If your batteries are fully charged they will power the heater for a while. How long depends on many variables.
I would not risk my pups for very long w/o heat.
2011 351RLTS Eagle, Mor/Ryde suspension & pin box
06 F350 Lariat PSD, SRW, LB, CC, EGR delete kit, 16K DrawTite hitch, Timbrens, TST TPMS
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