The 18650 battery typically has a power of 3.7 volts and a current of 2600mAh. An overwhelming number of 18650 types are rechargeable. This feature should become the uniform standard moving forward.
Kriya Yoga is a simple, psychophysiological method by which human blood is decarbonated and recharged with oxygen. The atoms of this extra oxygen are transmuted into life current to rejuvenate the brain and spinal centers.
Sometimes the breath practices along the spine are considered to be part of, one and the same with Kriya Yoga or Kundalini Yoga, as well as Raja Yoga or Hatha Yoga. See also the articles on sushumna awakening, kriya and kundalini Yoga in the: Sushumna page of Kundalini Awakening.