Cig lighter fuse capacity...

[DK327]

Why is the fuse rated at 15A if the cig lighter caps state 120W max @ 12V? That equals to a 10A fuse or am I missing something? If it's rated at 15A does that mean the cig lighter can handle 12V * 15A = 180W before blowing out? Thanks!

 

[jgue467]

The missing piece is that the fuse is for more than just the cig lighter, i believe it it will include the radio and other items. The lid to the fuse box tells what each fuse covers. :cowboy:

 

[TheDurk]

Why is the fuse rated at 15A if the cig lighter caps state 120W max @ 12V? That equals to a 10A fuse or am I missing something? If it's rated at 15A does that mean the cig lighter can handle 12V * 15A = 180W before blowing out? Thanks!

No, there is a fusible link built into the bottom of the lighter outlet, and that will blow before the fuse will. Not a good idea, because then you need a new outlet.

 

[DK327]

Thank you both! So I'm guessing it wouldn't be wise to connect a device that draws 10 amps @ 12V to the bottom cig lighter and have my CB radio hooked up to the top cig lighter at the same time... Would probably draw too much power and pop a fuse (if lucky) or worse...

 

[Frdmskr]

Never use the cig outlet for a CB. Wire it to the battery.


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[TXLX1]

Never use the cig outlet for a CB. Wire it to the battery.


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But why?

 

[Diezel]

Fuse rating vs Duty Cycle vs Wire Gauge. A fuse is nothing more than a thermal device. At a specific temperature, it will melt and fail. If you run a 10amp circuit with a 10 amp load, and a 10amp fuse. That fuse will fail at a certain amount of time, just due to a "normal" load. This is where duty cycle is observed and a circuit that would be capable of 15amp, will be down rated to x% of "duty".

A CB radio generally doesn't draw over 3amps. Some of the higher end models with more features can draw upwards of 5amp. Ham Radios, can draw significantly more amperage. "Best Practice" has always been to run any device installed in a vehicle to a fuse box "spare" terminal, or Directly to the battery with an inline fuse within 18" of the battery.

 

[scoobydew]

Mine is only on when key is on the (on) position or running weird to me or is this normal for toyota

 

[TheDurk]

Mine is only on when key is on the (on) position or running weird to me or is this normal for toyota

Normal.

 

[MyHigh]

My Midland portable 75-822 only comes with a pre-wired cig power supply. It works perfectly fine for me.

 

[UnderFire]

I'd recommend running a single 30A circuit with a relay if you're gonna be adding accesories, should hold up to anything you want to add to your interior and will make it cleaner if you do decide to add more down the road..

 

[jgue467]

Thank you both! So I'm guessing it wouldn't be wise to connect a device that draws 10 amps @ 12V to the bottom cig lighter and have my CB radio hooked up to the top cig lighter at the same time... Would probably draw too much power and pop a fuse (if lucky) or worse...

The cig lighter nearest the driver is on a different circuit (and fuse) then the two cig lighters nearest the passenger (also includes the cig lighter in right rear truck area). Crazy part is fuses locations: driver lighter fuse is inside on driver dash near left knee where as the other fuse is in engine compartment. Inside fuse is 10 and outside is 15 (may not be original), go figure!

 

[DK327]

The cig lighter nearest the driver is on a different circuit (and fuse) then the two cig lighters nearest the passenger (also includes the cig lighter in right rear truck area). Crazy part is fuses locations: driver lighter fuse is inside on driver dash near left knee where as the other fuse is in engine compartment. Inside fuse is 10 and outside is 15 (may not be original), go figure!

Thanks for that info! It'll definitely come in handy for future projects. For now I hooked it directly up to the battery pos terminal using a 12 gauge primary wire with a 15A inline fuse near the battery. Ground wire is also 12 gauge and is hooked up to the battery neg terminal. I'll keep the CB on cig lighter since it only draws 3A @ 12V.