Theo skips sleep pretty often, so when he does actually sleep he tends to sleep for a while. Kaede will probably wake up before he does.
"No idea how it relates to here, but I can be summoned from where I live to the mortal world, and for some reason or another came here this once, having never heard of here or this magic or Sin ever before."
"Not having heard of Sin sounds great," she says vehemently.
They reach a tent near the machina where a chief engineer is giving people orders and receiving reports. The woman informs him of this and explains to him what Theo can do, and he takes Theo to see the battery. It is very old but restored and seems to be completely unlike anything he's ever seen.
"… I'm afraid I have no idea how this battery was made so I'm likely to be of no use with it."
He can learn if they know how it was made! He has a basic idea of how batteries work, at least the ones he's familiar with.
But if they don't, no, unfortunately he has no special information-gathering powers.
So it's probably some kind of electricity but unfortunately he does not have anything handy with which to find out how it's made unless he cares to destroy it carefully. Which, uh, no.
Anything else he can do instead?
… Do they have any of the instruction manuals? 'Cause they might have useful things like composition of the battery or something, but he's sort of hoping they already checked for that?
He'll have a look at them! He has a decent high-school-plus-a-bit level of education in chemistry and physics and a passing acquaintance with how lots of this stuff works from general summons where they didn't require the angel to be perfectly knowledgeable about such things.
Is it more comprehensible to him?
He knows some about transistors because he has looked into computers a bit before, and he knows bits and pieces about quantum physics, so he can probably pick up bits of it… but unfortunately he does not understand it all.
He tells the engineers what he can, anyway, and hopes they will be sensible with the knowledge.
"No problem," he responds, then he goes to find Kaede.
He really really doubts it'll work and he really really hopes he hasn't made anything worse.
"They are apparently done!" he reports. "I have no idea about some of the stuff they were using, though."
"I don't know how it works, though it seems similar to some stuff I have seen at home, and they are just sort of blindly using the operator manual. Ish."