How Strax ended up with Jenny and Vastra

[Turbo]

I suppose that maybe they can still eat if necessary, it's just that recharging saves time on the battlefield.
Actually, that could make a nice mini-episode for them.

Strax: "So, you bite off bits of it and swallow it?"
Veshtra: "Yes."
Strax: "Disgusting. Primitive. Ooh, tasty. So is this the flesh of an enemy?"
Jenny: "No!"
Veshtra: "Not this time."

Nice.

Or I suppose they could have a steampunk style machine in the cellar that you drop food into. It whirls and steams as the camera follows a wire connected to the back of Strax's neck, whos sitting there looking bored, reading a copy if the Times.

Those would both be hilarious.