Help with Bluetooth project feasibility

Projects General Guidance
1

Hi I'm looking for some pretty basic advice on whether or not my project is feasible using Arduino.

I will have three units configured with Arduino boards, one will be the controller and the other two the slaves.
The controller will have constant power, no need for a battery.
The controllers job will be to monitor inputs (not really important at this stage where they come from) and once triggered, it will send Bluetooth signals to the slaves telling them to either turn on or off 30 LEDs.
The slaves will be approximately 20 feet from the controller and will need to be battery powered.
The slave(s) units will have a light sensor and return an acknowledgment to the controller that the LEDs did in fact come on.

Questions I have are as follows:

What kind of batteries would I need to power the slave units?
How would I be able to estimate how long the slave unit batteries would last for continual use under varying conditions?
Condition 1 - lets say no LEDs are ever turned on, only the Bluetooth communication between the controller and the slave.
Condition 2 - Going to the opposite extreme, the LEDs are turned on immediately and are left on continuously, how many hours could I expect the batteries to last?

I hope this is enough information to determine if this is a doable project, if not I will be happy to answer any follow up questions you have. Thanks for any input.

2

Unless you are using HID bluetooth modules, or are able to switch between the slave MAC address, bluetooth I not the way to go. There is however a way you could get it to work, but not the way you want it to. I'm talking about using to two different BT modules, one for each slave, or you make a slave a transmitter for the other slave.

Standard Bluetooth modules are one to one, meaning one master controls one slave. What you could do is use both regular serial and software serial and set up two serial connections.
The other way is quite the same except the first slave will filter out the commands for itself and then using another master module, transmit the rest of the filtered data to the other slave. Basically your making a repeater, only this one will keep its own data and send the rest to the other device.

You also have Xbee modules, I'm not sure if they are one to one, or if they can transmit to multiple receivers. You can do the research. Another alternative is RF modules.