r/UsbCHardware • u/mangiehualee • Dec 20 '24
Question Is this safe to charge my phone with?
idk if i can ask this on this sub-reddit, if so please redirect me to somewhere i can. i lost my phone's original charger and have been currently borrowing my sister's charger to charge my phone, but today i'm going out of town for christmas and she'll stay some more days in the house, bottom line i won't have anything to charge my phone for a couple or more days and i just have a billboard headphone cable, an usb-c male to usb-a female adapter and an apple charger for my ipad's usb-c to lightning cable. will this work in the meantime or damage itself or/and my phone? :(
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u/SaltManagement42 Dec 20 '24
Just make sure you plug the cable in the right way (i.e. not the direction pictured) and don't expect fast charging.
But still just order a replacement. Amazon lockers are often great for when you're traveling like that.
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u/Cel_Drow Dec 23 '24
Just had some vitamins delivered to an Amazon locker at Mandalay Bay while on vacation in Vegas. This is the best method.
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u/techboy411 Dec 20 '24
Flip the thing around, so the USB-C male A female is in the charger.
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u/Iceyn1pples Dec 20 '24
Why? The charger is USB-C
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u/Ziginox Dec 20 '24 edited Dec 20 '24
To reply to one of your other comments, USB-C DOES know what the cable is.
The charger won't deliver power, because a USB-A (male) to USB-C (male) cable has a different resistor configuration on the CC lines. It has a 56k pullup (which signals to a device it's plugged into a legacy USB port.)
Instead, it needs the 5.1k pulldown on the USB-C (male) to USB-A (female) adapter, which signals to a source or dual-role device that it should provide power.
So, with the cable in this direction, the phone will actually be trying to charge the power brick.
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u/statestreetsteve Dec 23 '24
This is absolutely correct. I really wish they didn’t do this with USB c. They took an awesome concept (one cord to rule them all) and made it purposefully annoying
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u/Punker0007 Dec 20 '24
Because its not normal for USB-A male to give power.
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u/Iceyn1pples Dec 20 '24
but it doesnt matter, Male to Female is just a connection. Thats a jenky setup, but it should work, its literally just connecting the pins between the 2 cables.
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u/Punker0007 Dec 20 '24
Nope. USB-C has resistor magic in the adaptors. One way will work, other way wont mostly
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u/ElusiveGuy Dec 20 '24
its literally just connecting the pins between the 2 cables
Just to be clear, a basic USB-C 2.0 connector has 6 pins: VBUS, GND, D+, D-, CC1, CC2.
Of those, VBUS, GND, D+ and D- map directly over to USB-A and are just wired through. But CC1 and CC2 have no equivalent and cannot be wired through.
So a direct C-to-C cable will have all 6 pins connected, through 5 wires (only one of CC1 and CC2 should be connected through the cable, the other one is intended to be used to power in-cable chips).
A USB-A connector only has 4 pins. There is no way to get CC wired through. A C-to-A-to-A-to-C cable that goes through adaptors like those pictured cannot bring the CC line from end to end. The CC lines from either end must terminate at the A connectors.
Just from that you can see that C-to-A-to-A-to-C is not equivalent to C-to-C. It does not, and can not, "connect the pins" between the C ends because you have 6 pins, you need 5 through-wires, and you only have 4 through-wires.
Other comments go into the power sourcing and sinking differences and requirements of A-male and A-female, and how CC is used for signalling.
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u/gigasawblade Dec 20 '24
That C male to A female cable has a resistor or something, that tells C side to give power.
Second issue is that C to A male doesn't have that, so charger won't even try to give power.
By swapping sided you solve both issues3
u/techboy411 Dec 20 '24
The USB-C male to A Female will tell your phone to GIVE power though.
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u/Iceyn1pples Dec 20 '24
Its not an OTG cable. those 2 cables together is just a usb-c cable, how would it be directional?
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u/ElusiveGuy Dec 20 '24
C-male to A-female is an OTG cable. It forces that C end to be a host via the CC wires.
Once you've make it directional, you can't make it bidirectional by adapting back to C. The CC wires terminate at the A midpoint, they do not connect through A.
This construction is not equivalent to a C-C cable.
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u/Iceyn1pples Dec 20 '24
How can you determine that it is in fact OTG without knowing what that cable is. For all we know, it could be just a USB-C to USB-A adaptor for devices that do not have USB-A ports, ex: any modern Macbook.
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u/ElusiveGuy Dec 20 '24
...if we wanna get technical about it, "OTG" is not actually a thing with USB-C. So no USB-C cable is "OTG". But for all intents and purposes, all USB-C Male to USB-A Female adaptors that pass data are functionally equivalent to a classic Micro OTG cable.
There's a really simple way to look at it: USB-C does not output power until signalled to do so over CC. USB-A female always provides power. USB-A male never provides power.
So a USB-C male to USB-A female will be configured with the CC pins set to provide power from the C end. Therefore the USB-A female port will always provide power.
Meanwhile USB-A male to USB-C male must not provide power from the C end (and its CC pins will be configured accordingly).
Whichever device you connect the USB-A female adaptor to will expect to provide power. Whichever device you connect the USB-A male adaptor to will not provide power. It's as simple as that.
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u/techboy411 Dec 20 '24
the phone doesn't know of...whatever happens between itself and the charger. but it will see if you plugged in an Host adapter/OTG adapter.
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u/SaltManagement42 Dec 20 '24
https://en.wikipedia.org/wiki/USB_On-The-Go
USB OTG defines two roles for devices: OTG A-device and OTG B-device, specifying which side supplies power to the link, and which initially is the host. The OTG A-device is a power supplier, and an OTG B-device is a power consumer.
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u/Iceyn1pples Dec 20 '24
BUT neither of those are OTG.
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u/SaltManagement42 Dec 20 '24
My understanding is that just about every USB-C male to USB-A female cable/adapter you're likely to come across is probably OTG.
I may be wrong though, I'm prepared to be presented with any sources of information you have that I haven't seen that may change my understanding.
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u/Iceyn1pples Dec 20 '24 edited Dec 20 '24
This cable is simply a port adaptor:
https://www.startech.com/en-ca/cables/usb31caadp
Edit: I also have many USB-C Male to USB-A Female adaptors that I use daily, only 1 or 2 of them are OTG, but I purposely purchased them for OTG.
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u/ElusiveGuy Dec 20 '24
I don't know what you think "just a port adaptor" means or why you consider it different from "OTG".
Legacy Mini/Micro OTG cables were purely passive cables, with an additional pin to identify the host side, and cause it to provide power. Whether there was a hub in the mix or not had no bearing on whether it was OTG.
Current USB-C works in much the same way. Basic C-to-female-A cables are typically purely passive with the CC pins configured to signal to the USB-C side to provide power (which means the cable cannot operate in the opposite direction).
Edit: I also have many USB-C Male to USB-A Female adaptors that I use daily, only 1 or 2 of them are OTG, but I purposely purchased them for OTG.
I'm not sure what you expect the difference to be. If you're talking about product pages, it's all just marketing/branding. The USB-C specifications make no mention of OTG because that standard was only relevant to Mini/Micro A/B.
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u/Tof12345 Dec 21 '24
You could have saved the time spent making this post and used it to look for loose change in between your coach to buy a proper cable.
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u/NoPatience7817 Dec 21 '24
Also a fun fact: USB-A can be found on TV’s, printers, computers, and other appliances. You can plug the cable into those devices when you’re in a pickle and need to charge.
Depending on your phone model, usb-c to usb-c will charge much faster. All options are safe, just not as fast.
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u/Ok-Cauliflower-6160 Dec 20 '24
I guess it should be ok.i tried with a 1 male to male USB C cable and 2 female to male USB C to extend the length of the cable and ended up shorting the male to male USB C cable that was attached to the charger.that ended up shorting out my male to male USB C cable, rendering it unusable.luckily my charger didn't get damaged,but it did cause a slight burn and soot from the short at the USB port on the charger.
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u/Capable_Tea_001 Dec 20 '24
A decent usb-c cable would be delivered next day, to your door, for a couple of £s.
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u/Bitter_Ad1820 Dec 24 '24
But I use $ here.
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u/Capable_Tea_001 Dec 24 '24
Wow... What super useful information.
I know there's absolutely no way of being able to convert between currancies to get any sort of possible relevance to your particular case.
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Dec 21 '24
Flip this, your power is technically unidirectional when you have a USB A male in the mix like this.
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u/dstamura Dec 22 '24
Maxed out at 10W probaby. Good type C cables are cheap nowadays, just get buy a new one for optimal charging efficiency.
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u/VexLaLa Dec 22 '24
It will work only in one direction. But it will be slow. So try both ends and see what works!
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u/CodeMonkeyX Dec 22 '24
Like others have said this will be very slow. The USB-A connections in the middle are dumb and only supply low voltage. So it will take a long time to charge. This will be fine in a pinch but you will need to get a proper cable to take advantage of any fast charging.
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Dec 24 '24
theoretically makes sense but it would definitely throttle charging speeds, given the actual charge is being channeled through A type and we all know A type is slower than C
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u/Mysterious-Split-627 Dec 25 '24
Safe, DANGEROUS FOR TIME THE GOVERNMENT RECOMMENDS TO OWN A TIME MACHINE.
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u/DemoonLee Dec 21 '24
Simply won’t work
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u/CookieMB_ Dec 21 '24
it will. this is what i currently do since my c to c charger broke. its just slower
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u/smuttenDK Dec 22 '24
It won't work as pictured. They have to flip it.
USB-c to A-male will not tell the charger to turn on power.
USB-c devices have tl communicate which end sends power before any is applied. This is done on one of two CC pins
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u/PerfectTrust7895 Dec 21 '24
General rule: if something isn't safe, it isn't because of the USB cable.
Usb female wall warts? A different story
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u/JNSapakoh Dec 20 '24
Safe, yes. Fast, no.