Develop Bugs

Max USB volts (6v solar?)

hi currently charger via inverter for 9W charge power. will the USB accept 6V to gain efficiency? as have 3, 6 or 12V at 13W. in daylight. if input goes through regulator to charge 3.3V Li-Ion battery anyhow, what is the chances of hacking a miniUSB connector to 6V? the crap 12V to usb thing I bought died. like I said crap.

usb is spc'd as being 5volt signaling and powering
any device unless it goes beyond that spc could burn from being powered or signaled at more than it's spc'd to

USB Power is a max of 5V at 500mA, but normally it's at 300mA and whatever is plugged in can request more current if required.

Yea today USB maxes out at 2 amps for the larger tablets. Used to max out at 1amp and most computers used to max out at .5 amps.

[Q] Charging Speed - Different from a/c than from USB?

So I was wondering: is there a difference in charging speed between the a/c wall charger and charging from my computer's USB port? Also, what's the difference between different chargers? For example, the Desire comes with a charger that puts out 1 amp. My girlfriend's BlackBerry has a micro USB charger as well, but the output is 700 mAh, or 0.7 amp. I've seen chargers ranging from 500 mAh (0.5 amp) to 1200 mAh (1.2 amp). How does this equate to charge time? Does it even? Or does the phone regulate the charge rate?

Benny_L said:
So I was wondering: is there a difference in charging speed between the a/c wall charger and charging from my computer's USB port? Also, what's the difference between different chargers? For example, the Desire comes with a charger that puts out 1 amp. My girlfriend's BlackBerry has a micro USB charger as well, but the output is 700 mAh, or 0.7 amp. I've seen chargers ranging from 500 mAh (0.5 amp) to 1200 mAh (1.2 amp). How does this equate to charge time? Does it even? Or does the phone regulate the charge rate?
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You've pretty much answer your own question!
The current supplied by a charger/USB port determines how fast it can charge the battery, which is why the wall charger (1amp) charges much faster than a PC USB port (0.5 amps).
Regards,
Dave

It's almost completely logical.. say you have a 1.5A battery (1500mA) and a 500mAh charger (ie USB) then it will take 3 hours for it to charge but with a 1000mAh charger it will take an hour and a half.
Can't really explain it more than that, so hth.

Well , Yes and No
This is only partly true ......
If you charge it on the PC , max output is 0.5 amps , and data is possible while charging .
Now with Desktop and car charger , the amp can be anything the manufacturer likes but you have to keep the following in mind :
USB Specs state the following :
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In Battery Charging Specification,[32] new powering modes are added to the USB specification. A host or hub Charging Downstream Port can supply a maximum of 1.5 A when communicating at low-bandwidth or full-bandwidth, a maximum of 900 mA when communicating at high-bandwidth, and as much current as the connector will safely handle when no communication is taking place; USB 2.0 standard-A connectors are rated at 1500 mA by default. A Dedicated Charging Port can supply a maximum of 1.8 A of current at 5.25 V. A portable device can draw up to 1.8 A from a Dedicated Charging Port. The Dedicated Charging Port shorts the D+ and D- pins with a resistance of at most 200Ω. The short disables data transfer, but allows devices to detect the Dedicated Charging Port and allows very simple, high current chargers to be manufactured. The increased current (faster, 9 W charging) will occur once both the host/hub and devices support the new charging specification.
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So if your Desire ( Yes , the Desire supports these specs ) detects the short , it will switch to fast charging mode otherwise it will limit the charging current .
Unfortunately , there's no way to know , just by looking at a charger, if it respects the specs or is just a low cost 5V powersupply . I've encountered quite a few ( mostly lowcost) desktop and car chargers that are rated between 1 and 2 amps , but still take bl**dy ages to charge the phone . Checking those with a measuring tool , you usually see the data pins are "Not Connected" instead of being shortened :-(((
Final Word .... don't try to save some money on a cheap charger , you'll regret it Genuine HTC works great , others do the same , but don't expect a $1 charger from Hongkong or whereever to do it !

These are the theoretical specs. Keep an eye on charger efficiency ratings and battery charge absorption won't be 100% in any case. Also bare in mind the charge is not linear, it will trickle after approx 80-90% with this phone.
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- Sent via my HTC Desire -

th3 said:
These are the theoretical specs. Keep an eye on charger efficiency ratings and battery charge absorption won't be 100% in any case. Also bare in mind the charge is not linear, it will trickle after approx 80-90% with this phone.
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- Sent via my HTC Desire -
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Ya, I noticed the charge slows down considerably for the final 10-15 %
I find myself charging my Desire more than I actually use it, lol.

I found now the answer to this problem: I use a Nokia charger (5v and 890 mA) with a microusb adapter. You can find one on eBay at ~2$
Now it takes about 2 hours from 20% to 100%
Lets hope nothing wrong happens to my precious Desire

look here for a method to charge at ac speed from usb, explains a few things too.

[Q] Using high amp charger

just wondering if it's safe to use my hp touchpad charger on the gio
Wall AC to USB power adapter, which has input specifications of 100-240 Volt 50–60 Hz 0.4 Amp AC, and output specifications of 5.3 Volt 2.0 Amp DC. It is cylindrical roughly the size of a "D" battery with a foldable 2-prong AC connector and Standard-A USB socket on its two ends.
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pretty high amperage, is it safe to charge with it? done it twice already

Standard charger have 5V output and 0,7A out. I do not recommend the use of higher voltages and currents, can lead to overcharging and thus the explosion.

The internal "censor" of the cell can and wil be fried wen you continue.
0.7 vs 2.0 is about 3 times faster, truth but also a bigger ammount in a shorter time.
If the cell not capable for that, it wil overheat and at worst case it wil blow up in your face...................
And take a second gues, those are not the most expensive celles.............

will charge battery faster if phone shut down? and how does FAST CHARGE work ??

as we know , for example the wall charger has output of 1A.
and battery capacity is 1750 mAh , so in theory , it should be 100% charged in 1750 mAh / 1000 mA = 1.75 hours.
but consider something like cable resistance or whatever , i think it should be fully charged like 2.5 hours or so ...
but what strange is, i have an old wall charger which was come from with Nexus S , only has 700 mA output and the new one came with Galaxy Nexus which has 1 A output. but my application , DX power booster , charge estimated time shows exact same with both 700 mA and 1 A ... i just don't get it as they have different output current ...
and i think , when charger is plug in, phones runs on power source directly from charger which will decrease the current goes to battery i think , so will the battery charging be short if i shut down my phone when it charges ?
and as for a USB , 5 V and 0.5 mA , which is only half of wall charger , then why does FAST CHARGE will make it as shortly as wall charger ?
because i think , no matter it is on or off , it doesn't alternate the fact that USB still only has 500 mA output ...
maybe they are stupid questions ... but i just failed my physics back the time i was student ...

My Gnex charges WAY faster when it's turned off. A few times I've left the house and realized I forgot to charge my phone overnight so I turn it off, put it on the car charger and usually have a useable charge even if it's a fairly short trip.

If you're phone is off, it's not using the power it's getting from the charger, therefore it will reach 100% faster
Sent from my Galaxy Nexus using xda premium

qtwrk said:
as we know , for example the wall charger has output of 1A.
and battery capacity is 1750 mAh , so in theory , it should be 100% charged in 1750 mAh / 1000 mA = 1.75 hours.
but consider something like cable resistance or whatever , i think it should be fully charged like 2.5 hours or so ...
but what strange is, i have an old wall charger which was come from with Nexus S , only has 700 mA output and the new one came with Galaxy Nexus which has 1 A output. but my application , DX power booster , charge estimated time shows exact same with both 700 mA and 1 A ... i just don't get it as they have different output current ...
and i think , when charger is plug in, phones runs on power source directly from charger which will decrease the current goes to battery i think , so will the battery charging be short if i shut down my phone when it charges ?
and as for a USB , 5 V and 0.5 mA , which is only half of wall charger , then why does FAST CHARGE will make it as shortly as wall charger ?
because i think , no matter it is on or off , it doesn't alternate the fact that USB still only has 500 mA output ...
maybe they are stupid questions ... but i just failed my physics back the time i was student ...
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wall charging is only faster because your phone is not using battery while charging, so of course it would take a shorter time to reach full battery, thus appearing to charge 'faster'.
Fast charge is fooling the phone into thinking your charging from a wall socket instead of a usb, as when in usb mode it uses some of the power to transfer files between the phone and computer, so when in fast charge mode it only charges and cant be used to transfer files. this is from what i understand so far

vincentistan said:
wall charging is only faster because your phone is not using battery while charging, so of course it would take a shorter time to reach full battery, thus appearing to charge 'faster'.
Fast charge is fooling the phone into thinking your charging from a wall socket instead of a usb, as when in usb mode it uses some of the power to transfer files between the phone and computer, so when in fast charge mode it only charges and cant be used to transfer files. this is from what i understand so far
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But what I don't understand is, no matter you transfer files or not, it doesn't alternate the fact that USB output is still 500 mA...
Sent from my Galaxy Nexus using xda premium

When you activate Fast charge you fool the USB port to think it doesn't have a communication device attached, and thus can deliver up to 1.5A on the port (dependent on port type). The phone charges faster when turned off because it doesnt use any power itself. The charging board on the phone will always control how much current you can recieve at all times (even when off).
Taken from Wikipedia.
Charging ports and accessory charging adapters
The USB Battery Charging Specification of 2007 defines new types of USB ports, e.g., charging ports.[46] As compared to standard downstream ports, where a portable device can only draw more than 100 mA current after digital negotiation with the host or hub, charging ports can supply currents above 0.5 A without digital negotiation. A charging port supplies up to 500 mA at 5 V, up to the rated current at 3.6 V or more, and drop its output voltage if the portable device attempts to draw more than the rated current. The charger port may shut down if the load is too high.
Charging ports exist in two flavors: charging downstream ports (CDP), supporting data transfers as well, and dedicated charging ports (DCP), without data support. A portable device can recognize the type of USB port from the way the D+ and D- pins are connected. For example, on a dedicated charging port, the D+ and D- pins are shorted. With charging downstream ports, current passing through the thin ground wire may interfere with high-speed data signals. Therefore, current draw may not exceed 900 mA during high-speed data transfer. A dedicated charge port may have a rated current between 0.5 and 1.5 A. There is no upper limit for the rated current of a charging downstream port, as long as the connector can handle the current (standard USB 2.0 A-connectors are rated at 1.5 A).
Before the battery charging specification was defined, there was no standardized way for the portable device to inquire how much current was available. For example, Apple's iPod and iPhone chargers indicate the available current by voltages on the D- and D+ lines. When D+ = D- = 2V, the device may pull up to 500 mA. When D+ = 2.0 V and D- = 2.8 V, the device may pull up to 1000 mA of current.[47]
Dedicated charging ports can be found on USB power adapters that convert utility power or another power source — e.g., a car's electrical system — to run attached devices and battery packs. On a host (such as a laptop computer) with both standard and charging USB ports, the charging ports should be labeled as such.[46]
To support simultaneous charge and sync, even if the communication port doesn't support charging a demanding device, so called accessory charging adapters are introduced, where a charging port and a communication port can be combined into a single port.
The Battery Charging Specification 1.2 of 2010 [12] makes clear, that there are safety limits to the rated current at 5 A coming from USB 2.0. On the other hand several changes are made and limits are increasing including allowing 1.5 A on charging ports for unconfigured devices, allowing high speed communication while having a current up to 1.5 A and allowing a maximum current of 5 A.
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Charging my phone using a high current supply, safe or not?

hi, nowadays many universal chargers come with 2 or more output sockets varying from 1 to 2.1A output.
If my phone was supplied with 1.5A charger which works just fine, can I safely use the 2.1A socket on my power bank, or am I only safe with the 1A socket? Using the 2.1A socket charges remarkably faster but also the phone(likely from battery) goes kind of hot (45°C measured). Does the increased temperature negatively affect the battery life cycle(capacity) or can it even damage my phone? ?