Correct.....except for the 'limited to a max' part. Read on.
With a wind turbine, if there is no load on the generator, there is little resistance to the spin of the blades. This means the blades can spin faster than they are designed to handle and the voltage will go way up. (This is called free-wheeling). At a minimum, this will wear out the bearings faster. At worst, the turbine can actually tear itself apart if there is high wind and no load. Furthermore, the high voltage could possibly cause damage to down stream electronics.
What this means is that there should always be a load on the system. Consequently, when the battery is full and no longer taking current the controller must send the energy into what is known as a dump load. This is often a bank of high-wattage resisters that turns the energy into heat. Some people will use heating elements in a hot water tank as the dump load so they can make use of the excess energy.
Some controllers just short out the inputs. This makes the coils in the generator heat up and dissipate the energy. (The coils become the dump load) This is usually done on lower-cost set-ups and in general, I would avoid systems like this. However, people have reported good performance and reliability from this type of system. It can be a bit of a crap shoot whether any particular system that does this was designed well enough to handle it.
Even controllers that use dump loads have a wide range in how well they work. Some of them have a simple relay that switches to the dump load at a predetermined voltage. This can cycle on and off very rapidly and be very jarring on the turbine. The best controllers have a sophisticated PWM system that gradually transitions to the dump load as the voltage goes up.
That is probably true.... but it is not a guarantee. You would need to check with the manufacturer to be sure.
Before you spend any money on this make sure you have a place where you are going to regularly have a steady wind or you
will be disappointed. Also, look very closely at the specs of the system. Some of the cheap hacked-together windmills available on ebay and aliexpress claim a wattage that is only possible in near gail-force winds and produce almost nothing in slower winds. If they don't provide some kind of wind-speed vs power output chart, be suspicious. If they don't tell you the wind speed needed for the rated power output, be
very suspicious.
I had a quick glance at the Marlec website and they seem OK. They don't look like garage-shop turbines with repurposed generators and a blade.... However, websites can be deceiving, I did not look closely, and I have no experience with Marlec so I can not say either way.
A couple of side notes:
- Water turbines have the same problems with free-wheeling and usually need dump loads as well (Particularly high-pressure, low-volume water turbines. Low-pressure, high-volume systems turn much slower and are less susceptible to problems for free-wheeling.
- Solar Panels don't have this problem. When the solar charge controller turns off the current, the panels just absorb the suns energy and get hot. The panels are designed to handle it.