Battery-Driven Tanis

I have a common problem of possessing a Tanis heater in my Warrior but
no electrical source by which to run it. Past newsgroup and online
knowledge (including an email from Tanis) say that at least a couple
of hours are needed to heat the engine in about 20 deg F temps.

An old post from 1999 suggested that a "deep cycle" battery be used in
conjuction with an inverter to be turned on a couple of hours prior to
flight.

Does anyone currently use this setup? If so, any suggestions on the
myriad of battery types and brands? Golf cart batteries are mentioned
quite a bit but they range in price so much that it demands some
research.

Although I live 3 minutes from my tiedown, sitting in my car two hours
before any winter flight kinda takes the wind out of that benefit.

Marco