I'm not sure if I can connect four brushless dc motors to my Lipo battery. I don't know how to calculate it. The brushless motor I have is the Turnigy L2210C-1200 brushless motor (150w) and the Lipo battery I have is the Turnigy 5000mAh 2S1P 20C Hardcase Pack (ROAR APPROVED). I should also probably say that the ESC I have is Turnigy Plush-32 30A (2~4S) Brushless Speed Controller w/BEC (Rev1.1.0). Also how long can I use the brushless motors? I would like to make a flying car.
The motor part number (Turnigy L2210C-1200) tells you two things: The 2210 is the physical size and the 1200 is the Kv rating. The Kv rating tells you the RPM (revolutions per minute) per volt applied.
The battery part number (Turnigy 5000mAh 2S1P 20C) tells you things about the battery. It is 2 cells in series and 1 parallel (2S1P). The 1P is a standard configuration. The 2 cells have a (nominal) voltage of 3.6v each, so a total of 7.2 volts. The 5000mAh says you can pull 5 amps for one hour. The 20C says you can drain it 20 times faster (at 100A) but only for a short time. This is useful for takeoffs and high speed maneuvers.
The motor specification has a minimum voltage of 7.2 volts and a maximum current of 15.8A. The ESC part number (Turnigy Plush-32 30A) is well above these requirements so everything should work together nicely.
How long you can run the unit is not really a question that we can answer. It all depends on the drone that these things are going on. The size, weight and type of drone that you are making will determine the run time. Other factors like speed and the environment will affect the amount of time as well.
Depending on the above factors you can probably expect between 10 and 30 minutes of use. One of the stated motors running full speed would last about 20 minutes or less. Run times are exceeding difficult to calculate and actual usage will usually be less than the calculation.
With more information about the drone someone may be able to give you a better answer.