Trailer Lights

[limitout]

Re: Trailer Lights

The amount and placement of yellow side lights depend on the length of trailer. Four yellow side lights on that trailer is not required. Two at most.One at the center on each side.Trailers over 80inches wide need the three lights (red) in the rear.
As said above, the law of the day is if there on there they technically must work.

that reminds me, I had an under 80" trailer and decided to put the lights up high on the guide posts. well to keep them clear I used the dog ear light brackets so they hung outside the poles so as not to hit the boat when driving on. lomng story short was I never realized by doing that I had made the trailer "over 80" and now required the extra lights in the middle.

just goes to show even if you are under 80 by law its not a bad idea to meet the over 80 regs because extra safety never hurts and if you change anything or lets say your kayak hangs out the boat, you might get a ticket for over 80" without the correct lights.

also I believe in overkill when it comes to safety so I put 4 marker lights, the 3 rear middle lights and tail lights but kept blowing fuses overloading my trucks wiring so I nixed the extra marker lights.

just be sure your wiring doesn't get over heated and it can handle it if you light it up like Christmas, but as long as you go with all LEDs now, I don't think that would be a problem anymore.

 

[bruceb58]

Re: Trailer Lights

DON'T use those blue plastic crimp connectors unless you just enjoy repairing trailer light problems. Those crimp connector should be outlawed!

If you are referring to these they aren't crimp connectors, they are called splice connectors. crimp connectors are fine to use.

 

[jayhanig]

Re: Trailer Lights

also I believe in overkill when it comes to safety so I put 4 marker lights, the 3 rear middle lights and tail lights but kept blowing fuses overloading my trucks wiring so I nixed the extra marker lights.

just be sure your wiring doesn't get over heated and it can handle it if you light it up like Christmas, but as long as you go with all LEDs now, I don't think that would be a problem anymore.

LEDs are definitely the way to go when it comes to lighting something up without paying for the privilege, energy wise. For the wattage of a single incandescent bulb, you can run lots of LEDs. They'll last longer too.

 

[bruceb58]

Re: Trailer Lights

just be sure your wiring doesn't get over heated and it can handle it if you light it up like Christmas

You could use 16ga wire and you could never have a problem even with regular incandescent lights. The wire would never overheat.

 

[limitout]

Re: Trailer Lights

You could use 16ga wire and you could never have a problem even with regular incandescent lights. The wire would never overheat.

it was the truck wiring that was overheating not the trailer, the trailer was fine and it was wired with all 16 guage wire

my truck did not have the towing package so it did not have the heavy duty rear wiring harness to the tail lights.

the power draw adds up very quickly when you add up 4 side marker lights (2 each side), two tail lights with built in side marker lights, and the 3 light center trailer light, all in the old standard bulb style lights. that's a lot of amps its drawing

 

[bruceb58]

Re: Trailer Lights

the power draw adds up very quickly when you add up 4 side marker lights (2 each side), two tail lights with built in side marker lights, and the 3 light center trailer light, all in the old standard bulb style lights. that's a lot of amps its drawing

Do the Math! 3W per bulb. 11 bulbs. 33 Watts. That's less than 3 Amps.

 

[limitout]

Re: Trailer Lights

Do the Math! 3W per bulb. 11 bulbs. 33 Watts. That's less than 3 Amps.

now that you read the package on the light bulb, tell us what happens to voltages and amperages over a long distance run through a small guage wire?

 

[bruceb58]

Re: Trailer Lights

now that you read the package on the light bulb, tell us what happens to voltages and amperages over a long distance run through a small guage wire?

Yes...they both drop. There isn't a problem so quit making believe there is one. If you are putting 10A or less through a 16 ga wire you won't even feel it getting warm. 1W per foot would require over 15A of current which you would never get with trailer lights unless you wanted to make it look like a Christmas tree.

 

[limitout]

Re: Trailer Lights

Yes...they both drop. There isn't a problem so quit making believe there is one. If you are putting 10A or less through a 16 ga wire you won't even feel it getting warm. 1W per foot would require over 15A of current which you would never get with trailer lights unless you wanted to make it look like a Christmas tree.

good guess but that's wrong, only the voltage drops over a long run of wire.

when voltages drop amperages will double or can even triple in the right situation.

I have over 35 years working with electricity

 

[oldjeep]

Re: Trailer Lights

good guess but that's wrong, only the voltage drops over a long run of wire.

when voltages drop amperages will double or can even triple in the right situation.

I have over 35 years working with electricity

OK - so now you have 6 -9 amps if it doubles or triples. Still fine

 

[bruceb58]

Re: Trailer Lights

when voltages drop amperages will double or can even triple in the right situation.

Not with a light bulb...if voltage drops, the current drops. I am an electrical engineer.

 

[limitout]

Re: Trailer Lights

Not with a light bulb...if voltage drops, the current drops. I am an electrical engineer.

ok i'll give you that

now that you read the package on the light bulb, tell us what happens to voltages and amperages over a long distance run through a small guage wire?

I was wrong about this and sorry for giving you attitude

good guess but that's wrong, only the voltage drops over a long run of wire.

when voltages drop amperages will double or can even triple in the right situation.

I have over 35 years working with electricity

again I was wrong about this and sorry for giving you attitude again

coming from a background of working almost exclusively with motorized loads, the rules of thumb I learned and used over 35 years are what I go by and I wrongly tried to apply them where they did not apply.

 

[bruceb58]

Re: Trailer Lights

now tell me every dual voltage motor ever made that only uses one set of windings is not possible to exist

We aren't talking about motors. We are talking about lights.

 

[limitout]

Re: Trailer Lights

any single phase load weather it is a light bulb or a motor or a resistance heater is going to be the same as far as the resulting amperage increase because you reduced voltages. now there are big differences in how well different types of loads can handle increased amps but we are just talking about the amp draw here.

the formula works the same for any type of load, electricity doesn't know or care about what type of load it is running.

I have been wiring dual voltage motors and dual voltage resistance heaters and dual voltage lighting all my working life and the formula for amps/volts never changes, when you reduce the voltage your amp draw always goes up by an equal percentage.

anyway we have derailed this thread enough with you disputing basic electrical formulas, there are pages full of this info all over the internet if you look for it, give it a read sometime when you want to learn about all of this stuff

 

[bruceb58]

Re: Trailer Lights

Get a light bulb. Put a resistor in front of it to simulate a drop in the wire and measure the resulting current. You will get your answer.

Or connect a battery to a light bulb and put a current meter inline. As the battery discharges, the current will go down as the battery discharges. Trust me, it won't go up.

You can say the earth is flat over and over but it still won't make it flat.

 

[limitout]

Re: Trailer Lights

Get a light bulb. Put a resistor in front of it to simulate a drop in the wire and measure the resulting current. You will get your answer.

ok, you proved your point, I guess I was stuck thinking about it the wrong way

 

[bruceb58]

Re: Trailer Lights

So, normally I wouldn't do this but since you are such a nice guy(sarcasm), I set up a little demo.

Picture #1. 12v battery connected to bulb through my multimeter measuring current

Picture #2 Dropping resistor 1.25 ohms( 2 each 2.5 ohm power resistors in parallel)

Picture #3. Resulting current after voltage drop


1.74A * 1.25 Ohms = 2.2V drop

Current dropped from 1.97A to 1.76A

Send your letter to General Electric right away. :facepalm:

 

[04fxdwgi]

Re: Trailer Lights

Let me chime in on this.

1st: #16 gauge wire is "rated" at 10 amps.

2nd: In the short runs on a trailer, usually less than 30 feet, the #16 will still pass 10 amps with no problems due to minimal added resistance

3rd: On long runs, the resistance of the wire will add up, causing an increase in resistance in the circuit, causing a reduced voltage available at the load end if the circuit. This is known as "Line Drop" in the electrical world.

4th: Bulb has a fixed resistance to generate rated wattage value when design volts are applied across the fixed resistance to create rated amperage (current flow). With a constant supply voltage for 12 VDC, the circuit will "drop" the entire 12 volts across the entire circuit, which produces your amps. (amps x ohms = Volts). If it didn't drop the entire voltage, that is called a "short circuit".

5th: Add the resistance of a long run / bad connection to the fixed bulb resistance, you still "drop" 12 volts across the circuit, by dropping the available voltage across the added resistance plus the fixed bulb resistance.

6th: Where as the 12 VDC is constant, each resistance drops an amount of voltage proportional to it's resistance, the amount of voltage available to the bulb drops accordingly (refer to step 4 formula).

7th: If you have a fixed 12 VDC and fixed bulb resistance, you will have rated current flow. Now, if you add more ohms of resistance in series, you will have same current flow but reduced voltage available to the bulb, causing a very dim light bulb because you have effectively "dropped" the amount of voltage available to the bulb for it to produce the rated output of current flow to heat the filament to produce the rated "Wattage" of the bulb..

8th: Since the voltage is assumed fixed and the bulb resistance is fixed the amps will be fixed. Change any one of those values and the amps will change. PERIOD. Or, if the voltage increases or resistance decreases, the amps will increase. Voltage remains the same and resistance increases, then amperage decreases, causing dim bulb.

If any values are fixed, and one changes, the other will automatically change in proportion.

I = E/R or Current = Voltage / Resistance
E = I*R or Voltage = Current * Resistance
R = V/E or Resistance = Voltage / Current


Perhaps we should consider this post closed, where as arguing Ohms Law in a "Trailer Forum Post" is kind of rediculous. I'm as guilty as the next guy on this one and won't post on this again.

 

[UncleWillie]

Re: Trailer Lights

04 and Bruce have it correct.
The bulb is a more or less fixed Resistant load.
The Current will decrease with decreasing Voltage.

If the current went UP as the Voltage went Down, the Power (Watts) would remain more or less constant and the bulb would not Dim out as the voltage dropped. Doesn't happen!

If the load were inductive, like say, a motor, the current would increase when the induction decreased as the motor slowed down.

To be 100% accurate; the resistance of lamp filaments does decrease as the bulb dims and the temperature of the filament decreases.
So while the Voltage decreases, the Current also decreases, but not in direct proportion to the voltage.
Think of an incandescent lamp as a Positive Temperature Dependent Resistor. (Thermistor)

This is an educational forum so as long as the arguments are directed at the topic and Not the Individuals, keep it going.

 

[bruceb58]

Re: Trailer Lights

To be 100% accurate; the resistance of lamp filaments does decrease as the bulb dims and the temperature of the filament decreases.
So while the Voltage decreases, the Current also decreases, but not in direct proportion to the voltage.
Think of an incandescent lamp as a Positive Temperature Dependent Resistor. (Thermistor)

Totally agree.