The Seiko caliber V158 is found in some Seiko solar-powered watches, including the exclusive Street Series Solar Divers. This caliber is part of the Seiko Watch Corporation V family/series of solar powered movements.
Some of the topics covered in this caliber listing:
V158 VS V158A:
The movement in your timepiece may actually be signed with the caliber number V158A. As with all Seiko movements, the trailing letter indicates the evolution or change-log of the movement, starting with A as the first release. Therefore, V158 is the same as V158A. As of this post, there is not a V158B, V158C, and so on.
V158 VS V157:
There is a similar Seiko caliber V157, with the main difference being that the V157 only has a date window at 3:00, and the V158 has a day/date at 3:00.
Seiko claims that the caliber V158 will maintain accuracy of +/- 15 seconds per month at normal operating temperatures of about 5C to 35C (41F – 140F).
The caliber V158 is a solar powered watch with a manganese titanium-lithium rechargeable capacitor. It is not a normal battery. The number is MT920, or more specifically: 302324Y. Order one here
The chart below shows how long different lights sources can take to fully charge the cell in the V158. This ranges from 120 hours to 9 hours of constant light source. A full charge can last up to 10 months.
Although there is an instruction manual for dive watches with caliber V157 or V158, there is also another instruction manual that combines the following calibers: V110, V111, V114, V115, V116, V137, V145, V147, V157, V158, V181, V182, and V187.