It takes about 2 hours time to fully charge Vivo S1 battery from 0% to 100%. Please note that Vivo S1 comes with a huge battery capacity of 4500 mAh. Hence despite fast charging support, it takes a little more time to fully charge the phone.
Yes, Vivo S1 does have a 3.5mm headphone jack.
Yes, Vivo S1 has a dedicated MicroSD card slot. You can use 2 sim cards and a memory card at the same time.
No. Vivo S1 does not have the FM radio support.