[Rainrider]

Sacrife, why don't you add a tooltip for it as in the standart interface instead of displaying powerName on the bar itself?

self.AltPowerBar.Tooltip = function(self)
    local powerName = select(10, UnitAlternatePowerInfo(self.__owner.unit))
    local powerTooltip = select(11, UnitAlternatePowerInfo(self.__owner.unit))
        
    GameTooltip:SetOwner(self, "ANCHOR_TOPLEFT", 0, 5)
    GameTooltip:AddLine(powerName)
    GameTooltip:AddLine("\n"..powerTooltip, nil, nil, nil, true)
    GameTooltip:Show()
end
    
self.AltPowerBar:EnableMouse()
self.AltPowerBar:HookScript("OnLeave", GameTooltip_Hide)
self.AltPowerBar:HookScript("OnEnter", self.AltPowerBar.Tooltip)