In most cases, heat tape requires an AC connection to power the heating element. Generating heat over a large area using electrical resistance requires a significant amount of current, which would quickly drain any battery used to power the system.
In addition to the electrical demands, household heat tape usually requires a GFCI outlet to protect against electrical shocks that can result from the close proximity of high current and water.
Vehicular heat tape runs on as little as 12 volts and can be powered by an automotive battery. This tape is designed for intermittent use only, such as thawing out pipes in an RV's water system, and should not be used for long periods of time.