After a few days on a business trip, the car battery ran out. I have a good idea！

After some years of use, car batteries can run out of power when they are not driven for a long time. You can use the car battery jump starter for battery charging, https://obd-soda.myshopify.com/products/car-jump-starter-battery-600a-portable-starting-device-16000mah-power-bank-12v-car-charger-battery-booster-buster-car-starter-ce? _pos = 3 & _sid = 9 e1a3a10e & _ss = r. The advantage is that the battery can be reused, but if the battery is used up every time, it will affect the battery life. Another method is to install battery switch, https://obd-soda.myshopify.com/products/adeeing-car-motorcycle-battery-terminal-link-quick-cut-off-switch-rotary-disconnect-isolator-car-truck-auto-vehicle-parts-r25? _pos = 1 & _sid = 14 fe0ee7f & _ss = r. After installing this switch, you can turn it on before you stop driving for a long time. In this way, the battery is disconnected, and when you come back to turn off the switch, the battery is normally energized.