Question about small panel and 18650 batteries pack

[Arqueboy]

I want to get this solar panel: 50W Solar Panel 12V Trickle Solar Cell Controller Maintenance Solar Panel For RV Car Charger Outdoor Battery Supply Camping, i want to make 5 12v series with 20 batteries, the small regulator this solar panel has can work with that pack?, or lithium requieres specific chargers?

 

[sunshine_eggo]

The panel you pictured isn't a 50W panel. It is too small. At most it's 15-20W. You get about 200W per square meter, and that panel is 0.088 square meters.