I really don't think this is an issue.
A full charge by itself does not significantly reduce the lifespan of the battery, unless it is stored at full charge for more than about two weeks. Your primary concern should be heat and unnecessarily deep discharges (to 20% or lower state of charge). Heat is the predominant concern with laptop batteries, because lithium-ion batteries degrade significantly faster at high temperatures that at low temperatures.
If your laptop allows it, detach the battery when it is fully charged while running on the AC adapter, so that it is not subject to the heat generated by the computer. Optimal battery life can be obtained by limiting the depth of discharge to about 50-60%, or discharging the battery to not less than 40-50% state of charge after a full charge. Detailed technical information on how to extend the life of lithium-ion batteries can be found in this Battery University lesson.
This is how I've maintained as much as 80% of the original charge capacity of my laptop's battery after 2-1/2 years of use.