Yeah, I agree the cycle life of drill Batts are very advantageous.
@gator that worklight is actually a really smart idea.
My biggest concern is I want to keep the system 12V DC so I can potentially power other items of the circuit, low draw stuff like TT comps as well as a pump on a switch (should my thermosiphon not be as effective as I need.
I'm gonna see what Ridgid offers in 12v as I already have some Ridgid tooling