Is vehicle actually overheating ?
and
Is it charging?
Many of this early Optimas have grounding issues that can cause the temp gauge to read higher than normal
The battery light indicates that the battery is not receiving a charging current. You may have a bad alternator or a broken drive belt (if you have a broken belt you'll have overheating and power steering problems too, though).
You have to disconnect the battery for couple minutes.
It means you battery is overheating Btw NOT GOOD
Trufully, my battery just died yesterday, and the battery light did not come on, the only time it comes on is when the alt isn't charging. I've replaced 2 batteries and 4 alts in my 01 optima!! Although it is a battery icon, what it really means 99 times out of 100 is that the battery is not being charged and although it could indicate a battery that is tired and due for renewal (I always get a new one every 3 years; 2 years if it's the original thing the car comes with) it usually indicates a fault with the alternator which has, more than likely, worn out. 2001 might still be under warranty I suppose.
It could
The red water level warning light is an indication the cooling system is overheating. The red battery warning light is an indication the charging system is malfunctioning.
could be a bad alternator or battery
The red water warning light is an indication your engine is overheating. The red battery warning light is an indication that the charging system is not working properly.
Could be a problem in the emission control system. Have vehicle scanned to determine the problem
There could be a sensor wire that is bad or going bad
The Ford Freestar several warning lights. The red water warning light indicates the cooling system is overheating. The red battery warning light indicates the charging system is malfunctioning.
Remove the positive terminal on the battery for 20-30 minutes and then replace the terminal on the battery and tighten the bolt very well. Also, for battery acid build-up on the terminals, pour several cups of boiling water over the battery terminals.