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] 2 3 Next   Go Down
  Print  
Author Topic: current rating of automobile cigarette lighter plugs  (Read 18968 times)
KU7I
Member

Posts: 122




Ignore
« on: March 19, 2013, 11:09:58 PM »

Anyone have any idea how much current you can draw from the cigarette lighter plug in most automobiles? I want to push ~ 400 watts mobile but not sure if this is too much current draw.

Lane
Ku7i
Logged
TANAKASAN
Member

Posts: 933




Ignore
« Reply #1 on: March 20, 2013, 01:18:22 AM »

The contacts on a lighter plug are not very good, the fuse may be rated at 10A but I doubt that you could pull more than 2A or 3A from one without it getting hot.

A 400W amplifier (assuming 50% efficiency) will draw 800W @ 13.8V. This is a 58A load and a fire waiting to happen unless you do it right. Head for Alan's site and do the job properly.

http://www.k0bg.com/wiring.html

Tanakasan
Logged
KF7CG
Member

Posts: 840




Ignore
« Reply #2 on: March 20, 2013, 04:40:54 AM »

If you have a newer Pickup or SUV, it may have 12V power points in addition to or in place of the cigarette lighter sockets. Same appearing connector but more solid contacts, ratings should be in owners manual. They won't exceed ten amps so won't power 100 watt HF rigs (18-22 amps).

KF7CG
Logged
AA4PB
Member

Posts: 12905




Ignore
« Reply #3 on: March 20, 2013, 05:35:27 AM »

I've seen some labeled by the mfg for 20A - but I don't think it is suitable for radio use at that current. One issue is the voltage drop in the small guage connecting wires in the vehicle.
Logged
AD4U
Member

Posts: 2174




Ignore
« Reply #4 on: March 20, 2013, 05:44:18 AM »

The auto manufacturer may accurately rate the accessory 12V jack at 10 amps or 120 watts, but the typical cigarette plug found on many accessory cords will not "handle" that much current without a major voltage drop.

Dick  AD4U
Logged
KX8N
Member

Posts: 542




Ignore
« Reply #5 on: March 20, 2013, 05:49:20 AM »

Head for Alan's site and do the job properly.

http://www.k0bg.com/wiring.html

Tanakasan

Definitely read that page. What you are planning to do is simply a fire waiting to happen. It's a bad idea to even run a rig barefoot through the cigarette lighter plug, let alone an amp.
Logged
K6AER
Member

Posts: 3525




Ignore
« Reply #6 on: March 20, 2013, 09:57:07 AM »

Wire directly to the battery. Fuse at the battery. If the battery is over three years old replace the battery with one that has the highest cranking amprage rating. At 400 wattts you can draw 50-60 watts on voice peaks. Also run the negitive lead from the radio and amplifier all the way back to the battery.
Logged
NO2A
Member

Posts: 802




Ignore
« Reply #7 on: March 20, 2013, 10:38:38 AM »

There`s a picture on Alan`s site of a fire started by an ht using a cigarette plug. Hard to believe. It did much damage too.
Logged
W9MMS
Member

Posts: 121




Ignore
« Reply #8 on: March 20, 2013, 11:30:07 AM »

If you cannot do it right the first time, then don't do it period!

As K6AER so correctly stated .......

<snip>>>>> Insert Quote
Wire directly to the battery. Fuse at the battery. If the battery is over three years old replace the battery with one that has the highest cranking amprage rating. At 400 wattts you can draw 50-60 watts on voice peaks. Also run the negitive lead from the radio and amplifier all the way back to the battery. <<<<<

Also, be mindful of your ALTERNATOR. ......... www.k0bg.com

If you are going to be "Cheap" about it then forget it as well.

Do it right and save yourself a lot of grief!

just my $0.02 worth

((((73)))) Milverton.
Logged
KU7I
Member

Posts: 122




Ignore
« Reply #9 on: March 20, 2013, 05:42:52 PM »

Got it. The cigarette lighter plug is a terrible idea and will not be pursued. Thanks to all for the intel.

Lane
ku7i
Logged
KM3F
Member

Posts: 512




Ignore
« Reply #10 on: March 20, 2013, 06:19:21 PM »

Always look in your owner Manuel for fuse sizes per the function.
The auto wiring is in a harness, not large enough in size and can melt into the other wiring creating a big problem beside the voltage drop.
Anything that draws more than 8 amps needs to have a dedicated feed.
Many 2m FM radios that have a high power setting of 65 watts or more can't be run out of a lighter socket unless set on lower power.
You need to know that running a fuse at or near it's rating will fail in a short time from heat fatigue.
Goodluck.
Logged
KU7I
Member

Posts: 122




Ignore
« Reply #11 on: March 20, 2013, 09:11:03 PM »

Ken,
My previous call was KM3G, non-vanity from ~ 1983.

Lane
Logged
G7DMQ
Member

Posts: 40




Ignore
« Reply #12 on: March 25, 2013, 08:26:49 AM »

I had a similar problem - but running a cool box which kept melting plugs & sockets!

I machined this:
http://www.x-eng.co.uk/images/forum/lighterplug.jpg
(Is there a way of embedding images on the forum?)

With a socket to match!  It would be much easier just to use a better connector, such as an Anderson however!

Si
Logged
N6AJR
Member

Posts: 9912




Ignore
« Reply #13 on: March 25, 2013, 11:59:31 AM »

I have 2 radios in the car and 5 in the truck.  in both cases I ran a heavy pair of of wires ( 8 or 10 gauge) from the battery to the radios. Well fussed and protected where it passes through the firewall.

  in the truck I actually have an 800 watt 110 volt inverter and I use the terminals on the back of it as my power take off point. from there i feed a power pole  gizmo that has several contacts on it to feed the radios.

I have a dedicated 900 mhz rig , a 2m dedicated rig, a 220 mhz radio, an ft 857 for all hf and some other bands too. and on the top of the stack is a kenwood 742 with 2m, 440, and 1.2 ghz. so I can monitor several 2 m frequencies, and most any band I want.  I have 8 antennas on the truck, 4 on NMO mounts through the roof and 4 on the bed rails, including 2 screwdrivers.

Any how do it right the first time. run a nice pair of heavy wire to feed the radios, ( you could even cannibalize a set of jumper cables), well fused and all radios and antennas with a good ground where appropriate

. I even added a separate 12 volt ciggy lighter plug for charging the cell phone and such. I also like the 110v on the truck as if you need to run the laptop or a coffee pot or a soldering gun, you have 110 volts and don't need a special 12 volt converter for each device.

Figure it out, allow for expansion in the future and do it right.  I really enjoy operating mobile.
Logged
KF8SJ
Member

Posts: 14




Ignore
« Reply #14 on: March 26, 2013, 07:46:40 PM »

if you have to replace the battery:
1.  get the highest rated capacity that will fit in the battery holder. won't cost much more and will probably
     last a lot longer-currently have 6 years in an 01 silverado.
2.  check clearances and see if you have room for a dual post battery-side and top terminals.use whichever 
     set is not connected to the vehicle for your radio connections-simplifies things and gives a more
     secure connection.

     happy mobiling   73  jim studer kf8sj  aka jimthegoatman
     
Logged
Pages: [1] 2 3 Next   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!