MySQL Syntax Error - INSERT INTO

I've banged my head enough trying to figure out this problem and have given up.

I've inserted data into an SQL DB before without any problems.  Not sure what's going on here.  This is my code:

	$charge = function_read("vehicles/" . $status[0]['id'] . "/command/charge_state");
	$miles = mysqli_real_escape_string($con, $charge['battery_range']);
	$battery_level = mysqli_real_escape_string($con, $charge['battery_level']);
	mysqli_query($con,"INSERT INTO battery (Date, Range, Percent, Sleep) VALUES ($date, $miles, $battery_level, 1)");
	echo $con->error;

This is the error message (completely worthless, IMHO).  Could it be any less descriptive?

 

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'Range, Percent, Sleep) VALUES (2013-12-01 10:15:07, 189.18, 82, 1)' at line 1

MySQL table is configured as follows:

Any ideas?