官網說是1伏電壓以上自動衝；手動通吃。我個人使用中還沒遇到過不能衝的情況。

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.