I am sure a lot of us, especially those with V1 switches, have often hoped for a bigger battery. I actually attempted to do that a year ago. However, this is the new and actually working properly version of the mod.
I'll start with the results in case that's all you're interested in:
Battery life:
Stock-1h45min
Modded-2h45min
Test conditions-Persona 5 Royal 720p & 60fps mod, Shibuya Station Square, standing still in the interaction zone out towards Central Street. Overclocked to 1326MHz(CPU), 614MHz(GPU), 1600MHz(RAM). Max Brightness. 24C ambient.
Maximum Viable Clocks in Handheld mode:
Test Description-Increasing the clock speeds until I get the low battery warning or a system crash, which means the battery can no longer handle the load.
Stock-Anything above 614MHz GPU would result in the warning or a system crash.
Modded-Could run at maxed out clocks(1785MHz CPU, 921MHz GPU) for 5 minutes. Did not test further since the battery drained 10% in that 5 minutes.
Weight:
Stock:297g
Modded: 330g
Now for the Guide on how you can do this mod:
Before we start, I'm sure we all know how dangerous lithium batteries can be. I myself am not even close to an expert. Do this mod at your own risk. If you have any proven expertise in this area, please don't be shy to point out anything that seems wrong.
Step 0-Tools:
Stuff you will need:
Step 1-Cell selection:
This is the step that was surprisingly the hardest for me. The generic pouch cells you can get online generally are fine for loads<1.5A, but above that they quickly get overloaded and extremely hot. So before buying any batteries, ask the seller for the C rating of the battery for discharge. C x Capacity of battery in Ah=maximum current. However a lot of sellers may not give you this data. In order to bypass this problem we will use batteries made for smartphones, which can consume up to 15w. My previous attempts at the mod failed due to incapable cells.
The next problem is finding a high capacity battery that fits. The battery bay for the switch measures 72(w)x77(l)x8~(h)mm. You will not be finding one single cell that size. Instead we will use 2 cells in parallel. Preferably, 2 of the same cells. Generic batteries usually have their sizes listed as 804080 or some other sequence of 6 numbers. This format is hhwwll, where 80=8mm in this case. For phone batteries, this information is hard to find, so ask the seller or try looking online for the size of that particular battery.
The cells I ended up with were from the LTF26A battery, which was from the LeEco Le Pro3 AI Edition, a 2017 phone from a now-bankrupt company. You may know LeEco's CEO as the CEO of Faraday Future. They are exactly the size of the battery bay with a few mm to spare. They are technically 4000mAh batteries, however their age and the fact they charge up to 4.4v instead of the switches 4.2v max means you will never actually see that capacity in real use. While you're buying the batteries, buy a zb2l3 battery capacity tester and a 1.5Ohm load resistor, along with some sort of lithium charging circuit(I used a TP4056). Optionally buy a few 4A 1s BMS boards. You should also consider buying more than 2 batteries in case some are wonky.
Step 2-Testing:
Before Testing, if you bought a smartphone battery, you will need to desolder the stock BMS. Peel off the tape surrounding the battery connector and BMS to reveal it. Be careful not overheat or short the Battery while de-soldering. Solder on the BMS you bought and some wires.
Fully charge the battery with your charging circuit and use the ZB2L3 to test the capacity of the cells with the 1.5ohm resistor down to 3.2V.
My results:
Therefore results for the final battery we will be putting in the switch:
If you are performing this mod on a v2/OLED/Lite, 2.6A will probably be enough. On a v1 however, you will need more. I would say about 4A minimum, but I'm testing at 5.2A just to be safe. You are looking for a capacity that you are satisfied with and the batteries to stay somewhat cool during the test(warm, comfortable enough to touch is fine). If the batteries you bought are under-performing, go back to step 2. If they meet performance standards go to the next step. If you bought >2 batteries choose the 2 with the closest capacity.
Step 3-Preparing the Switch for the mod:
Disassemble your switch to the point where the battery can be removed.
Remove the BMS from the stock battery intact. I don't have pictures of this, but just peel off the black tape near the connector and de-solder carefully.
Next, you have to trim the EMI shield
Cut along the blue line first.
Now, how much you need to trim from here depends on how big the cells you chose are. With the LTF26A, we can fit the whole battery+BMS if we choose to remove the individual BMSs we soldered on in the previous step and just solder the cells directly to the Switch BMS to let it do the work of protection. The concern here is some sort of catastrophic event where one of the cells somehow ends up with a way lower voltage than the other, causing excess current to flow from one cell to the other due to the voltage difference. We are going to use a 5A SMD Fuse between the 2 cells, which will stop the flow if the current gets too high to try and mitigate this risk. If you can't be arsed like me, you can just make some more space and bypass the switch BMS. It is also possible to fit generic cells that would otherwise be too big by removing their stock BMS and using the switch BMS outside of the battery bay.
In conclusion, cut along the red line you can make it all fit in battery bay and along the green line if you can't. If you're not sure, move to step 4 first.
Step 4-Creating your modded battery pack:
First, charge both your cells till full. Measure their voltage to make sure they are within 0.01V.
Create a mega battery pack like that below with Kapton tape
Next, attaching your cells/batteries to the switch BMS:
If you removed the BMS, solder one of the cells directly to B+ and B- on the switch BMS and for the other cell, solder negative to B- and solder the fuse to B+ and positive to the fuse. Else do what I did and solder directly to the connector wires after removing the conformal coating on their contacts with heat, isopropyl and some tweezers. The reason we do this instead of just taking the connector off and soldering directly to that is because we still want a temperature reading for the battery. You can just do that, it will still work, but I'm pretty sure the Switch uses that reading for fast charging and stuff.
Use multimeter to test if there is an output from the connector.
Step 5-reassembly:
Make 2 breaks along the wall of the battery bay if your pack has wires extending beyond the battery bay like mine.
Connect the battery to the switch. I used some blutack to secure the connection since there's no metal shield to hold it down anymore.
Boot up the switch. Turn it off. If it does not turn on check the connection on your batteries.
Put your battery into the bay and secure it with some double-sided tape.
If you're following what I did, the bms should be hanging outside of the battery bay. This is fine.
It should look like the very first photo in the post after all is done:
When reassembling the switch, there will be parts of the back cover that will interfere with the overhanging BMS. Cut those parts off. Additionally stick some additional foam to the exposed speaker to press it down and secure it after reassembly. You will notice the back cover may be tight. This is because at 8mm, the battery is a bit too thick. Sanding the part of the cover above the battery will fix this issue. I didn't do this because I was lazy but you probably should.
Step 6-Enjoy:
Fully charge and discharge the switch until the low battery warning flashes and your Switch turns off. Don't get battery anxiety when it reaches 1%-the battery probably still has plenty of capacity-the Switch just thinks it doesn't because you've already discharged 4667mAh. It will run for quite a while at '1%'. Do this as few times. This is to make sure you get a (somewhat)accurate battery percentage displayed on the switch.
What the internals look like after the mod.
What it looks like all put back together.
6400mAh of usable capacity, as reported by the Switch itself.
I'll start with the results in case that's all you're interested in:
Battery life:
Stock-1h45min
Modded-2h45min
Test conditions-Persona 5 Royal 720p & 60fps mod, Shibuya Station Square, standing still in the interaction zone out towards Central Street. Overclocked to 1326MHz(CPU), 614MHz(GPU), 1600MHz(RAM). Max Brightness. 24C ambient.
Maximum Viable Clocks in Handheld mode:
Test Description-Increasing the clock speeds until I get the low battery warning or a system crash, which means the battery can no longer handle the load.
Stock-Anything above 614MHz GPU would result in the warning or a system crash.
Modded-Could run at maxed out clocks(1785MHz CPU, 921MHz GPU) for 5 minutes. Did not test further since the battery drained 10% in that 5 minutes.
Weight:
Stock:297g
Modded: 330g
Now for the Guide on how you can do this mod:
Before we start, I'm sure we all know how dangerous lithium batteries can be. I myself am not even close to an expert. Do this mod at your own risk. If you have any proven expertise in this area, please don't be shy to point out anything that seems wrong.
Step 0-Tools:
Stuff you will need:
- A good soldering iron and accompanying equipment
- Some wire-I used 20AWG silicone wire.
- Kapton/Polyimide tape
- Multimeter
- Screwdrivers for disassembling the switch
Step 1-Cell selection:
This is the step that was surprisingly the hardest for me. The generic pouch cells you can get online generally are fine for loads<1.5A, but above that they quickly get overloaded and extremely hot. So before buying any batteries, ask the seller for the C rating of the battery for discharge. C x Capacity of battery in Ah=maximum current. However a lot of sellers may not give you this data. In order to bypass this problem we will use batteries made for smartphones, which can consume up to 15w. My previous attempts at the mod failed due to incapable cells.
The next problem is finding a high capacity battery that fits. The battery bay for the switch measures 72(w)x77(l)x8~(h)mm. You will not be finding one single cell that size. Instead we will use 2 cells in parallel. Preferably, 2 of the same cells. Generic batteries usually have their sizes listed as 804080 or some other sequence of 6 numbers. This format is hhwwll, where 80=8mm in this case. For phone batteries, this information is hard to find, so ask the seller or try looking online for the size of that particular battery.
Fun fact: the seller was being mega shady about the specs of this battery. I found out later the reason why was because they were new-old stock of smartphone batteries from 2017 modded with a standard bms.
The cells I ended up with were from the LTF26A battery, which was from the LeEco Le Pro3 AI Edition, a 2017 phone from a now-bankrupt company. You may know LeEco's CEO as the CEO of Faraday Future. They are exactly the size of the battery bay with a few mm to spare. They are technically 4000mAh batteries, however their age and the fact they charge up to 4.4v instead of the switches 4.2v max means you will never actually see that capacity in real use. While you're buying the batteries, buy a zb2l3 battery capacity tester and a 1.5Ohm load resistor, along with some sort of lithium charging circuit(I used a TP4056). Optionally buy a few 4A 1s BMS boards. You should also consider buying more than 2 batteries in case some are wonky.
Step 2-Testing:
Before Testing, if you bought a smartphone battery, you will need to desolder the stock BMS. Peel off the tape surrounding the battery connector and BMS to reveal it. Be careful not overheat or short the Battery while de-soldering. Solder on the BMS you bought and some wires.
It should look something like this after removing the original BMS
Fully charge the battery with your charging circuit and use the ZB2L3 to test the capacity of the cells with the 1.5ohm resistor down to 3.2V.
My results:
Discharging single cell at 2.6A yielded a capacity of 3100mAh per battery
Discharging both in parallel at 2.6A yielded 6700mAh
Therefore results for the final battery we will be putting in the switch:
| Average Discharge Current(A) | Average Power(W) | Capacity(mAh) |
|---|---|---|
| 2.6 | 9.6 | 6703 |
| 5.2~(2.6*2) | 19.2~ | 6224(3112*2) |
If you are performing this mod on a v2/OLED/Lite, 2.6A will probably be enough. On a v1 however, you will need more. I would say about 4A minimum, but I'm testing at 5.2A just to be safe. You are looking for a capacity that you are satisfied with and the batteries to stay somewhat cool during the test(warm, comfortable enough to touch is fine). If the batteries you bought are under-performing, go back to step 2. If they meet performance standards go to the next step. If you bought >2 batteries choose the 2 with the closest capacity.
Step 3-Preparing the Switch for the mod:
Disassemble your switch to the point where the battery can be removed.
Remove the BMS from the stock battery intact. I don't have pictures of this, but just peel off the black tape near the connector and de-solder carefully.
Next, you have to trim the EMI shield
We are doing this to give more space to the battery.
Cut along the blue line first.
Now, how much you need to trim from here depends on how big the cells you chose are. With the LTF26A, we can fit the whole battery+BMS if we choose to remove the individual BMSs we soldered on in the previous step and just solder the cells directly to the Switch BMS to let it do the work of protection. The concern here is some sort of catastrophic event where one of the cells somehow ends up with a way lower voltage than the other, causing excess current to flow from one cell to the other due to the voltage difference. We are going to use a 5A SMD Fuse between the 2 cells, which will stop the flow if the current gets too high to try and mitigate this risk. If you can't be arsed like me, you can just make some more space and bypass the switch BMS. It is also possible to fit generic cells that would otherwise be too big by removing their stock BMS and using the switch BMS outside of the battery bay.
In conclusion, cut along the red line you can make it all fit in battery bay and along the green line if you can't. If you're not sure, move to step 4 first.
Step 4-Creating your modded battery pack:
First, charge both your cells till full. Measure their voltage to make sure they are within 0.01V.
Create a mega battery pack like that below with Kapton tape
Remember to cover the BMS/contacts on the cells with kapton individually as well.
Next, attaching your cells/batteries to the switch BMS:
If you removed the BMS, solder one of the cells directly to B+ and B- on the switch BMS and for the other cell, solder negative to B- and solder the fuse to B+ and positive to the fuse. Else do what I did and solder directly to the connector wires after removing the conformal coating on their contacts with heat, isopropyl and some tweezers. The reason we do this instead of just taking the connector off and soldering directly to that is because we still want a temperature reading for the battery. You can just do that, it will still work, but I'm pretty sure the Switch uses that reading for fast charging and stuff.
Use multimeter to test if there is an output from the connector.
Step 5-reassembly:
Make 2 breaks along the wall of the battery bay if your pack has wires extending beyond the battery bay like mine.
Connect the battery to the switch. I used some blutack to secure the connection since there's no metal shield to hold it down anymore.
Boot up the switch. Turn it off. If it does not turn on check the connection on your batteries.
Put your battery into the bay and secure it with some double-sided tape.
If you're following what I did, the bms should be hanging outside of the battery bay. This is fine.
It should look like the very first photo in the post after all is done:
Ignore the nut, I cut off too much of the metal shield and had to find something to act as a heatsink for the charging IC.
When reassembling the switch, there will be parts of the back cover that will interfere with the overhanging BMS. Cut those parts off. Additionally stick some additional foam to the exposed speaker to press it down and secure it after reassembly. You will notice the back cover may be tight. This is because at 8mm, the battery is a bit too thick. Sanding the part of the cover above the battery will fix this issue. I didn't do this because I was lazy but you probably should.
Step 6-Enjoy:
Fully charge and discharge the switch until the low battery warning flashes and your Switch turns off. Don't get battery anxiety when it reaches 1%-the battery probably still has plenty of capacity-the Switch just thinks it doesn't because you've already discharged 4667mAh. It will run for quite a while at '1%'. Do this as few times. This is to make sure you get a (somewhat)accurate battery percentage displayed on the switch.
