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Some chargers slower than others

Unfortunately I left my Nexus 7 charger in a hotel room a month ago and it has not yet been handed in. Consequently I have had to buy an off the shelf charger. One I tried stated that it was rated at 2 AMPS, and it does work, but at about 1.5-2x the charging time as the stock charger. I also noted that when using that charger the Nexus system did not say it was charging, although it obviously was.
I just obtained another charger rated at 2.5 AMPS and it performs exactly as the stock charger. Has anyone else noted this - that if the charger outputs less than 2 AMPS the Nexus 7 does not notify the use that it is charging and does so at a much slower rate?
Larry

My understanding - the charger has to let the device know it supports high current mode. Otherwise the Nexus limits it to 500 ma, which is correct for a cable plugged into a computer.
Sent from my Nexus 7 using xda app-developers app

rmm200 said:
My understanding - the charger has to let the device know it supports high current mode. Otherwise the Nexus limits it to 500 ma, which is correct for a cable plugged into a computer.
Sent from my Nexus 7 using xda app-developers app
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This is true; the same method applies to samsung chargers. There has to be 5v on one of the data lines as well to let the device now it should change to high-power mode.
Search for a tutorial on what to solder together inside of the charger or buy an official samsung charger of at least 1A (I believe Galaxy S2 chargers have that output).

Maximum safe charging amps?

SO I am thinking of building my own charger for the Nexus 10 (for personal use only, not to sell). I am thinking of using a 5v PSU that puts out 6 amps (30 watts). I would be wiring the USB cable into the outputs of the PSU for connection to the tablet. Does anyone know if this would be safe to do for charging? I know the USB charger has a max amperage of 2A, and that is what the official spec says. But there are rumors of a pogo pin charger that will charge much faster, so higher *should* be safe enough to do for charging through USB right?

The tablet will only pull what it needs
Sent from my HTC PH39100 using xda app-developers app

See the lengthy discussion on this in the pogo charger thread, or just take the comment above.
With current, you only need to make sure your supply can "suoply" enough current, it can never be too much.
Sent from my GT-I9300 using Tapatalk 2

[Q] Any electricians here? 5V 2.1A charger for N4

The one that came with the phone is rated at 5V 1.2A...
The problem is, it's constantly giving off buzzing sounds and it also seems that sometimes it charges more slowly than other times, it also happened that when left overnight, in the morning the phone was charged to only ~85%... So I'm thinking of getting a new one. Is it safe to get a 2.1A charger?

Yes because it's the phone that courses hour much current to draw, the value of the charger is just a maximum that it can supply. The Nexus 4 doesn't even draw the Max 1.2A of the stock charger.
Sent from my Nexus 4 using xda premium

The Nexus 4 only pulls 900mAh. 2.1A is overkill, but won't hurt anything.

Nexus 4 wireless charger plug amperages

Having just got the Nexus 4 wireless charger and looking at the plugs that come with the phone and wireless charger I am questioning using the usb wall adapter for the wireless charger directly with the phone. The amperage is different from the two plugs,
the phone plug is 5.0 volts at 1.2 amps
the nexus 4 wireless charger plug is 5.0 volts at 1.8 amps.
Just wondering how much the 0.6 amps will degrade my battery over time if I choose to use the wireless charger plug say for traveling because I only want to bring one plug and may use both the wireless charger and directly plug the phone into the usb cable.
**edit
From Nexus 4 Manual
"Use only the travel adapter and micro USB cable that come with your Nexus 4. Using a different travel adapter or cable may damage your phone"
From Nexus 4 wireless charger manual
"Use on the power adapter and micro USB cable that come with your nexus 4 wireless charger. Using a different power adapter may damage your phone or reduce charging efficiency"
It also tells me that the output is 5.0 volts at 1 amp
So basically this is telling me it will "damage" my battery over time if i use the wireless charger adapter with the phone directly via a USB cable?

The N4 only draws around 0.8A max. So both the stock charger and the wireless charger will never use their full current, because the phone will never draw more than 0.8A anyway.
Chargers don't "push" current, the phone is in control and "pulls" what it needs.
You will not damage your phone.
Sent from my Nexus 4

steviewevie said:
The N4 only draws around 0.8A max. So both the stock charger and the wireless charger will never use their full current, because the phone will never draw more than 0.8A anyway.
Chargers don't "push" current, the phone is in control and "pulls" what it needs.
You will not damage your phone.
Sent from my Nexus 4
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Thanks you, never knew this

Also keep in mind the additional 600mAh is probably to make up for the loss of current thru the inductive charging process. wait, is it inductive? brain fart,, either way its probably meant to compensate for the fact that there is no direct link to the phone.

If you read around, you'll find out that inductive charging does produce quite an amount of heat, its not as effective as direct charging, the conversion rate is around 70%. Hence the extra 0.6A to compensate for the loss of energy via heat. The efficiency of most wireless chargers is a little more then 70% (70% of 1.8A is 1.26A)

leader288 said:
If you read around, you'll find out that inductive charging does produce quite an amount of heat, its not as effective as direct charging, the conversion rate is around 70%. Hence the extra 0.6A to compensate for the loss of energy via heat. The efficiency of most wireless chargers is a little more then 70% (70% of 1.8A is 1.26A)
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Acutally the conversion rate could reach around 75%, the heat is very low if you put the phone on the right place. Actually different wireless charging pad requires different input working current, but qi standard do required a 2a input ability.

steviewevie said:
The N4 only draws around 0.8A max. So both the stock charger and the wireless charger will never use their full current, because the phone will never draw more than 0.8A anyway.
Chargers don't "push" current, the phone is in control and "pulls" what it needs.
You will not damage your phone.
Sent from my Nexus 4
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I'm not a nexus 4 user but u do use the wireless charger. Did you use any app to measure that 0.8 mA current drawn from Nexus 4? On S4, using galaxy current app i got 640 mA on 3rd party receiver at back of S4. I wonder what is the actual built in wireless receiver on Nexus 4 able to take?
Sent from my GT-I9505 using Tapatalk 4
---------- Post added at 11:10 PM ---------- Previous post was at 11:09 PM ----------
ibnmurad said:
I'm not a nexus 4 user but u do use the wireless charger. Did you use any app to measure that 0.8 mA current drawn from Nexus 4? On S4, using galaxy current app i got 640 mA on 3rd party receiver at back of S4. I wonder what is the actual built in wireless receiver on Nexus 4 able to take?
someone kind enough to provide me actual current drawn by Nexus 4 from the wireless charger. thanks
Sent from my GT-I9505 using Tapatalk 4
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Sent from my GT-I9505 using Tapatalk 4

different charger amp levels

I recently bought the nexus 4 and have been having a blast with it. For a little while I lost the USB charger in my house, so I started using my iPad charger for it. Since the stock nexus 4 charger has an output of 1.2 amps 5v DC and the iPad charger has 2.0 amps 5v DC would prolonged use of the iPad charger possibly affect how long the battery last since it charges it faster then normal, or am I just being stupid and its fine to use the higher amperage charger?

There is a lot of threads explaining this but I'll explain the best I can higher amp equals quicker charge however gets the battery hotter so the battery life could be affected
Sent from my Nexus 4 using xda premium

It is the phone that decides how much current to "pull", not the charger that "pushes" it.
So it's fine to use a higher-rated charger.
Sent from my Nexus 4

steviewevie said:
It is the phone that decides how much current to "pull", not the charger that "pushes" it.
So it's fine to use a higher-rated charger.
Sent from my Nexus 4
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This info is correct. You have nothing to worry about.
Unless you go stupidly over. Like 13 amps will probably overload and Fry the charging circuit.
But at 2 amps you will be fine
Sent from my Nexus 4 using xda app-developers app

Current is not pushed... it is drawn. You could have 20 Amps available (like a typical 120V outlet). Whatever current the device plugged into it needs it will draw... nothing more.
With that said, Apple chargers do not short pins 2 & 3 (data pins) of the USB connector. Instead, they put a resistive load across them to communicate the charger specs to the device. Nexus (and most OEM Android) chargers short these pins. Some android devices, Nexus 7 for example, sense the load on Apple chargers' data pins and assume it is a computer and drops the load to draw only 500 MA. I have not tested the Nexus 4, but would assume it behaves the same way as a Nexus 7.

Okay thanks guys. I did notice it was a little warmer, but i think that might have been from the emulator on that i was using. Just wanted to make sure i was killing the overall possible battery life.