Sick of Apple chargers? Solution: SupperCharger+, the Next Generation

[SharpEars]

So, I've had it with Apple mobile device chargers. You get them from Apple for $19 for the 12 Watters. Or, you get them on eBay for $5 for the Chinese 12 Watt knock offs. Both put out 5 V, more or less via a female USB connector (definitely less in the case of the knock offs).

It's not the price that bothers me. It's how slow the charging process is - quick charge my ass. So:

The bad: I want to charge my device as quickly as possible. Apple chargers just don't cut it. Chinese knock offs that drop their voltage to 4.75 V when loaded cut it even less than the Apple ones. The device limits the maximum rate of charge. The theoretical max is stated as 2.4 A at 5 V (i.e., 12 W).
The other bad: When using one of those Apple chargers, you're charging blind. I want to be able to see how many volts my supply is producing and how many amps of current my mobile device is pulling.
The other other bad: I want a clean supply with low ripple. Does it really matter? Probably not, but I want it anyway! Real Apple adapters have less ripple. Chinese knockoffs ripple like a lake under a thunderstorm.
The other other other bad: Apple's ultra thin lightning cable at a 2 A load sure drops some serious volts. I might consider using a shorter lightning cable not made by Apple. I might also consider taking a genuine Apple cable and cutting it close to the lightning connector to minimize the cable's length.
The good, finally: Apple devices can actually receive up to 5.30 V and still charge just fine. The charge current increases as the voltage increases, because the resistance of the device appears to stay constant. In other words the device does not adjust its load as the voltage increases (up to a point). This is true until the OVP kicks in at somewhere in the 5.4-5.5V neighborhood (will need additional testing to isolate this point across multiple devices).
The ugly: To charge at max current, you have to present a constant (and fairly accurate, +/- 3-5%) 2.7 V on the D+ and D- USB pins to fool the Apple mobile device into believing that it is in fact connected to a 12 W charger. This means that whatever I build will either need very good load regulation, so that I can use a resistor ladder divider to create the 2.7V or I will need an additional regulator for the 2.7V data line requirements.

So, enraged by slow charging times and fueled by my OCD, I've decided to build myself a charger - the SuperCharger+. I will spare no expense (OK, up to $300)! Saving money is not the object here. Weight of charger is not the object here (OK, maybe a little, I need to be able to transport it on my body or in a bag to work - its final home). I want:

• The quickest charge possible
• The ability to charge two disparate devices (e.g., iPhone and iPad) simultaneously or maybe even an iPad and a high current Android device that requires totally different D+/D- voltages
• Ability to monitor what is happening (i.e., voltage/current at/of the load).

The idea: Build the SuperCharger+. What is the SuperCharger+, you ask? Well, it will most likely consist of the following connected together:

1. Take a 5V +/- 10% adjustable power supply with sense screws ($300 budget on this). This puppy better have awesome load regulation (i.e., not 5-10% like ATX supplies). Hell, it might as well be linear to cut down on the ripple, too. The line input will be a steady 120 V (US), so I don't care much about line regulation.
2. Take two in-line USB dongles that show the voltage/current at/consumed-by the devices being charged. (Note: High end, not the wildly inaccurate $1 Charger Doctors/Shmuckders)
3. Create a voltage divider to take care of the 2.7 V USB D+/D- pin requirements (i.e., fool the Apple device into believing it's connected to an Apple 12 W charger)
4. Compensate for the voltage drop of the USB dongle from item #2 by using the power supply's (from #1) voltage sense inputs
5. Tune everything so that the output is a stable 5.3 V, independent of device load currents (the hard part)

The result - Be able to charge my devices as quickly as possible and have the ability to check periodically to make sure that they charge at the max current and max voltage they are configured to handle.

If you read this far, I am interested to hear your thoughts on my crazy (or not?) idea.

Update: This rant is about Apple chargers, but I have Android devices and they need charging too.
Update 2: This thread will be updated as progress is made on this project. For now I am at the power supply selection stage and your recommendations are welcome.

[IanB]

Meh. Much ado about nothing. Sorry.

[SharpEars]

Meh. Much ado about nothing. Sorry.

One man's nothing is another's fun project idea . Also, how many times have you had to leave the house/work and discovered your phone is dead? I have, many times! I wanted as quick a charge as I could get then and there. It would need to last me the hour (several hours?) I would be away. I didn't want to pack a battery pack or use a car charger. I just wanted to charge and go.

My common scenario is I have to leave in 5 mins and discover that my phone is dead or nearly dead. I want to get it charged as much as I can in that time frame. When your phone is about to die, every little bit counts.

[Mr.B]

2. Take two in-line USB dongles that show the voltage/current at/consumed-by the devices being charged. (Note: High end, not the wildly inaccurate $1 Charger Doctors/Shmuckders)

If you want high end... Here it is...

Forum member here iloveelectronics has an ebay store selling the YZXstudio USB Power Monitor.
Here: http://www.ebay.com/itm/USB-3-0-Power-Monitor-Red-YZXstudio-Voltage-Current-Meter-High-Resolution-OLED-/171606912751

He also runs a sales thread on the forum.
Here: https://www.eevblog.com/forum/buysellwanted/franky's-sales-thread/msg694265/#msg694265

I purchased a couple of them and they are very accurate.

[SharpEars]

2. Take two in-line USB dongles that show the voltage/current at/consumed-by the devices being charged. (Note: High end, not the wildly inaccurate $1 Charger Doctors/Shmuckders)

If you want high end... Here it is...

Forum member here iloveelectronics has an ebay store selling the YZXstudio USB Power Monitor.
Here: http://www.ebay.com/itm/USB-3-0-Power-Monitor-Red-YZXstudio-Voltage-Current-Meter-High-Resolution-OLED-/171606912751

He also runs a sales thread on the forum.
Here: https://www.eevblog.com/forum/buysellwanted/franky's-sales-thread/msg694265/#msg694265

I purchased a couple of them and they are very accurate.

Wow, nice! I already have one of these that I picked up for $8 on eBay:



But the one you linked to is much better, both in terms of functionality and precision (maybe even accuracy) at the 100 uA level.

[Melt-O-Tronic]

By "SupperCharger+", do you mean that it only charges during dinner time?  Or will it work at lunch too?   

My Apple experience is pretty limited (iPhone 6), but I've not had any issues with charging at all.  In fact, it charges much faster than all my Android devices, charge lasts longer, the display is informative & accurate with respect to charge level, etc..  So I guess I'm not seeing the pain point.   

[mtdoc]

I have one of the YZX monitors from Frankie as well. I agree, their great, especially the small size.

But for even higher end, the PortaPow premium USB power monitor is even better.

Resolution is 0.0001A and 0.0001V.

But, I agree with others. I've had no issues with Apple charges over many years.

[LabSpokane]

Before you spend much more effort criticizing Apple's chargers, you might do well to stick one on an oscope and actually see the output. Spoiler: they're solid - particularly in comparison to the cheap, off-brand models.

[Richard Crowley]

Before you spend much more effort criticizing Apple's chargers, you might do well to stick one on an oscope and actually see the output. Spoiler: they're solid - particularly in comparison to the cheap, off-brand models.

Can you explain whether that has any importance in the Real World?

[suicidaleggroll]

But, I agree with others. I've had no issues with Apple charges over many years.

I don't get it either, they're perfectly fine.

I also don't get what this fascination is with charging faster.  The faster you charge the battery, the more damage you do to it, especially if you start trying to "fool" the internal charging logic by cranking up the input voltage as high as you can.

[wraper]

I might consider using a shorter lightning cable not made by Apple.

Most of the knockoff cables have super thin strands. Quiet likely you'll get more voltage drop than with longer original cable.

The result - Be able to charge my devices as quickly as possible and have the ability to check periodically to make sure that they charge at the max current and max voltage they are configured to handle.

And waste more time of your life on designing/making than would ever save by "faster" charging 

[SharpEars]

This is in reply to several people that raised the concern that the Apple chargers are solid, if you monitor them (CV), hook them up to a scope (ripple and load regulation), etc...

Yes, but what they do not do is put out a constant 5.3 V output independent of load (charging) current. The SuperCharger+ will allow for the charging of up to two devices that will be getting 5.3 V (constant and well regulated) regardless of current load and whether they like it or not. This is the difference - up to 0.3 V extra per port.

Also, in answer to this having a detrimental affect on the battery being charged, it's all within spec, the USB 3.0 spec (max VBUS voltage is 5.3 V), so Apple has to have allowed for this and I will be just taking advantage of it.

[SharpEars]

I might consider using a shorter lightning cable not made by Apple.

Most of the knockoff cables have super thin strands. Quiet likely you'll get more voltage drop than with longer original cable.

The result - Be able to charge my devices as quickly as possible and have the ability to check periodically to make sure that they charge at the max current and max voltage they are configured to handle.

And waste more time of your life on designing/making than would ever save by "faster" charging 

You do realize that I can just trim the USB Type A male connector part of the lightning cable to shorten it and still keep the lightning connector side none the wiser, while cutting resistance by a factor of four or five.

[Monkeh]

This is in reply to several people that raised the concern that the Apple chargers are solid, if you monitor them (CV), hook them up to a scope (ripple and load regulation), etc...

Yes, but what they do not do is put out a constant 5.3 V output independent of load (charging) current. The SuperCharger+ will allow for the charging of up to two devices that will be getting 5.3 V (constant and well regulated) regardless of current load and whether they like it or not. This is the difference - up to 0.3 V extra per port.

Also, in answer to this having a detrimental affect on the battery being charged, it's all within spec, the USB 3.0 spec (max VBUS voltage is 5.3 V), so Apple has to have allowed for this and I will be just taking advantage of it.

You are making the assumption that this will increase the battery charging current. This could easily not be the case.

[wasyoungonce]

I've pulled apart and repaired apple chargers.  One thing to note...the USB power pins (on the charger socket) get burn't (carbon'd up) due to the excessive current.   USB was only supposed to be ~ 500mA ~1A max and at max current this is really exceeding the ability of the contacts of these pins....IMHO Apple is almost pushing these too much.

[SharpEars]

This is in reply to several people that raised the concern that the Apple chargers are solid, if you monitor them (CV), hook them up to a scope (ripple and load regulation), etc...

Yes, but what they do not do is put out a constant 5.3 V output independent of load (charging) current. The SuperCharger+ will allow for the charging of up to two devices that will be getting 5.3 V (constant and well regulated) regardless of current load and whether they like it or not. This is the difference - up to 0.3 V extra per port.

Also, in answer to this having a detrimental affect on the battery being charged, it's all within spec, the USB 3.0 spec (max VBUS voltage is 5.3 V), so Apple has to have allowed for this and I will be just taking advantage of it.

You are making the assumption that this will increase the battery charging current. This could easily not be the case.

I have empirically tested this and in fact it does increase the current until a cutoff voltage is seen at the device being charged. There is a built in safety mechanism that cuts the current at a certain, let's call it, overvoltage, a sort of OVP.

5.30 is well below the OVP and within the guidelines of correct and acceptable USB voltage.

[SharpEars]

I've pulled apart and repaired apple chargers.  One thing to note...the USB power pins (on the charger socket) get burn't (carbon'd up) due to the excessive current.   USB was only supposed to be ~ 500mA ~1A max and at max current this is really exceeding the ability of the contacts of these pins....IMHO Apple is almost pushing these too much.

Thanks for letting me know, I will check the female Type A USB socket periodically on the final charging unit and clean and/or replace it. It's going to cost me a total of $0.25 to do so (and some soldering, of course). With an apple adapter, assuming you can't clean/repair it, you're out $19 at current prices.

Additionally, I may cut off the USB Type A male end from a lightning cable and skip the whole USB end of the equation, plugging in the actual cable strands into my charging board and the lightning end into the device to be charged. Running a parallel micro-usb terminated cable (with dangling wires on the other side) will enable me, via a screw terminal for example, to be compatible with Android devices as well.

All food for thought as I make my nefarious plans for world domination the SuperCharger+ .

[Monkeh]

This might also be an interesting time to point out that many devices use linear charge controllers, which means you're just increasing heat dissipation..

But you need your phone charged five minutes sooner.

[SharpEars]

This might also be an interesting time to point out that many devices use linear charge controllers, which means you're just increasing heat dissipation..

But you need your phone charged five minutes sooner.

I don't think that the change in current resulting from a change from 5.0V to 5.3V will result in a very significant change in heat buildup within the device itself. Mobile devices are often charged in purses, on top of hot laptops, in one hundred degree climates, under the sun and who knows what else. They are designed to handle these extremes. The SuperCharger+ is going to sit in a climate controlled office that is kept at seventy degrees Fahrenheit with excellent air circulation at all times. It doesn't get much better than this for heat reduction, so I do not foresee a heat issue when the actual load and surrounding environment are taken into account.

[wasyoungonce]

Some info on Ken Sherrif's blog about Apple chargers.
http://www.righto.com/2012/05/apple-iphone-charger-teardown-quality.html

[rs20]

Geez, there's a lot of hate on this thread. Haven't we all done pointless* projects in the past? Isn't it more about the journey than the end result?

* I'm not saying the OP's project is pointless, but even if it was...

This might also be an interesting time to point out that many devices use linear charge controllers, which means you're just increasing heat dissipation..

Would that explain the increased current draw seen by the OP at higher voltages? A linear reg would have more-or-less constant input current, right?

Given the voltage drop that can occur over a cable at high currents, it seems legit to up the voltage at the charger end. I doubt there's a need for having sense wires running to the phone end of the cable; although it would be very interesting for the purposes of investigation. As an alternative, you could measure the internal resistances of various cables by replacing the phone with a short circuit, and seeing what the voltage drop is around that loop for typical charging currents.

[Mr.B]

How to fast charge your phone:
1. Throw iPhone in the rubbish.
2. Buy a Samsung Galaxy S6

The charger is 18w.
Runs 5V @ 2A unless it detects that it is plugged into an S6, then steps it up to 9V @ 2A.


<<<Exits quickly before the flaming starts...

[WZOLL]

What Iphone device do you have. Some can only charge at 1A no matter the wire or charger.

[BradC]

I have empirically tested this and in fact it does increase the current until a cutoff voltage is seen at the device being charged. There is a built in safety mechanism that cuts the current at a certain, let's call it, overvoltage, a sort of OVP.

5.30 is well below the OVP and within the guidelines of correct and acceptable USB voltage.

I'm not ragging on you and I'm not being negative. I'm actually genuinely interested in the figures. Have you actually measured this and what sort of current increase are you seeing (in actual numbers)?
What you say makes perfect sense from a logic perspective. I'm actually interested in the hard data to see *how* much of a speedup this will give you? (and me if I build one).

I have the iPad 3, which happens to be the unit with the longest charge time, so anything greater than 10% increase I'd find interesting.

[SharpEars]

What Iphone device do you have. Some can only charge at 1A no matter the wire or charger.

I have an iPhone 5 (aware of the 1 A limit, but that's 1 A at 5 V), so I am trying to break 1 A. My iPad Air 2 can theoretically max out the 12 W Apple adapter (so 2.4 A, there). I want to push that to the limit as well. Both devices have OVP, so no harm in finding when that kicks in.