box-For-Phone-MP3-4-/400896416020?var=670439291743&_trksid=p2056016.l4276 The first time I used the car charger to charge it started smoking heavily within a few minutes. It was so severe I thought the batteries may have caught fire so I took it apart and discovered that an IC chip on the PCB had burned completely. I noticed afterwards on ebay comments from other sellers of similar devices that if you plug them into a car charger that doesn't limit power they will blow and they will not warrant replacing the unit. I've used the second power bank now and charged it with a 2.1A rated USB AC wall adapter charger with no problems. So I conclude that there is definitely a problem with current not being limited, but not sure which device is at fault, the car charger or the power bank. Both devices work fine with other devices, but not with each other.
On April 20, 2015, jayvl wrote:
The wording at the end makes it seem like USB 3.1 allows for 3A charging on the 5V line, concurrent with data. This is not accurate, it is the c-type connector and the PD2.0 specification that allow this--according to wikipedia. So a normal USB 3.1 A-type connector should still follow the PD1.0 spec and not be able to charge faster than 2A. Also the A-type and B-type connectors have 9 pins in USB 3.0, not 4.
On April 16, 2015, mihvoi wrote:
@Irelia : it could be the cable resistance or the negotiation: http://meaningofstuff.blogspot.ro/2015/04/why-my-smartphone-is-changing-very-slow.html
On January 26, 2015, Joe wrote:
I recently bought a Sylvania portable dvd player for a trip for my wife and I. I'm just curious if anyone knows if the USB port will charge the battery without damaging it? We have two 7 hour plane rides and the battery wont last that long. I was thinking of buying one of those speaker/usb charger things but I want to make sure it will work first. any info would be GREATLY appreciated. Thanks! Jakarta311@eatel.net
On January 12, 2015, Bhanu pat. wrote:
Can a u.s.b charger be used in place of 5.5V panasonic cordless phone charger?
On December 11, 2014, tucker wrote:
actually the usb port is not uni-directional, I've used it for both directions in multiple electronic projects
On December 8, 2014, Orlin wrote:
Follow-up on my above comment - with the phone switched off, the battery charged up to 57%, then went down to 56% charge, and went on an on like that. I disconnected it and switched off the phone - the battery index was still at 56%. After reading some more (quite a helpful site - thank you for the effort), I have one possible explanation - due to the constant (every 10-20 sec.) port switch off (see item (3) in above comment), the battery has performed great number of mini-cycles (more than 1000 in my calculation), which in turn has distorted its gauge. Any other explanation will be greatly appreciated. Also any advise how to get the gauge back to initial state. Thank you.
On December 8, 2014, Orlin wrote:
I have a query - I tried to charge a smartphone (with original 1000 mA charger) through USB port on my laptop. The charge went up with good speed to about 50%, then it stalled at about 53%. Half an hour later, when I checked, it showed 46%. I switched the phone off, and then it started to go up again. Three more points - (1) I have been using an older USB cable (not sure if that matters, not the original one); (2) during the charge I also used the laptop for browsing and running live stream; and (3) when the phone was switched on, the WinXP would find the 'new hardware' every 10-20 sec. (I presume the phone drew too much power and WinXP shut the port off periodically) My query - if the USB port is unidirectional, how could the battery dis-charge during charging. Could someone explain, please?
On November 25, 2014, PeteTy wrote:
#20 wire is 10.1 ohms per 1000' this is about the largest you will see in usb cords if the cord is 5' long thats 5'out and back for 10' total .1 ohms for the wire e=i*r i=1amp you start with 5 volts the most you get at the end of the cord is 4.9v with 2 amps its 4.8v about 4% voltage loss power is I^2*R with 1 amp youve lost 0.1 watts with 2 amps you lose .4 Watts multimeters in the digital age imply killohms 3 1/2 digits th ohm i a 1 or zero the old analog ones you had a zero and perhaps 5 ticks until you see a 1 and a knowb to set the zero on zero ( negate the loss in the test leads) if you can measure the resistance of the cord you can find the voltage loss for any particular current or you can measure the voltage at the charger and the voltage at the "powerbank" and divide to find the resistance ethernet Thicknet #10 wire(rg8) is good for about a mile ethernet thinnet #16 is good for 700' ethernet with twisted pair telephone wire is good for 300' USB is good for 15' do the arithmetic
On November 24, 2014, Irelia wrote:
I wonder if the cable itself makes a difference. For some reason my powerbank charges with my tablet charger + the cable that came with the charger significantly slower than with the cable (which feels rather cheap) that came with the powerbank. the tabletcharger has 1.4amps so the cable should be designed for it right? I even checked it with a multimeter, the current is about 33% higher with the cable of the powerbank. with other devices like my tablet and phone which also charge at around 1 amp the cables make no difference. Tried it several times, always the same problem. also all cables I tested have got all pins connected (plus and minus, data + and -, and of course ground) and are all USB 2.0 cables.
On October 29, 2014, Ron wrote:
I use an iPhone as a GPS distance finder while playing golf. The battery on the iPhone dies before the end of the round as GPS uses a lot of power. I have tried wiring the red and black wires of a USB cable directly to the golf battery (26AH) but it provides no charge current to the iPhone. Am I missing something?
On October 10, 2014, vishnu wrote:
can anyone pls tell me if the small usb charging port found in mobile phones are unidirectional or bidirectional in terms of power flow by design??
On September 13, 2014, PeteTy wrote:
@ibattery the ipad regulates the charging so absolutely no problem the usb supplies 5.0V Li-ION can go to 4.5v or so without damage some usb chargers and hubs are rated 3-4A some motherboards dont monitor current so can be 70A-120A
On September 13, 2014, iBattery wrote:
My iPhone charger is 5V 1A, which is a 5W. iPad charger is rated as 5.1V 2.1A 12W. If I use iPad charger to charge my iPhone, would it cause problem? With 2.1A, would it pumping in too much current to the battery. Note: iPhone battery is around 1400 mAH.
On August 25, 2014, PeteTy wrote:
@jerry perhaps the fone jammers should a 10 ' bubble beyond the car ive seen people reach across the seat or into the back seat to roll up windows and slap kids around ... a minor thing like rolling down a window and holding a fone 3' away is not a deterrent even if a cop should notice Italy fines anyone with a cell fone in a public building concert or movie with cell fones ringing is kind of annoying but still it didnt help a lot no most concert halls and librarys and court rooms have jammers cell fones are UHF a few 10s of milliwatts with a line of sight range of under a mile walkie talkies in a GIjoe play set are 1/4 or 1/2 watt with a range of 3-5 miles cb car radios are limited by law to 5W an lower frequency HF so can skip around the globe most truck stops sell CB linear amplifiers from 100 to 2000 watts laws do nothing jammers work
On August 12, 2014, Jerry wrote:
@PeteTy Couldn't agree more about the mobile phone jammers. Quite right that they should be illegal. I used to work as a car delivery driver, when mobile phones were still pretty much in their infancy, but even then then influence it was having on the safety, or lack thereof of driver yacking away - more often gesticulating wildly whilst doing so. I understand why it wouldn't be practical to jam the entire car, as there could be passengers that it would affect as well, but to work on devising a jamming 'bubble' in the driver's section & making that a compulsory attachment would be ideal.
On August 12, 2014, PeteTy wrote:
@Jerry yes using a usb port to charge a LiIon battery to run a heater that delivers nicotine kind of like any auto safety ignores the fact that more than 1/2 the fatalities involve booze drugs or cell phones ( DWI impaired includes cell phones) ONLY someone like FORD has the resources to pull this off if you remember the most rollovers of any vehicles were ford broncos Firestone took the hit for that we need Gun control since as many guns are involved in injuries an deaths in a year as cars in a day a lot of new cars have blue tooth they would be safer with cell phone jammers and legal in 44 states that is to say cell phones while driving are illegal in 44 states
On August 12, 2014, Jerry wrote:
@PeteTy After a few re-reads I think I may now understand the relevance of the comparison with safety.
On August 12, 2014, Jerry wrote:
@PeteTy Sorry if I misunderstood how the system worked here. I was just under the impression that the general subject matter was meant to be batteries (USB charged or otherwise), and I was confused as to where the subject of tobacco came from.
On August 12, 2014, PeteTy wrote:
@JERRY usb is a source of 5V to charge/power many devices USB is actually a serial communication protocol with a small power source since USB is on all sorts of things from cars to tv's to phones to picture frames it is universal, more universal than actual mains power "USB batteries" is an unfortunate oxymoron used to start the thread this "thread" does not have a tree from the original article most unorganized "threads" such as this one that dont reply to specific questions you may put @JERRY on top to help the not thread organized reply system become somewhat organized the shelf at the library has Dewey decimal PDR is next to aromatherapy Innumeracy is in 510[math] it belongs in psychology or religion not math
On August 12, 2014, Jerry wrote:
And this has what to do with the charging of USB batteries?
On August 12, 2014, PeteTy wrote:
@PETE KAY drug dealers supply their poisons to their victims with absolute disregard to the victims health or well being The tobacco institute is an organization to maximize profit they have managed to get surgeon generals fired at least 9 times and have many congressman paid off Dont expect nicotine delivered by patches pills gum or ecigs to be any safer to you as an addict (these are also higher profit items) burns and shrapnel damage are quickly treatable and curable (perhaps a wake up call) The addiction to nicotine is also curable but may take years. it is well worth the investment and will be much better and less expensive in the long term
On August 12, 2014, PeteTy wrote:
Most Li-ION battery packs have rather sophisticated circuits that shut down the pack if any cell is below 3.5 Volts if you can get access to the cell themselves you can sometimes brig them back if they havent dropped below 3.1V (be VERY careful monitor voltage and current with kelvin connections and temperaterature) if the cell voltage is below 3V DO NOT try to charge it if you can charge the offending cell to 3.5V the normal charger can take over if you are a bit safety conscious do your charging outside away from anything combustible in a metal bucket filled with dry silica sand it the battery case is cracked and water hits the lithium you WILL have a fire a company known as Boeing ( 787 Dreamliner ) decided they should write the FAA standards for charging Li-Ion batteries and ignored all other standards ( ntsb doe erda epri )
On August 12, 2014, PeteTy wrote:
standard spec on usb port is 5v 500milliAmp some of the motherboard plugs are merely connected to the 5v buss (100A or so) the wire in the cord is very small newer motherboards sometimes monitor current draw thru the bios and you may receive an error if you draw more than 500 ma usb hubs sometimes give that error with 3-4 devices connected, but most hubs have a plug for external power the usb chargers in the wall or on the car cigar lighters are sometimes rated at 1 or 2 Amps and these usually use high frequency switching regulators if you need 10A or so at 5v from your computer you are better to use one of the 4 pin HD molex plugs and you have a choice of 5V or 12v (big wire) these connecters are free since most drives are sata now
On July 28, 2014, rejoice clark wrote:
I have an android tablet with a3.7V Li-Polymer battery. I can't get the battery to take a charge, Therefore I can't get my device to power on . Plugged in or not. What can I do?
On June 21, 2014, Evan Giles wrote:
There are two ways of listing power for electrical devices input or output, if the input is 500 mA then so long as the device you attached to it supplies this amount or more you can use it, if the output is 500 mA then that is all you will get out of it and if you attach some thing that requires more it will simply take longer to charge so long as you don't use the device at the same time then device short the charger because you will pull to much current so the rule more current in is better then less out And just so you know I have had two friends blow the charger for their Laptops not because they were under powered but because they are not designed to run them continuously and they simply shorted out
On May 27, 2014, Jerry wrote:
I have an MP3 player which charges from USB. I was wondering if there's any way of monitoring the level of charge in the battery, so as to avoid over charging & possibly harming the battery.
On April 13, 2014, stephen wrote:
There's a typo at, "With the USB supply current limited to 500mAh..." mAh should just be mA
On February 28, 2014, Sanjeev wrote:
I have a Samsung ATIV 10.1" Tab 3 that has a pin charging port for which I have a wall AC charger. I want to know if tgere is a USB charger available. My information is that the Tab has a 12V power requirement and the USB system can charge only upto 5 V. Need clarificatory help that will lead me to hunt for a USB to Samsung proprietory pin charger or abandon my search. Thanks in advance.
On November 24, 2013, pete kaye wrote:
Yesterday I had a smoketastic e-cig battery explode in front of me after about 1 hour on charge via USB port.can a nyone explain .The computer was damaged and Iwas hiot by the xploding cartridege .The remains burst into flame and needed an extinguisher to put out. I have photos! I could have been seriously hurt as my face was only 12" away. Any comments???
On November 5, 2013, justo wrote:
used 4 diodes,2 going to + battery line, 2 from the - line to a usb port.used the data usb modem cable. Without the diodes the battery overheats with them takes time to charge but safe to run both as modem and charger without the usb hub warning power failure.
On August 7, 2013, Vase wrote:
Hello. I usualy charge my phone using a USB cable (I have a smartphone witha a micro usb connector and conect it via usb to the computer). I wonder if I can wire a 5V power supply to the usb instead of the computer. Do I need a current limitater circuit? Thank you!
On July 24, 2013, Shai wrote:
Hello, A li-ion phone charger shuts itself when the battery is full . This is done because the overcharging the li-ion battery is very dangerous ... it can explode . What about charging a li-ion phone ( or device ) from the USB port of a pc ... Does the pc knows to stop charging when the battery is full ?
On July 11, 2013, Brett wrote:
question,Can you charge at a 10C for a 200mAh Lithium battery via a USB 5.0
On June 13, 2013, Fer wrote:
Hello, I have an LG Optimus G which has a non-removable battery, so I want to extend the battery life to make my phone last longer. So, a part from turning off features when not needed I ask myself how to propertly charge the phone. So I have three possibilities, can someone help me? 1) The phone comes with a 1.2A charger 2) The phone can be charger from USB-PC 500mA 3) I can use other chargers I have in my home. I own a 0.7A charger from Samsung 1 & 2 are supported by LG instruction manual. 3 is not supported. so, what method should I prefer to make my battery life last longer??? is it safe 3?
On February 16, 2013, Frank wrote:
Nice article and website, very useful information! I got some questions, I am building a USB loading station for 4 smartphones that is indirectly powered by a solar panel through a 12V lead battery. For the lead battery, I have a battery charge controller, that keeps the voltage for charging at the right current with build in protections. But from the lead battery trough usb ports to the smartphones i have some trouble designing the right configuration. Because how can i control the amperage/voltage through the usb to be the right, and what is the right amperage (1000mA and then it will be tuned down further by the smartphone? or 0.3C sow 600mA?) . And does every usb then needs its own regulator? or can you build them in series (what if one is only in operation?) I cant find any standard components for this like the 12V charge controller. Thanks in advance.
On February 15, 2013, Seth Fasig wrote:
To answer Jay's question, yes. In almost every modern phone or other device that can charge off a USB there are internal components that control charging. The phone monitors how much charge is in the battery so it knows how much current to pull or when to stop pulling (though they will still pull a small amount) based off the batteries charge. This is no to say that using an incredibly cheap charger is a good idea though, some may not have the ability to supply the necessary current and some really bad charges may risk shorting and attempt to pull far to much current through your device, of course that is a worst case scenario. As for Cole's question, in addition to the different types of cable you can get that jay talked about, the size of the cable could theoretically be the problem. It really depends on the device. Take, for example, the iPad. It requires massive amounts of current, therefore it probably has very strict charging circuitry built into it (I really don't know if it does but my guess would be it does). Now with some device that must keep such an accurate account of the current flowing into it, that small 350mV drop through the wire could greatly impact the supply. Consider, V=IR. You need 2 amps and the USB supplies (ideally) 5V so the resistance must be 5/2 =2.5 ohms. Now take that means the if the supply voltage drops to 4.6V you are only drawing 4.6/2.5= 1.84A that is a considerable difference, not to mention that 350mV could increase/decrease depending on the length and gauge of the wire. just something to consider.
On February 9, 2013, Jay Sndler wrote:
From what I know, unless the USB cable is defective, they should all be the same.... EXCEPT, there are actually at least 2 versions of micro-USB connectors. I've seen diagrams online that make them seem obviously different, however in real life, to me anyway, I can hardly tell them apart. I can't remember which is which, but I think a b-type socket is what is on a Droid (and most devices of seen) but the other type is an "a" or an "ab". I think the ab will accept either cable, but the b requires a b cable... I have only one device I know of, a Vizio Tablet, that has what I think is an AB socket... My Droid charger will fit in the Vizio, but the connection is kind of loose... The cable that came with the Vizio, however, though it fits in the Droid (albeit not as easily as the correct cable if you pay attention) will not charge the Droid... The chargers that came with both devices feature standard USB ports and will charge either device with the correct cables. Otherwise, it has been my experience that every other USB powered/charged device I own seem to work well with any of my chargers (save for the low current chargers that I have... Including the car charger I bought from Verizon with my Droid 2 which only outputs 600ma and does not seem to charge the phone while its powered on- frustrating) Maybe you have some devices that are using "A" or "B" or "AB" connections and they are not all the same.
On February 8, 2013, Cole wrote:
J: That makes sense....but I've also noticed a difference in just the cables themselves .....For example..I had a micro usb from my old blackberry storm and with everything else the same it couldn't keep up like the stock motorola cable....now what you said makes sense but is there differences in basic usb cables? If so there is no need to go buy off brand cables to save a couple bucks anymore if its not made the same... Thanks, Cole
On February 8, 2013, Jay Sandler wrote:
Cole: (if you haven't gotten an answer already) I believe what you are experiencing is that some devices require higher amperage to charge their batteries - especially if the device is powered on while charging.... While nearly all USB based chargers output 5v, if you read the output current, it varies quite a bit... A simple flip phone may come with a 250ma charger, your Droid (as my Droid 2 does) may come with a 1000ma charger. I also have a Motorola GPS watch which came with a charger that looks identical to the one that came with my Droid, but it only outputs 800ma. I think my iPad charger outputs 2 or 3 amps. Which brings me to my next question... Does anyone know if the charge circuitry is built into modern smart devices? A USB port is not a charger, just a power supply in a sense, and those cheapo car chargers for $5 at the gas station can't be too high tech so I wonder if today's smart devices just expect 5v and take care of the rest... Anyone know? And my last question is... I want to try making a portable charge pack for 5v charged devices. ( I know I can buy these, but its a project I want to make)... I wondered if just using a 5v battery as a source would be workable or would I be better off with a 12v battery and charge circuitry (like that used in a car charger). Thanks for any help! J
On February 2, 2013, jimmy owen wrote:
very good website learned a lot info
On February 2, 2013, Steve wrote:
I always charging my devices using usb ports only. its never created any issues. I refer to my friend and relatives also. steve @ http://www.indcel.com/
On December 5, 2012, dave_shah wrote:
Can Anyone say me How can i plug the red and white(i.e Here pin 1 and 4) wires to my cellphone batries or direct to cellphone to get charge my cell phone
On October 24, 2012, Chaiyan Pongcharoen wrote:
Very Good and education info. Thank
On September 21, 2012, nadeem wrote:
i want to charger chip but farst i want chip rate becouse again quantty you ak
On September 6, 2012, Cole wrote:
Thats one thing I've been noticing a lot lately...for example i got a new droid razr and if i use an older usb it will connect and be accessible by computer or if u use a usb car charger it will connect and say charging...but will never really increase at all... Now if i use the motorola usb it works great... So some things have to be using the data connections also...I've also hard wired an Micro usb into my truck directly but it was basic 2 wire cable + and - and it also would say charging but never really did...Makes it frustrating when you save old cables and u end up having to get new ones anyways.
On June 1, 2012, Angela wrote:
This is not quite true, the data pins in the USB specification play an important part in charging circuits. Depending on voltages applied to those data pins, current limiters on the host device can operate anywhere from 500mA to 1000mA. By default, with no data pins used, 500mA will be provided, but the computer may conserve power once draw becomes significant. By telling the computer that there's a device pulling power (by applying standard voltages to these lines), the computer will be able to allocate further units of power out, in 100mA increments. There's some changes with the USB 3 spec, so I'd recommend reading them if you're planning on using USB charging.
On February 10, 2012, David Olive wrote:
I need to find out charge time of lithium battereis versus depletion...ie...if it takes 2 hours to get a 100% depleted battery back to full (or close to) charge, how fast will it take a battery that has been depleted by only 80% back to full charge....I am trying to design a high powered dual bank battery based system and need to know how long it will take to charge one bank of batteries based on depletion %? Also, do I need to "rest" the battery between charge & use cycles, or can I drop the battery into the circuit as soon as it is charged...ie...will I diminsh teh life charge cycle times by not giving the battery any "rest" between cycles? Thanks.
On January 4, 2012, barak wrote:
Charging Li-Ion From USB trough Series 0.7V Diode will give 4.3V which is the charging voltage (~4.2V), enother option is to use PNP transitor with the Base connected to the gnd or to 10K thermistor in order to protect from high temperature (50deg), what do you think about this?
On December 28, 2011, Bob Stuart wrote:
Have you done any research on AC powered USB chargers? My family is accumulating a number of USB charged devices (i.e. mobile phones, game controllers, e-readers, etc.) and I'm wondering if any AC powered USB charger can be used with any of these devices or if there are limitations. Thanks!!
On August 11, 2011, DR ABBAS ABUDAYYAH wrote:
Charging from a USB
On August 9, 2011, John B. wrote:
Thanks I allways wanted to know which side caried the positive charge ! chers John
Sometimes overshadowed by its data bus partner, each USB connection also contains a power bus. With a maximum power rating 5.25V/500 mA, the USB power bus is a great source for charging a single-cell Lithium-Ion battery.Can you charge A battery through A USB port? ›
USB ports are convenient for charging battery powered devices, but this can be slow on a standard USB downstream port (SDP), which only supplies a maximum of 500 mA @ 5V. To meet the demands of high-current and battery-powered USB devices, the battery charging specification (BC v1.What is the USB port for on the Polycom phone? ›
The lower USB port can be used as a host port for headsets or USB adapters. Then connect the other end of the USB-C cable to your computer. When you enter a call on your computer, your Poly CCX phone will appear as an audio option.How do I enable USB ports for charging? ›
- Click the Start button and type "regedit" (without quotes) into the Start Search box. Press "Enter."
- Click "HKEY_LOCAL_MACHINE | SYSTEM | CurrentControlSet | Services | USBSTOR."
- Double-click "Start" in the right pane. ...
- Click "OK" to re-enable the USB ports.
Rechargeable batteries are convenient in that they can be recharged via any USB port. Plug them into your computer, power bank, solar panel, or a USB port in your car. Any USB port capable of charging other electronic devices is suitable for USB rechargeable batteries.Can you charge A 12v battery with A USB? ›
If you mean to charge a 12-volt battery, then yes. Just get three USB chargers of the same type and connect them all in series. That will give you 15-volts. The internal current limit of less than three amps will limit the charge current to a safe value.How do I use the USB port on my phone? ›
- Connect a USB storage device to your Android device.
- On your Android device, open Files by Google .
- At the bottom, tap Browse. . ...
- Tap the storage device you want to open. Allow.
- To find files, scroll to "Storage devices" and tap your USB storage device.
- On the Android device, open the settings.
- Tap Developer Settings. The developer settings are hidden by default. ...
- In the Developer settings window, check USB-Debugging.
- Set the USB mode of the device to Media device (MTP), which is the default setting.
The USB 2.0 data port (like earlier and successive versions) is used to connect a variety of peripheral devices, such as: Mice. Keyboards. Printers.How do I switch from USB mode to charging mode? ›
- Connect your phone to computer with a USB cable.
- Swipe down from the top of the screen using one finger.
- Tap System UI > CHARGE & DATA.
The most common reasons for a phone failing to charge are: A faulty cable, charger, socket or adapter. Dirt or debris in the charging port. Third party apps interrupting the charging process.Are all USB ports charging ports? ›
If you have a modern USB device, you should be able to plug into a high-amperage USB port and enjoy faster charging. If you have an older product, however, it probably won't work with USB ports that employ the Battery Charging Specification. It might only work with old-school, original (500mA) USB 1.0 and 2.0 PC ports.What is the best way to charge A rechargeable battery? ›
You should always charge rechargeable batteries in the device it's used in, the charger it came with or a charger recommended by the manufacturer. Chargers are designed for specific battery types; mixing chargers and batteries could result in unexpected problems.How do you charge A rechargeable without A charger? ›
Use Your Cellphone Battery
If it is, remove it and get some metal wires. If you have several AA batteries, connect them 'in serie' You should then attach them to the cell phone battery, connecting the batteries' negative side to the cellphone battery's negative connector. Do the same for the positive sides.
USB is nearly universal, but 12V USB adapters rely on another ubiquitous technology to work: the 12V accessory socket. If you've never used a 12V USB adapter, you may be wondering if you can plug one into a cigarette lighter, or if you need a dedicated accessory socket. The answer is it does not matter.Can 12V run from USB? ›
Note - your USB port must be equipped for high current charging (2.1A or greater). Some USB ports are 500mA rated. The device will work perfectly, but will not be able to provide the full 1A current at 12V.Can USB give 12 volts? ›
You can use a boost converter to "boost" the voltage from 5 V to 12 V. USB ports have a current limit of 500 mA. Some specialized specifications can deliver more, but higher current limit needs to be requested from the port, so you'd need an USB interface chip.How do you power a car battery with an outlet? ›
- Plug the surge protector into the outlet of the power inverter.
- Turn the power inverter on. The internal components will charge up.
- Turn the surge protector switch on, and you can now plug electronics into the surge protector.
2) Take a Voltage Reading.
|State of Charge||Voltage|
|Discharged||0 - 11.6|
A car USB charger is a small adaptor that plugs into the cigarette lighter/accessory port found on virtually all cars and provides one or more USB outputs. As the cigarette lighter/accessory port provides a nominal 12 volt output, the car USB charger converts this voltage to the 5 volts required for the USB supply.
Most computer USB ports supply 5V of electricity with a maximum current of 0.5A. This amount of current is standard across the majority of computers and means the overall power output will be 2.5 Watts at best.How much power does A USB 2.0 port supply? ›
The USB 2.0 specification allows Hosts to deliver 5V at 500 mA, for a total power output of 2.5 watts.Where do I find charging this device via USB? ›
Once you plug in your device, at the top of your screen where all your usual notifications typically come in should be a notification alerting you that the device is connected to the PC. The notification will say something like ”Charging this device via USB” notification. On your device, tap the notification.What is a USB charging port? ›
The Universal Serial Bus (USB) port on computers and laptops is a data port that also serves as a 5-volt power source. Personal handheld electronics like cell phones, personal digital assistants (PDAs), and digital music players can make use of this port to recharge their batteries by using a USB charger.Can you enable USB port? ›
You can also easily enable or disable the USB Ports through Device Manager. You can click Start and type Device Manager. Then click Device Manager to open Windows Device Manager or press the "Windows + X" key, and click Device Manager to open it.How do I know if my USB is 2.0 or 1? ›
- If your USB port name contains "Universal Host", your port is version 1.1.
- If the port name contains both "Universal Host" and "Enhanced Host", your port is version 2.0.
- If the port name contains "USB 3.0", your port is version 3.0.
USB 2.0 has a black “block” inside the USB port. In contrast, USB 3.0 has a blue “block” inside the USB port. The more recent USB 3.1 port also differs visually in that the “block” inside the USB 3.1 port is red.What happens if you plug a USB 2.0 into a USB 3.0 port? ›
You can plug a USB 2.0 device into a USB 3.0 port and it will always work, but it will only run at the speed of the USB 2.0 technology. So, if you plug a USB 3.0 flash drive into a USB 2.0 port, it would only run as quickly as the USB 2.0 port can transfer data and vice versa.How do I access USB power settings? ›
Click the Start button and type edit power plan in the Windows Search box. c. Scroll down to USB settings and click the little plus next to USB selective suspend setting to expand the options. Set both the On battery and Plugged in settings to Disabled then click Apply and OK to save changes.How do I exit USB mode? ›
To exit USB mode, press INPUT to open the INPUT SOURCE list, then select another input source.
- Select Start, type power options in the Start Search box, and then select Power Options in the Programs list. ...
- Under the selected power plan, select Change plan settings.
- Select Change advanced power settings.
- In the Power Options dialog box, expand USB settings, and then expand USB selective suspend setting.
First, plug the device into a different USB port, if your computer has more than one, to see if the problem is specific to one port. You can also try a different cable with the peripheral you plugged in; make sure the existing one is not torn, melted, or otherwise damaged. Another option is to change devices.How can I charge my dead phone without a charger? ›
You can plug your phone into your laptop for a quick charge or find alternate USB ports that can do the job. Most USB ports found in airports and some coffee shops provide enough power to charge a standard smartphone. Also, some hotels have USB ports built into lamps and bedside tables.What is the difference between A charging port and USB port? ›
Mechanically, the USB charging ports use the same standard Type A USB connector. The only difference is the power available on the USB ports. A DCP is used strictly for power, requires no host connection and offers no data transfer capabilities.Can I charge I phone from any USB? ›
You can use either a USB-A to Lightning cable or the newer USB-C to Lightning cable with your iPhone. You can use any of the adapters listed below to charge your iPhone, iPad, Apple Watch, or iPod. You can also use a Mac USB-C Power Adapter or third-party adapters that comply with applicable safety standards.Can I use a regular charger on a lithium battery? ›
You can use a lead acid charger on a lithium battery if you want, HOWEVER, you must NOT use a lead-acid charger if it has an automatic “equalisation mode” which cannot be permanently turned off.Can lithium batteries be charged with regular charger? ›
Generally no. A straight Lithium 12-volt battery will not be 12 volts. A 12v lithium LiFePO4 battery fully charged to 100% will hold voltage around 13.3-13.4v. Its lead-acid cousin will be approx 12.6-12.7v.Do you need a special charger to charge lithium batteries? ›
There is no need to replace your existing charger(s) you've been using on a lead acid battery and upgrade to lithium battery chargers. A lead acid charger will do the job.Do you need a specific charger for a lithium battery? ›
Lithium batteries require a Constant current/Constant voltage (CC/CV) charge type with simple Bulk, Absorption, Float stages. Many lead acid chargers have desulphation and equalisation stages built in, which will pulse high voltages of 15.3-15.8V into the battery.What is the best way to charge a lithium-ion battery? ›
Charging properly a lithium-ion battery requires 2 steps: Constant Current (CC) followed by Constant Voltage (CV) charging. A CC charge is first applied to bring the voltage up to the end-of-charge voltage level. You might even decide to reduce the target voltage to preserve the electrode.
Use a two to three year life expectancy for batteries that do not run through complete charge cycles. Rechargeable Lithium-Ion batteries have a limited life and will gradually lose their capacity to hold a charge. This loss of capacity (aging) is irreversible.What happens if you recharge a lithium battery? ›
We've talked about how a lithium battery works, but what happens when it recharges? Essentially, the flow of lithium-ions between the anode and cathode reverses. Instead of moving from the anode to the cathode, the lithium ions flow from the cathode to the anode.Can I use regular 12v charger to lithium battery? ›
You can use a lead-acid charger to charge lithium batteries as long as you can set the maximum voltage of the charger and as long as the charger does not have an automatic equalisation mode enabled.What's the difference between a lithium ion charger and a regular charger? ›
The differences with Li-ion lie in a higher voltage per cell, tighter voltage tolerances and the absence of trickle or float charge at full charge.How do I know if my battery is lithium? ›
Lithium Primary batteries may be marked “Lithium;” button/coin cells may begin with (CR###). Lithium Primary Batteries (non-rechargeable) can be found as AA/AAA, C, D, Coin/Button cell, and 9v. They are starting to replace many common alkaline batteries because they are longer-lasting.How many amps do I need to charge a 12 volt lithium battery? ›
A lithium battery can be charged as fast as 1C, whereas a lead acid battery should be kept below 0.3C. This means a 10AH lithium battery can typically be charged at 10A while a 10AH lead acid battery can be charged at 3A. The charge cut-off current is 5% of the capacity, so the cutoff for both batteries would be 0.5A.What is the difference between a lithium battery and a lithium-ion battery? ›
The main difference between lithium batteries and lithium-ion batteries is that lithium batteries are primary cells and lithium-ion batteries are secondary cells. The term "primary cell" refers to cells that are not rechargeable. on the other hand, lithium-Ion batteries feature secondary cell construction.Should you let a lithium battery run down before charging? ›
Unlike other types of batteries that need to be recharged throughout their storage time, lithium batteries do better at 40%-50% DOD (depth of discharge). Pro-Tip: After every 30 charges, allow your lithium based battery to completely discharge before recharging. This helps to avoid a condition called digital memory.