Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Power Connection Via Cigarette Lighter?  (Read 3309 times)
AB0SQ
Member

Posts: 7




Ignore
« on: March 18, 2002, 06:36:52 PM »

MFJ suggests that it is alright to use the cigarette lighter as a mobile radio power source as long as the mobile rig is set to a lower power output level.

Considering the source, I would like to get additional opinions from the group here at eham.net:

1. Do you agree that it is safe and effective to power a rig from the cigarette lighter?

2. If not why not?

3. If yes, how high a power setting is reasonable? 5 watts? 10 watts? 25 watts? Higher?

TIA
Logged
KL7IPV
Member

Posts: 984




Ignore
« Reply #1 on: March 19, 2002, 05:32:16 PM »

Well, YES and NO. No if you aren't sure the source for the cigarette lighter is fused and of sufficient wire size to handle the load. YES, if you have a DODGE like I do and the lighter is labeled with the voltage and current wiring. Mine says 12VDC 20AMPS. Pretty clear and will handle ANY rig I have used or plan to use. Once you determine that the lighter will handle the load, be sure the plug you use will as well. Some are rated way below what you can draw on the radio. You may have to make up your own plug. If all those critieria are met, I know of no reason why you cannot use the cigarette outlet for ham radio. Good luck.
73
Frank
KL7IPV
Logged
WB2WIK
Member

Posts: 20666




Ignore
« Reply #2 on: March 19, 2002, 07:11:06 PM »

At lower current, I'd agree it's normally safe.  20A for a cigar lighter outlet sounds like a lot, but Frank's Dodge might have something special going on there, like an intended ACCESSORY outlet that just happens to look like a cigarette lighter outlet and is wired with heavier gauge conductors than normally used.

I've seen many cars where the cigarette lighter is wired with only #18 gauge stranded wire.  That's good enough for 10A for 15 seconds or so, which is the intended application (to make an electric heating element glow red), but is insufficient for 10A continuously.

Drawbacks in this case:

-Possible damage to the outlet wiring, which is a pain to replace;
-Possible fire hazard, if wiring insulation melts before a fuse blows*;
-Even if no damage occurs, voltage drop in the wiring can be pretty severe, so what reaches your rig isn't the 13.8Vdc you think it is (and it ought to be), but something much lower, due to simple IR loss in the wiring.  Many mobile rigs are optimized to operate at 13.8Vdc +/- 0.5V, and below 13.0V can get a bit squirrely, with reduced transmitter output, and noise and whine modulating the transmitted signal, and even CPU or synthesizer resets caused by noise spikes and too-low voltage.

(*Actually, a fire would be very rare.  Usually you get smoke only, and any fire extinguishes itself immediately, as the insulating materials used are flame-retardant.  But it's still scary.)

I've found every cigarette lighter will support operation of a handie-talkie (typically 5W output, or maybe 1.0A drain on the outlet), and I use them for this in rental cars all the time.  But for my own vehicles, I always just run wiring straight to the battery.  Safer, surer, frees up the cigarette lighter outlet for "other stuff" (cell phone, HT, laptop computer or PDA, whatever), and almost always results in better operation of the mobile equipment due to higher voltage, and less noise on the 13.8V bus, provided by the direct connection.

I use #8 gauge stranded, high-temperature automotive zip cord, readily available (red and black insulation, bonded together) at many retail outlets.  Even in a 15' run, the #8 gauge only has about 0.2V drop at 20A.  Smaller gauges have surprising drop...

WB2WIK/6
Logged
KL7IPV
Member

Posts: 984




Ignore
« Reply #3 on: March 19, 2002, 11:25:05 PM »

Dodge puts outlets meant to be used with computers and other appliances that require 12VDC @ 20 AMPs . My minivan also has two in the rear for the same use. They are labeled clearly so they will be used accordingly.
73
Frank
KL7IPV
Logged
KA9KHD
Member

Posts: 2




Ignore
« Reply #4 on: March 21, 2002, 10:04:23 PM »

Hi All,

 I have been wondering about the lighter question too. It seems that most of the newer vehicles

now have accessory outlets for use with mobile phones,computers and the like.

My 98 Chevrolet pick-up has a cigar lighter and two accessory outlets in the dash

and the accessory outlet fuse is 24 amp and the lighter fuse is 20 amp. So obviously

there is some difference, just be careful which one you chose to use and don't exceed

the fuse rating or it will blow.

Thank you

KA9KHD
Logged
KD7EVS
Member

Posts: 84


WWW

Ignore
« Reply #5 on: April 02, 2002, 03:38:26 PM »

I have a ranger and it's got an extra outlet. the cigarette lighter on my ranger is straight from the fuse box whereas the extra outlet (marked 12vdc) is regulated to 12vdc.   now the question for accesory outlets are this.   are they the implied 13.8 vdc that most radios are designed to run at and most car systems supply?  or are they specificly regulated at 12vdc? if they are at 12 volts that would under power a radio designed for 13.8vdc.  my mobile won't run full power through my extra outlet. however it will run through my cigarette outlet.   (I do have it wired in right but tested both outlets when I first got the truck). by the way both outlets each have a 20 amp fuse on them.

zeb
Logged
WB2WIK
Member

Posts: 20666




Ignore
« Reply #6 on: April 05, 2002, 06:42:41 PM »

Re: The accessory outlets etc.

Interesting.  My vehicles currently do not have the accessory outlets, so I'm going to have to make some measurements on someone else's.  

If the accessory outlet is actually regulated at 12V, this would be good for alternator whine and conducted ignition noise (there shouldn't be any), but bad for running "full power" from higher powered mobile rigs intended to run at 13.8V.  I notice in my mobile rigs (a 70W output 2m rig [Yaesu FT3000M] and a 200W HF rig [TT Scout running at 10W into homebrew 10 in/200 out mobile amp using Mot MRF247's]) will absolutely suffer from limited output power if run at 12V.  I can see this simply by shutting off the engine.  Within 2 mins, the battery voltage is down to 12V or so, and the rigs' outputs start dropping quickly.  With the engine running and 13.8V provided, the outputs come right back up again.  The difference is not small.

Also, the comment about "both having 20 amp fuses" is kind of interesting.  Obviously, you cannot draw 20 amps from an outlet which is fused at 20 amps.  So, in this case, both the cigarette lighter and the accessory outlet are probably limited to 15A or so.  That would not be sufficient for any kind of 100W output mobile rig, but of course is more than sufficient for a handie-talkie and other lower-powered devices.

WB2WIK/6
Logged
N4DFP
Member

Posts: 7


WWW

Ignore
« Reply #7 on: April 28, 2002, 02:19:54 AM »

I successfully used a lighter plug on my Patcomm PC-500 (15WPEP). I know folks who have used lighter plugs up to 25W, and I have a 50W power inverter that uses a lighter plug. Key advice.... no matter how well the the lighter socket is fused ALWAYS use a fused plug.
Logged
AA4PB
Member

Posts: 13032




Ignore
« Reply #8 on: June 06, 2002, 09:32:04 AM »

Have you actually measured the output voltage of that Ranger's accessory jack?  I would be highly surprised if Ford went to the trouble and cost to put a 20 Amp regulator in to set it at 12 volts. More likely it is just labeled 12 volts but gets its power from the distribution system like everything else. If that is the case, it will be 13.8 volts with the engine running.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!