The best USB car charger is the compact but powerful Scosche reVOLT 12 W + 12 W. At 4.8 amps, it’s rated as one of the most powerful car chargers you can buy. When we had an engineer test the claim, it exceeded advertised performance specs, which means it provides the fastest charge possible for tablets and phones outside of a wall plug. We seriously considered and tested 8 models to find that though other chargers are as powerful, the Scosche exceeds its power claims, is by far the most compact charger available, and has the benefit of being cheap as well.
But there’s an important note to Android users: this will NOT work with a Samsung Galaxy S5 (even Scosche doesn’t know why). For all other phones, tablets, or USB-charged items, it’s the best charger for your car.
If you have a Galaxy S5, or if our main pick sells out, get the Anker 24 W charger. It costs the same as the Scosche and performs as well, but it’s about twice as large. The only reason to get this is if you have an S5, the price of the Scosche doubles, or the Scosche disappears completely. We confirmed with Anker that it will work with any device, Android or Apple.
It’s worth noting that while our pick will probably charge your Android device, it may not be able to do so at full speed unless you buy a charge-only cable (like this one) to go with it. This is due to various incompatibilities between Android and Apple circuitry that we touch a bit more on towards the bottom of the guide.
Who should buy this?
Traveling with driving apps means having USB charging readily available in your car is a near necessity for most of us. Unless you don’t own a car, it’s worth having a dedicated USB charger for your 12-volt outlet (aka, the cigarette lighter).
Even if your car is recent enough to have a USB integration system for playing music or handling phone calls, it can still be worth spending $15 or so for a charging device like this in order to get faster charging speeds. That’s because your car’s built-in ports usually only put out 1 amp, which is not enough to charge a tablet. If you’re running an app like Waze or Google Maps and charging with your car’s USB, you will arrive without much charge added to your phone. Even if you got equal power from an integrated port, most cars usually only have one. It’s worth spending to have an always-ready high-speed charger, especially since you can get two outlets from one cigarette lighter.
Similarly, if you have a charger that you bought a couple years ago, it’ll probably only output 1 amp. Upgrading to this for just a few bucks will provide you with faster charge times and the ability to charge tablets along with other high-current devices. Same goes for people stuck with a charger that only has a single USB port. We’re living in an multi-device age, so it makes sense to have multiple USB ports.
However, if you just bought a USB charger with at least 2 amps in each of the ports, there’s no reason to upgrade. Though you’ll be able to charge your iPad Air slightly faster, it’s not so fast that it’s worth paying extra for.
How we picked
There are hundreds of USB car chargers for sale that plug into your car’s cigarette lighter, but most of them aren’t even worth considering because they don’t have enough power to simultaneously charge two devices at full speed. These days, you should expect a good car charger to have 2 USB ports capable of outputting 2.4 amps for a total of 4.8 amps. In plain English, this means you’ll have enough power to charge 2 phones or 2 tablets (or any USB-charged devices) at speeds comparable to what you’d get from your wall charger.
There’s no reason to consider anything with less than 4.8 total amps because chargers with less power aren’t any cheaper. With that in mind, we eliminated anything at or below 4.2 amps. This left us with about a dozen models for further consideration.
We also dismissed models with permanently-attached cables because cables are prone to failing. If and when your charge cable fails, it’s nice to be able to replace just the cable without having to buy a whole new charger.
There are a lot of imposters that are capable of charging at 2.4 amps from either port, but not from both.
We then looked closely at their full specs to make sure that both ports charged at a full 2.4 amps simultaneously. This is important because there are a lot of imposters that are capable of charging at 2.4 amps from either port, but not from both. For example, this Satechi has a compact design, a good reputation, and can output 2.4 amps from either USB port, but only has 2.4 amps of total output. That means if you’re charging a phone from one port, you won’t be able to charge a tablet from the other. Again, there’s no reason to consider these when other options with similar designs can be had for the same price.
With a list of chargers that, according to their fine print, could produce two 2.4-amp charges at once and power two tablets, we looked at price. After weighing the cost and warranty options between the smattering of 4.8-amp USB car chargers now on sale, we eliminated anything over $20 or any models that had no clear advantages over their peers. For example, Aleratec makes two different 4.8-amp car chargers, but one (Dual USB Car Charger) was bigger and cost $4 more than the other (Dual 2-Port USB Rapid Car Charger). Naturally, we went for the cheaper, sleeker model.
In the end, we had about a half-dozen of the highest performing USB car chargers available to send to engineer Dan Siefert, a veteran of the electronics industry with names like JBL on his resume. He also specializes in car-specific electronic optimization. We sent our finalists to his lab to test their maximum power output, which meant variables like the device receiving the charge and the cables used were not a factor — he just found the raw performance numbers for each model.
This device monitored the voltage traveling through each charger. The screen read out the figure for the power each model could handle.
Specifically, he tested each charger for:
- Nominal output voltage: 12.6 V supply, 100 mA load
- Load regulation: any output voltage variation over a range of loads
- Voltage regulation: any output voltage variation as a function of supply voltage
- Maximum power output vs. specifications
Here’s what we found.
Surprisingly, the makers of 4.8-amp car chargers are modest: all the testers met or exceeded their advertised performance specifications, which meant that they all were capable of delivering power beyond the maximum charge speed of any tablet or smartphone. All of the finalists can charge two tablets simultaneously at their maximum charge speed.
Knowing that the finalists all performed beyond expectation and necessity, we researched to make sure every model would work with a variety of devices. We asked the companies directly through our media contacts and then anonymously called customer service to find out if any chargers had any known issues with specific models. We also asked for details on the warranties and return policies for defective models to make sure that the companies stood behind their products enough for us to recommend them, even before we conduct longterm testing.
Finally, we weighed price, ergonomics, warranty, and brand reputation to find the best model.
The Scosche reVOLT exceeded its advertised performance specs during our tests. It’s the best designed and best performing, but be warned: it won’t work with a Galaxy S5.
The Scosche USBC242M reVOLT 12 W + 12 W won because it’s unobtrusive, affordable, and solidly constructed out of quality materials. Other chargers can match its performance, and some are even a few bucks cheaper, but none could match the Scosche’s compact design and ability to blend into your car’s dash. It’s about half as long and much thinner than the majority of its competitors. In fact, last year’s pick was the the 10-watt 2.1-amp version of this same charger. That’s because the 12-watt 2.4-amp version wasn’t out yet. But now it is and it’s every bit as good, except more powerful and cheaper as well.
The Scosche (left) performs as well as the rest of the most powerful car chargers in the world, like the Anker (right), but at half the size.
It’s rare that the best-designed product is also the best performing, but that’s the case with the reVOLT.
It’s rare that the best-designed product is also the best performing, but that’s the case with the reVOLT. In our tests, it produced a maximum current output of 5.8 amps total. That’s well beyond its claimed 4.8 amps. Its competitors put out similarly superfluous power, but none could do it for cheaper and from a more compact and convenient body.
Standing at just under 2 inches high and less than 3 inches in circumference, it is significantly smaller than any other charger we looked at – it’s about half the length of almost all competitors. In fact, depending on the depth of your cigarette port, it could even potentially sit flush with your dash. This might not matter in cars that have ample space around the dash area, but the small size is a big advantage in cars that have cigarette lighter ports jammed into small spaces. It’s like having two high-powered USB ports directly integrated into your car.
The small size also means it will easily fit into an overstuffed carry-on or purse if you’re bringing it along to use in a rental car.
Another nice touch is the blue LED indicator light, which lets you know that it’s on. It’s not so bright as to be distracting when driving in the dark (more common than you’d think), but it’s bright enough to let you see the ports in the dark.
The one caveat is that it will not charge a Samsung Galaxy S5.
The one caveat is that it will not charge a Samsung Galaxy S5. The company’s site specifically lists the Samsung Galaxy S4 and S3 under the compatibility tab, but we anonymously asked Scosche customer service and they confirmed that every device besides the S5 should work with it.
If you make this mistake or find you actually don’t need a charger, Scosche has a solid return policy. The charger comes with a standard one-year warranty, but it can also be returned for a full refund for up to 60 days after the purchase date. The warranty, we found from anonymously calling Scosche, covers it against defects, so if it breaks or doesn’t work, they’ll refund or replace it.
Who else likes it?
Few publications have comparative reviews of USB car chargers, and fewer have tested the dual 12-watt model we picked. For now, it’s just customer reviews and our own Wirecutter testing, discussed above.
On Amazon, the Scosche averaged 4.5 out of 5 stars over around 40 reviews — most negative reviews are from customers who found out it doesn’t work with a Galaxy S5. A Crutchfield customer liked it, too.
We’ll update with more reviews if they arise, but for now, we are the only publication to fully review our pick. Our testing, combined with the brand’s past performance and list of satisfied customers, makes us confident that this is the best car charger out there.
Flaws but not dealbreakers
The biggest flaw of the reVOLT is that it’s designed specifically for iOS devices, which doesn’t preclude it from working with other devices, but your charging speeds may vary depending on your device’s charging circuitry. We tested it with a HTC Desire and found it charged at full speed just fine. We also successfully tested the previous 10 watt version with a Motorola Razr Maxx, iPod Touch (4g), iPad Mini, Nokia Lumia 1020, iPhone 3GS, HTC 8x, iPhone 5, and Samsung Galaxy S3. But your mileage may vary—especially if you have a Samsung Galaxy S5, which doesn’t work at all (as of this writing).
Runner up/if you have a Galaxy S5
The Anker 24 W charger performs as well as our main pick but is twice as large. It’s a good choice if our main pick sells out or if you own a Galaxy S5.
The Anker 24 W 4.8 Dual Chargeis a lot larger than our pick but is wired to automatically adjust to Android or iOS devices in order to avoid slow charging times. It’s also confirmed to work with Samsung Galaxy S5. CNET liked a previous version of this model, even before Anker updated it with automatic power detection. We made anonymous customer service calls and confirmed with Anker directly that this charger will work with all tablets and all phones.
The Anker costs the same as the Scosche but protrudes more than an inch outward when plugged into the lighter. It’s not as great an overall package as our pick, but if you have a Samsung Galaxy S5, this is the charger we’d get. Similarly, if you’re not getting the fast charging speeds you’d expect from the Scosche and don’t want to buy a charge-only cable, the Anker is a good bet.
So will my Android device charge at full speed?
This charge-only cable has no data line, which means your Android phone will draw the maximum allowable current to charge as quickly as possible.
The short answer is yes, if you use a charge-only cable such as this one. This has mentioned in many user reviews.
The long answer is a bit more complicated. As Gizmodo explains, all USB devices charge at 5 volts. The variation in power has to do with how much current (amps) is being drawn. Power is measured in watts, and watts equals voltage multiplied by current, so: theoretically, if you have 5 volts drawn at 2 amps, you’ll get a maximum of 10 watts of power.
The problem is that the amount of power available doesn’t always equal the amount of power you can use.
The problem is that the amount of power available doesn’t always equal the amount of power you can use. This is dependent on how your device communicates with the USB port itself, a step ExtremeTech calls “negotiation.” This is where we run into issues with chargers designed for Apple devices. Everyone wants their stuff to work with Apple’s stuff because if you’re going to pick one proprietary circuitry loop to adopt, Apple is your best bet. Unfortunately, what negotiates well with Apple doesn’t necessarily work as well with non-Apple devices.
ExtremeTech goes on to explain that “it can be quite hard to coax an Android device to charge quickly from a laptop or PC that also wants to initiate a data connection (which reduces the max draw over the power lines).” So basically, if your Android is charging in “USB” mode as opposed to the faster “AC” mode, it means that it thinks it’s plugged into a data port as opposed to a wall charger and as a result, is limited to drawing 5 volts at .5 amps for a paltry total of 2.5 watts of power.
Your best bet is to use the manufacturer’s included cable with your car charger. If that won’t activate the “AC Mode” indicator (if your device even has one), get a dedicated charging cable like the one shown below.
This cable will let your Android devices charge at full speed when using Apple-leaning USB chargers like the models above.
The easiest way to ensure that your Android device charges at full speed is to use a cable that is unable to recognize a data connection. A charge-only cable is just that: a USB cable without data capabilities, which means there’s no chance for your device to mistake a charging port for a data port, since there’s no data cable. A lot of people like this cable for delivering power quickly to Android devices. It’s basically the trump card in USB power negotiations.
Here are the Scosche’s closest competitors, and why they didn’t win. Again, we only considered 4.8-amp chargers.
Aleratec Dual 2-Port USB – The Aleratec performed as well as all our finalists in testing, but its chunky design couldn’t match the Scosche’s ability to integrate seamlessly into the car’s port.
Ventev Slim Car Charger – It costs $20-plus and is twice the length of the Scosche without any greater performance.
We like the Ventev’s port layout, but it protrudes more than the Scosche and costs $10 more.
XOXO Mobile Duo – Also a great performer and well-reviewed on Amazon, the XOXO is chunky next to the Scosche and adds no performance or aesthetic benefits.
What we skipped entirely
Aleratec Socket Lighter Plug – This model has the same specs and performance as the Aleratec Dual 2 Port, but it costs $4 more in a much uglier package. Like the other Aleratec, it doesn’t charge any more quickly than the Scosche and is much larger.
iFlash – We tested the iFlash for the previous version of this review when it was one of the only car chargers with two 2.4-A ports. In those tests, we found it couldn’t even give faster charging times than 2.1-amp car chargers. It’s also much bigger than the Scosche.
Bolse High-Output 3-Port Car Charger – This three-port model can charge two phones (1.5 amp maximum) and a single tablet, but we don’t think the third port is worth the added size.
Moshi ReVolt Duo – Same performance specs as the Scosche, but in a bigger package and for a higher price.
Saicoo – This charger has four ports, but at the cost of a clunky design. We haven’t ever needed to charge four devices simultaneously, either. We’d spare ourselves the inconvenience of another flopping cord and alternate devices among the Scosche.
As we mentioned earlier, there are literally hundreds of options for car chargers out there, but very few are 4.8 amps and cheap enough to consider. We will review and update as new models come out, but if you know of one we missed, let us know in the comments and we will test it out.
Wrapping it up
The Scosche reVOLT would likely win our pick based on its consistently fast charge performance alone, but the fact that it’s designed so unobtrusively and for the same price as competitors seals the deal. It can quickly charge just about any device you throw at it, and its minimalist low-profile design is the most efficient of any charger we’ve seen.
This guide originally appeared on The Wirecutter on 6/10/2014 and is republished here with permission.