Nintendo Switch user added a 60% larger battery to his Switch to drastically improve its battery life
Even though Nintendo has improved the battery life of recent Nintendo Switch models (2019 models, Switch Lite, and the Switch OLED), a user over at Reddit (u/boiniqqua447) was still not very happy with the battery life he got on his Switch so he decided to take matters into his own hands by replacing the stock battery. Whereas a stock Nintendo Switch has a battery capacity of around 4.200 mAh, this reddit user mounted two 3.500 mAh cells into his Switch (+62% increase in capacity). Using two large batteries, the Reddit user was able to significantly improve the battery life on his Switch and he even managed to use the stock Nintendo Switch shell, which didn’t need any further modifications.

Extreme battery mod – 16.800 mAh
However, while these battery mods are quite rare, a user over at GBATemp was able to fit 4 18650 battery cells in his Nintendo Switch. Granted, he needed to 3D print an extension piece to fit these cells, but this way he was able to increase the battery capacity to a massive 16.800 mAh. As for the battery life, playing an intensive title such as Zelda BotW still resulted in over 10 hours of play time. Playing a less demanding title such as Terraria lead to a stunning 23 hours of uptime on a single charge.

How to further improve battery life on a Nintendo Switch?
While simply adding more battery capacity is the most effective way to extend the battery life of your Nintendo Switch, most users may not have the skills or experience to open up their Switches and mess around with the battery system. Therefore, an easier way to improve the battery life of your Switch is by underclocking the CPU and GPU so your Switch consumes less energy (hence improving the battery life). Tools such as sys-clk exist that allow users to change the clock behavior of the Tegra X1 SoC on a game by game basis. This requires your Nintendo Switch to be modded though and to have a custom firmware installed. If you don’t know how to install a custom firmware on your Nintendo Switch, then please follow this guide, which explains step by step how to install a CFW on a first generation, unpatched Nintendo Switch.