FYI, you've got one now, I have cold weather issues and the $0.09 cent difference between a crystal and the ceramic oscillator on the pro-mini is the primary suspect. Ideally I'd rather pay the $0.09 upfront than every 5 days in a heater ideally, thats another $7/year operating cost for a 6watt...
This is what I'm hoping to accomplish too, use existing power supplies up to the 10kw range and a buck converter/controller. but so far the messaging part is still pretty cryptic, and it is just a convenience to avoid hacking the battery connectors really.
Thanks everyone for sharing this info, it is terribly appreciated.
I've got a plug printing (thanks jclemens!), is there an implementation of a ch@demo controller posted somewhere for reference, or other useful information can message repository that I might have missed somewhere?