I can’t speak for the X270 in particular, but most machines do not like not having a battery, and will run at their slowest speeds possible. Some older thinkpads with a 95 watt adapter would run at full speed without the battery, but turbo boost on newer machines is probably too much.

Is there a reason why you want to run it without it’s battery vs just limiting it’s charge to ~60% and pretending it’s not there?

I don’t think the current is possible… But it’s worth a shot. Just X280 support it natively… sadly X280 doesn’t have native ethernet port… need extension…

@schizoidman I saw X270 and X230 mods on Reddit that replaces Lenovo’s power connector to USB-C.