A 400w or 500w inverter would be suitable for any of the fans that we’re going to cover here, and this inverter is one with very solid reviews from Amazon at a great price point.ĭue to the fact that the inverter is being used, we are going to lose about 15% of our efficiency overall when powering our fans. In order to switch the current type, we need to use an inverter as an intermediary between the battery and the fan so that the direct current can be changed into alternating current.

With the exception of the USB fan, we’re looking to power household fans that run on alternating current (AC). Theoretically, a car battery with a 50AH equivalency should be able to release 1 amp for 50 hours, 2 amps for 25 hours, etc. This is a common estimation in the battery world since car batteries are “starter batteries” which are rated in CCA (Cold Cranking Amps) and not AH like other “deep-cycle” batteries. How much Energy does my Car Battery have to Power my Fans?įor all of these examples below, we are going to assume your car battery has an ampere-hour (AH) rating of 50 hours. If you want though, you can also skip to any of the specific fans by clicking them below but you can refer to the battery section if you have any questions about the numbers I used. This article will not be taking into account Peukert’s Law. We’ll take a look at the most common types you’ll probably run into, how I reached these numbers, and the best fan for conserving your battery’s life.īefore we cover each of the fans individually I’m going to briefly go over the car battery and the inefficiency factor of using an inverter. How Long Can a Car Battery Power a Fan? Fan Type 100% Discharge (Total Time in Hours) 50% Discharge time in Hours (to still start your car) Desk Fan 12.76 6.38 Tower Fan 9.45 4.73 Window Fan (Both fans on High) 9.1 4.54 Box Fan (High) 5.31 2.66 Box Fan (Med) 6.21 3.11 Box Fan (Low) 7.97 3.98 Oscillating Fan 6.21 3.11 USB Fan (3-watt) 200 100 50AH equivalent car battery.Ī car battery can power a fan - many different types of fans, in fact.

12 volt car battery watt hours