Smartphone charging confusion and advice, please

[hornylamb]

1. Can I charge my Samsung A55 phone with a Lenovo 65W USB-C AC Adapter? will cause any damage if I charge my Samsung phone with this adaptor?
2. Can I charge other brand phones with my Samsung A55 charger, which came with it?

Thank you

 

[steffi]

Different chargers are using different fast charges protocols, charging on any USB charger should be safe. If phone and charger don't match in protocol it will just default to slow 5V charge. thats it.

 

[B. Diddy]

steffi is correct, it will not damage the phone. Your A55 charger will also work fine for other devices, as long as it supplies enough wattage -- e.g., if you wanted to charge your laptop with the A55's charger, and if the charger only maxed at 15 W, that won't be enough (since laptops typically need at least 30-45 W).

This is assuming your A55's charger is the original one from Samsung, or from a reputable 3rd party manufacturer. If it's a cheapo no-name/off-brand one from AliExpress or a similar site, then all bets are off.

 

[gomezz]

Different chargers are using different fast charges protocols, charging on any USB charger should be safe. If phone and charger don't match in protocol it will just default to slow 5V charge. thats it.

Yep. I looked into this recently and the protocol is that the charger starts off at the old slow 5V level that is backwards compatible with all devices then negotiates with the device as to how much faster the device can handle. If the device is not capable of negotiation as older devices will probably not be then the charger sticks at the 5V level.

You may see this in action when you plug a fast charger into a newer phone in that it briefly displays a long time to reach full charge then a second or so later changes the display to show a much shorter time.

There are even hacks shown on Youtube etc on how to force an old device into fooling a fast charger into giving it the juice at a faster rate. Aimed at more robust devices that were designed before fast charging was a thing but which can handle it anyway.

 

[hornylamb]

Thank you all making me undestand.. Have a nice weekend.