iPad Pro 87W USB-C charger doesn't charge 12.9" iPad Pro @ 29W

[masotime]

That is good news indeed. Perhaps it's time to re-run a test against the 87W adapter.

 

[Macyourdayy]

We are interested. Please bring along to test too a non-Apple PD PSU. With your analyser instrument, please observe whether iPad Pro+MacBook Pro-C PSU run at nine volt, or twenty volt (top range).

I think your main obstacle is to access an iPad Pro, when its battery is of a low state of charge. Because store display models are usually plugged-in, you likely will find their batteries are already topped-up.

Funny you should mention the battery state of in store iPad pros. You would imagine they would be fully charged, or close, but I'm constantly amazed to see the varying, usually bizarrely low, levels of charge on the iPads, especially the big ones.

 

[masotime]

So I managed to acquire the 87W adapter again and re-running tests I have these new results:

87W USB-C Charger (iPad Pro 12.9", iOS 10.2.1)

• 0% to 17% in 30 mins,
• 0% to 35% in 60 mins (cumulative testing)

Which yields 0.58% / min, which is in line with my previous test results (all around 0.6% / min). In other words, there is no change in the performance of the 87W adapter. This is all done using the official Apple charger and USB-C to Lightning cable.

However I did take the time to test the official Apple 12W charger w/official Apple USB-A to lightning cable:

12W USB-A Charger (iPad Pro 12.9", iOS 10.2.1)

• 0% to 12% in 30 mins,
• 0% to 27% in 67 mins (cumulative testing)

which yields 0.4% / min. The difference is significant.

At this point, my best guess is that the 87W charger is charging at 18W, even though it's not part of the specifications (very odd). If anyone wants to contribute additional data points, it would be great (these tests are pretty tedious to setup).

However, these still fall short of the much faster charging rates of the 29W adapter.

In 1 hour

• 12W | 0 to 24% (projected)
• 87W | 0 to 35%
• 29W | 0 to 56% (ref. 1st post)

Well this will probably be my last testing on this. I'm expecting a new iPad Pro 12.9" in March - hopefully Apple will get it right this time instead of these inconsistencies in charging rates.

 

[masotime]

After reviewing this thread, I have a few conjectures:

@Brookzy mentioned that Apple had updated their support document with the language "fast charge" - https://support.apple.com/en-gb/HT205807

The language is inherently vague - technically 18W is faster than 12W, so I suppose Apple is "legally correct" that the 87W fast charges, but it's definitely nowhere as fast as the 29W charger.

Given also that @Nathan-K found the USB-C to lightning cable to only negotiate at a "dumb 2A", and that the 87W adapter supports the voltages 20.2V, 9V and 5.2V, it makes sense that the iPad Pro 12.9" would select 9V @ 2A = 18W. 20.2V x 2A ~= 40W, which is too high, and 5.2V x 2A = 10.4W < 12W.

 

[Marshall73]

My 12.9 Pro charged from 2% to 100% in 2hrs 46mins on my rmbp 87w charger vs 4hrs+ on the 12w charger. Quite happy with that though.

 

[masotime]

My 12.9 Pro charged from 2% to 100% in 2hrs 46mins on my rmbp 87w charger vs 4hrs+ on the 12w charger. Quite happy with that though.

Yes that seems accurate.

• The 87W charger will charge 35% per hour, and take about 2hr 50mins from 0 to 100%
• The 12W charger will charge 24% per hour, and take about 4hr 10mins from 0 to 100%
• The 29W charger will charge 56% per hour, and take about 1hr 50 mins from 0 to 100%.

 

[John.B]

Yes that seems accurate.

• The 87W charger will charge 35% per hour, and take about 2hr 50mins from 0 to 100%
• The 12W charger will charge 24% per hour, and take about 4hr 10mins from 0 to 100%
• The 29W charger will charge 56% per hour, and take about 1hr 50 mins from 0 to 100%.

Do we know how the 61W charger compares?

 

[masotime]

Do we know how the 61W charger compares?

Unfortunately I didn't test with that charger, although I would assume it is the same as the 87W.

This photo from macotakara suggests the same 9V/3A output, which when regulated down to 2A by the cable would provide 18W:

 

[butterburger cookybutter]

Well, in that case unfortunately this is as far as I go.

Please enable private messaging, or as it is called here, Conversations. If you are interested in iPad and USB PD, then please 'Watch this thread' and enable email notifications. We were really glad to have your attention while it lasted, and we might have further development to catch your attention. If you had returned here to read newer posts, then you would have read this:

Last night I charged up my iPad Pro using the Apple 61W USB-C power brick and an Apple USB-C to Lightning cable. It was definitely faster than a standard 12W charge. Maybe it is negotiating 27W now, as of iOS 10.2.1.

And then you would not have been mistaken:

Nathan K.
> I was discussing with some pro-users on the Mac Rumors forum, and
> apparently the iPad Pro 12.9" will not fast charge even with Apple's
> own 61w/87w adapters.
Brad Cox
> The iPad Pro 12.9 inch requests the 9V profile with the MacBook 61W
> and 87W chargers.
Nathan K.
> Really??

edit add:

The USB-C ports on the 2016 MacBook Pros charge the iPad Pro no faster than modern USB-A Macs unfortunately. Well, at least according to System Information.

Current Available (mA):    500
Extra Operating Current (mA):    1600
Sleep current (mA):    2100

I have a MacBook 12-inch which, like iPad Pro, recognises Apple 12W (2.4 A @ 5 V) power supply. I measured it drawing 2.277 A from a 12W supply, and 2.277 A from MBA2013 and MBP2013 (when tricked to think it is "12W" instead of rated 2100 mA) . This measurement is repeatable, not a one-time coincidence: MacBook 12-inch 2015 draws actual 2.277A from nominal 2.4A supply. (Measured with a Keysight U1232A, less than one year since calibration.)

 

[Nathan-K]

Butter, I apologize if I did not reply. But as a volunteer, I have extremely limited time and funds to pursue testing. This is especially the case for Apple devices, as I do not own many and they are quite expensive. Any testing I do involves driving 45 minutes to the nearest Apple Store, waiting in line, asking the manager for permission, then conducting (limited) tests under the supervision of a Genius. And this is at my own volition.

As for the charging, there may have indeed been a firmware change on Apple's side. But I have not seen proof of it beyond a few comments *with no data*. At the time of my posting, all my statements were true and correct. The iPad Pro does something proprietary, and frequently fails to charge at all with USB-PD complaint supplies. This much has been proven.

Additional data corroborating this can be found at GTrusted (www.gtrusted.com). If there has been a change, there is still some kind of bug restricting the device's performance. I simply do not have the time resources or motivation to investigate it. Sic:

--------------------------------

http://gtrusted.com/review/apple-ip...w-usb-c-power-adapter-over-usb-power-delivery
"The oscilloscope confirms the Apple iPad Pro draws around 5 volts @ 2.4 amps from the Apple 87W USB-C Power Adapter when fully charged."

http://gtrusted.com/review/verizon-...-pro-using-usb-power-delivery-although-slowly
"The Apple iPad Pro finally only requests 5 volts @ 2.4 amps from the Verizon USB Type-C Wall Charger with Fast Charge Technology."

http://gtrusted.com/review/ivoler-7...st-as-using-the-apple-29w-usb-c-power-adapter
"The Apple iPad Pro needs 14.8 volts for charging quickly over USB Power Delivery but for some reason the iPad Pro only requests 12 watts (5 volts @ 2.4 amps) of charging from the iVoler 75W USB Type C Charger."

http://gtrusted.com/review/charging...-google-pixels-charger-via-usb-power-delivery
"The Apple iPad Pro then requests 12 watts (5 volts @ 2.4 amps) of charging power from the Google 18W USB-C Power Adapter."

http://gtrusted.com/review/proving-the-apple-ipad-pro-supports-usb-power-delivery-over-lightning
"Based on the protocol trace below, the Apple iPad Pro supports can be charged through USB Power Delivery either at 5 Volts @ 2.4 Amps or the 14.8 Volts @ 2 Amps (29 Watts) that you get from fast charging with the Apple 29W USB-C Power Adapter."

-----------------------------------

If there have been any changes since then, I need to see the data first. And that entails redoing all those tests I cited above. Again -- I lack the means to do this as an unpaid volunteer. If there is additional data, please do share it with me.

(I will re-read this thread right now to see if there have been any developments I have missed.)

 

[masotime]

It actually looks like butterburger copy / pasted some of the website's documentation, which made his message seem cryptic, and perhaps a little moody in the context of the rest of his message.

 

[butterburger cookybutter]

If I ever seem cryptic, confusing, misleading, impertinent, or moody; then tell me so. We have the technology: private messages in Webforum software. I like criticism, and I like clarity, and MacRumors allows us to revise our words.

If there is additional data, please do share it with me.

I do not have any data to share regarding iPad Pro. A few weeks ago, I very much wanted to tell you something. It is completely off-topic, not related to this thread.

I bought a Samsung T3 SSD. It is (of course) a power leaching liar (claims to be self-powered, but storage module is always powered, so draws in exess of 400 mA even when USB device not configured, or behind bus-powered hub) like almost every other bus-powered bridged ATA storage device ever. Its storage module of course features ATA Security (which I consider an antifeature). But what is really interesting, and what I wanted to bring to your attention, Nathan-K, is its included cable.

Samsung T3 SSD comes with a SuperSpeed A to C cable which is peculiar. Whenever its C end is connected to MacBook and A end is connected to VBUS (so C plug is facing downstream, MacBook receptacle is UFP), then MacBook believes it is connected to a 12W power supply.

Maybe MacBook is misinterpreting a truth, and MacBook is the one misbehaving, tripping overload in every little USB PSU I can find. But my MacBook behaves as expected when connected with a proper A to C cable: does not always believe power is supplied, looks for Apple power adapter signal scheme voltages on data pins (it recognises all four power levels of 2W 5W 10W & 12W). So I suspect this Samsung cable is the one doing something fishy.

I checked, and this Samsung cable is not pulling data pins to 2.7 V (2.7 V on both data pins is Apple's signal of 12W (2.4 A @ 5 V) supply). Can an E-Marker say "I'm a 2.4A@5V PSU"? I am too lazy to research. If E-Marker cannot say anything about power supply: then maybe a PD chip is inside C plug, and this cable is negotiating PD. (! whoah!)

I wanted to give this T3 to you, Nathan-K. Gratis, no strings attached, I only hoped you might inspect its cable for your own curiosity. But I did not know how to contact you, so I returned it.



I also wanted to clue you in regarding those PCIe AHCI to SuperSpeed USB bridges:
maybe so-called LM900 exists, or maybe it is PLX USB 3380 (USB3380). It has been seen in OWC Envoy Pro since December 2014 (available for order then, though I do not know when orders began shipping). (I like to word bus bridges as downstream bridged to upstream. Benson Leung described it upstream to downstream 'USB device to PCIe host controller bridge'.)

 

[masotime]

The Google+ post had some great info posted by "Brad Cox". The charts show how the 87W charger charges the 12.9" iPad Pro, and confirms the 18W charging rate:

It's interesting that it initially negotiates 5.2V/2A before stepping up to 9V/2A.

I suspect that charging the other iPads with Apple's USB-C to lightning cable may actually be slower because of the 2A limitation (12W requires 5V/2.4A).
[doublepost=1488556005][/doublepost]Seems they have a 45W charger for $45 that does charge the 12.9" iPad Pro at 29W! First time I've seen this, pretty cool. Apparently it's out of stock though

https://mobileaccessories.ventev.co...rgers/4468042__Ventev-wallport-pd1300-Charger

 

[Nathan-K]

(Regarding notes)

Hey Burger, thanks for the heads-up. Let me try to respond to your points in order, pardon the mess:

• I do not have PM's enabled here since I found I was on too many sites and I was getting messages from people that I was never able to discover/respond to, and felt horrible about that.
  
  To me, it's more polite to honestly refuse PMs in the first place, than have people send e-mails to a "black hole" and be in limbo when I do not reply. (Also, it helps me CYA regarding NDA's since everything is out in the open.)
  
  
• Regarding iPad pro data, Brad Cox (a professional associate at Ventev, a peripheral maker) kindly ran an experiment on the latest firmware/hardware. You can see the photos here, Apple did change the firmware and it charges at 9v. However, it still charges slower than 14.5v according to him.
  
  I greatly thank him for being kind enough to provide this data -- although to be fair, it is a bit of PR for his company. But I don't care as long as the data is good and the charger is safe, and users are protected.

iPad Pro (as of today)

iPad Pro 12.9 on 87w with 9v profile only (as of today):

iPad Pro on "Ventev" new charger:
https://mobileaccessories.ventev.co...rgers/4468042__Ventev-wallport-pd1300-Charger

• Regarding a donation of a Samsung T3, I appreciate the offer but I cannot accept at this time. There were a number of reasons why I (temporarily) stopped accepting equipment donations, some personal, some professional. I detailed them briefly here: I greatly appreciate your kindness, however!
  
  https://plus.google.com/u/0/102612254593917101378/posts/6ZNa598V5Mi
  
  
• USB products drawing current when not enumerated is bad, but 400mA is around a "2" on the 1-10 "evil meter". About as bad as Jaywalking. It is a flaw, for sure -- should limit itself to 100mA until enumerated -- but it's not something I suggest starting a riot over. (Things like Anker cable, however, were! That was like an "8". Belkin 27w car charger is about a "6". Etc.)
  
  Frequency x Severity = Impact. The impact in this case is rather low.
  
  
• "Whenever its C end is connected to MacBook and A end is connected to VBUS (so C plug is facing downstream, MacBook receptacle is UFP), then MacBook believes it is connected to a 12W power supply."
  
  This is odd. What chargers are you using? It would only do this if the USB D+/D- signals were 2.7v/2.7v. If the charger can't actually SUPPORT 12w, despite sending those signals, that would be the charger's problem -- not the MacBooks.
  
  Now, if the cable ITSELF falsified 2.7v/2.7v signals.... that is incredibly unlikely and would be a pretty freakin' weird. (Mailman opening your letters, replacing all instances of "now" with "meow". Not saying it can't happen, but it's VERY unlikely.)
  
  
• "Can an E-Marker say "I'm a 2.4A@5V PSU"?"
  
  I can't answer that, the question is too vague. Theoretically anything is possible, but without clarification what you mean I can't say.

"I also wanted to clue you in regarding those PCIe AHCI to SuperSpeed USB bridges: (LM900)"

I'm listening. Benson explicitly told me they did not exist. I'm inclined to trust him. Although the LM900 chip still intrigues me.

 

[butterburger cookybutter]

I do not have PM's enabled here

Okay.

> There were a number of reasons why I (temporarily) stopped accepting
> equipment donations, some personal, some professional.

I did read that. But I was not hoping to "submit a cable for outsourced safety and suitability evaluation", have you run tests and rate it between minus- and plus- three.

My thought was "Whoah, this is bizarre; like, they added expense and went out of their way to make this cable tell a lie; I bet Nathan-K has not seen this quirk yet!". And if you were too busy then I thought, you could just add it your "projects to take a look at and puzzles to solve, eventually" box. (I think everyone has a milkcrate/shoebox/closet/attic/under-bed where projects accumulate until free time is found.)

> This is odd. What chargers are you using?

Any. If you really want to know, then I will post model numbers. It does not matter. Whether actual supply is a real USB bus, Apple power scheme PS, generic "data shorted to each other, together floating" PS, or data pins not connected (using tape or paper as insulator, or using bare USB A receptacle wired to a high current power supply), my MacBook always treats this Samsung cable as a 12W supply.

My MacBook behaves as expected in all of those situations, when using a "proper" cable. Where "expected" is: not connected data = not a power supply, draw less than one milliamp; data shorted to each other, together floating = "2W" (500mA); Apple scheme = Apple scheme (2W 5W 10W 12W). (I trust Belkin F2CU029bt1M is proper.)

> Now, if the cable ITSELF falsified 2.7v/2.7v signals.... that is
> incredibly unlikely and would be pretty freakin' weird.

Right, and I expect that would interfere with USB traffic. But I poked at it, and both data pins are "clean", isolated from V & G.

(I poked at an A receptacle while bus power was "live". I do not have any C receptacle breakout, so I just assume: if data pins were totally isolated in A receptacle, then they've "gotta be" likewise isolated in C plug. It would be weirder than weird if there was Apple power scheme voltage at C data pins while NOT at A data pins.)

> It would only do this if the USB D+/D- signals were 2.7v/2.7v.

Right, so I conclude this cable is doing something tricky with C pins in C plug. Possibly E-Marker, possibly Power Delivery communication, possibly MacBook is deranged.

>> Can an E-Marker say "I'm a 2.4A@5V PSU"?
> I can't answer that, the question is too vague.

I know that E-Marker can say things like "I have auxiliary communication bus" (those sideband wires for, such as, DisplayPort or whatever) "I have conductors rated for so many amperes" "I have optical fibre" "I have a serial number" "I can communicate at ten gigabaud".

Can an E-Marker say "I am a 12W power supply" or "I can supply 2.4 A at 5 V"?

If an E-Marker can say something about power (not just electrical current), then maybe this Samsung cable lies through its E-Marker. Otherwise, I do not know what is left, but Power Delivery. So if not a crooked E-Marker, then I imagine Samsung put a crooked PD communicator chip into their T3 SSD cables.

Does A-to-C cable even need an E-Marker?



> Benson explicitly told me they did not exist.

A "turnkey" IC might not exist yet, and might never exist. (I see no point.) But PLX USB3380 existed since a few years, and "anybody" could program it to act role bridging (host a PCIe AHCI)-to-(SuperSpeed USB MSC peripheral).



Off topic off topic: I do not know what to call that "ten gigabaud USB speed". Is it most properly referred to as: SuperSpeed+, SuperSpeedPlus, SuperSpeed Plus, SuperSpeed 10Gbps? If USB-IF put naming convention in their Web site for all to see (without downloading a PDF file), then USB would be that much better. See SATA-IO's Naming Guidelines as an example of what such Webpage should look like.

Off topic off topic off topic: Intel said we eventually would see NVMe (interface) over USB. I cannot wait for that. I wish it were here already. I wish it were here seven years ago. I doubt many people during nineteen eighties thought, that ATA would be so prevalent thirty years later.

2017-09-10 edit : substitute one word mistake

 

[KPOM]

Butter, I apologize if I did not reply. But as a volunteer, I have extremely limited time and funds to pursue testing. This is especially the case for Apple devices, as I do not own many and they are quite expensive. Any testing I do involves driving 45 minutes to the nearest Apple Store, waiting in line, asking the manager for permission, then conducting (limited) tests under the supervision of a Genius. And this is at my own volition.

Obviously this won't be as accurate as your elaborate equipment, but are devices like these useful?
https://www.amazon.com/gp/product/B01NAWYSVK/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

I can afford the $25, so I got one. It does report that the 29W charger delivers that to my 13" rMBP (14.5V and usually somewhere between 1.9 and 1.99A), and that it drops down to 12W when charging a battery pack that I have that has a USB-C port.

The reason I ask is that I recently ordered a Dart-C cable for an original Dart that I'd like to test. Finsix claims that the Dart-C is fully USB-PD compliant, but they haven't explicitly said so for the adapter cable for the older Dart. I plan to at least perform some basic tests on my MacBook Pro using the Plugable meter when the cable arrives (supposedly later this month). I like the idea of small travel chargers, and the original Dart seems to work with my HP notebook. It's too bad that it seems to be only startups pushing this.

On a side note, if you'd be interested in testing a Dart let me know and I can ping you on Google+.

 

[Jaap]

@Nathan-K please give us a link to your Patreon account if/when you set one up.

 

[Brian Murray]

I tested my 12.9" iPad Pro with several combinations of USB-PD chargers and cables. I tried chargers and cables from both Apple and from 3rd parties. I used a Satechi USB-PD power meter to measure the power draw.

The iPad Pro was 25% charged. I took measurements with the display on and set to 100% brightness. The Apple cable was 2m and the 3rd party cable was 1m.

Both chargers were rated for 29w USB-PD. I purchased the 3rd party charger on ebay. The third party charger output ~29w when connected to a non-Apple laptop. I could not measure the 3rd party charger when connected to an Apple laptop since a compatible laptop was not available.

I'm trying to find a 87w Apple charger for additional Analysis. If I am able to do so, I will post the results.

For verification, I measured the chargers power draw with a Kill-a-watt meter. The wattage readings from the Kill-a-watt were consistent with the figures from the Satechi USB-PD power meter.

I have access to a USB-PD protocol analyzer at my job. If I have time, I may capture the USB-PD negotiation and try to figure out why the iPad Pro is not interoperable with standards compliant USB-PD chargers.

 

[masotime]

Thanks for taking the time to do the analysis @Brian Murray. Your data certainly supports the fact that the Apple cable is locked to 2A.

The Ventev charger is in stock, and I suspect it is one of the few 3rd party chargers than can charge @ 14.5V/2A. You might want to test with it - I'm personally tempted to try it myself.

 

[Mike Boreham]

I found this thread researching a related question about the 87W Apple USB-C charger. Since my question is not related to iPads I started a new thread in the appropriate section.

I am posting a link to that thread because I see there are some seriously knowledgable people here who likely know the answer.

Would be very grateful if anyone could take a look at my new thread:

https://forums.macrumors.com/threads/use-apple-87w-charger-with-macbook.2040394/

Thanks

 

[butterburger cookybutter]

Hi all. I, too, bought a Satechi Type-C Power Meter. I am sorry I took so long to write this report. (I wanted to have it done two weekends ago.) I bought too Plugable USBC-VAMETER; I hope to post a report about it within a week. To readers who want to know which to buy, and do not want to wait until I complete my report, I tell you this during the meantime: they are very similar, only Satechi's is skinnier and Plugable's is cheaper. When I mention numbers measured by "my Keysight", I am referring to a Keysight U1232A which is within one year of calibration.

Voltage measurement accuracy:

My Satechi Type-C Power Meter agrees with my Keysight on measured voltage, though it measures slightly lower. Its measurement is noisy: readings continually vary from mode by ±2 counts, and infrequently by ±3. (Its count resolution is 0.01 V.) Its 0.01 V resolution is useful to compare qualitative test results. ("Which cable sags more? Which mobile power bank will give me a competitive edge in speed charging a current-limited iPad?" A one user may compare relative centivolts of devices.) However, I think it is not quantitatively significant. (It is not accurate enough for product reviews or to compare with others. If a user ninelives says "my deluxiPad charges at 9.09 V according to my Satechi" and a user ninetails says "my fanatiPad charges at 9.01 V according to my Satechi", then we should consider their measurements to be equal.)

My Keysight's accuracy around 5V is ±0.027 V, my Keysight's accuracy around 20V is ±0.12 V, and my Satechi jitters by ±0.03 V. I decided to round both of them to decivolts. Here are some samples to compare my Keysight to my Satechi:

Keysight 20.3 Satechi 20.1
Keysight 15.8 Satechi 15.6
Keysight 13.9 Satechi 13.8
Keysight 8.1 Satechi 8.3
Keysight 6.3 Satechi 6.2
Keysight 5.2 Satechi 5.1
Keysight 3.2 Satechi 3.5 V (18 mA draw per my Keysight)
Keysight 2.4 Satechi 3.5 V (17 mA draw per my Keysight)
Keysight 2.2 Satechi 3.5 V (15 mA draw per my Keysight)

Amperage measurement accuracy:

I did not try very hard to test my Satechi Type-C Power Meter. I only tested its amperage measurement with three Apple power levels "2W" (nominal 2.5W, System Information.app calls it 2W) 5W and 12W, not 10W. My Satechi Type-C Power Meter agrees with my Keysight on measured amperage. Its measurement is noisy: readings continually vary from mode by ±2 counts. (Its count resolution is 0.01 A.) Its 0.01 A resolution is useful to compare qualitative test results. ("Which mobile power bank / battery pack fills-up faster? Which colour of light-up widget is more wasteful?" A one user may compare relative centiamps of devices.) I think its centiampere resolution is not quantitatively significant, especially when users do not realise that this appliance does not compensate for its own 2 cA draw. (However I think, its reading rounded to the nearest twentieth ampere (0.05 A), has quantitative significance.)

My Keysight's accuracy around 0.5A is ±0.008 A and around 2.4A is ±0.027 A; I decided to round it to centiamps. My Satechi jitters by ±0.02 or +0.01-0.03 A, so I am taking the mode of its readings. Here are some samples to compare my Keysight to my Satechi:

"rated 0.5A": Keysight 0.48 Satechi 0.47
"rated 1.0A": Keysight 0.95 Satechi 0.94
"rated 2.4A": Keysight 2.28 Satechi 2.30

Satechi measurement ability:

Satechi Type-C Power Meter takes both its own power supply and voltage measurement toward plug side of shunt resistor. Shunt resistance is nominal two milliohm (2 mΩ, mark code R002). It is powered through a linear regulator which breaks-down somewhere below 4V (it is specified 'range is 4V-30V'). It draws 19–20 mA at any USB PD voltage. (As measured by my Keysight, current accuracy is ±3 mA.)

When my Satechi Type-C Power Meter is powered through its receptacle and NO load is attached to its plug, it measures 0.00 A, though it itself draws 19 mA across its shunt resistor. In a comparable reverse setup, Satechi meter is powered through its plug and a computer mouse which draws 14 mA through its receptacle, it measures 0.00 A. (It is specified 'range is 50mA-9.99A'.)

It does not compensate for its own draw. My MacBook draws a very steady 2277 mA from an Apple 12W supply, as measured by my Keysight (either alone or downstream of Satechi). My Satechi measures 2300 mA (mode; range 2280–2320) downstream of its own draw (its plug is connected to power supply and its receptacle is connected to power load). Upstream of its own draw, my Satechi measures 2330 mA (mode; range 2300–2340) and my Keysight measures 2296–2297 mA.

Because Satechi Type-C Power Meter does not negate measured electrical current drawn by itself, its user must be mindful of this, for accuracy, especially when comparing/evaluating cables/powersupplies for their conductivity. That being said, its own draw is only two measurement counts, which a user may decide is not significant.

comments:

It always displays a pointing arrow, even when it measures zero amperes. I consider this a (minor) bug, a flaw which can be fixed by not displaying an arrow when its readout is 0.00A. My specimen seems to have one dead pixel in its arrowtip.




My specimen's circuit board is marked (screen print) "1710" in seven segment style. (I assume this means circuitboard was manufactured at year 2017 week 10.) It is marked with reference designators and an ESD susceptibility symbol, but no meta information (such as model or file numbers, revision, person place or thing names). Its main controller is a STMicroelectronics STM32F030F4 (package marked 32F030F4P6). Its USB receptacle is not anchored well, but its plastic body/case should prevent receptacle from being bent/lifted/broken-off from circuit board. Its USB plug is not well braced at all.

Its (OLED) screen flickers. I HATE flickering PWMing LEDs, I cannot stand it. This is a dealbreaker for me: I want to not own this tool. It does emit a faint high-pitched squealing/screeching "electronics hum"/"coil noise"/"inductor whine", which is quiet enough to not bother me.

 

[JTravers]

Does anyone know if the 2017 iPad Pros better adhere to the usb-c charging specs? My hope is that the 2017 iPad Pros are able to negotiate more "standard" volt and amp combinations over usb-c and, therefore, can be fast charged by many more third party chargers.

 

[dannys1]

Does anyone know if the 2017 iPad Pros better adhere to the usb-c charging specs? My hope is that the 2017 iPad Pros are able to negotiate more "standard" volt and amp combinations over usb-c and, therefore, can be fast charged by many more third party chargers.

Just ordered the new 10", it's coming today. I saw them say something about it in the Keynote. I know I never got round to testing properly before (not testing with official cable) but i'll try to do it this time with the new one.

I don't suppose i'm getting a USB-C charger in the box though am I.

 

[JTravers]

I don't suppose i'm getting a USB-C charger in the box though am I.

Definitely not

 

[Krevnik]

Pumping Amps faster and faster and current into a Lithium Ion battery is not wise. It shortens its overall lifespan.

I'll just counter by saying this sort of comment needs to be qualified with the ideal charging current for the battery in question. LiIon prefers charge rates of 0.5-1C. The 12W charger is under 0.5C, while the 29W charger is still under 1C.

A lot of the discussion about fast charging comes from the use of chargers on raw NiMH and LiPoly batteries where you routinely run into chargers that can do 4C or more. Neither NiMH, LiPoly or LiIon like charge rates over 1C. But those are not the rates you will see with the 29W charger.

EDIT: Curses, thrown off by the necro...