What Voltage is your Trailer At?

[mmandley]

I am working on adding LED run way lights to Bestia. My idea was to have yellow in the front to the just behind the fenders, then it switches to red. This way its legal on the highway and would light the trailer up and also work as evening docking lights.

I got everything done and was ready to hook it up when i discovered the voltage on my trailer is 7.5V not 12 as i would expect.

I checked at several light locations and they are all 7.5

I have all LED lights on my trailer, i checked my truck and its putting out 12.5 to the hitch harness, and then in tongue when it changes from the 7 pin harness to the trailer harness its drops to 7.5. I don't see anything that can cause this drop.

With only 7.5V my lights don't work as intended. Kinda stumped what direction to go now.

[beat taco]

Don't led's have built in resistors to keep them from burning out? That's my thought.

[KSmith]

Never heard for a voltage drop like that on a boat trailer. Perhaps a badly corroded connection in the connector itself may cause a voltage drop. I would look real closely at the connectors and replace if I suspected one was bad and couldn't be salvaged.

[Boonejeepin]

At what point in the trailer wiring are you splicing in at?

Where is the first reading of the lower voltage?

[EarmarkMarine]

Mike,
There can be multiple causes.
Corroded or oxidized connections.
Wire gauge too small for the total draw.
Too many lights drawing down the voltage in respect to the wire gauge.
A shorted light or strand down the path that is bringing down the voltage.
The cause is absolutely measurable so you don't have to speculate.
So try the following.
Measure the voltage at various points.
Measure the voltage with and without a load.
Run jumpers around suspect areas.
Clean up the connectors, perhaps with hydrogen peroxide or do a serach?, and coat the disconnects with dielectric grease.
Upgrade the wire gauge and connections.
Convert to a Western Electric splice type, soldered and heatshrunk, getting rid of crimps.

David

[mmandley]

Mike,
There can be multiple causes.
Corroded or oxidized connections.
Wire gauge too small for the total draw.
Too many lights drawing down the voltage in respect to the wire gauge.
A shorted light or strand down the path that is bringing down the voltage.
The cause is absolutely measurable so you don't have to speculate.
So try the following.
Measure the voltage at various points.
Measure the voltage with and without a load.
Run jumpers around suspect areas.
Clean up the connectors, perhaps with hydrogen peroxide or do a serach?, and coat the disconnects with dielectric grease.
Upgrade the wire gauge and connections.
Convert to a Western Electric splice type, soldered and heatshrunk, getting rid of crimps.

David

Will look at these.

What i have seen so fare.
Everyhting is first brand new on the boat as its a 2013
The voltage drop looks to happen when the factory 7pin changes to a 5 pin, i also noticed what they have is the left side and the right side of the trailer run on seperate wire harneses. I can actually unplug just the right side lights or the left. These are both spliced at the 5pin to 7 pin.
Might be easier with a pic but im working today.

I tested the rear corner marker lights, the rear Tail lights and the front marker lights. Only thing i didnt test was the license plate light and the etched marker lights.

As for the LEDs i used they are 12v 300 LED strands, i can power the entire thing with a small hand held 9v battery. I dont think they are placing too much load compared to the normal lights.

What happens is if i unplug say a marker light, then plug my LEDs into the mix everything goes really DIM. I think this is due to the trailer only having 7.5V but im not positive.

So fare every connectory i have checked does have dielectric stuff to protect it from corrosion.
Wire guage too small, trailer wires are all 12-14 as fare as i can tell, the LEDs are 18-22 they are small.

[maxpower220]

LEDs pull very little power, that's why TVs use them and homes are going to them.

I don't understand your "factory" 5 pin to 7 pin.

My trailer has a 5 pin flat connector. I use an aftermarket Round to 5 pin adapter. That adapter was not from the factory. Is your?

[jstenger]

Sounds like it is a faulty 7 pin to 5 pin adapter. Try plugging the 5 pin harness from the trailer directly to a vehicle with a standard 4 pin and check voltages again.

[mmandley]

LEDs pull very little power, that's why TVs use them and homes are going to them.

I don't understand your "factory" 5 pin to 7 pin.

My trailer has a 5 pin flat connector. I use an aftermarket Round to 5 pin adapter. That adapter was not from the factory. Is your?

Yes part of the new options is to get a factory 7 pin plug, this is simply a extension to the 5 plug. The 5 plug is now inside the tongue just past the break away section.

After talking to a couple of the electricians at work they all seem to agree that i have a short in the trailer. The only part of the trailer thats spliced into the factory harness are the Etched lighting on the fenders i have.

I think ill unplug those, and recheck my Voltages. If everyhting is 12 again then i know my Eteched LEDs are bad. Not too worried about this as i bought new white LEDs for this area because the factory LED strip to too short, I get Moomb on one side and OOMBA on the other LOL.

[MLA]

I am working on adding LED run way lights to Bestia. My idea was to have yellow in the front to the just behind the fenders, then it switches to red. This way its legal on the highway and would light the trailer up and also work as evening docking lights.

I got everything done and was ready to hook it up when i discovered the voltage on my trailer is 7.5V not 12 as i would expect.

I checked at several light locations and they are all 7.5

I have all LED lights on my trailer, i checked my truck and its putting out 12.5 to the hitch harness, and then in tongue when it changes from the 7 pin harness to the trailer harness its drops to 7.5. I don't see anything that can cause this drop.

With only 7.5V my lights don't work as intended. Kinda stumped what direction to go now.

Too lazy to read all the replies, so sorry if this has been mentioned. With the trailer connected to the hitch and harness plugged up, connect your meters ground lead to the trailer and test the voltage on the truck side. If its low, you have a ground issue. If its same as before, then reverse the leads. meters ground lead on trucks chassis, then probe the trailer side and see what the voltage is. If its low, then the there is a problem in the connector.

[zabooda]

Check your voltage from the ground where you are reading 7.5 volts to the actual ground (truck chassis). Sounds like a floating grounding. It should be in your connector. If you have 12 volt on the hot then your probably have 4.5 volts on the negative which means you have no negative to ground but is back fed through the ground to another part of the ground circuit which is usually lights but not with LEDS so perhaps the backup device or license plate bulb. Bottom line: no solid ground to the vehicle.

[rsinger]

I think you need to sell the boat and trailer. Give me a call, I'm sure we can work something out.....

wtf, everything's new. I go with the floating ground issue. I got burned by that a couple of years ago. My meter ground connection just wasn't making a 100% connection to the trailer ground connection.

[mmandley]

It could be a floating ground but i am checking the + AND - of the wires going to the lights. Only reason i can think of a floating ground is if the trailer is actually grounding through the hitch on the truck.

I had the lights pluged into the truck but not the hitch

[rsinger]

It could be a floating ground but i am checking the + AND - of the wires going to the lights. Only reason i can think of a floating ground is if the trailer is actually grounding through the hitch on the truck.

I had the lights pluged into the truck but not the hitch


Someone can correct me if I'm wrong, but I think one of the connector leads pushes the ground through to the trailer. Then on the trailer end that same lead will eventually connect to the trailer frame, which is used as ground and one terminal of each light fixture connects there. So even with the hitch not connected the appropriate voltages should be found on the trailer.

http://i1203.photobucket.com/albums/bb397/rsingerwpg/7_pin_zps60749377.gif (http://s1203.photobucket.com/user/rsingerwpg/media/7_pin_zps60749377.gif.html)

[zabooda]

I'm thinking the connector's ground wire is either poor (high resistance) or non-existent and the hitch doesn't help either way. Running all LEDs there is very little current flow so any type of ground should work as there would be no voltage drop along the ground circuit. Those electrons are lazy and found an easier way back home than through the ground wire.

[mmandley]

Looked as this again last night after work, its been a hard week, sun and 75 almost every day and i get home so late i cant work on the trailer.

Last night i unhooked the burned out LEDS from the MOOMBA etching and still same low voltage. This morning im going to go in the tongue where all the wires split and start testing in there, see if i can fine the voltage drop point.

[EarmarkMarine]

Mike,
When testing the various points within the trailer circuits, use BOTH the vehicle ground (with a heavy jumper) and trailer ground as a reference.

David

[mmandley]

Update:

I worked on this yesterday and this is what i found out.
I have 12.3 volts from my truck plug.
I have 12.3 volts through the 7 pin to 5 pin adapter from Boat Mate
At the 5 pin it has 2 of each wire molded in,
2 Brown < running lights >
2 White <ground>
Several others for the tail and turns < not important >

Checked voltage out of that plug and everything was 7.5v

What i first did was unplug the License plate light as this is a 194 bulb not an LED BAM instantly my LEDS got real bright again. So i thought i found my problem. Checked my Voltage and it was now 9.5 up 2 volts from where i started.

I then started checking each light thinking i might have a shorted LED light. Each light has a small LED board inside.

Each time i disconnected a maker light my overall voltage increased .25
By the time i disconnected all my LED marker lights i gained 2.25v for a total of 11.7 V

Only thing connected was the tail lights, i disconnected them and had mt 12.3V

I reconnected each light and checking the voltage each time and it was a consistent drop so no big deal i guess.

And once i had everything done, i plugged the Etch Lighting LED bars in and they worked again. They were showing burned out but now they work.

IDK i talked to the Dealer and they are stumped as well. All i can think is this has something to do with the daisy chain effect of how the trailer is wired from the factory.

Unlike cars, nothing is home ran to the 12V source.

[EarmarkMarine]

Absolutely predictable as the wire and connector resistance becomes more of a loss issue with greater current draw.
If you do a dedicated circuit with its own disconnect and heavier wire gauge you can eliminate almost all of the voltage drop.

David

[mmandley]

Absolutely predictable as the wire and connector resistance becomes more of a loss issue with greater current draw.
If you do a dedicated circuit with its own disconnect and heavier wire gauge you can eliminate almost all of the voltage drop.

David

Yea i was thinking this might be the way i have to go with it. Run a line right up the inside of the trailer frame like the factory is, then tie it into the main hardness at the voltage source. I was just hopping this project would have been more plug and play not so much design an entire setup lol.

[MLA]

Where was the meter's ground lead connected though all that testing? Remember, voltage is 0 with out a ground path. Leave the meters ground lead off and touch the pos lead to the battery B+ and see what the meter reads. This is where the term "voltage = the difference in potential" comes in. I would focus more on the ground circuit then the B+ circuit. I think you will probably find something.

[parrothd]

Did you install the LEDs? Did you install them in series instead of parralle?

Sent from my Nexus 4 using Tapatalk 2

[rca]

You have any idea what gauge wire is used for the trailer wiring? Do they wire each light in series or parallel. Most of those LED circuits are probably constant voltage or constant current setups. I'm not sure what is most common in trailer wiring. You know that the wire acts as a resistor, so you can get pretty significant voltage drop over long distances for thinner wire.

[mmandley]

@MLA I used the trailer as a ground, and the wire ground, both read the same at each point. The meter readings where consistent any place i checked.

@parrothd I have been working on the LEDs i want to install. All the testing i wrote up today was how my trailer came optioned. I Should have measured the trailer before i touched it but i didn't. The last post is only the factory trailer wiring. Nothing has been changed or added as of this point. Trailer is a paralleled system + to + and - to -. LEDs only work in 1 direction, if you try to hook any of them up with + to - they just don't work.

@rca its the factory harness which i believe is 16 or 18

[rsinger]

Absolutely predictable as the wire and connector resistance becomes more of a loss issue with greater current draw.
If you do a dedicated circuit with its own disconnect and heavier wire gauge you can eliminate almost all of the voltage drop.

David

I can't disagree with David, but something just doesn't sit right with me. With only the factory lights on there still shouldn't be any noticeable voltage drop anywhere. You should be reading 12 volts right up to each trailer light.

This trailer is brand spankin new, and I'm assuming a boat mate which is irrelevant anyhow. But I'd check with the manufacturer as well as your dealer. I would assume whoever engineered the electrical aspect of the trailer would have guaged the wiring appropriately, so it's resistance would not impact the current and voltage to the lights. That's what the fuses are for.

I'm concerned if you're getting voltage drop through a connector or the wire itself. If there is a loose connection (maybe) or the wire itself is to small (highly unlikely), I'm worried about heat buildup by the bad connection.

A parallel that I would draw, this really happened. We had a heater plugged in, in our basement. The plug actually started smoking, it got so hot. Luckily enough I was there when this happened, and I yanked the cord as soon as I saw the smoke. I was amazed that the breaker didn't go, but looking at the heater end of the connector, I found that a number of the stranded wires were already broken causing all the current trying to go through the remaining good wires. In retrospect it didn't blow the breaker because it wasn't drawing 15 amps but it was trying to draw more than the remaining wires were capable of carrying. If I could have metered both sides of this connection, I'm positive there would have been a voltage drop similar to what you're seeing on the trailer.

[MLA]

@MLA I used the trailer as a ground, and the wire ground, both read the same at each point. The meter readings where consistent any place i checked.

@parrothd I have been working on the LEDs i want to install. All the testing i wrote up today was how my trailer came optioned. I Should have measured the trailer before i touched it but i didn't. The last post is only the factory trailer wiring. Nothing has been changed or added as of this point. Trailer is a paralleled system + to + and - to -. LEDs only work in 1 direction, if you try to hook any of them up with + to - they just don't work.

@rca its the factory harness which i believe is 16 or 18

I would go back to the point where you 1st recorded the low voltage and measure again, but this time, place the meter's ground lead on a ground point on the truck instead of the trailer.

[EarmarkMarine]

Think in terms of the length of the vehicle plus the length of the trailer plus the round about path. Double that for the collective B+ and ground. Then measure the current consumption with all trailer lights active. Consider the wire gauge along the way, which might also be inconsistent. Coinsider all the connections. Crimps can be serious sources of resistance. Again, with this data a substantial voltage drop doesn't surprise me. The higher the current draw (with all lights plus a few additions) will expose the limitations of both wire gauge and connection quality. A bad connection may not show up using the minimal current used in a multimeter to check resistance. Problems are exposed with a higher current draw and especially measuring voltage when the circuit is loaded. Measuring the voltage drop is the most effective method. You just have to use a little logic to narrow down the specific cause or location. It's very simple if we don't complicate it.

David

[rsinger]

It's very simple if we don't complicate it.

David

You kidding? We're 3 pages deep on this thread. I think we've complicated this, and a half.

You are right though. Stuff like this always ends being something simple.

[EarmarkMarine]

You kidding? We're 3 pages deep on this thread. I think we've complicated this, and a half.

You are right though. Stuff like this always ends being something simple.

Not kidding a bit. Just end the speculation and keep measuring voltage at various junctions with a multimeter. The conclusion will be easy enough. It may not be the most convenient news but the results will be inarguable.

David

[jstenger]

Mike

Just for comparison, I measured the voltage on my trailer. I had 12.4 V at the truck plug and 11.6 V to 12.2 V at various lights on the trailer. Trailer was not hooked to truck, so ground was completely through plug. Trailer is 2010 basic single axle Boatmate. All LED's except license plate.

Sent from my Droid Charge using Tapatalk 2

[mmandley]

Mike

Just for comparison, I measured the voltage on my trailer. I had 12.4 V at the truck plug and 11.6 V to 12.2 V at various lights on the trailer. Trailer was not hooked to truck, so ground was completely through plug. Trailer is 2010 basic single axle Boatmate. All LED's except license plate.

Sent from my Droid Charge using Tapatalk 2

Thanks for checking, im still working through this as i get time.

[zabooda]

Each element that you disconnect affects the voltage significantly considering the LED tail lights at the most takes 0.5 amps each. There should be no loading affect so you have a high resistance connection on the positive or negative that drops the voltage with an increase in current leaving the trailer with the remainder voltage. Basically, the voltage divider rule with the unknown high resistance connection being one leg and the boat lighting being the other.

http://circuits.solved-problems.com/482/voltage-divider-voltage-division-rule/

typical led tail light draw:
Amp Draw:
Tail light: 40 milliamps
Stop/Turn: 460 milliamps


Update:

I worked on this yesterday and this is what i found out.
I have 12.3 volts from my truck plug.
I have 12.3 volts through the 7 pin to 5 pin adapter from Boat Mate
At the 5 pin it has 2 of each wire molded in,
2 Brown < running lights >
2 White <ground>
Several others for the tail and turns < not important >

Checked voltage out of that plug and everything was 7.5v

What i first did was unplug the License plate light as this is a 194 bulb not an LED BAM instantly my LEDS got real bright again. So i thought i found my problem. Checked my Voltage and it was now 9.5 up 2 volts from where i started.

I then started checking each light thinking i might have a shorted LED light. Each light has a small LED board inside.

Each time i disconnected a maker light my overall voltage increased .25
By the time i disconnected all my LED marker lights i gained 2.25v for a total of 11.7 V

Only thing connected was the tail lights, i disconnected them and had mt 12.3V

I reconnected each light and checking the voltage each time and it was a consistent drop so no big deal i guess.

And once i had everything done, i plugged the Etch Lighting LED bars in and they worked again. They were showing burned out but now they work.

IDK i talked to the Dealer and they are stumped as well. All i can think is this has something to do with the daisy chain effect of how the trailer is wired from the factory.

Unlike cars, nothing is home ran to the 12V source.

[zabooda]

Out of curiosity, did you find the problem?

[mmandley]

No and the Dealer looked at it and basically said,

Its Bright now....

I just shook my head, :-(
Just like i took it in for the Check Engine Light no codes, nothing found on the computer
Told them about the way when we surf goofy the Dash GPS is 1.2 MPH off all the time, it shows 11.6 mph when we are really going 10.5. Nothing found, i was told the guy water tested and filled both sides and drove it and it worked fine. BS because i didn't even have the Goofy bag hooked up due to testing the gravity games. Was a big Dealer Let down to be honest.

Not sure what route to take, i will prolly do some more testing this week when its hooked tot he truck on the hitch. Only thing the dealer said that was encouraging is they think it could be a ground wire, a bad wire or something but since the trailer lights are bright its not high on the priority list at this time of the season...

[EarmarkMarine]

Mike,
I realize this is very thin....but, is there a difference between when the trailer is dry versus after it was recently splashed?

David

[parrothd]

Dump the dealer and take it to a trailer shop..

Sent from my Nexus 4 using Tapatalk 2

[zabooda]

As far as the GPS. Do you surf on a body of water that has a current. At those slow speeds it will make a difference.

[mmandley]

As far as the GPS. Do you surf on a body of water that has a current. At those slow speeds it will make a difference.

It does this in the Lake and River.
What i Did Monday on the river was just set it to RPM like i did in the 08 LSV, set it to 2900 RPM and it held just fine, i dont get why its reading off, in the River i would expect it too, on the Lake it shouldnt. IDK like i said still working through that one LOL.

Dave, Havn't tested it yet, im not done playing with it just backed off for the moment as May 18th i have a Dealer Event my boat is in and i dont want any issues before the event.

I still havnt called Boat Mate to check on their ideas but i will be after the event.

Right now all my focus has been getting my boards delivered, Soul Craft and now i got a Doomswell, getting my ballast figured out. Should be good this weekend, just got my Enzo sac in today. Will be on the Lake this weekend testing and hopfully have her all dialed in.

Only problem is i only have 1 enzo bag, they have been back ordered for some time and Wake Makers made sure i got one when they got them in.

[zabooda]

Find yourself a electrical tech or engineer as they enjoy tracing out circuits and after doing a lot of this stuff it takes very little time. If I was closer........