Was Vader still powerful?

Despite these setbacks, Vader still became one of the most powerful Force-user in the history of the galaxy; only Palpatine, who was considered to be the strongest Sith-Lord of all time, surpassed him due to his disabilities, and only Luke Skywalker, Vader’s own son, rivaled Vader’s power at its full potential.

Did Vader get weaker?

Vader started out much weaker than he was as Anakin, but eventually grew so close to the Dark Side that he eclipsed his former self. That said, his potential power was cut severely. So much that, barring a miracle, he would never have become powerful enough to defeat Sidious in a straight fight.

Could Vader become stronger than Sidious?

Darth Vader is not stronger than Darth Sidious. The latter is without a doubt the most powerful Sith Lord in the original movie canon. Vader had the potential to become the strongest, but he never achieved his full power, something the Emperor was well aware of.

How did Anakin become so strong as Vader?

Anakin was raw power and insane saber skills. As he became Vader, his rage fueled his power to grow even stronger and he learned to control it. Since his saber days were past him, he had to focus all that energy into his force abilities.

Why is Darth Vader so strong as a force user?

Since his saber days were past him, he had to focus all that energy into his force abilities. Even though his rage as Anakin gave him the ability to force choke, his days as Vader to control that ability made him stronger.

Is Darth Vader weaker than Darth Sidious after the accident?

Initially he was definitely weaker as he lost at lot of his power from his injuries and loss of his limbs. Before the accident he had twice the potential power of that if Darth Sidious. Afterwards his maximum potential power diminished to 80\% of that Sidious.