If it is the Dot or new Portable charger, the operating voltage is 185V AC - 275V AC
Although @Shreyas.G might still know the answer and may or may not answer, @Shreyas can not and will not answer this question of yours.
You may address such questions to @abhishek.balaji (again, don’t send it to @abhishek.balaji2) now and in future.
Sorry if I confused you 