Ampere APP and "max. possible USB current" - Nexus 5X Q&A, Help & Troubleshooting

Hello N5X users. As far as you probably know, Ampere has now functionality for measuring maximum possible USB current.
I've noticed one interrested thing when charging (during testing some C2C cables). When I'm repeatedly connecting my original Google's A/C typeC chager, readings give always different values - very often less than 3000mA (meanwhile other apps show value 3000 which is the teoretical maximum). With some crappy C2C cables even less. I dont understand what it does mean and how do they compute the maximu possible USB current. Can you give me a clue? Do you have similar experience?
I'm wondering whether my USB charger is working correctly. I.e. my PCI-E ASUS extension card gives max. possible USB current 3000mA (reported by Ampere) at every attempt.
Thank you for sharing your experiences.

To work out the current we need to know the resistance of the cable (including the resistor). So the way we do this is by taking the voltage and sharing it by the resistance to give us current.
We can work out the resistance in a cable though by taking the voltage and sharing it by the current.
The USB c to a cable that I have draws 600mA so the resistance in the cable (this includes the resistor) is: 3100mV shared with 600mA which is 5100mOhm or 5.1 ohm

The question is why my phone with the same cable and charger often reports different maximum possible current (3000mA, 2100mA, 1900mA, ...).

It will depending on the charge of the battery and the temp of the phone. The charging circuit will pull only what it needs or what is safe.
Sent from my Nexus 5X using Tapatalk

Of course it depends on temp and level of charge. But I'm talking about situation which is happening almost at the same moment. I was trying to plug and unplug it over and over again (with the same level of charge and temperature) and the maximum possible USB current was often different - 3000mA then 2300mA ater that 2100mA and then again 3A. I still don't know the way they compute this max. possible value (because the resistor in the cable should tell what is the maximum current - 3000mA, 1500mA or standard USB port).
This happens with the original Google charger but not with ASUS PCI-E card in my computer (it alwas reports 3000mA) using the same cable.
Is there anybody who could try to measure max. possible current using Ampere app and A/C charger? A few attempts of plugging and unplugging would be enough.
Thanks!

I don't know if you found out what was going on... Did you? I'm observing exactly the same in my N5X
Desde el móvil...

I also see different max USB current settings each time I plug a USB charger in then unplug and plug back in again
Sent from my Nexus 5X using XDA-Developers mobile app

Additionally, I would like to ask you all if it's normal that Ampere reports positive mA (so charging), but the % si descending... ¿¿¿???
My phone is a Nexus 5X, with Mashmallow. No other method of obtaining charge in basic options.

marshall.cze said:
Hello N5X users. As far as you probably know, Ampere has now functionality for measuring maximum possible USB current.
I've noticed one interrested thing when charging (during testing some C2C cables). When I'm repeatedly connecting my original Google's A/C typeC chager, readings give always different values - very often less than 3000mA (meanwhile other apps show value 3000 which is the teoretical maximum). With some crappy C2C cables even less. I dont understand what it does mean and how do they compute the maximu possible USB current. Can you give me a clue? Do you have similar experience?
I'm wondering whether my USB charger is working correctly. I.e. my PCI-E ASUS extension card gives max. possible USB current 3000mA (reported by Ampere) at every attempt.
Thank you for sharing your experiences.
Click to expand...
Click to collapse
The answer is simple. AMPERE does not work in the Nexus 5X under Marshmallow. I tested with a variety of cables and chargers, all passing the current through an inline USB Volt/Amp meter. The amps reading on the meter bore no relationship to the indicated value from AMPERE. Nor did the app give a sensible value when plugged into the Nexus-supplied charger.

Related

Highest output car charger

Is this the highest?
http://www.seidioonline.com/product-p/pmc.htm
Post links if you know of higher ones, thank you.
Sent from my ADR6400L using XDA App
There are 2.1A usb adapters, but I don't think microUSB can take advantage of it. The one you linked is a 1A, which is the same as the wall charger HTC gave with the phone. I'm currently using a 1A usb adapter in my truck.
Ok that's probably what I'm looking for then. Are there wall chargers greater than what came with the phone that I can take advantage of?
Your best bet would be to try the USB adapters made for iPads. The Apple products can utilize the 2.1A chargers with their sync cables, but I'm not sure if a microUSB cable can though. I have some 2.1A wallchargers from some of my Apple products, I'll test them later and let you know what I find out.
http://www.verizonwireless.com/b2c/...ryDetails&archetypeId=12299&accessoryId=46370
I just got an Enercell from Radio Shack with dual usbs. Max output is 2.5A divided between the two ports.
http://www.radioshack.com/product/index.jsp?productId=11329448
on sale now for only $14.99. Seems to be of good quality.
The Motorola rapid chargers rock.
Guys, unless you mod the usb adapter 5V spec, you aren't doing squat with a "high power" adapter. The device has an input impedence that will draw a certain amount of current at 5v., and that's it.
Standard battery: 1400 mAh
Time to charge: 4 hrs (according to manual)
That's 1400/4 = 350 mA.
Most adapters on the market spec more than that, they're usually 500 mA or above. And again, unless you boost the volts, you're not going to be able to push more than 350 mA or so.
So don't waste you're money.
On the other hand, if your going to share a car outlet with another device like mp3 or ipod, then yeah, you'll need a higher output, two port, adapter.
Edit: It just occurred to me that if you're using the phone heavily while charging, then yeah you may need more than 500 mA. My currrent widget shows the phone can draw another 250 mA or so during use. That plus the charge totals to around 600 mA. But depending upon design, the phone may not be able to pull in all 600 mA. A test with a current meter would be real interesting.
The charger shipped with the Thunderbolt is a 1 Amp charger.
If I use a 500 mA charger the Current Widget shows a +450mA charge current. However if I use the 1A charger, I get a charge current of about +850mA.
Given that the google navigation gobbles over 400mA when running, you need a car charger with greater than 500mA capacity of you want the phone to charge at the same time.
Sent from my ADR6400L using XDA App
boingboingbilly said:
The Motorola rapid chargers rock.
Click to expand...
Click to collapse
Good to hear, I ordered one today for $11 on ebay. I had heard other people say they liked that one too.
Ecomaniac said:
Guys, unless you mod the usb adapter 5V spec, you aren't doing squat with a "high power" adapter. The device has an input impedence that will draw a certain amount of current at 5v., and that's it.
Standard battery: 1400 mAh
Time to charge: 4 hrs (according to manual)
That's 1400/4 = 350 mA.
Click to expand...
Click to collapse
You're making the incorrect assumptions that the charging rate is constant, and charging is 100% efficient. Li-ion batteries can be charged at up to a 1C rate (i.e. 1.4A for a 1400 mA cell). Add the power drawn by the phone itself, and a 1.8 Amp charger might not be unreasonable (1.8 A is the specified limit for micro USB connectors). Whether the phone will actually do a maximum rate charge, I don't know.
This, from a TI Application Note (Google for SLAA287, board won't let me post links):
A Li-Ion battery charging process consists of three stages:
· Slow Charge: Pre-charging stage using current of 0.1C
· Fast Charge: Constant current charging stage using current of 1C
· Constant voltage charging stage
During the slow charge stage, the battery is charged with a constant low charge current of 0.1C, if the battery voltage is below 2.5V. The slow charge stage is rarely used during the charging process of a Li-Ion battery.
The fast charge (constant current) and constant voltage charging are the most important stages during a recharge process. Most Li-Ion batteries have a fully charged voltage of 4.1 or 4.2V.
The battery is first charged with a constant current of 1C until a battery voltage reaches 4.1 or 4.2V. The firmware continuously checks the charging current by sensing the voltage at the current sense resistor (Rsense) and
adjusts the duty cycle of PWM output from the MCU. The battery's voltage is checked frequently.
Whenever found the battery's voltage reaches 4.1 or 4.2V, the charger will switch to constant voltage charging mode. The battery is then charged with a constant voltage source at a fixed battery voltage of 4.1 or 4.2 V...When the charging current falls below 0.1C, the charging process must stop.
Click to expand...
Click to collapse
Monoprice has Cig to USB(1A) chargers and the USB to Micro cables in multiple lengths(I ordered 6' ones) for far cheaper than you will find anywhere else
mike.s said:
You're making the incorrect assumptions that the charging rate is constant, and charging is 100% efficient. Li-ion batteries can be charged at up to a 1C rate (i.e. 1.4A for a 1400 mA cell). Add the power drawn by the phone itself, and a 1.8 Amp charger might not be unreasonable (1.8 A is the specified limit for micro USB connectors). Whether the phone will actually do a maximum rate charge, I don't know.
This, from a TI Application Note (Google for SLAA287, board won't let me post links):
Click to expand...
Click to collapse
very useful, thanks!
walbuls said:
Monoprice has Cig to USB(1A) chargers and the USB to Micro cables in multiple lengths(I ordered 6' ones) for far cheaper than you will find anywhere else
Click to expand...
Click to collapse
I second monoprice.
I tried bunch of cig to usb car charger and none matched advertised output... They all showed Charging (USB). I now use AC inverter and it charges just like a wall charger.
eccenpix said:
I tried bunch of cig to usb car charger and none matched advertised output... They all showed Charging (USB). I now use AC inverter and it charges just like a wall charger.
Click to expand...
Click to collapse
I suspect you need to find one which properly follows the USB Battery Charging Specification. That link is to the most recent version, which came out on 7Dec2010 (remember Pearl Harbor!). Version 1.1 is easier - a Dedicated Charging Port is indicated by shorting together the data lines (the two middle conductors on a full sized USB connector. By doing so, it indicates the device may try to draw up to 1.8 A of current (although a dedicated charging port is allowed to limit the current to less than that, it must provide at least 1.5 A).
I bought a cheap USB hub with 5 ports, used an exacto knife to cut the traces going to the data lines (the middle two) on all the ports, and then shorted them together on each port. It's now no longer a USB hub, but a USB charger with 5 ports I can used to charge stuff (phone and Bluetooth, quite often). The AC adapter which it came with does 2 Amps. My Thunderbolt says "Charging (AC)" when plugged into it.
So, if you can open up one of your adapters, just solder a jumper between the middle two contacts (make sure they're not connected to anything else).
Just got the Rocketfish premium microUSB at Best Buy and it has a captive coiled cord and a USB port. TBolt says "AC plugged" and reads +670 mA.
Good choice on the Motorola Rapid Charge - I've burned through 3 other cheap car chargers trying to keep my phone alive while using Google Nav and this is the first one to work!
i have the rapid motorola one on amazon
lippstuh said:
i have the rapid motorola one on amazon
Click to expand...
Click to collapse
+1 Works great! Battery widget usually shows about +800mA while only charging. Real close to the wall charger

Charger

I have a car charger that outputs 5.3V and 2A. Will I damage my phone if I use this?
No because the phone will limit it plus it depends on the charges and cable whether it will take an AC charge or USB
Hi
milomak said:
I have a car charger that outputs 5.3V and 2A. Will I damage my phone if I use this?
Click to expand...
Click to collapse
The amps aren't a problem as a device will only draw what it needs. The voltage requirements however for USB is 5 Volt +- 5%, which gives a valid range of a maximum 5.25V and minimum 4.75V. If that voltage of 5.3V is the measured voltage and is accurate, it is probably going to be fine, however if that voltage is what it states on the label, then that figure has some leeway also, so if the charger is leaning towards being over rather than under, it is going to be going quite a bit over the USB spec.
Regards
Phil

USB Charging Slow

Can someone tell me why is it that when i charge my phone when USB connected to PC its takes hours together to charge and Wall Charger takes 1/4th of that time why is that can anybody tell me what is the login behind it and which is best way to charge ?
USB only outputs 5v, which is why it takes makes longer. You have more power outputted from the ac adapter therefore it charges quicker. Simple as that. They will both eventually charge the device, but it's recommended you use the wall charger all it's faster, no one likes to wait
+1
U cannot compare usb charging with ur charger as output voltage varies across both n btw usb is jst an alternative for charger it's not a replacement
Sent from my LT22i using Tapatalk 2
You can use a custom kernel and change charging current.
Sent from my GT-N7100
Ok thanks Guys to know what is the main difference
Technically, voltage has little to do with charging. The amperage is what counts. USB on a computer gives ~500 milliamp, where ac chargers give 1-2 amps
Sent from my SGH-I997 using xda app-developers app
For a more detailed answer...
All compatible chargers output the same voltage, 5 volts. (Otherwise they just would burn out the charging circuits in the phone. It can happen both if there's too much volts and if there's too little, but for very different reasons.) However, voltage is not the only characteristic of electricity, the other most important is current, that is, amperes. Think of volts as 'water pressure' and amperes as 'amount of water pumped per minute' through a water pipe -- with real water, those are connected, with electricity they're quite separate.
Every source of stabilized electricity you will find in any kind of power supply will have a set voltage it outputs electricity at, and maximum current it can output. Trying to draw more current than it can supply can damage the power supply, so your phone limits the current it attempts to draw when it detects a standard USB port -- to what the USB standard says it should be able to safely supply. For standard ports, it's 500mA. Galaxy Note II by default plays it safe and draws 425mA. The stock AC charger is rated at 2000mA, and Note draws 1700mA when it detects one. This specifically affects the speed of charging -- AC chargers will charge battery faster, because three times more power gets in.
The USB standard was written before everyone and their mother started using it as a charger, and today, USB ports can usually handle more than 425mA, and on some computers they can supply just as much power as the stock AC charger. There are a few standard ways to detect how much current can a phone safely draw from an USB socket, but not all of them are universally accepted or correctly implemented, so the phone always plays it safe when it can't be sure. If you install a custom kernel, you can directly tell it how much power to draw if you know your USB port can handle it.
:good: :good::good::good::good::good:
aukhan said:
:good: :good::good::good::good::good:
Click to expand...
Click to collapse
You can use the app Galaxy Charging Current (GCC) from the S3 thread which can measure the output of the incoming current. It will also allow you to detect faulty cables and chargers, as you will be able to see different ratings with different cables and chargers.
Testing on typical USB ports will get you a reading of 460, while the original charger and a good cable will give you 1800 (about the max current draw for the Note 2).
If you use a known good charger and get a lousy reading, it indicates a bad cable. I once had a cable give a readout of 100. I promptly threw it away.
Yes i am using that thanks nyways

Issue charging current mod

Hello everyone! My i9300 has some issues. I cut a USB cable female-male, i shorted data lines to the phone, and i take several chargers to measure the current
1. normal usb charger, max 4.8W-600-700mA
2. sam charger aproximative the same-600-700mA, and one time the ampermeter indicates 1A but now aprox 0.4A (
3.lm2576 suplly capable of 3A, the same crt 500-700mA
My kernel suports Stweaks, and i've set current to 1500mA, but the current didn't rise. What is the problem? It's clear that the phone charge with 1A ony on the stock wall charger, all the others neahhhh. I've tried with several usb cables and the same problem. Ideeas please?
On stock kernel will never rise above 1A. On custom kernel you must have a quality charger that can provide constant amperage. Otherwise the current will drop automatically to usb values (failsafe value)
Sent from my GT-I9300 using XDA Premium HD app
You're right. I bought a "quality" charger an the cuurent didnt't rise above 1A, in first seconds it stays on 1A but after that moment it drops to 0.6A even if i disable the safe margin.
The values in STweakes must be equal? All chargers that i've found are creappy! Nothing real, i've watched at one that say it can carry 3,1A but i don't think that it can power it's own led

G5 charging slow on 99% of cables

Hey!
I noticed recently that my G5 charges quite slow. So I tested all of my powerbanks, cables, and wall chargers, in various combinations. I had 4 different powerbanks, 3 wall chargers, and 4 cables.
I used a USB ammeter to measure the power draw going through the USB cable.
On the motorola charger and cable that came with the phone, it charges at 1.8a. I then charged my phone from each powerbank and wall charger, using each cable in turn. The average charge speed for my phone was about 0.5a. Out of 28 combinations, only 2 yielded a draw over 1a.
I have created a spreadsheet detailing the charge speeds of each combination, but unfortunately cannot post it yet (10 post permissions).
I then charged my USB powerbanks from the same wall chargers, using the same cables. One powerbank charged at over 1a with every combination, and reached over 2a on numerous combinations. This proves that the cables and wall chargers are not at fault, it is a phone issue.
Why? Has motorola put something in their chargers that 'talks' to the phone, and allows for faster charge speeds? 0.5a is awful!
Secondly, does anyone know of cables that I can buy, which will support fast charging for the motorola? I have looked at genuine motorola cables, but there is no way to tell one from the other.
Thanks!
Paul
P.s. charge speeds were the same, whether the phone was switched on or off.
Welcome @agour
I've come up to a similar conclusion with a lot less data (thus I didn't share them).
I caught power consumption at the wall outlet when charging my device with two chargers: Motorola stock charger and a Samsung Adaptive Fast Charger.
The Samsung has the following specs: 5V 2A or 9V 1.67A with fastcharging capable device.
Using Samsung Adaptive fast charger and Samsung 1.5m cable : 6W, so the device charges at something like 5V 1.2A...
Using Samsung Adaptive fast charger and the cable provided with my XT1676 : 11.3W (which is coherent with the max 9V 1.6A, and would mean the charger provides 2.2A if at 5V which more than the specs.)
Using stock charger and stock supplied cable : 11.3W ==> fast charge for similar reasons as above
Using stock charger and Samsung 1.5m cable : around 6W ==> low power charge
I'd need a USB multimeter to confirm those data. (mostly due to the variable voltage that can provide fast charge adatpers)
matmutant said:
Welcome @agour
I've come up to a similar conclusion with a lot less data (thus I didn't share them).
I caught power consumption at the wall outlet when charging my device with two chargers: Motorola stock charger and a Samsung Adaptive Fast Charger.
The Samsung has the following specs: 5V 2A or 9V 1.67A with fastcharging capable device.
Using Samsung Adaptive fast charger and Samsung 1.5m cable : 6W, so the device charges at something like 5V 1.2A...
Using Samsung Adaptive fast charger and the cable provided with my XT1676 : 11.3W (which is coherent with the max 9V 1.6A, and would mean the charger provides 2.2A if at 5V which more than the specs.)
Using stock charger and stock supplied cable : 11.3W ==> fast charge for similar reasons as above
Using stock charger and Samsung 1.5m cable : around 6W ==> low power charge
I'd need a USB multimeter to confirm those data. (mostly due to the variable voltage that can provide fast charge adatpers)
Click to expand...
Click to collapse
Interesting! It's suprising how much difference the combinations can make.
I don't think I have experienced this on a phone before, however I have never felt the need to test it...
I tested the original cable that came with the phone, and an off the shelf 'genuine motorola cable'. The stock cable is still the fastest, however the secondary cable still worked very well.
Interestingly, one of my powerbanks will charge at 2.2a from pretty much EVERY powersource and cable combination. This is with 7 cables tested, and 3 USB wall adapters.
Shame that motorola doesn't allow their phones to draw maximum power from hardware that can provide it..
agour said:
Interesting! It's suprising how much difference the combinations can make.
I don't think I have experienced this on a phone before, however I have never felt the need to test it...
I tested the original cable that came with the phone, and an off the shelf 'genuine motorola cable'. The stock cable is still the fastest, however the secondary cable still worked very well.
Interestingly, one of my powerbanks will charge at 2.2a from pretty much EVERY powersource and cable combination. This is with 7 cables tested, and 3 USB wall adapters.
Shame that motorola doesn't allow their phones to draw maximum power from hardware that can provide it..
Click to expand...
Click to collapse
If I have some time, I may test internal impedance of the cables, it is possible that the device somehow probes the cable (or the cable + charger) and then decides if it can or not draw that much power without overheating/melting the cable; and then it will negotiate the quickCharge with the charger.
there has been a discussion about quick charge on this thread a while ago (before I got this devices : https://forum.xda-developers.com/g5/help/quick-charge-3-0-support-t3632457)
Lenovo adds the following that I have not tested:
Lenovo said:
If your device is below 78%, but it does not begin Turbo charging when you plug it into the Turbo Charger, try uplugging and plugging back in using one fluid motion.
Click to expand...
Click to collapse
[Source]
It is quite obvious that especially cheap cables will charge phones much slower as the resistance is too high, even if the phone does not perform any checks. Those cables are basically too thin. Resistance limits the current (amps) that can flow. Newer phones most likely just look at the charge current during the first x seconds (or less) and then decide wether to enable fast charging or not to keep the cable from heating up. A wire with high resistance is basically a heater. So it's a necessary safety feature (from the companies POV).
Regarding the power bank, it may be possible that this particular design provides a voltage slightly higher than the nominal 5 volts (still fine for most devices), which helps overcome the resistance. That is also the reason why the Samsung fast charger provides 9V: You don't need a cable as thick as with 5V.
Keep in mind that the USB specifications only recently got updated for such high charging currents, so it is advisable to use only the cable that comes with the phone as USB cables in general don't need to provide such high currents by spec!
71n4 said:
It is quite obvious that especially cheap cables will charge phones much slower as the resistance is too high, even if the phone does not perform any checks. Those cables are basically too thin.
Resistance limits the current (amps) that can flow. Newer phones most likely just look at the charge current during the first x seconds (or less) and then decide wether to enable fast charging or not to keep the cable from heating up. A wire with high resistance is basically a heater. So it's a necessary safety feature (from the companies POV).
Regarding the power bank, it may be possible that this particular design provides a voltage slightly higher than the nominal 5 volts (still fine for most devices), which helps overcome the resistance. That is also the reason why the Samsung fast charger provides 9V: You don't need a cable as thick as with 5V.
Keep in mind that the USB specifications only recently got updated for such high charging currents, so it is advisable to use only the cable that comes with the phone as USB cables in general don't need to provide such high currents by spec!
Click to expand...
Click to collapse
That sounds correct, although my Samsung wall adapter is fast charge capable, and was provided with a cable (and not a cheap one), that basically can't be use for fast charging with the G5, that looks silly...

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