Stargazer said:
Doesn't matter driving or not. If the blanket power draw is higher than the wire rating, the wire may overheat and worst case start a fire. Basic electrical fact.
hmmmm..... wires can indeed be over heated, by excessive loads. Most vehicles (if not all) will however have a fuse for every wire. So the fuse will blow, before the wire overheats.
I think that the overheating issue is more likely to happen in the connector.
Especially if a 12V cigi-style plugs is involved - as this style of plug does not have a vibration proofed lock-in mechanism in its design.
The 12V cigi-style connectors rely on spring loaded friction to prevent it from becoming a weak/bad/overheating connector. And this is simply not a reliable design.
So even though it is in widespread use (for historic reasons) it is often due to a weak connection in a plug, that anything overheats.
notsosure said:
Does running a 12V blanket in a running auto wear your battery out faster?
If you car is running, the power typically comes from the alternator, and not from the battery. So using a heating blanket while driving, will basically not have any effect on your battery.
Many cars even come with a heating option built right into the seat.
When the car engine is however only idling, the alternator may not produce enough energy to fully power all things electrical in a vehicle, so you should not rely on an idling engine to be able to power things for hours on end.
If you need something electrical to function, for hours on end, when only idling the engine, them make sure to turn off the high power loads, like; headlights, vent air-blower, electric window defrosters, and the likes.