[cooperadymas]

My X201 has no battery and a charge cord. Infinite runtime.

It's easy if you change the parameters.

[1letterunixname]

Your "laptop" in disrepair is a desktop. You can't hot-swap that Linux laptop's batteries.

24 Wh built-in with unlimited hot-swap 72 Wh batteries, pretty much 96 Wh + 72Wh * N.

Got anything constructive to add?