comments:
Yes you should. I travel a lot and end up using mine 3-4 times a month for something or someone stranded. Here is a good video from Project Farm that reviews many brands. https://youtu.be/jlK7UWHD3sY?is=97cVb1WcWZLKKk11 I bought this one based on his recommendation. https://a.co/d/02hgCHbU
Not quite what you were asking for but I* use the Gooloo GP4000 jump-starter as a power bank for charging my phone on camping trips and such all the time. Massive capacity (24,000 mAh) plus it will jump-start your car.
As others have said - the Noco Genius 5 is a great trickle charger, and as a true on the road backup contingency I have a gooloo jump pack https://a.co/d/06xoNoG5 which I keep stored under the cargo floor. That being said I wouldn’t worry too much about the 12v issue, some have had massive drain while others have been fine. Ultimately it’s an issue with the connected services and seems to be the service connect in particular based on some initial empirical research.
Can't say enough good things about the Gooloo GP4000 jump starter. This thing is badass. I could charge it up, toss it in my trunk, leave it there for a year through a -10F winters and +100F summer, pull it out and it would still be able to jump-start 10 completely dead-battery cars. It will even jump-start my diesel tractor in the winter which is really saying something. Just remember you have to push the "Boost" button on the plug if your battery is really dead.