we have been using a 12v heated mattress pad from backwoods solar for about 8 years with great results.
we live in our winne fulltime.
it draws 5 amps per side when first turned on, about half that, depending on how the thermostat is set, when the bed has warmed up.
we are definitely using it tonight.
01 WINNEBAGO 35U W20.8.1L SW Wa, Hi. Good Sam, SKP. AMSOIL fluids. BANKS ecm program. SCAN GAUGE II w/ Ally temp. 2 LIFELINE GPL-6CT AGM Batts on their sides. TST tptts. K&N panel air filter. AERO mufflers. TAYLOR plug wires. ULTRA POWER track bar. KONI fsd shocks, toad '14 smart car