Correct. The panel give load & no load voltage and optimum operating voltage are on the panel.
I must admit, the ChiComs are known for playing around with ratings of solar panels. They way over rate the ability of the panels to produce power in watts.
Bought my first 3 panels in the early 1980’s, still have them. Only time I use them is for field day for a QRP rig. They were new surplus from Los Alamos Labs. rated at 1/2 amp at 16 volts. The size of the battery is also important.
Recently I bought a small 5V solar panel to charge my cell phone away from commercial power. It is simple and does a good job of charging my smart phone (computers and computer phones are really stupid).
I ordered some 18650 Lithium ion batteries and charger a week ago, am waiting for delivery soon. Have mixed feelings about them. They are very low leakage (charge leakage) and physically very small for the current capacity, but I am not sure how safe they are when unattended. When you see the stupid electric cars burn up it is sobering.
TF
I am fortunate when it comes to batteries. I am in the big rig repair business. Most trucks need all three batteries to be in very good condition to produce the cold cranking amps they need to start.
Every winter when the temps drop, usually one of the three will take a dump and stop putting out it’s share of the total amps needed. So standard practice is to just change out all three because the other two are not far behind. I keep these takeouts and turn in actual dead and good for nothing batteries or old batteries off my solar system to the vendor.
For a solar system that doesn’t need “cold cranking amps” they are still good to go for a few years. In fact, I have found having them on the slower charging solar system actually repairs most of the cold cranking amps they lost over a couple weeks. Why and how I am not sure, but it does... But when they start getting weak on my system I just swap them out again for fresher take outs.