https://artosalminen.github.io/tags/bluetooth/ Recent content in Bluetooth on Arto's dev time by-products Hugo -- gohugo.io en Thu, 05 Nov 2026 00:00:00 +0000 https://artosalminen.github.io/posts/how-to-monitor-car-12v-battery-in-home-assistant-with-esp32/ Thu, 05 Nov 2026 00:00:00 +0000 https://artosalminen.github.io/posts/how-to-monitor-car-12v-battery-in-home-assistant-with-esp32/ <p>My car is a Hyundai Ioniq 5. Like most EVs, it still has an ordinary 12 V battery, and that battery decides whether the car wakes up at all. If it&rsquo;s flat, a full high-voltage pack doesn&rsquo;t help: the car won&rsquo;t go into ready mode. The 12 V battery is charged from the high-voltage pack, so a problem on that side can drain it without warning. I want to know the 12 V voltage every day, not only when the car refuses to start.</p>