Hello, as you know, for Lenovo laptop, the AC adapters have an identification pin. They use a simple system with a resistor to ground from the ID pin.
Here are some values for the resistors:
65W adapter: 270 ohms
45W adapter: 116.5 ohms (you can use 120)
We had a T450s in with trouble recognizing adapter, due to poor quality power jack (not broken, just poor quality). Tried 3 adapters and it was hit and miss on all of them. I have disconnected the ID pin from the connector that plugs in the motherboard, and soldered a 270 ohm resistor from the connection of the ID pin to ground. Now any adapter plugged in is recognized as 65W, no problem charging the battery now.
Here are some values for the resistors:
65W adapter: 270 ohms
45W adapter: 116.5 ohms (you can use 120)
We had a T450s in with trouble recognizing adapter, due to poor quality power jack (not broken, just poor quality). Tried 3 adapters and it was hit and miss on all of them. I have disconnected the ID pin from the connector that plugs in the motherboard, and soldered a 270 ohm resistor from the connection of the ID pin to ground. Now any adapter plugged in is recognized as 65W, no problem charging the battery now.

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