Question:
Is there a problem wearing an automatic watch over a two day yom tov? If left unworn the watch stops running even on full charge after 36 hours. Thank you.
Answer:
According to most poskim it is permitted, and that is the minhag. On a two-day Yom Tov, although it is permitted, as you say, since it will not last that long on its own it is a nice chumra not to wear it.
Sources:
Chelkas Yackov 1-75, Shalei Tzion O:CH pg. 103, Tzitz Eliezer 9-20, Mishne Halachos 8-59, Shmiras Shabbos Khilchoso 28-ftnt 57 in the name of R’ S. Z. Auerbach zt”l, Ashrei Hoish O:CH 2 Chap.33-3, Divre Chachomim O:CH 295 in the name of R Schienberg, R’ Yitzchok Berkowitz shlit”a.
