Stress Testing the Switch: Challenging Misinformation About Charging Nintendo’s Latest Console, Part 1

No, not that kind of stress test.

Edit: Part 2 is now up and can be found here! Despite it being “Part 2,” it’s actually better to read it first if you’re new.

So how much charger do I need to charge the Switch?

Short answer: Probably~8.75 watts. For assured minimum viable charging performance, you’ll want at least a USB Type C (“USB-C”) charger (battery pack, AC adapter, car charger), or even better, a USB-C charger with USB-Power Delivery (“USB-PD”).

Long Answer: Probably ~8.75 watts under the most demanding of conditions currently available at launch. This means that the majority of the best available USB Type A (“USB-A”) chargers rated at 10+ watts (5V 2.1-2.4A) still end up falling beneath this point, as part of the USB-A limitation is that the Switch will almost always only request 7.5 watts (1.5A) using USB-A (more on this in the upcoming part two of this article). In other words, a USB-A charger sits right at the point where the Switch may (1) lose charge with maxed-out settings, (2) hold its charge with dialed-back brightness, and also (3) slowly charge with yet more conservative settings. Only USB-C and USB-PD chargers offer a more certain guarantee for charging the Switch under intense gaming.

Why so many different possibilities? And why does this run contrary to much of the charging advice already out there on the Switch?

Well, this is actually a more complicated question than you’d expect, because the Switch’s power consumption when portable depends on a lot of factors — some that you’d expect like brightness, and others that complicate an otherwise straightforward answer.

Let’s first take a look at the known factors that affect the Switch’s mobile power consumption:

  1. Screen brightness (auto brightness affects the min/max of the brightness setting, so leave it off for testing!)
  2. Volume (and whether the Switch is using speakers or headphones)
  3. Wifi/Bluetooth on (Airplane mode)
  4. Whether Joycons are attached and are discharged (the Switch appears to charge drained Joycons up to 50% battery when mobile and AnandTech found that drained Joycons increase charging demands.
  5. The CPU/GPU demands of the game being played

On point 5, unsurprisingly, Breath of the Wild represents the most demanding launch title and is the current “best” worst-case scenario test— but it turns out that the power draw for BOTW varies, and is quite dependent on the complexity of the scene (more on this in a bit).

So our ideal stress test setup should have full brightness with auto-brightness disabled, the highest volume setting, Wifi and Bluetooth on, with drained Joycons, running on BOTW in a location with the highest rendering demands. A charging setup that can successfully charge the Switch under these conditions, ought to be able to handle anything.

…the “lab bench” 😉

For the purposes of my testing, I was able to get pretty close, but I removed the charging of Joycons as a factor (keeping yet another device at low charge reduced repeatability). For my BOTW location, I chose none other than the infamous Korok Forest. And as far as volume goes, the way I have my timelapse set up actually reduces volume (with the quick menu’s power and time shown). However, even with these caveats, the differences between the three “categories” of charging solutions are well illustrated in this test.

Presenting… The Korok Forest Nintendo Switch Charging Stress Test

Video editing is not quite my thing… sorry about the music.

In the above timelapse comparison video, I first have a control test to show the Switch’s power draw in Korok Forest without any charging. Next, I have three timelapses using the three major categories of Switch chargers:

  1. USB Type A (5V 2.4A), using the Anker 60W PowerPort 6
  2. USB Type C (5V 3A), using the Google Nexus 6P USB-C charger
  3. USB “Power Delivery” or USB-PD, using the Google Pixel XL 9V charger

Note in the video that I’ve got an inline voltage/current meter indicating the actual/measured power drawn by the Switch. The relevance of the measured power is only touched upon here, and it will be the topic of a more thorough discussion in part two to this article.

The results in easy table format, and USB-PD wins the day! …the results are strangely symmetric.

Without any charging, the Switch is losing close to a percent a minute (and under this test, one could actually expect ~2:20 play time). Charging out of a 5V 2.4A USB-A is actually shown to slowly lose charge in the most demanding of circumstances, with a 3% battery loss over ~31 minutes. The USB-C (5V 3A) fares better, getting positive charging over the ~31 minutes, though slowly — gaining 4% in that period. The runaway clear winner here was USB-PD, bringing the Switch’s battery up by 17% over 25 minutes of charging (I got bored waiting), which when normalized to 31 minutes like the others, yields 21% charge.

Given the fortuitous symmetry of the results, we can take a stab at figuring out the maximum power consumption of the Switch under the Korok Forest Stress Test — as it would stand to reason that the input power that allowed the Switch to maintain the same battery level would be this maximum power consumption. Assuming this is roughly the midpoint between the USB-A 7.5 watts (-0.10 %/min) and the USB-C 10 watts (+0.13 %/min), we can conclude that the Switch’s most demanding power consumption is ~8.75 watts.

Interestingly, the conclusions of this approach appear to be consistent with AnandTech’s own findings on power consumption, though merely from measuring inline power draw at 100% battery in their case:

Meanwhile cranking up the brightness to maximum increases the power consumption to 8.9W, or about 25%. In practical terms this means that going brighter definitely has an impact on the Switch’s battery life… Otherwise, keep in mind the 8.9W number. This is (roughly) the maximum power draw for gaming on the console when it’s undocked.

Now to address the elephant in the room: Are you sure a USB-A charger loses charge? Why doesn’t that match my experience/Digital Foundry/etc.?

If you search for threads and comments about third-party chargers on /r/NintendoSwitch, you’ll see redditors sharing their positive experiences with many USB-A chargers, Digital Trends noted, “we didn’t find any noticeable difference in charging efficiency between USB-A to USB-C and USB-C to USB-C,” and even very well-respected technical gaming publications like Digital Foundry make these same (technically incorrect) observations:

Firstly, you don’t need a USB-C port on the external battery itself to make this work. A regular USB port with 2.1 amps output minimum will do the job, though much less is likely to not charge as the Switch as fast as it depletes. … Even in intensive areas, they supply enough power to run the game, and gradually top up the battery. Provided you’re running from a minimum of a 2.1A USB port as mentioned, there’s enough throughput to achieve this, though expect the charge to be very slow while playing.
What Not to Do: If your fancy new charger has a USB-C port… DON’T HANDICAP IT BY USING USB-A! (Source: Digital Foundry)

For me, the key revelation around reconciling this was recognizing that where you were in BOTW mattered just as much as making sure that brightness was maxed out. And this could be the difference between your battery draining, holding the line, or charging. And I suspect it’s this variation (as well other possible factors like auto-brightness) that has led to quite a bit of confusion with how sufficient USB-A is for charging the Switch. Digital Foundry even hints to this as well in their article:

That said, this is proportionate to rendering load; Switch’s battery percentage rises faster in Zelda’s less demanding interior areas for example, like shrines. So yes, all power banks here not only keep the hardware juiced, but there’s a surplus of power that means they recharge the console while playing.

…but it seems their testing scenario was not really the most challenging BOTW had to offer, thus throwing off their conclusions. I mention this not to pick on anyone sharing their battery experiences or to disparage Digital Foundry (which I think is one of the best technical gaming publications around), but to point out and explain how these previous findings are flawed.

Some of my earliest timelapse testing with BOTW was around identifying that different areas of BOTW had different rendering demands, and yielded different charging results. For example, when I tested a 5V 2.4A charger at the Cape Cales/Muwo Jeem Shrine, a fairly non-demanding setting — the Switch primary battery held the line at 41% for over 20 minutes. But, when I tried Lakeside Stable (prior to my discovering Korok Forest), the result was a 1% drop in the Switch battery every ~11 minutes — unsurprising given the significant rain, lightning, particle effects, and transparency/fog there.

Wall power draw when docked. Left: Shrine of Resurrection, 11 watts; Right: Korok Forest, 14 watts

Also, looking at the power draw of the Switch when docked (as measured from the wall) gives us good insight into the variation of the power draw in different scenarios in BOTW. In informal testing, I was seeing as much as a 3 watt swing between the extremes of the most and least challenging areas in BOTW. For a USB-A 5V 2.4A charger that maxes out at supplying 7.5 watts, a 1–3 watt variation between BOTW locations could be enough to tip the balance between a slow Switch discharge and a slow Switch charge.

It seems clear to me that for consumers interested in a future-proofing purchase, a charger with USB-PD is the clear winner, with a USB-C charger as a reasonable, more inexpensive runner-up. USB-A chargers are often good enough, especially if you already have one, but I wouldn’t spend new money on a new USB-A charger when there are plenty of USB-C options out there.

However, using Korok Forest as a stress test is just that — a worst-case scenario stress test. At the end of the day, there is no “typical” way to play BOTW, and each player will likely run through a mix of both demanding and less demanding environs in BOTW. And so for most people, the 7.5 watt output of a USB-A charger may probably enough for them to get by — as even when it drops charge, the rate of decrease is much, much slower than if the Switch were running off its own power.

If the above discussion left you still confused by all the charger choices out there and which charging combination is the right for you, don’t worry. It is confusing. In part two of this article, I’ll take a stab at (hopefully) clarifying this a bit. Until then, happy gaming!

As an epilogue, it will be interesting to see if these findings will be refined over time. For all of its graphical splendor, many have nonetheless concluded that BOTW is not well-optimized for the Switch. Perhaps a better AAA title will come out in a year or two that pushes the Switch’s Tegra X1 even closer to the edge and increases the power draw further. There have also been rumors about future support for gameplay video recording and possibly live streaming — something that may add additional power overhead to already demanding titles like BOTW.

BTW— if I got something wrong or there’s a flaw in my testing procedure, definitely drop a comment! I’m happy to get feedback and corrections.

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