Dynamo Lights

Lael was testing a new version of a light (from Sinewave) during her Baja record that had a battery in it so that when the speed was too low (happens a lot MTBing) to light up the dynamo the battery would power it.

EDIT: battery is NOT in the light, it uses an external battery...
"Lael was riding a prototype Sinewave Cycles dynamo light on this ride which I mentioned in a previous post. I realized while editing these photos that the beam pattern and brightness are displayed nicely here, although minor changes in optics and output may occur before the production models are finalized. This light features a very bright beam, USB charging, and a unique battery power mode where the light can be provided additional power from a standard cache battery which allows for substantial light output at low speeds and while stopped. Dynamo lighting typically flickers and dims at low speeds, but with a battery backup the light remains bright even when walking the bike up a steep grade or churning through the sand at 3mph. Lael began her ride in Tecate with a 10,000 mAh Anker battery which was fully charged. She used it every night in addition to the power coming from the dynamo hub, and charged the battery from the light during the day. In ten nights of riding, she never plugged into a wall."
https://gypsybytrade.wordpress.com/2017/03/15/lael-wilcox-establishes-the-baja-divide-fkt-in-111302/

I thought the Revo was just a normal dynamo light, ie. no internal battery?