There is no restriction on the number - you can control an unlimited amount of devices through your account. Just make sure to name them differently, so you know which Maya V2 you are sending commands to.
Alongside the Maya V2 devices, you can also add as many MClimate devices as you want, in order to make your home smarter and your daily life - better.
Learn how to rename your Maya V2.
Learn how to add a new Maya V2.