USB-C needs to get smarter before it gets better [Updated]

Update, March 20: This article was updated with quotes offering more detailed explanations.

A few nights ago I was away from home and didn't have my power cord with me, so I had to rely on a battery backup to charge my USB C-based phone for the night. This battery had been stuffed down in the bottom of my backpack for a few days, after having been used to power something else for several hours, so it didn't have a lot of juice left to begin with. If I had to guess, there was just about enough to get my phone to about 70%, which was more than enough to get me to a power outlet the next morning.

I plugged in my phone, confirmed it had charged to 10% before I closed my eyes, and didn't think about it again until the morning. When I woke up late because my alarm didn't go off, I realized it was because my phone was dead. What's worse, my battery backup actually had more power in it than it did before I'd plugged it in to my phone.

My phone and was dead and my battery pack was recharged — the opposite of what I wanted!

What happened here sounds bizarre, but it's actually all of the individual pieces of this charging system working as designed. The battery backup charged my phone until it was drained, and then started pulling power back from the phone because it was drained. USB-C is designed to allow simple power sharing, so anything can charge anything else. In theory it's amazing, and has seriously come in handy when I needed 20 more minutes of juice on my Chromebook for work and only had a phone nearby. In this situation, though, it didn't work out the way I wanted it to.

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This isn't a failing on any one particular phone manufacturer, OS, or battery backup designer, either. This is, largely, how USB-C was designed to function when these things were made. Some handle this worse than others; for example, many Anker USB-C batteries have the Type-C port set to draw power by default, with a key press required in order to reverse direction, but in general this is a small problem lacking a standard solution for all devices. And the solution, at least to my specific problem, probably lies in software.

In my opinion, our phones shouldn't be allowed to give power to other things without our express permission. In much the same way that Android offers USB selection modes for file sharing that require a manual selection from me, power management should offer a similar option. That way, if my phone is sharing power with something, it's no accident and doesn't interrupt the ability to use the phone. This is something Google would need to implement at the OS level, but it seems like the best possible solution for this kind of problem.

But it's not as simple as all that, as I learned after publishing this. Google's public-facing USB-C rockstar, Benson Leung, schooled me a little over on Google+.

The battery pack, if it was implemented with USB Power Delivery and is connected to a USB-PD phone like the Pixel, could identify that the other party is a dual-role device with a small battery like a phone and not a fixed power source like a wall charger and hold-off on draining from the phone.If i were to design the pack, i'd allow the battery pack to just draw enough power to boot itself up until it can recognize the other device is a dual-role device without its own external power source using PD, and then stop charging. That way neither phone or the battery pack charge.We could make the phone behave in the way you want... such that it only ever acts as a power sink until you explicitly ask to turn on power source and host mode, but that would mean that if you wanted to plug in a USB thumb drive, or a USB accessory like, oh I don't know... USB-C digital headphones, they WOULDN'T work unless you explicitly change some setting first. You'd not even get any notification when you plugged in your USB-C headset because the port is fixed in sink-only mode, and it needs to supply power to the headset before the OS can even identify it as a headset.

USB Connections

It may be a fringe issue in the grand scheme of things, and with any luck this USB-PD feature will become a global standard over time. Unfortunately, that's not going to happen overnight, and in the mean time there are a huge number of these battery packs being sold on a regular basis. Even if you spend the extra cash to grab a battery pack with USB-PD enabled, if you already have a phone with a Type C port and it doesn't support USB-PD you'll need to upgrade before this all works like it should.

Frankly, we're beyond the point of shrugging off Type C related concerns as "early adopter" problems. It'd be nice for Google to take the lead on addressing this issue beyond strongly recommending the use of USB-PD in its documentation, instead of waiting for another big company to implement USB-C and show everyone how it's done.

Russell Holly

Russell is a Contributing Editor at Android Central. He's a former server admin who has been using Android since the HTC G1, and quite literally wrote the book on Android tablets. You can usually find him chasing the next tech trend, much to the pain of his wallet. Find him on Facebook and Twitter

  • But things like USB flash disks and headphones need power too. How should that be regulated?
  • With more government control...
  • Here here,
    I second that, The government should regulate phone size how big the batteries when they get updates. Now honestly that I think about it they the federal government should just give out free phones for everybody. I mean think of the children. What could go wrong the federal government knows best.
  • Hell they should make both the hardware and software too. What could possibly go wrong! I mean its not like they're gonna spy on us or anything.
  • Not just that guys. They should make only one color for the sake of being equal. Plaid should be the color. And also, who we can talk too and for how long. Would be the best thing EVUUUR!
  • Yes and the new government agency should be called. The department of listening and phone equality.
  • Lol! I love it when they listen in on all of us equally. The DLPE should be formed and shared capabilities with the CIA, FBI, NSA, and all other 3 letter acronym agencies!
  • They can build a wall around it too!!!
  • Concrete provided by cemex? I'm in!
  • Deal!! Let't start today!
  • I like this idea. And can we appoint a very wealthy person who's never used a smartphone to head the department?
  • Agreed. I people that have never used a smartphone are the best knowledgable people to run things!
  • Great idea! Except i think a person who has never used anything more advanced than a calculator should be in charge and regulated by congressman that have been in office for 100+ years. This would make me all giddy inside!
  • No idea why you got a -1 and everyone commenting below you is making light of it... You make a very very astute observation in light of Russell's poorly researched and informed opinion piece. He's expecting a non PD battery to somehow follow PD rules or for the phone to make up for the fact that it doesn't... That's crazy. I don't wanna tap a prompt each time I plug in Type C headphones or drives, or batteries for the matter. That isn't the solution, we should be putting the onus on accessory makers to follow PD rules instead of blaming Google/phones/the port (which isn't really in charge of anything)... Too bad even after having all this explained Russell chooses to stand by his opinion and leave an article up that's just gonna confuse the consumer further.
  • Would this really be better, or more practical? I can't imagine how you persuade 3rd-party accessory manufacturers from all over the world to comply if they're not doing that already, whereas a software phone switch could presumably by sent out in the next update. (Forgive me if that's not the case - I bought my first device was USB-C only a couple of weeks ago: a laptop, and I've had no cause to use its USB-C port yet. I may well be ignorant of how this works!)
  • This seems to be the main disagreement between Russell and, well, everyone else who already understands how things work or are supposed to. I can see how the argument for the software switch makes sense, but it would have a negative impact on many other usage cases. Flash drived, Type C headphones, and even video out cables would then require the user fiddle with said toggle before they would work. The only software alternative to that would be that default state of the switch keep the current behavior, I'm not sure if that would satisfy Russell. His particular issue should be with the battery he bought. This isn't a universal issue with all Type C banks as he makes it sound, even amongst those without Type C. Some banks feature in/out ports rather than using the same one for both (inelegant but foolproof), some feature a hardware toggle switch, some just feature smarter logic period. In the long run most will probably transition to PD but it'll take a while, even phones have barely started to... Up until last year and possibly thru the first half of this year Qualcomm QC was more popular than PD. Google has strongly recommended phone makers use PD if they're gonna use Type C ports tho and Qualcomm has announced QC 4.0 will be more cross compatible. It's somewhat understandable accessories are lagging behind but it's not a matter of persuading anyone... PD is just the road forward, it'll simply take a while. In the meantime Russell could call out the individual battery pack that caused him consternation rather than damning everything and asking for a band aid solution to a very isolated problem... That would be a lot more useful to all AC readers. I'm still curious why he didn't name any brands tbh. This is all IMO but one that seems to be shared by many who at least understand what Type C is and isn't.
  • Don't all USB devices identify themselves? It seems trivial that Android could ask a device if it needs to be powered by the phone and if the answer is No (or there is no response in the case of a dumb battery controller), default to receiving power only. If the response is Yes, default to providing power. In either case, offer a notification to switch modes. Failing that, I don't see why a simple notification to modify the default behavior is such an inconvenience...
  • My phone actually CHARGED my Samsung USB-C battery bank when I connected it to the battery bank's USB-C port. Wasn't there supposed to be a prompt to choose what the port does when you connect it to a peripheral that also has a USB-C port? The Nintendo Switch also charges the MacBook Pro instead of doing it the other way around.
  • After an OS update, my Nexus 6P fried my car charger. Somehow, the option to receive power was toggled to send power instead. It's never done that since (with a new charger, of course.)
  • I have a feeling that it was more likely you were using a bad USB Type-C cable that didn't follow the US Type-C spec.
  • You have no clue. USB-C only has active components for compensating for voltage drop in long cables. What USB-C does have is wires that can be used for many things depending on negotiations between the connected devices.
  • There's actually quite a few non-PD Type C car chargers out there that allow current back into the circuit, the vast majority of Type C car chargers I've seen are pretty lousy... Hard to say what really went wrong but an update being the culprit sounds unlikely.
  • So dose this work from phone to phone ?!? Could I charge say a Nexus 5x with my 6p?
  • Yes
  • Yes, I have used my Pixel to change my wife's Pixel.
  • Good to know. Just got a Pixel, but I have 3 battery packs (2 New Trent and 1 Aukey).
    Now I wonder is this could happen with the aftermarket battery cases for the Pixel and XL.
  • Your phone will be dead but your battery chargers will be fully charged.
  • It could absolutely happen, specially with anything that doesn't follow any sort of PD logic. There's a lot of Type C chargers out there that wrongly identity as power sinks under some conditions (like a car charger in an unpowered car) that are just downright dangerous and little is being done about singling out issues like that. Sites like AC could buy a Twinkie or a Total Phase testing system and do in depth reviews, instead we get ill informed opinion pieces.
  • So in the meantime it's best to use a standard USB A to USB C cable and battery packs
  • This, exactly. It's the safest solution.
  • But A to C cables can't carry the same amount of power a C to C cable can. So while it may work with charging a phone it wouldn't work for charging a laptop.
  • So long as it is a 3.1 cable it will ;-)
  • But the USB-A port on the battery pack also has to output the right amount, and I haven't found any that do.
  • Uh, no. 2.0 vs 3.1 doesn't have anything to do at all with charging speed.
  • USB 2.0 is limited to 500 mA whereas USB 3.0 is limited to 900 mA, not sure how 3.1 compares though
  • Legacy USB ports when used for data are limited to 500mA, for years phones have used various pin bridging techniques to signal charging rates up up 2,400mA tho, ergo not really limited. It's called the BC 1.2 spec FYI, so it's not really an afterthought or something they just hacked together. I was talking about Type C specifically tho where neither kind of cable are really limited either way. Fact: the OEM Type C to C cords the come with the Pixel, Chromebooks, and even MacBooks are USB 2.0 and they're safely made to handle and charge at up to 100W. The 2m and 1m Type C cables Google sells can handle up to 3,000mA which is the max without an e-marker but the $20 2m charging cord Apple sells is rated for 5,000mA. The caps you quoted are strictly for data ports on PCs, not for charging purposes. Russell could spend time explaining all this instead of trying to grab headlines.
  • Definitely won't work for a laptop, and even for most phones it'd only work very very slowly... 7.5W slow (5V at 1.5A) The only exception to that is the Pixel which can react to chargers and batteries which have Apple-like signaling, in which case it can ramp up to 10-12W even with a Type C to A cable. Kind of against the rules but a pretty handy and undocumented "feature".
  • On my Pixel, I get charging options. Screenshots here
  • I have the same choices on my v20
  • Why you have a v20 when you could have had a v8? :)
  • Yeah, I'm confused. This already IS a function in Android. My phone asks too.
  • It's an option yes, but when I plug my 2 V20s into each other with a C-C cable, the Apple 2 meter one in this case, one automatically starts providing power to the other.
  • Is it always the same phone supplying the power? Can it be changed by flipping the cable ends, plugging in one of the devices first, or powering on one of the devices first?
  • Why have a V8 when you can have two and a half V8's?
  • Too many vitamins at one time? Lol
  • Not possible, excess water-soluble vitamins let go from the body via urine. Excess fat-soluble vitamins are stored for later use.
  • You can absolutely OD on vitamins. Some vitamin companies have been hit hard by the FDA for dramatically overloading past the labeled amount to legitimately dangerous levels.
  • And also, taking vitamins on a regular basis can make your body not produce those vitamins naturally.
  • Um,'re getting confused with hormonal supplements.
  • Not sure where you're getting your "facts", but there is no known problem anywhere with vitamin overdoses. Statistically you are probably more likely to die in a plane crash or be eaten by a shark than overdose on vitamins. This is in addition to there being only a handful of vitamins that can actually have adverse effects, like vitamin A (pretty serious poison if overdosed) and vitamin K. The real problem with vitamins is that many contain fillers that are harmful or may be harmful over time. The vitamin content itself is not dangerous at all. In fact, quite the contrary.
  • You're mistaken. A basic Google search is enough to find plenty of reputable sites that indicate vitamin overdosing is more than possible.
  • I think you need to read consumer reports.
  • I've got the same options on my OnePlus 3T.
  • You stated on G+ that this is when you connect the Pixel to your Chromebook. The same thing happens when connecting two USB-C phones together. However, Russell's situation is in regards to the USB-C battery pack drawing power after being drained.
  • I figured it was handled by the phone so it wouldn't matter what I plugged it into.
  • The problem in Russell's case is that the phone correctly accepted being charged by the USB-C battery pack, but afterwards, also accepted being discharged by the same battery pack due to how USB-C works. Since a Chromebook is able to transfer data via USB-C, in addition to being charged, that's why the prompt shows up when connected to a phone. In the battery pack's case, there's no data to be transferred and that's why Russell didn't get the prompt.
  • I wonder why the battery pack didn't start charging the phone once it was drained.
  • This would be a lot less confusing if Russell hadn't mixed up all kinds of things in his article. That's a function of Power Delivery, or more accurately, two PD devices being interconnected. It's the smart way to do things. Russell bought a non PD battery that he expects to work more intelligently, and instead of identify why it doesn't (it's a "dumb" battery with no PD charging logic) he's blaming the physical port, which doesn't have anything to do with anything. It's probably true people shouldn't have to know all this when shopping, but it's also true that tech writers should be better able to steer people in the right direction instead of further confusing the matter.
  • Russell should at least add an addendum to the article to include the info Benson Leung provided in his response to this article. Russell already stated his opinion on this matter is firm, but Benson still made good points that shouldn't be ignored.
  • Russell's opinion isn't based on facts or anything but one bad personal experience, which is fine, my biggest issue is with the rush to (wrongfully) assign blame and then even come up with a technical solution (when there is one already). It's not the first time Russell writes a confusing article about Type C and/or PD without fully understanding what's going on either... /shrug An addendum would be great, this not happening again and again would be even better... AC actually putting out some articles that put accessory makers on the spot (them being the real culprit in many cases like this) would be the bestest.
  • so does this mean whatever is below 50% takes power from anything over 50%? or once it starts charging it goes to zero, then switches back?
  • I don't think so, because the battery pack would have far more capacity than the phone. He said there was enough power in the battery to get the phone up to about 70%. It would be a strange thing for the two devices to share the available power so that the phone was on 35% and the battery was on some fraction of that, and if there was that kind of intelligent monitoring going on then there'd be a provision to stop the phone feeding the battery at all. The phone took all the battery's power, at which point the battery responded to being drained by calling for charge. The phone fed it back, and Russell caught the problem when the phone had dropped to the 10% mark.
  • When I plug my pork into the car charger, I often get a notification that my device is supplying power to another device, despite the fact that the phone is definitely charging. It's weird.
  • Oh boy. Pixel, not pork. Thanks, Gboard!
  • I was wondering what you meant by pork?? LOL
  • So when I'm cooking pork chops in the USB-C powered griddle that I keep in my car...
  • I thought maybe it was your other pork. Being lonely maybe? Lol
  • My other pork? Oh, you must mean bacon!
  • Lol no. Was referring to porkin' the 12v power outlet.....but bacon is good too!
  • Damn I would think that you would be notified in a hurry lol
  • So when I plugged my Pixel into my George Foreman grill the pork chops seemed to take longer than usual to cook.
  • Should've plugged the grill into a Note 7. TIMELY JOKE!
  • Lol!
  • And set the pork chops directly onto the Note 7 screen.
  • That's actually a sign of a very bad charger, I'd stop using it immediately. A charger should never identity itself as a power sink, and if it ever acted a such it could do very bad things like feed current from your phone to your car's electronics.
  • Great article. Learned something new today.
  • Agreed! I didn't even know that this was a thing. The more you know...
  • It's actually full of opinions based on inaccurate facts and wrongful expectations... Somewhat useful as a warning to readers, but woefully inadequate at explaining the how or why of things.
  • What did you not understand after reading it? Maybe I can help clear some things up.
  • Thanks but no thanks, I understand how things work just fine, unlike Russell.
  • Woah, you must have a lot of friends that respect you.
  • Does the cable need to be USB C on both ends? What about a USB A to USB C cable?
  • When the standard was being created, why didn't they know this? New standards can't have oversights like this.
  • They did, Type C isn't a standard, it's just a physical plug. The Power Delivery standard makes provisions for things like this. Russell bought a "dumb" non PD battery pack (regrettably common right now) and failed to identify the real issue.
  • I disagree that Type C isn't a standard. It has specifications and if everyone follows those, it is a standard.
  • It's a port standard, but not a charging standard, PD is the charging standard... The inner that Google is strongly recommending OEM use if they're gonna use a standard Type C port.
  • Tech bloggers need to get more informed before they write opinion pieces on how things should work at a technical level... I kept the snark out of G+ but I couldn't help myself here. ;) I said my piece there, but anyone reading this should be aware the article is placing blame on the wrong culprit. Using a non-PD battery or charger and expecting it to work intelligently, then blaming the phone or the spec when it doesn't, is ill informed at best. Getting on your editor podium and crowing about it is a disservice to readers... Jerry or someone that's bothered to research the matter should be writing this sorta piece, no offense. Yeah the average buyer shouldn't have to do any research, but this isn't about that, this article is more about assigning blame and that can't be based on your personal view of how things *should* work... It has to be based on the specs and rules already written.
  • nexus 6p owner here for over a year. I have never ran into this problem. I use external batteries all the time.
    there is a setting that allows you to charge other devices. but, that setting on my nexus 6p has to be selected by me in order for it to work.
    my device defaults to charging only (receiving power)
  • A Nexus 6P would actually behave differently than a Pixel or a Chromebook in this regard... Which is one of the many things the article fails to clarify by confusing functionality, specs, physical ports, and responsibility...
  • I'm in the same boat. I had a nexus 6p for a little over a year and got a pixel about 4 months ago and gave my GF the 6p. I've never once had an issue with this and I use an Anker power bank daily to keep my device charged up. power bank I use:
  • "USB-C needs to get smarter......." I don't get the title. How can a plug/port type be smarter (or dumber for that matter). It's just a type of plug. The author should really be talking about the power delivery standards here not the port itself.
  • USB-C is a physical port and a standard.
  • This. And the fact that he bought a battery which doesn't adhere to those standards yet are the same time doesn't offer a way to control it's behavior. Other non PD packs feature in/out ports or a switch. Russell is more worried about his attention grabbing headline than the facts, he has a janky battery and he should be writing a negative review of THAT.
  • When I get the "disable your ad blocker" blocker pop up, I look to that little red stop sign on my browser. If the number is less than 10 or so, I'll gladly disable it. On Android Central, it's usually 30-40. Now, I'm happy to pay a subscription to AC. I read a lot of their stuff. But, 40 ads on one article, no, I will not disable my adblocker. I'm glad AC doesn't completely block me out of articles because of it. Some sites are actually doing that now. I always enjoy Russel's articles. I also love the fact that he is open minded to Benson's reply. Anyway, has AC thought about a monthly subscription to do away with ads?
  • Well, if you are like me and you fkn hate how USB charging is so so nonstandard (this is an age old problem), use charging ONLY USB cables. You will never have an issue again. They basically loop the data pins back. I have one of those brick battery USB chargers and it works find with my 6P/5X/Note 5. If I want to backfeed something from my phone, I use a USB OTG cable and my phone will charge the connect device. Use the right cable and you won't have these issues.
  • Duplicate post.....
  • Kind of make me glad my phone do not have USB-C. I think I will stay clear of it if I can.
  • You won't be able to eventually.
  • "I was away from home and didn't have my power cord with me"
    - Plan better next time.
  • This happened to me months ago with my HTC 10. I finally figured out that charging using the USB-A port on external battery packs prevents it from happening, except that half the battery packs I own tend to turn off after a few minutes when I connect a USB-C device to the USB-A port, as if they detect nothing connected and the auto-off kicks in. Drives me nuts.
  • Quick solution to avoid battery drain, Russell, ease up on the Pokémon Go!
  • What was the update? The article doesn't specify.
  • Found it?
    "But it's not as simple as all that, as I learned after publishing this. Google's public-facing USB-C rockstar, Benson Leung, schooled me a little over on Google+. The battery pack, if it was...... "
  • Thx!
  • It's beyond early adopter. Every major smartphone release (minus the fruity variety) now has USB-C. This is no longer early adopter space. This is mainstream. This kind of stupid behavior, along side plugging the "wrong charger" into your phone blowing it up, is unacceptable for a mainstream consumer device.
  • I read the original article and.... well lol, what a complete mess type C is. There are still low to mid spec phones with mini usb, Lenovo P2 is looking good for me, and I'm going to stick with that connection if I can.
  • Thanks, Russell, for updating the post. I think Benson's points are an important part of the conversation.
  • This may be a phone specific or battery pack issue. The one thing I couldn't tell is if your battery pack was also USB-C or if it used USB-A ports. Just this past weekend, I used an older battery pack (definitely no USB-C connectivity) with an A-to-C cable to charge my HTC 10 while camping. Like the author, I also checked to make sure it was charging. I woke up to a fully charged phone. Perhaps it's something in the battery pack? All of mine use the micro-USB port to charge the pack and USB-A to charge other devices. If it was C-to-C, then I could see how this could suck. I don't have any C battery packs, so I haven't tried that. Definitely a good thing to be aware of if it is indeed a C battery.
  • It's absolutely a battery pack issue and the author is trying to make it something that it's not by suggesting a scorched earth solution that would negatively impact things like headphones, video out, flash drives, etc.
  • " This isn't a failing on any one particular phone manufacturer, OS, or battery backup designer, either. This is, largely, how USB-C was designed to function when these things were made. " Not entirely true, even after edits the article is mixing up the facts. What happened IS THE FAULT of the particular battery Russell is using and won't name... There are other batteries without said flaw even without intelligent PD logic (which is the path forward for all, as encouraged by OS guidelines, Qualcomm's recent moves, and the entire ecosystem, it'll just take a while). Some batteries have in/out ports to not drain devices, others have hardware toggle buttons, others have some sorta non PD logic, etc etc. Russell wants an OS level solution for a particular third party product problem, one that would in turn affect other products. Mostly because he doesn't understand what he has or how it works, or doesn't.
  • sounds like a battery pack issue, I've not experienced this when using USB Type C it charges the pac when I need it and devicea properly until its empty, never a reverse lol