Under normal circumstances with no exotics or other perks, kills of any kind grant a tiny amount of Super energy. When Phoenix Protocol's bonus charging caps out, kills inside the Well of Radiance give no base Super energy at all. As you can see in the video, the charge for my next Well of Radiance stops ticking up with kills when inside the well with Ringing Nail, but resumes when I leave the well or when well expires. Bad Juju's String of Curses still works, but the payoff is less because you're not getting the normal kill charge, only the bonus charge from Juju.