Thanks.
I am having both Huawei and Samsung phones, both not QC3.0 compatible. So, does it mean that there is not much added benefit even with a QC3.0 certified charger/power bank?
There is no added benefit to a device that supports QC2 and not QC3 to get a QC3 power supply other than perhaps when you do upgrade to something that does support it you will be able to take advantage of higher output modes it supports if it does actually support the modes that QC2 doesn't.
If you are searching for QC2 only likely you won't find very much as when QC3 came out it supports QC2 fully which means QC2 only devices were phased out of production for QC3.
My phone is an older phone that I got in 2017 and when I bought it I didn't know about fast charging at all and when I found out it supported it and the previous version of the phone that I passed over didn't I was pleased as it charges almost twice as fast vs standard USB charging. I've since looked for chargers and power banks and even purchased car chargers that support QC plus have a few Anker power banks that support it. I even bought a small circuit module that supports QC3 that works well for about $3 off Ebay.
I have one power bank that supports PD input for charging but doesn't support QC for charging it and I've researched what PD is (Power Delivery) and it was an eyeful I still don't completely know the full scope of it as they are coming up with upgraded new standards supporting even up to 20V input and 100+ watts output. The silly thing about it is that most PD supplies/chargers tend to only put out about 18watts which isn't any better than QC2.0 and 3.0 as QC2/3 support 9V @ 2A or 12V @1.5A which is the same amount of power. I've been looking at 35W PD and higher supplies as these will be useful for faster charging and higher capacity battery devices like tablets and even laptops can take advantage of the higher voltage and current outputs that require heftier power supplies.
With QC4.0 and the same voltage ranges of both QC2/3/4 and PD standards with the exception of higher than 12V and higher amperages on some voltages over the other have essentially being merged with chargers that support QC4 now also supporting PD also but the issue of QC is most devices supporting it use USB A while PD is mostly USB C. I believe that PD type charging that favors USB C will become the standard and that USB A will be dropped more and more and just kept on to support older devices. I have no USB C devices other than power banks and some chargers I picked up for pocket change at thrift stores and flea markets.
If you are going to buy something new and pay a non discounted price I would strongly recommend a device with PD support along with QC as sooner or later you likely will transition to that standard of charging as it supports higher power charging rates and a power bank that can be charged at higher than 18watts that is the max for QC2/3 will benefit greatly especially when it is 10,000mah or larger in capacity which even with QC support will take several times longer than charging an average phone these days and charging at even high amp USB only (2A) can take insanely long times to charge. I have a 15000mah power bank that I drained down to less than 20% by the LED gauge that took like 18 hours to charge fully I do have a power bank that has PD charging but I do not have any PD chargers or USB C to C cables either.
I hope I didn't confuse you with so much excessive info and my rambling.
