There's no indication that wedge start-up times are a function of available power.
All we're told is
On Basilisk Station wrote:. It took almost forty minutes to bring your impeller wedge up from a cold start; by starting with hot nodes, you could reduce that to little more than fifteen minutes.
Note that bringing the wedge up from hot nodes is still nearly twice as long and it takes an MDM to cover its entire powered range. If you don't snap your wedge on until someone launches at you you're very unlikely to be far enough away for the wedge to come up before their first salvo or three hits.
Shadow of Saganami wrote:Then he'd shut down to the absolute minimum impeller strength. He would have liked to shut down completely, but even with hot nodes at standby he would have been looking at a significant delay in bringing the wedge back up. So instead he'd held it at the barest possible maintenance level, which would let him bring it back to full power in less than eighty seconds if he needed to.
[ex-SLN BC]
War of Honor wrote:She turned her head, letting her gaze sweep over the nearest ships of her gathered task force. They floated in orbit about the planet Sidemore, the space-going equivalent of a fleet anchored in a safe harbor, but she'd been pleased when she arrived to find that Rear Admiral Hewitt had insisted upon maintaining a heightened state of readiness. All of his vessels' parking orbits had been carefully arranged to avoid any problems with wedge interference if it was necessary to bring up their impellers quickly. And he'd also seen to it that at least one of his battle squadrons' impeller nodes had been hot at all times. The ready duty rotated among his squadrons on a regular basis, but his precaution meant that its units could bring up their wedges in as little as thirty to forty-five minutes.
[This implies that even with hot nodes a battle squadron still takes 30-45 minutes to bring up their wedge; compared to the 15 minutes an old light cruiser can.
In Enemy Hands wrote:Unlike the Manties, Tourville's officers had known their drives and defensive systems would be needed, and they'd been at standby for over fifteen hours, but even with hot impeller nodes, they would need at least another thirteen minutes to bring their wedges up.
[note there's no indication of how long they've already been bringing the wedges up for; but even partway through the process it'll take
another 13 min.
The only time we seem to have seen wedges snap on instantly has been as part of an ambush (Fearless in the wargames against Home Fleet; Honor's ships at Cerberus). But there the attacker has the advantage of picking their moment to attack; so (at some risk of the powering up up nodes' signal leaking through their stealth field) they can carefully time when to start the wedge activation sequence so it completes just as, or very shortly after, they attack.
Wedge activation times don't seem to have improved from Travis Long's time (I didn't bother digging up and posting the quotes from those books, but it's still in the 40 minute range for cold nodes). And in fact the few indications we have are that larger ships take longer to bring up their nodes. Yet those larger ships have far more total power generation capability; and when activating nodes to maneuver out of orbit they're not running any of their power-hungry sub-systems (energy mounts, sidewalls, missile launchers, ECM, etc.) so if available power was the key element of wedge start-up speed we'd expect to see a battle squadron able to bring their wedges up from hot nodes in less than the 15 minutes a CL seems to be able to, yet Honor is happy that the RMN forces at Sidemore have a battle squadron with hot nodes because that'll allow them to bring the wedge up quickly; but quotes a time similar to what a CL would take from cold nodes - over twice what it needs with warm nodes.
So very little evidence; but what little we have hints that ship size (and hence wedge size) is far more likely to be the primary factor controlling wedge startup time than available power is.
Also note that it seems to take 80 seconds simply to ramp a wedge up from minimal possible power to full power. 80 seconds is forever at energy range, it's less time that a Viper needs to hit a target at 3 million km, while a Mk16 or Mk32 could hit a target 2.8 million km away in that time. I suspect (but don't know) that you'd need the wedge to be significantly more than minimal possible power before sidewalls would be usable/effective. That again make very close range engagements very risky; no mater how stealthy you are. And if it takes 80 seconds to bring an already active wedge up to power it's got to take
far longer to got from even hot nodes of no wedge up to a useful wedge.