Hello Chris, Thank you for your inquiry! All the Sea Breathe systems run from a 12-Volt battery. The deck units can run from either the boat battery or an auxiliary battery. The requirements are that it should be a deep cycle sealed type battery. Approximate running time per charge is 3 hours. NEW: This unit is able to be switched from Two person mode to One person mode in seconds. This reduces power usage by 7 Amps. Also, this One Diver mode can be used if Two divers are in Shallow water.
http://www.scuba.com/scuba-gear-152/031897/Sea-Breathe-Two-Diver-Floating-Unit-Diving-Hookah.html If you have other questions, need help or would like to place an order, please contact one of our Instructors at SCUBA.com by calling 800-247-2822 <> 949-221-9300 or e-mail us at: info@scuba.com