12V socket rating

[iainfm]

Hi,

I'm looking for a temporary solution to prevent me getting stuck with a fogged/iced up windscreen while my heater is borked.

There are various 'cigarette socket' heaters on amazon etc, which generally have terrible reviews but might just get me out of a tight spot.

The bigger problem is they're rated at 150W, but the 12V socket is 120W max, according to to manual.

Is there likely to be enough wiggle-room in the rating for a 150W device, or is it best not to risk it? The fuse for it is 15A, which (at 12V) is 180W.

 

[Ozzie1989]

You certainly won't blow the 15a fuse as you've already suggested, but the socket itself may only be rated to 120w.

They will have selected 15a as running the circuit on 10a/120w continuously on a 10a fuse will create excessive heat at the fuse and over time cause issues.

For short term use (e.g. a few mins at a time) it'll be fine, my only worry is that you're powering a heating element which will naturally heat the cable making the plug/socket even warmer than if you were powering something else not involving high resistance.

Of course you also have to remember if you use it when the vehicle is in ready mode the battery should actually be at ~14v so your heater will then only draw ~11a.

 

[Kithmo]

You could try one of the anti-mist sprays.
Anti-mists | Auto Express

 

[iainfm]

Thanks for those replies. I've found a 12V 120W PTC assembly on ebay. Looks like it's got 3 separate elements so I've ordered that and some flick switches to see what I can bodge together.

Now it's a race between getting the car fixed and the bits arriving