[General Accessories] doublehp:
I have recently bought an Oukitel K6000 Plus.

I also own an HTC One M8, several chargers, and several USB meters.

The HTC One M8 was sold with a classic 5V 1.5A charger, but the phone by itself has a QC2 chip, and can accept 9V chargers (QC2). When you put a USB meter between a QC2 charger and the M8, you see that after 5s, the charger goes for 9V.

With very recent phones, and QC3, you should see 12V.

QC3 protocol is designed to never burn an uncompatible phone; but, take care about your USB meter, some USB meters may not accept above 7V. I have various USB meters, some take 7V, some 9V, some 13V, some 20V. The protocol is harmless for active devices; but since the USB meters is a spy, it may burn if not designed for high voltage.

On my desk, I have set-up a classic 9V PSU with a USB plug; this way, my phone does not negocate; and I have put a thick copper cable, to have no loss. My HTC M8 was happy with this; the QC2 chip can accept direct 9V. All other devices would burn on this plug, because on this plug, I send raw 9V without any protocol or negociation. This is home made.

Note that older HTC phones like the Sensation do not implement yet Quick Charge (Sensation is not even QC1), and still it accepts up to 7V (it's written in some file under /sys). So, while most people used to use 5V USB chargers for the Sensation, I have already built my fixed 7V charger for this phone ... and i was charging twice faster than any one else; and I was probably the only person on the planet to charge the Sensation at 7V.

Now, I own two 9V phones, and two official 9V chargers. When I plug the K6000 on the provided charger, USB meter nicely adverts 10V. When I plug my M8 on a QC2 charger (from Amazon), USB meter also shows a nice 9V. This means super fast charge (90-100 min to fully charge from 0% to 100%; at most 120mn if I am using the phone during charge).

The issue I had was when I tried to swap the chargers: put the M8 on the Oukitel charger, and the K6000 on a QC2 charger. Then, in both cases, the USB meter sticks to 5V.

This means ... neither the Oukitel charger, or K6000 phone are QC2 compatible. Oukitel does a fast charge, at 9/12V; but not with the Quick Charge protocol.

This means, if you buy any faster charger from anywhere, the Oukitel phones will charge at only 5V; and when you count on voltage loss over the USB cable, I sware you will be luck if you charge your phone in 4h, phone switched off.

After spending a few hours on Google, I have those three sellers, who sell the original Oukitel charger:

https://fr.aliexpress.com/item/Orig...51960957.html?spm=a2g0w.search0304.4.9.Si9JZR

https://fr.aliexpress.com/item/Ouki...730221.html?spm=a2g0w.search0302.4.142.rUQMcL

https://fr.aliexpress.com/item/Orig...129853.html?spm=a2g0w.search0302.4.180.ZOEQRv

Out of this, I have been completely unable to find any 9/12V charger for Oukitel on any other website: Ebay, Amazon, BangGood ...

This becomes a huge issue for car chargers: since absolutely no-one builds "Oukitel compatible" chargers, and Oukitel does not seem to build any car chargers ... there is no car charger for the Oukitel.

The workaround is to buy a 9V car supply, and solder a USB cable on it. Most Oukitel phones take 9V (K6000 pro and plus; several K4000). IMHO, the K10000 takes 12V (but, you should check this yourself).

Even if the K10000 accepts 12V, you can not provide the raw 12V from the car, because the car voltage may vary from 11.4 to 15V (strictly, all car devices must be 18V compliant; truck devices must be 36V compliant). Your phone may dislike the 15V peaks (which occur frequently).

I am not yet sure about the exact voltage my K6000 Plus wants. My USB meter shows 10.4V, on PSU side. I don't know if this ought to be a very low 12V because PSU has a poor design, or if the Oukitel protocol includes a fine tuning communication, so that the phone receives 9V on phone plug, and PSU has to over-voltage the output voltage to compensate the loss over cable. When USB meter says there are 10.4V on USB-A plug, the phone claims 9.2V on phone side. Not sure the reason of this. More testing would need a few hours digging (insert the USB meter at the micro-USB-B side).

So, can any one give any detail on the Oukitel protocol used for charger voltage tuning ?

When I plug my Oukitel on the raw 9V USB plug, if Android is running, the phone is happy, and will charge the battery. If the phone is turned off, then, the phone will refuse to charge from 9V (you either need a 5V charger, or start Android - have not tried to dig what happens with TWRP, Recovery, FastBoot, FactoryTools ...).

I am very sad to see this phone completely uncompatible with classic protocols. I understand that the license for QC2 chip is very expensive, and the Oukitel phones are designed to bring huge power at low cost; they walked around the QC2 patents by redesigning the Faster Charger; I can understand this from a dev point of view; but I completely reject it from a user point of view. All my QC2 chargers are useless; and without the original Oukitel charger, charge time has to be 4-8h, with phone iddle or off.

Unless you solder a USB plug on a 9V PSU ... which is very dangerous if you accidently plug an uncompatible device (earset, power bank, old phone ...).

And, don't just take any 9V PSU; it needs to be able to feed at least 1.5A !!!

I feel disapointed.

Quick Charge just came out with a good standard, and more and more phone brands were starting to use it (Samsung, Nokia); and chinese companies now re-invent the wheel ... this brings me back to the old times of Mac being uncompatible with Windows ... when saving a word document on a floppy was the most complicated thing on earth because you had to take care about bitwise issues (a file written on a floppy with Microsoft-Word from a MAC could not be read with Microsoft-Word on Windows-PC ... then, after a few years, they published an update to fix the issue )