A solar panel can do a great job of helping recharge your batteries. They are rated in watts and this indicates how much power they can send through to the batteries.
A 90 watt panel operates at about 17 volts and in bright sun can put out about 5 amps. The energy has to be channelled through a charge controller. This is a small box that regulates the voltage. Without the controller you can have dangerous erratic voltage and feedback that can kill your batteries. Unless it is a tiny solar panel (say 10 watts) it should never be hooked up directly to the battery.
On a overcast or cloudy day your panel may only produce about 1 amp to charge the batteries. This is barely a trickle charge so unless you are where it will always be sunny, keep in mind they should be considered supplemental to your overall charging system.
A solar panel can charge any type of battery. The closer the panel is to the charge controller and the closer the charge controller is to the batteries, the more efficient the set up is. We don't generally recommend mounting the panels, as you may find yourself parked 5 feet away from the sun in the shade and unable to move your panel into the sun for maximum efficiency. The panels have special connectors that enable you to add lengths of wires so you can have the panel, the charge controller, and the batteries some distance apart. These are generally not included in the price of the panel.
The solar panel feeds the energy into one side of the battery, and the things you have plugged into your inverter on the other side of the battery are drawing the charge out . It's all about determining how many amps you can get and for how long from the panel in order to keep your batteries charged up.
We always have free information and advice for any questions.