These are custome made li-ion batteries specifically made to provide onboard power solution for the Helix.
Posted by Lau on 27th Aug 2015
The 2600mAh lasts a good 4-5 hours even when powering both my Sony A7S and TVLogic monitor. For a shoot I did recently where there's a lot of handheld gimbal work, I only ran through 1.5 batteries in about 7 hours of work. They also charge up pretty fast, and hold charge for a while. Highly recommended.