by navver Wed 18 Dec 2013, 9:36 pm
These are 12 volt and most electric blankets are rated at 80 or 100 watts or so. Therefore the current will be 6 or 8 amps. This is a lot to run from a battery especially in cold weather when the battery capacity is reduced anyway. On EHU it will go through your transformer/charger unit and may overload it. The transformer/charger unit will, at best, get hot and need lots of ventilation, at worst overload, possibly catching fire.
A fully charged 85AmpHour battery will last approx 5hours, less if you use it for anything else as well.
I'm not sure what the rating of this particular blanket is, it may well be less but I think you would be wise to check.