Slow charging at just 5W with 10W chargers.

shiv1gshiv1g Level 2
edited November 2020 in ZenFone 6

I have been noticing this issue since I brought 6Z.

The problem is, when I connect my 6Z with a regular 10W (5V-2A) charger, the phone will only charge at 5W (5V ≈ 0.9-1A) max. Not matter if it's either switched off or on. I have tried several different combinations of chargers and cables, but I only get a max of 5W. Charging at this speed is real slow. It takes an average of 6 hours to charge the phone from dead to 100%.

Below is the screenshot from the Ampere app with a 10W charger.

However, when I use any other power source with a higher amp like a 5V-2.4A Asus powerbank, the phone would charge at roughly 10W (5V ≈ 1.9A). I have confirmed with my testings that the phone would only trigger into 10W charging if it's plugged into a 2.4A power source. When I charge my phone using this, it charges quickly from dead to 100% in 4 hours.

Below is the screenshot from the Ampere app with a 5V-2.4A Asus powerbank.

See that + sign near the battery icon, it only appears when I use a 2.4A charger. We get ++ sign when we use a18W charger.

I know that we can quick charge 6Z with a 18W charger in 2 hours but, I like to use slow yet snappy 10W charging along with battery care method to prolong my battery life endurance.

I just want Asus to kindly enable a true 10W charging, so that we can easily charge our devices with the already available 10W chargers laying around us.

Also, when I use a Gionee 18W charger, the phone should technically charge at 18W but, it only charges at 5W max.

However, when I use the inbox Asus adapter, the phone charges at normal 18W with the same and different cables I use to test out. The same also happened to me with a different (I don't remember the brand but I know it wasn't a cheap one) 18W charger too. The phone would like to charge at a maximum of 5W. I do like to clarify that I have tried some other 18W chargers, and they all work flawlessly. It seems that only about 10-20% of 18W chargers don't work. What is happening here with the 6Z? Why do 6Z love to charge at 5W? Can someone please explain?

@Anders_ASUS @Titan_ASUS @CH_ASUS @LP


  • Hi, we suggest you to please visit the nearest ASUS service center for better assistance. Locate here :

  • I don't think the servicing will help. Not every 9V charger is Qualcomm QuickCharge 4 compatible. If it's not it will revert to 5W as it is a USB standardized max power draw. The charging speed is negotiated via phone-charger handshake.

  • True. Service center has nothing to do with this issue.

    I have tried to replicate the charging issue on my friend's 6Z with 3 regular 10W chargers, and surprisingly got the same results. Both the phones would only charge at just 5W.

    It's easy to understand that it has basically nothing to do with the device hardware and neither with the chargers. As many other smartphones Oneplus 3, Xiaomi, Samsung and realme when plugged with the same 10W chargers, would easily draw the full current and charge at 10W speed. However, for some unknown reasons, 6Z just doesn't like to do the same. Why is that?

  • This is most probably not a bug. Rather a question about if there was a proper handshake between the charger and phone. What I'm saying in plain English is that they are not compatible. This is why your phone defaults to only 5W. It's a security thing. If the charger is a cheap Chinese charger that doesn't support the right charging protocol, this is what happens to prevent any accident from happening.

  • Ok. But the chargers I use aren't cheap. They all are from reputed brands. They all are the OEM chargers that came with the phones I brought like Oneplus, Samsung, Motorola, Xiaomi, Gionee, Oppo and Vivo. Still not a single one is able to charge the 6Z at 10W. However, the same ones are able to charge other smartphones with similar battery specifications and capacity at 10W. . This is so frustrating.

  • I've noted the same thing with Samsung and Apple chargers. 2A is significantly slower than 2.4A. I also like the middle speed of charging that isn't really slow but isn't really fast (and hot). I have bought 2.4A chargers so it doesn't bother me, but it would be nice to be able to trust the 2A chargers I have to be a bit faster.

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