OK. Simple question is....
I have a L298n H-bridge controller that is supplied with 12v. The output of this H-Bridge goes to a geared motor that I have now found out is 6v.
If I code in that it can never go full throttle (so only ever 50%), do you think this will be OK?
I really don't want to have to source new motors, and I have no 6v ability.
The voltage is not your problem. Time is your problem. The motor temperature will tell you when you have the motor running for too much time.
Time should be OK, These motors only run for 30 seconds occasionally.
If the motors do not have internal fan, then their mounting should be a heat sink to help in cooling. So, no wood or plastic mounting!
They are small little winches on an RC boat.
I suppose sticking the output of the H-Bridge through an LM2596s voltage buck reducer is a bad idea...
I can't get the buck reducer before the H-bridge unfortunately.
No! Know that the power and heating in Watt calculates Voltage in square! Use max 25% and You could be safe.
Overvoltaging a motor in this fashion to this extent will typically be safe, so long as you don't let it stall. A winch, of any kind however small and low load, sounds likely to stall though. When you give a dc motor too much voltage it will run faster so that the back-emf generated within it (acting like a generator when the coils are spinning in the magnets' fields) will be greater and the motor will reach a higher speed at which the back-emf and the supplied voltage reach a kind of equilibrium and a steady speed is reached. But if the motor stalls, there is no back-emf generated and it acts like a plain old resistor. Doubling the voltage doubles the current which flows in this situation, so the motor heats to damaging temperatures more quickly during a stall. Furthermore, for motors with a built-on gearbox, the gears are often manufactured only to cope with the torque they may find themselves under when the motor is stalled at the rated voltage, and sometimes they are only rated strong enough for torques less than this. A stall at doubled voltage produces double the torque of a stall at the expected voltage, some gearboxes won't cope with this.