Yes, a 10-watt solar panel can charge a 12V battery, but the panel must be a 12V with a 10-watt specification. Every 10W 12V panel will have a peak voltage of 13.8V, which can easily charge a car battery. How Long Will It Take To Charge A Deep Cycle Battery?
The 20A (12V/24V) PWM solar charge controller works with the 200W solar panel to charge the battery on your RV, boat, trailer and more. Select and recharge lead-acid (Flood, AGM, Gel) or Lithium-ion batteries. Features an LED display with adjustable modes and parameters,dual USB outputs and safety overcharge and overload protection.
It overcomes limitations caused by insufficient voltage from a single photovoltaic panel, ensuring reliable battery charging. This 10Amp MPPT solar charge controller has up to 99% tracking efficiency and peak conversion efficiency of 98% to allow you to charge the battery from solar panes at the maximumpower point!
so charging time would be 7Ah/0.833A = approx 8.5 hours. This is an theoretical assumption. It takes more than this time to charge the battery full of rating 7Ah with 10w solar panel as while charging always there is power loss. Can an inverter through a battery charger charge its own batteries (batteries, inverter, dynamo, electronics)?