Hi everyone:

I recently purchased an Foam electric plane that came with 2 7.4volt lithium ion batteries. plus all the servos and ESC installed and i have flown it for quite a while.

But I recently purchased an 11.1volt lithium-ion battery from hobbyking for an EDF jet i had that passed to a better life..

Question could i use that battery on the foamy?

I honesly dunno the brand or maximum battery the ESC can handle since it says nothing in either side of it..

How can I tell if the ESC can handle thebigger battery or not??

Find the specs on the ESC. If it can handle the higher voltage, THEN you need to find out if the motor will too.

What was the plane? Brand on the box? any brands on anything else?

Is there any info available from the vendor you bought the foamy from?

Sadly the only thing that says brand name is the rim fire engine in the front which is a: Rim Fire 22M-1000

Beyond that nothing else says brand or name.

This is the only info I got from tower hobbies about this engine.

22M-1000 Motor;
Input Voltage: 7.2-12V
kV Rating: 1000rpm/V
Max. Constant Current: 11A
Max Surge Current: 15A
No Load Current: .65A
Internal Resistance: 235 milli-ohms
Ball bearings: Two, shielded
Motor Diameter and Length: 1.1" x 1.14" (28mmx29mm)
Shaft Diameter and Length: .16" x 1.73" (4mmx44mm)
Total Weight (VPP and Motor): 2.1oz (59.5g)
Length prop tip to tip is approx. 10"

 22M-1000 Motor;
          Input Voltage: 7.2-12V
          kV Rating: 1000rpm/V
          Max. Constant Current: 11A
          Max Surge Current: 15A
          No Load Current:  .65A
          Internal Resistance: 235 milli-ohms
          Ball bearings: Two, shielded
          Motor Diameter and Length: 1.1" x 1.14" (28mmx29mm)
          Shaft Diameter and Length:  .16" x 1.73"  (4mmx44mm)
          Total Weight (VPP and Motor): 2.1oz (59.5g)
          Length prop tip to tip is approx. 10"

From what I gather the rim fire motor can handle the 11.1 battery..

But how do I know if the ESC it has installed can??

Try it and see if it gets too hot in a few seconds.  If you burn it up get one from Hobby City - 18-25 amps. They are cheap.

Oh okay.. then tomorrow i'll test it out..

I imagine that if the ESC doesn't get hot. means it works fine right?

Yeah, If it can't take the voltage it will burn out.  But you can get one to handle a 3 cell for $15.

The specs state right off the voltage the motor is designed accept for input is: 7.2-12volts

If you use LiPos, then a 3 cell is the most cells it can use.

As for the ESC, they usually have some printing on them that looks like specifications. It usually is.

Does the ESC play some tune when you plug the battery in? or when you move the throttle to arm it?

Was the plane sold as a ready to fly? What is the airplane? P-51? Cub? name on the wing?