Wirecutter

More-sensitive gadgets may not function correctly while using this DC-to-AC converter, but a smoother converter costs $100-plus.

More-sensitive gadgets may not function correctly while using this DC-to-AC converter, but a smoother converter costs $100 or more.

If you don’t have a generator or enough batteries on hand in a blackout, you can plug this small inverter into the 12 V socket in your car and use its AC outlets to run or charge small devices up to 300 W. It’s not an efficient way to make power, but it’s small and affordable.

TechGearLab

The BESTEK 300W Power Inverter is a fully-featured mobile charging device for remote professionals. It has two 120V plugs for charging larger devices like laptops, drones, and camera batteries, and it also has two USB plugs for more conventional mobile devices like tablets and phones. The high wattage provides plenty of charging capability for multiple high-powered devices at the same time, and is very useful for photographers and videographers who need to charge multiple batteries from their vehicle in remote locations. It features a cooling fan to ensure safe handling and also comes with a fixed 24-inch cord with a DC &#40;cigarette lighter&#41; plug at the end. It even has an on/off switch to ensure that the charger is not drawing from your vehicle's battery when not in use. All components are well-constructed and seem built to last, and we have not had any issues with durability during our 6-month test period. 
The two USB-A outlets can dish out up to 12 watts each, meaning that most devices see average charging times. It lacks the fast-charging capabilities of USB-C and Quick Charge Devices. If you'll only be charging your modern smartphone or tablet in your vehicle, this charger is probably overkill, and you should check out some of the other small and fast chargers in our review. The body of this product is the size of a small brick, measuring 5 inches long, 4 inches wide, and 2 inches thick, taking up much more real estate than the smaller car chargers that barely protrude from the outlet. Compared to the comparatively sleek and unnoticeable two-port chargers on the market, this one certainly has a footprint, but for the right individuals, it can't be beaten. 

Power Inverter Comparison