Dual-port 30W Charger for slow charge?

The official Dual-port 30W Charger has a fast charging 30W port, but also a smaller 18W USB-A port. Can this one be used to slow charge your phone? Has anyone tried that?

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18W is still a fast charger.

The phone requires a nominal 1A for 4 hours (4000mAh)
That’s 5V at 1A for 4 hours that’s 20W
18W can supply 5V at 3.66A for 1hr so not slow and in theory the phone can be charged in just over an hour.

Slow charging is decided by the chips on the main board. If the voltage can go about 5V and the QC3 protocol is available in the charger it will attempt a quick charge.

Why do you want to slow charge and at what rate do you want to charge for that reason ??

Another slowing factor is the cable quality and the USB port contacts for example

Actually yes, what was I thinking… :smile:
Any idea how many amperes does the phone’s logic consider the threshold between slow and fast charging?

Prolong the battery’s life, since I’m not in any hurry. I spend a huge part of a day chained to a desk, and my phone can slowly roast charge besides me… I usually plug it into my laptop to transfer files, and charge it at the same time. At least that’s what I did with my previous one, it hadn’t seen a charger for years.

Since I didn’t have any USB C cable I also bought the impressively thick official “Long (and I hope happy) Life” cable…


Any of you know if slow charging is something that a software solution could make an available user choice option in the user interface/operating system? That is, make slow charging available while using charging hardware made for quick charging. (I guess “throttling” is the word :wink: )


No :slight_smile: this is a question I asked 2 years ago as I wanted to build my own charger. After the best part of the year I dropped the query . . . .

Slow charging isn’t all it’s cut out to be. I have a new laptop and am monitoring the Li-ion battery for wear. Batteries are often not quite up to the nominal capacity and it looks like mine was a few percent below par.

I in effect do charge slowly by using mostly when plugged in an dlimmiting the charge to 78% Occasionaly I run the battery down and charge to 100% to recalibrate and get the battery ‘moving’ Despite some ideas LI-ion batteries degrade even when not used.

To see an example of my slow charging (the laptop) I do not worry about my FP3 and found soem apps that give unrealistic info.

How long do you hope the battery will last as even a degraded battery will last for years. With little dialy use of the phone on battery then you may be fine for 4 or 5 years or more.

Long, I hope. :grin:

Went right over my head…
Anyway, I’m trying to not damage it unnecessarily, since as I said I’m usually in no hurry to get it charged, so I don’t see the point of fast charging.

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Definetly not for you it seems, so you can try a 5V charge/USB A on a computer etc. and/or one without QC3 or PPS.

The PPS protocol can deal with the Qualcom ( QC3) and the more common laptop PD ( Power Delivery)

All the best

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I use AccA for that, lets me set profiles and change basically any aspect of charging, current, voltage, temperature, cool down, capacity limits, idle-mode, you name it.

So it is possible, but it would have to be integrated into the ROM, because something similar to acc needs root / system-level access.


I’ve had that topic as well. :slightly_smiling_face:

The charger from my Fatboy LED lamp has 5 V and 1000 mA. I use that now also for the slow charging.


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