Best USB-C Car Charger for Your iPhone or Android Phone

This is an interesting question. Theoretically, the maximum output from a 12-volt "cigarette lighter" socket is 180 watts, since most run through a 15-amp fuse (15Ax12V=180W). In practice, it's far lower. The last thing any manufacturer wants is for you to blow fuses in your car trying to recharge three phones, a laptop and a curling iron or something. For the most part, the fastest car chargers will charge your phone in a similar, though probably somewhat slower, timeframe as a decent charger at home.

No. 

That said, if you consider that the number is split between the different USB outputs… also, no. 

The wattage output ratings for each charger is a theoretical maximum based on what could be supplied by the specific outputs. It's always all the outputs combined into a single number; you'll never get close to that on a single USB connection.

That all considered, they should give you an idea, within a brand, which charger offers the highest potential output. One company's 48-watt charger should charge devices faster than that same company's 12-watt charger. But there's no way to know if one company's 48-watt charger is faster or slower than another company's 30-watt or 80-watt, as you can see in our testing.

Maybe. There are several fast-charging specifications and most phones don't include them all. Most chargers don't include them all either. Before purchasing any charger, even our picks, it's worth finding out what kind of charging your phone is capable of and making sure the charger supports it. The two protocols to consider are PD and QC. PD is extremely common, QC is found in many, though not all, phones/tablets that use Qualcomm chips.

Not unless there's something really, really wrong with your charger and your phone. The beauty of USB is that the changing device only draws as much power as it needs from the charger. 

There are endless varieties of car charger outlet combinations. For any reasonable-length guide such as this, a narrowing down is necessary. That's why we focused on chargers with one USB-C and one USB-A port, for the greatest flexibility. However, if you don't need a USB-A port, most of the companies we've mentioned above also make dual USB-C chargers that likely perform similarly. Click on one of the options above that looks good to you, and there's likely a dual USB-C option listed as a recommendation elsewhere on that page.

Most likely a good charger with four USB-C inputs will charge a single device just as fast as our picks, possibly even two devices. However, there's only so much power that can go through one of these devices. Four USB-C devices all charging at the same time aren't going to charge as fast as a single device on the same charger.

They're also huge. Maybe I'm overly sensitive to this since I drive one of the smallest cars you can buy, and the last thing I want is a USB charger the size of my passenger seat taking up space. If you regularly charge that many devices, and you have the space to spare, they're worth considering. Some of the companies we looked at also make big multichargers, but not all.

Maybe. Apple products are persnickety about their cables, so you might need a MFi-Certified Type-C-to-Lightning cable to enable fast charging. Non-Apple devices should be fine with any decent USB-C cable. 

I did find a difference in charging times with longer USB-C cables, so for the best times it's good to keep the length of the cable as short as possible.