Reddit reviews Ailun Car Charger Adapter Dual Smart USB Ports 4.8A 24W for Mobile Device for iPhone 11/11 Pro/11 Pro Max/X Xs XR Xs Max 8 7 Plus Galaxy s20, s20+ S20Ultra S10 Plus S7 S6 Note 10
We found 2 Reddit comments about Ailun Car Charger Adapter Dual Smart USB Ports 4.8A 24W for Mobile Device for iPhone 11/11 Pro/11 Pro Max/X Xs XR Xs Max 8 7 Plus Galaxy s20, s20+ S20Ultra S10 Plus S7 S6 Note 10. Here are the top ones, ranked by their Reddit score.
Dual USB Charging Ports- Dual smart USB ports quickly and easily identify your mobile devices, to provide optimal charging efficiency automatically, simultaneous charging any two devices at high speed with 4.8A total output power.Safety Usability-This USB car charger has multiple built-in voltage regulators fully protecting your devices against over-current, over-charging and over-heating for safe and rapid charging, ensuring superior performance and reliability.Practical Inner-Glowing - Featuring cool blue LED inner glowing from dual USB ports. The glowing ports are bright enough to helps locate ports in the darkness or at night without being distracting. It is also specially dimmed to avoid distracting you when driving in dark.Compact & Portable - Compact design with small and lightweight features for added portability, easily fits in socket with limited space.Universal Compatibility: Universal compatible with any Android and Apple mobile devices,including Apple iphone SE 2020 iPhone 11/11 Pro/11 Pro Max/X/Xs/XR/Xs Max, 8/8 Plus, 7/7 Plus, 6/6s, 6/6s Plus, SE/5s/5/5c, Samsung Galaxy s20, s20+ S20Ultra s10s10 plus,S7/S7 Edge/S6/S6Edge+/S6 active,S5/S4,Note 10/9/8/5/4/3, Nexus7/6/5/4,Nokia,HTC,Motorola,LG,SONY,and other smartphones and tablets, GPS units, iPods, MP3 players and more.
If it really helps you out, I'll buy you the adapter.
If I understand you correctly the Arduino will only need to:
Even the smallest of Arduinos could do that. The arduino is not really providing power to anything because your actuators are switched over the relay and the servos control their position internally. The 5v are already provided over USB so the Arduino doesn't have to do anything there but conduct them to the right pin. (I think there is a diode on the USB input which will cause a small voltage dropoff but it shouldn't matter for your application)
Using a very high estimate of the power consumption of 25mA you can expect your Arduino to idle for at least 25 days. Using sleep modes even significantly more.
If you don't want to use another battery you could also use a buck converter running off your 12v battery, that might make charging a little easier. Something like this (not the exact model just some random car phone charger) could easily be connected to the battery to provide power to the 5v electronics: https://www.amazon.com/gp/aw/d/B01IQWC2WC