An hour until sunset with 日没

Kanji Explanation: Sinking and disappearing with 没

During a game of hide-and-seek in the park, Ayumi hides in the trunk of a car only to fall asleep. Since the car drove off a while ago, Conan plans to track Ayumi’s communication badge with his tracking glasses and follow the vehicle on his turbo-engine skateboard. Since the engine is solar-powered, he can only use it during sunlight.

コナン:: 「日没(にちぼつ)まであと１時間(じかん)ちょい…」; “Just over an hour until sunset.”; 「えーっと　奴(やつ)らの車(くるま)は…」; “Let's see, their car is...”

Key Points

1日没(にちぼつ) = sunset

Here 日没(にちぼつ) refers to the sun going down below the horizon.
Conan is thinking about the remaining daylight because his skateboard depends on solar power.

2まであと１時間(じかん)ちょい = just a little over one hour left

まで sets the endpoint: until sunset.
あと１時間(じかん)ちょい is a casual way to say “a bit more than one hour remains”.