Question about PowerOak Solar panel

Each battery always needs a charger that is exactly right for it. The charger must, for example, be "set" for the battery so that it does not break, for example by being "overcharged" or charged with too high a current. This can therefore not be done by a converter integrated in a panel, as it does not know the data of the connected (car) battery. However, this 420W SunPower panel has a USB output (with 2x 2 connectors), which can charge USB devices (mobile phones, USB power packs, etc.). The USB devices (unlike simple rechargeable batteries such as car batteries) always have a charge controller integrated to match the built-in battery. The solar panel simply supplies "requested" voltage between 5V and 20V via the USB connection. Unfortunately, I don't have the diagram of this SunPower converter, but the USB outputs seem to be connected in parallel, as only one of the connected USB devices is charging (presumably the one with the lower input voltage).

No, a solar charge controller must be installed, i.e. connected to charge the car battery for 12 volts.