Ogniem i Mieczem - By Fire and Sword

well, the target should be to avoid a cav open charge at all, using village buildings, fences, remote houses, woods, hills, you name it.
Playing usually offensively as a Swede, I can tell you that open charges are a rare occasion. And if they occur you are charging those pesky teleporting Poles with a larger range than yours -.-
Make sure you get some cannon fire on them first, and remember that you cannot widen during a charge move, only reduce width; use this to your advantage. try to get some flanking fire on them (remember: field of fire for close order is measured by unit, not by base; only LOS and range are measured by base).

If you cannot avoid it, remember the game's restricted rounds: luring a charge far out can well mean that the cav unit is out of command range and has difficulties finding its way back to the action or defending itself agains follow-up attacks until the game is over. Even if they killed a unit of lesser worth on the way.