ThinkPad T400 blinking battery and charger leds on charger. - YouTube
battery patch did not work with my X230 · Issue #183 · hamishcoleman/ thinkpad-ec · GitHub
Lenovo thinkpad T400 blinking battery and power leds when connected to power : r/thinkpad
T480 charging issue. Red light is showing but laptop is not charging. Sometimes it gets opened and gives error message- "The connected AC adapter has a lower wattage than the recommended model