Can I use a 90W adapter on a 120W laptop?

Yes, Your laptop has been designed to draw up to a certain amount of power when running at full power. If your laptop was supplied with a 65W charger we know that the laptop will never draw more than 65W, so you can use a 65W, 90W,120W, 150W, 180W, 240W or higher charger.

Can I use a 65W charger instead of 135w Lenovo?

For charging it would be fine. It wont damage the system but if it needs say 90w then it will pull from the battery instead of the adapter. That’s why it depends on how much power the laptop actually needs.

What type of charger does a ThinkPad use?

USB Type-C
The Lenovo 65W Standard AC Adapter (USB Type-C) offers fast and efficient charging at home, in the office, or on the go. This 65W charger is compatible with ThinkPad USB-C enabled laptops and tablets.

Can I use 90W charger instead of 180w?

If the voltage, amps,… are all the same you can use it for CHARGING ONLY. There is a reason the adapter is 180w. This means that your laptop when being used can consume a lot of power and once you go past 90w you can easily damage the charger, laptop,… by doing that.

Can I use 65w charger instead of 90W?

If its the same voltage, then you can use it. But if you are using more power then it can provide, your laptop will start drawing from the battery as well as from the power brick.

Can I use a 19.5 V charger on a 20v laptop?

Yes: technically it can be used, but you need a higher amount of power (watt). if the adapter is 19V 6A, it might start the PC but you will have strange side effects.

Can I use a charger with higher amperage than the original?

Yes, it is absolutely safe to charge a device with a charger that has more current capacity than needed. Since the voltage is held constant (5V), the only factor that determines current draw is the load (another term for resistance) the device places on the charger.

Can I use a 90w charger instead of 150w?

Yes of course. A good battery. Run the laptop on battery. At lunch hour turn it off at the remote location and let it charge up with the 90w adapter.