Yep. That is why bigger is better with fusion. In order to start it up you need really strong lasers in order to contain it you need a super strong magnetic field. All this takes energy. So the key is to get a big enough fusion reaction so that the amount of energy you put out is greater than that which you put in. IE: You need size. You get larger and larger energy outputs and the energy required to start it remains static and the energy required for containment increases much much slower than the output. In addition you want to reach ignition or very close to it for maximum energy output. Ignition means you no longer need outside energy input to sustain the reaction. It is a self sustaining reaction. This requires size. When was the Last time you saw a small star?
You can have all the small fusion reactions you want. You just won't get any more energy from it than you put in, not unless you can figure out how to A> Start it without using lots of energy B> Contain it without using lots of energy C> Get a low level ignition or near ignition.
While A and B might eventually be overcome C itself defies our understanding of physics and thus can be considered impossible, at least in our lifetimes I would bet.
Thus no small fusion reactions to power things like cars etc... at least not directly.
Use a battery charge it using plentiful fusion energy and then run a car on that.
