I have the CTEK US 7002 (Part no: 56-353) and Battery Tender 10 watt Solar, both work well for me and can be hooked up for long periods. I use the solar panel in my spare daily driver, which is left outside, I've tried the 2 watt solar panels and they don't have enough capacity for my vehicles. The CTEK is used on my garaged vehicles when left for extended storage or to recarge a neglected battery.
https://mechanicbase.com/reviews/bes...tery-chargers/
https://earthtechling.com/solar-car-battery-chargers/
https://www.batterytender.com/10-Wat...-in-Controller