How long will the battery be discharged by means of the fan?

Question

Electronics

Akum
3200 mAh 3.7V
Fan
DC 12V 0.30A
Or tell me the program/online calculator.
What if you connect 2 of them?
Don't ask me why I need this.

Answer 1

Roughly speaking, 3200 * 3.7 / (12 * 300) ~ 3.2 hours.
Minus the losses on the DC-DC converter, which will make 12 out of 3.7.
Total hours 3 maximum.
If there are two fans, then obviously half as much.
If there are two batteries, then obviously twice as long.
And if you want to directly connect this battery and this fan, then it is unknown. It all depends on whether the fan will start at all and how much current it will consume at such a low voltage - you need to measure the current.