You know you can CALL THEM BACK when the charge is over. I highly recommend it. Get yourself onto the enemy flank and issue the "follow me" command. Once you cav is mostly formed up you can tell them to charge in again. In large battles you need to control the cav yourself. Keep them together until the enemy all routs and then let them finish off the survivors.
I have also reformed my infantry into a new line to meet the enemies second wave. You have complete control over your army. I suggest you use it.
Oh, I know, but then re-issuing the charge command leads them to pursue the nearest unit. Which in the scale of a large battle, is usually some infantry unit running away, which results in like 6 horses chasing after one fleeing soldier, instead of charging full on into an infantry assembled line formation... or into the archers to prevent them from raining **** on your troops.
Oh an also - constantly getting your troops to stop fighting and follow you, can result in unnecessary troop losses, since their priority is to follow you, and not engage... So really, it just isn't that effective at all.