Batteryless Nintendo Switch is possible!

[fwannmacher]

UPDATE: The quoted text bellow is deprecated. I'm keeping it only as history for the thread.

I'm doing a "consolized" Nintendo Switch where I want to mod it and overclock the hell of it xD. Anyways... I didn't want to use the battery so I used a buck converter wired to 15v from the dock and then step it down to 4.2v.
It works! During the startup there is 0.4A consumed for booting the system and from there on the energy will be supplied by the dock itself. The only thing needed is to ground the sensor wire (grey one in the middle of the connector).

The Nintendo Switch always needs a battery - even when docked - to boot as it uses the battery power to do so. That means the Switch will became e-waste when no more batteries are produced for it. Because of that and because I want to do a "consolized" Switch - for overclocking it and having better thermals - I started a little project for having a Switch without a battery,
As said before a battery is needed for booting the device which requires ~0.4A in the process. Other than that, a fully charged battery gives ~4.3V. For achieving the results I wanted I have used the battery's PCB in conjunction with a buck converter so the PCB will tell the Switch that no charge is required while the buck converter will give power to the PCB making it believe that battery is fully charged.
The buck converter I'm using is this one https://www.ebay.com/itm/255283221975 but any converter capable of outputting 4.3V from 15.3V is good enough. The power is supplied to the converter from a 15.3V line from the dock board as shown in the image bellow.

Spoiler

This is what my installation looks like

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Other than that a 10K resistor is need between the test points shown bellow.

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This resistor is need to overwrite the battery PCB temperature sensor. As we are not using a real battery the PCB will tell the system that the temperature is -32C and it won't let the Switch to complete the boot sequence. The resistor then will "emulate" 28C.

[Konsolkongen]

Nice It’s sad to think about the millions of Nintendo Switch consoles that will be e-waste in the future when their batteries die. Hopefully replacements will be available for a long time, but it’s good that a simple solution like this can at least make the console run, although only docked.

[Josh128]

Good job!

[LDigital]

I didn’t know this. I’m pretty worried from a preservation point of view.
So if you remove the battery it won’t work even docked without a mod?
I hope this is easy to do eventually as I don’t even use my switch as a handheld and want to keep it for decades like my old nintendo consoles.

To be honest I never even thought about the batteries inside of a switch

[Konsolkongen]

Yes without a battery the Switch won’t power on.
Not sure if it will still work with a dead battery though, but it might get so swollen that it will have to be removed regardless. The back of the Switch looks like pretty thin plastic, presumably to allow the battery to expand. I wonder if that plastic will crack or the PCB’s could become damaged from the pressure over time?
Regardless very few will ever replace the battery, most will probably just recycle a non working console, and even fewer will mod it like this to keep it working docked.

I rarely use my Switch anymore, but last night we wanted to play Snipperclips. With no charge in the battery it took at least 10 min before I could turn on the console in docked mode. Another annoyance to look forward to for retro enthusiasts. It won’t be plug and play like other systems, so that’s actually another good reason one might consider doing this mod. Because that should allow for instant booting

[LDigital]

Hmm, hopefully what you designed can be shrunk down to a small internal unit that clips to the battery port and can sit in that area with the battery removed or something.
As a retro console enthusiast this situation is a complete shock. I just assumed it would work docked no matter what.
Fortunately as a retro enthusiast I am no stranger to getting my hands dirty and modding old machines to improve them, but I would rather the mod be a product than a jerry-rig.
I will keep an eye on this topic. I am surprised that this isn’t more widely known or worried about.

[fwannmacher]

This mod is a overkill as I wasn't aware of how much current the Switch needed to boot. So as I mentioned it only uses 0.4A and the voltage has to be between 3.3v and 4.2v. So a simple 5v to 3.3v board should be enough for making it boot and there are tons of small ones doing that.

I'll try to get one of those and test it.

[Taiyaki]

This thread is great, thanks!

[fwannmacher]

I have done some testing with my bench PSU and the minimum voltage for the Switch to boot is 3.4V but it will identify the battery as running low and it will keep poping up the message about that. But with 3.5V there is no such message as it identifies the battery as at 25%-ish.

Long history short: a small buck converter from 5V to something between 3.5V and 4.2V is enough. With such converter being small enough to fit in the battery compartment it would be possible to open a hole in the top corner of the Switch and then run an USB cable thru there. This way such cable could be plugged to the dock and no mod in the dock itself would be needed.

I have to say that I'm just a hobbyist so I don't have major knowledge about the hardware. Probably there is a way to get the voltage from inside the Switch itself instead of the dock but when I tried to do that the console didn't boot up. Maybe cutting some traces or maybe using some diodes to guarantee the current flow would be enough. But for that we need someone who knows what they are doing

[fwannmacher]

One of those cheap chinese buck converters with 3.7V output should be good enough https://www.ebay.com/itm/175414185706?_ ... 1465.m3507

[fwannmacher]

After testing I discovered that the voltage sent by the buck converter has to be something between 4.22V and 4.25V otherwise the Switch will think the battery needs charge and then recognize it as "depleted" over time.

[fwannmacher]

After even more testing I found out that the battery sensor (grey wire) can't be left grounded otherwise the Switch will think that the battery is not charging. The ideal solution is to have a way for keep switching between grounded/not grounded from time to time. We actually need it to be grounded twice: once during the boot (before the Switch logo appears) and then when the HOS is loaded for the first time. After that we can keep it not grounded.
A possible solution could be soldering the power button to the sensor so it would only have to hold the power button during boot and use it once after HOS has started.

[jd213]

Thanks for looking into this, I'm sure it will come in handy for many people. There's millions of Switches out there and not everyone cares about using them in handheld mode, so not needing a battery will be a great mod to keep them going into the next generation and beyond.

[fwannmacher]

Even with the last "solution" of grounding the sensor wire in the power button the Switch will try to recharge the battery after a while and then the battery will "discharge" eventually. I'm still looking for a reliable solution.

[fwannmacher]

After a ton of tests and a dead Switch :'-( I finally found a reliable solution. There are 2 test points next to the battery connector. Those are ground and battery sensor. The solution is soldering a 10k ohms resistor between them. This way the Switch will never try to charge the battery again.
PS. the sensor wire has to be ignored and not grounded as I mentioned before.

Spoiler

[fwannmacher]

More info can be found here https://gbatemp.net/threads/battery-les ... ct.631849/

[NewSchoolBoxer]

W-Why not replace the battery that I see costs $10 by itself and $15 with a toolkit? Am I missing something obvious or this is more a scientific pursuit? Losing the portability of the Switch is kind of a big deal.

But I'm glad to see the design improve over time. Using a 15V source is suboptimal and the 5V buck converter route is what makes sense to me. Someone should probably tell the person in the gbatemp thread not to rely on custom firmware for battery info.

[fwannmacher]

Yes, the battery can be replaced. But thinking about the long run, lets say, in 20 years we probably won't have those batteries anymore and then the Switch will be e-waste. Other than that, like in my case, some people may want a "consolized" Switch and don't want to replace the battery in the future.
Well... I'm not an engineer, so I don't have the knowledge for getting it much further. But, maybe, some one can use my findings to build a replacement were we can use a power bank as battery. Who knows what the future will provide

[ldeveraux]

Yes, the battery can be replaced. But thinking about the long run, lets say, in 20 years we probably won't have those batteries anymore and then the Switch will be e-waste. Other than that, like in my case, some people may want a "consolized" Switch and don't want to replace the battery in the future.
Well... I'm not an engineer, so I don't have the knowledge for getting it much further. But, maybe, some one can use my findings to build a replacement were we can use a power bank as battery. Who knows what the future will provide

I like what you're doing here, but the Switch is already consolized, it's the dock.

[Bratwurst]

I like what you're doing here, but the Switch is already consolized, it's the dock.

This discovery still feels important to me, noting the earlier mention that the Switch will not run docked if the battery is dead or missing.

[fwannmacher]

I like what you're doing here, but the Switch is already consolized, it's the dock.

In my case I created a custom shell for using a 140mm Nocta fan for keeping things cool as I overclocked the system. That is what I mean by "consolizing" it.

[emphatic]

Is there a good solution to hooking a Switch up to a TV when the dock's not outputting any video? My son's Switch only work with the built in screen, I suspect he's been too rough when placing it in the dock, causing the video part of the USB-C connector to fail.