官网说是1伏电压以上自动冲；手动通吃。我个人使用中还没遇到过不能冲的情况。

The all-new start-voltage sensor allows the Genius to detect and charge dead batteries as low as 1-volt. For extremely dead batteries lower than 1-volt, manually turn on force mode to detect and charge batteries all the way down to zero volts.