Accuracy: it uses a specific battery, which can separately buy a second copy. Charging time: 8 hours - time to observe - They also recommend you remove the battery for charging. We can then use the loco 1/2 hour to 1 hour continuous (with battery).
However, be aware that this locomotive is not made to go fast, and can even less vary its speed. It is not remotely controlled.
Still, the BRIO system is in this awesome sense that it can be a real electric train, modular, easy to assemble and use, sturdy, attractive and not too expensive. I bought it for my 2nd child aged 3 and retrospectively Regrete I have bought earlier for my first (8 years) a classic electric train "to big" (crazy about trains!): I think that it would more fragmented with BRIO together.