Cigarette lighter socket capacity? 12 volt to 120 volt AC converters

Excuse this for being slightly off topic but it could apply to a
vintage or any car?

Some of the 12 volt to 120 volt AC converters now available at quite
reasonable prices can have a capacity of 175 watts or more. Some are
advertised as "Just plug in to your cigarette lighter".

Even at an efficiency of, say, 90% the DC input will have to be
(175/0.90)/ 12 = at least 16 amps! That's equivalent to approx. four
old style headlamps all on at once? I think I've seen a 25 wat model
that would take 23+ amps.

Recalling some difficulties with cigarette lighter sockets where
underdash wiring either caught fire or the socket itself got extremely
hot is this perceived as a problem?

Better, I guess, to use a pair of clips onto the battery itself and/or
use a separate fused circuit.

TIA welcome opinions.

On 14 Jan 2007 07:14:39 -0800, "terry" >
wrote:

>Excuse this for being slightly off topic but it could apply to a
>vintage or any car?
>
>Some of the 12 volt to 120 volt AC converters now available at quite
>reasonable prices can have a capacity of 175 watts or more. Some are
>advertised as "Just plug in to your cigarette lighter".
>
>Even at an efficiency of, say, 90% the DC input will have to be
>(175/0.90)/ 12 = at least 16 amps! That's equivalent to approx. four
>old style headlamps all on at once? I think I've seen a 25 wat model
>that would take 23+ amps.
>
>Recalling some difficulties with cigarette lighter sockets where
>underdash wiring either caught fire or the socket itself got extremely
>hot is this perceived as a problem?
>
>Better, I guess, to use a pair of clips onto the battery itself and/or
>use a separate fused circuit.
>
>TIA welcome opinions.
========================
Well...I think I see a math error, but it doesn't help much. I believe
the formula should be 175*0.90/12 but that is still 13+ amps, which is
a bit to pull through the typical 16 gauge wire used to connect a
"power outlet".

I have used the battery clips, and have also wired dedicated outlets
(in travel trailers) with12 gauge wire.

Joe
--
Heather & Joe Way
Sierra Specialty Automotive
Brake cylinders sleeved with brass
Gus Wilson Stories
http://www.brakecylinder.com

Heather & Joe Way wrote:
> On 14 Jan 2007 07:14:39 -0800, "terry" >
> wrote:
>
> >Excuse this for being slightly off topic but it could apply to a
> >vintage or any car?
> >
> >Some of the 12 volt to 120 volt AC converters now available at quite
> >reasonable prices can have a capacity of 175 watts or more. Some are
> >advertised as "Just plug in to your cigarette lighter".
> >
> >Even at an efficiency of, say, 90% the DC input will have to be
> >(175/0.90)/ 12 = at least 16 amps! That's equivalent to approx. four
> >old style headlamps all on at once? I think I've seen a 25 wat model
> >that would take 23+ amps.
> >
> >Recalling some difficulties with cigarette lighter sockets where
> >underdash wiring either caught fire or the socket itself got extremely
> >hot is this perceived as a problem?
> >
> >Better, I guess, to use a pair of clips onto the battery itself and/or
> >use a separate fused circuit.
> >
> >TIA welcome opinions.
> ========================
> Well...I think I see a math error, but it doesn't help much. I believe
> the formula should be 175*0.90/12 but that is still 13+ amps, which is
> a bit to pull through the typical 16 gauge wire used to connect a
> "power outlet".
>
> I have used the battery clips, and have also wired dedicated outlets
> (in travel trailers) with12 gauge wire.
>
> Joe
> --
> Heather & Joe Way
> Sierra Specialty Automotive
> Brake cylinders sleeved with brass
> Gus Wilson Stories
> http://www.brakecylinder.com


Ask your local mechanic what ,p[eraage the fuse built intop the back of
the lighter socket is.... but remember that is just for a short time in
normal use.

(hard-wire is a good idea for just about anything)