The rumor of excessive consumption
Many travelers worry when installing their first eSIM and using the "Dual SIM" function on their smartphones, believing that having two active lines will drain their battery by half. What is true in this?
The Truth about Dual SIM
It is a partial reality. Technically, having two active lines means that your phone maintains a connection to two different cell towers. This requires a slight additional effort from the baseband processor. However, in practice, the impact is only 5% to 8% in total daily consumption, something almost imperceptible compared to the massive consumption of the screen, cameras and GPS.
What really eats up your battery when traveling
Don't blame the eSIM. What really drains your battery on an international trip is:
- Intense use of Maps and GPS: You are browsing continuously, and the GPS receiver is active for hours on end.
- Camera: You are taking 100 photos and videos a day with the brightness at maximum.
- Poor coverage of your original SIM: This is key! If you have your SIM from your home country activated without roaming, it will desperately try to search for a network without finding it, quickly draining the battery.
How to optimize the battery with Dual SIM
- Turn off unused lines: If you don't need to receive urgent SMS from your country, temporarily turn off your main line in the settings and leave only the eSIM active. You will notice a great increase in battery.
- Activate Wi-Fi Calling (VoWiFi): If you leave your original line on but with data roaming disabled, activating Wi-Fi calling will prevent the phone from searching for foreign towers when you are connected to the hotel Wi-Fi.
- Lower the brightness outdoors: Automatic brightness in the sun is the battery's number one enemy. Wear sunglasses and lower the brightness a bit.