Power supply rated for less power than needed by laptop

E

eem2am

Member
Hi,
I use a Lenovo thinkpad E15 at work.
It has a 65W power supply.
The power supply says it does
20v at 3.25A
or
15v at 3A
or
9V at 2A
or
5V or 2A.
(INPUT IS 100-240VAC)

...I havent any idea how the power supply "knows" what voltage to give.

Anyway, it has a USB-C connection to the laptop.
Would the laptop still work if i connect a 20W rated power supply (20V).?
..I mean supposing i was just surfing the internet, it might not need the full 65w for that?

Lenovo thinkpad E15

ThinkPad E15 | High-performance 15.6” business laptop

Everyday computing gets a real boost with the Lenovo ThinkPad E15. Seamless performance, plus built-in security, durability, and reliability, means great value for money for any small business
www.lenovo.com
 
Intel_man

Intel_man

VIP Member
johnb35 said:
You need to use a power adapter that matches the output of the original. If you don't you either damage the battery or even worse the laptop itself.

https://www.amazon.com/Genuine-Lenovo-ThinkPad-Adapter-ADLX65YDC2A/dp/B07CGP4SB2/ref=sr_1_3?keywords=lenovo+laptop+charger+65w&qid=1666386337&qu=eyJxc2MiOiI0LjEwIiwicXNhIjoiNC4wOSIsInFzcCI6IjQuMDgifQ==&sr=8-3

I know you don't live in the USA but at least that gets you close.
Click to expand...
From what I can see on the thinkpad E15, it uses usb-c for charging. So, in theory if the OP uses a 20W charger through usb-c instead of 65W, it should do one of the following, but shouldn't damage the battery.
  1. Charge slowly because you're providing 1/3 of the wattage recommended.
  2. Not charge at all because the laptop is drawing more power than 20W.

But as @beers has said, just get a 65W USB-C PD adapter. They're not expensive and not worth the hassle of dealing with the aforementioned scenarios above.
 
You must log in or register to reply here.
Top