Does Using a Keyboard via OTG Cable Drain My Android Device's Battery?

When you connect a USB keyboard to your Android device via an OTG (On-The-Go) cable, there are indeed some implications for your device's battery life. This article delves into the specifics of how a keyboard connected this way affects your Android device's power consumption and battery drain.

Understanding Battery Usage and OTG

When you connect a USB device such as a keyboard to your Android through an OTG cable, the device is designed to provide power to the keyboard. This process can lead to increased battery consumption. However, the amount of power drawn from the Android device is typically quite minimal, especially when compared to other power-hungry peripherals like screens or high-performance devices.

Significant Battery Drain?

The extent of the battery drain can depend on several factors, including the specific model of the keyboard and whether it has a built-in LED backlight. For instance, if the keyboard's backlight is off, the power consumption is notably lower. The Drok USB power meter was used to measure the power consumption of a Wasd "Code" keyboard:

The power consumption of the keyboard, even with the backlight on, is still significantly lower than the typical power consumption of a smartphone, which can be around 3W or more, especially during screen-on usage.

Comparing Power Consumption

Typically, the amount of power drawn from the Android device is negligible. A phone with a less efficient battery might consume around 3W of power during active screen-on usage. Therefore, even with a fully lit keyboard, a reduction of around 2 hours in battery life would be expected over a full charge cycle. For most users, this is a small and imperceptible difference.

Alternative Power Solutions

To avoid any potential battery drain, you might consider using a wireless keyboard with a USB adapter or a Bluetooth keyboard. Wireless keyboards with a USB adapter still draw power from the USB port but, in many cases, they consume less than a wired keyboard. Additionally, Bluetooth keyboards operate on batteries, eliminating the risk of battery drain from the USB port. However, even Bluetooth keyboards draw a minimal amount of power, mainly used for data transmission to the Android device.

OTG Circuitry Power Consumption

It's also worth noting that the OTG circuitry itself consumes power, although usually a small amount. However, this added power draw is generally insignificant and wouldn't significantly impact the overall battery life for most users.

For a comprehensive understanding, the best approach is to monitor your device's power usage with tools like the Drok USB power meter. These tools help validate the minimal impact or provide empirical data to assess the actual power consumption.

Bottom line, while there is a slight increase in power consumption when using a keyboard via an OTG cable, this impact is generally minimal and not noticeable in most everyday use cases. However, in situations where battery life is critical, opting for a battery-powered or low-power wireless keyboard is advisable.