Cell phone: is fast (USB PD) charging bad for batteries?

I have a Pixel 5 phone. It’s 6 months old. It replaced a Pixel 2 which had its battery swell up - charging wirelessly caused a lot of heat and I’m sure that’s what did it.

So I’m being very careful with the Pixel 5. I’m charging it using an old Blackberry Playbook (remember those?) charger and a USB micro to USB-C adapter. 5V, something like 2.1 A. It’s a slow charge, but it barely heats up the battery.

With my Framework Laptop, I’m considering getting a 78W+ charger with two USB-C PD ports, one 60W port for the Framework, one 18W port for the Pixel 5.

This would mean the Pixel is fast-charging all the time. Would that mean additional heat? Would it impact the life of the Pixel battery?

Extra question: does wireless charging create more heat and damage batteries? Or is it that I was using a bad charger? It was a cheapie IKEA charger.

Quick overview of the things that damage or wear batteries down

-charging past 80 percent or draining charge past 20 percent

-Heat(you already knew this one) and bonus, wirelessly charging is inherently less efficient than wired, thus the increased heat

-CHARGERS THAT ARE OUT OF SPEC, this is the big one, so long as the charger and device to be charged properly agree on charging rates and such(voltage and amperage) then everything is gravy and you could use a charger that can deliver 100w to a phone that can only accept 20w as the charger will only send 20w

If you are paranoid like me, find the USB-IF certification number and make sure it’s legit certified, if it is then you will be fine

Don’t ever use no name or cheap cables(cables can screw you up as well, not just the wall wart)


Thanks. Strongly considering this charger:


It says USB-IF certified and comes with a USB-C cable.

I’ll use the original Pixel 5 cable to charge the phone. I still have the Pixel 3 cable, I might use that for charging the Framework.

No PPS though, which the official Framework charger has.

Also considering this:


but no included USB-C cable, no USB-IF listing, lower power, larger, not GaN (less efficient). That super thin 120V wiring makes me nervous.

In terms of cables, how does something like this look?


100W PD, E-marked, 20Gbps for use as a data transfer cable. Could be a bit longer though.

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If it doesn’t carry USB-IF certification, straight up don’t buy

Look up a spreadsheet of cables reviewed by Benson Leung, he’s a (current?) google engineer who accidentally melted his pixel book laptop using a bad cable and has sorta gone on a rampage reviewing cables on Amazon

He buys a retail sample with his own cash and then tests the cables and some chargers as well

I would pretty much only buy cables/chargers he has recommended and tested


Pretty sure that he no longer maintains that list or that effort…

Here is a post that goes into detail on USB-C by a gent with an unfortunate pseudonym but is otherwise good info: https://www.reddit.com/r/GooglePixel/wiki/officialguide/usbcinfo/

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@JoshuaB Even if he doesn’t, the rest of my advice still holds and that list however outdated will still have products listed that likely still exist on the market, it’s a decent place to start if nothing else

Really just buying accessories that are USB-IF certified is all you need, I’m sure there is a database maintained by USB-IF for consumer use to verify certification

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If you want more information: BU-409: Charging Lithium-ion - Battery University
BU-415: How to Charge and When to Charge? - Battery University
If you are willing to root your phone there are various mods that allow you to set smart charging so you don’t have to worry about having more than one charger brick and can have low amp charging with the option of fast charging only when you really need it

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Recently Google has pushed a feature in Android for the newer Pixel phones that detect when you are “charging for the night” and it only trickle charges once it gets past 80% with the goal of being at 100% by your normal “wake up alarm” without overheating the battery.


I absolutely agree with this. Make sure they are USB C certified!
BTW that “spreadsheet of cables reviewed by Benson Leung” has been deleted by him.

A few things to add for OP’s question of what USBC cables are safe. Like GhostLegion said it matters what Volt and Amp the device supports. Most Samsungs support 5V/3A or QC4.0 or PD3.0 all the way up to 100W but I recommend using 25W or less with Google Pixels and if it’s a newer Pixel like a 5a or Pixel 6 Pro you should be able to use a 5V/3A or QC4.0 USB A to USB C.
I’d stick with well known top brands like iOrange, Anker, Belkin and UGreen absolutely avoid most brands on Amazon since they are not certified, lie about their specs and in some cases list the specs wrong and that can be very disastrous for your AC Adapter or device and especially the battery.
I don’t use the Pixel line and mostly run with Samsung Flagships but I even limit the Wattage on my PD chargers to what Samsung supports in my case that’s 25W. The S22 Ultra will support 45W.
But I can’t stress this enough, get a GaN charger with name brand quality. GaN runs much safer and colder while also being smaller. They usually have all the safety features you need. Anker is a very good place to start for AC adapters. But it’s extremely important you snag a cable that is trusted for listing specs correctly and is certified.

I saw a YouTube video by Linus that explained how batteries work and don’t like to be stressed. So when I bought a new Mate 10 Pro back in early 2018 I decided to have a strict charging regime for it. It only gets charged to a max of 90% (usually around 75% is typical) and no overnight charging.

I don’t play games on my phone…I just use it like a phone.

Now 4+ years later I still have 92% battery health, estimated 3678mAh of 4000mAh. I think it only had like 3850mAh when it was new.