I have a BRAT with a Botboarduino that originally had the 6 volt battery BAT-03. I purchased the 7.2 volt battery robotshop.com/en/lynxmotion- … ttery.html for it to have some power in reserve since I added more sensors to it. I just wanted to make sure that will be safe to use, specifically for the servos.
The BRAT use servos which are made to run at 5-6V and if you power them at 7.2V they might burn.
To increase your reserve, you should increase the mA value not the voltage.