Two questions...

[inthewoods]

I'm wondering two things about the 12v electrical systems

I've been planning to have my trailer 12v system isolated from the TVs 12v and the trailers running lights however I've heard about a few people who have setup the systems in such a way as to be able to turn on the side marker lights of the trailer from a switch and run them from the trailer's battery when the TV isn't even connected. What's the secret to this magic?

Also do I need to tie the trailer's battery / 12V system into the trailer frame? I see the trailer lighting is connected that way and I've seen a few 12v wiring diagrams on the forum showing that people have tied the trailer's battery system into the frame. Can anyone provide clarity on this?

Thanks,

Matt

[Hogdaddy]

What your wanting to do would be pretty easy actually. Just splice into the trailer wiring harness, white to ground on trailer battery, brown wire to switch,other side of switch to positive on trailer battery. that will do it ! you could even wire in a flasher on another switch & make them flash. If you leave your tow vehicle pluged in will turn those on also. As far as grounding the trailer thats not a good idea as it will only cause trouble down the road . I always run a dedicated ground to all my lights. Hope this helps & thanks for the idea, I'll do this to mine in the morning. Your trailer is looking real good I should add, Nice job!

[bobhenry]

What your wanting to do would be pretty easy actually. Just splice into the trailer wiring harness, white to ground on trailer battery, brown wire to switch,other side of switch to positive on trailer battery. that will do it ! you could even wire in a flasher on another switch & make them flash. If you leave your tow vehicle pluged in will turn those on also. As far as grounding the trailer thats not a good idea as it will only cause trouble down the road . I always run a dedicated ground to all my lights. Hope this helps & thanks for the idea, I'll do this to mine in the morning. Your trailer is looking real good I should add, Nice job!

This is the best lighting tip you will ever get.

90% of all lighting troubles are ground related.

I even apply a dedicated ground wire from tow vehicle to trailer so as not to have to rely on the tow ball for the only ground.

[bdosborn]

Why would you want to isolate your trailer 12V from the TV? It sure is nice to be able to charge your battery while you drive. A battery charge line also lets you turn your running lights on like this:



Bruce

[Corwin C]

I'm planning on putting a vehicle side trailer connection on the trailer with manual switches so I can #1 run the marker/backup/brake lights without the tow vehicle and #2 just to hold the trailer plug off the ground when it's not hooked up. When parking, simply unplug from TV and plug into Teardrop. Added advantage ... no possibility of accidentally back-feeding power to the TV.

[bdosborn]

Added advantage ... no possibility of accidentally back-feeding power to the TV.

Good point. I have a battery charge line and a battery separator on my trailer so I never have to unplug it from the TV. You need to unplug the trailer from the TV if you don't have a separator so you don't accidentally run the TV battery down when parked.

Bruce

[inthewoods]

This is all really great advice... Thank-you!!! Right now the trailer frame is acting as ground for all the running lights but I think I will add a dedicated ground wire at least up to the hitch.

Corwin - that's a great idea on adding a trailer side connector. I think I might do that. I also like the thought of storing the connector plugged in. I don't want to mess around with a battery isolator or things like that.

Right now I've just got a basic 4 pin trailer connection and wiring. No brakes on this trailer. May do that in the future but is not in the cards for right now.

[Dale M.]

What your wanting to do would be pretty easy actually. Just splice into the trailer wiring harness, white to ground on trailer battery, brown wire to switch,other side of switch to positive on trailer battery. that will do it ! you could even wire in a flasher on another switch & make them flash. If you leave your tow vehicle pluged in will turn those on also. As far as grounding the trailer thats not a good idea as it will only cause trouble down the road . I always run a dedicated ground to all my lights. Hope this helps & thanks for the idea, I'll do this to mine in the morning. Your trailer is looking real good I should add, Nice job!

Careful here.... NOT all trailer use four wire color codes..... White/Brown/Yellow/Green.... Be sure of your colors and function relationships before you start splicing into anything.....

Dale

[Shadow Catcher]

I do not have to unplug as the solar will charge the TV battery

[GerryS]

One thing to worry about, if you are charging your battery from your tow vehicle, you can run down the tow vehicle battery IF you leave it attached to the trailer, and the engine isn't running.

Something called a battery isolator a to protect you from this, if you chose not to use one, be sure to unplug the trailer if you will be parked for any length of time.

Bobhenry is dead on...grounding problems make up almost all of the problems when dealing with trailer lighting....

Be sure to use dielectric grease too...I put it on the bulb contacts and on the trailer plugs...everywhere electricity and moisture mix...corrosion makes up a big part of the other problems besides grounding issues.

-me

[bdosborn]

Something called a battery isolator a to protect you from this, if you chose not to use one, be sure to unplug the trailer if you will be parked for any length of time.

Battery isolators are usually diode based and have a forward bias voltage drop across them of about a volt. This voltage drop pretty much ensures your battery won't charge if there's any length of wire back to the trailer. Battery separators are usually relay based and don't have the volt drop of a isolator. It's a persnickity difference but an important one if the TV battery is in the trailer and not right at the engine alternator. 90% of TV battery charging issues seem to be due to voltage drop and a diode based isolators just makes it worse.

Bruce

[bdosborn]

I do not have to unplug as the solar will charge the TV battery

I must be more paranoid than you. I have two batteries in the truck with solar on the trailer and I would still unplug at night before I put the separator in. I just don't want to risk hearing that sickening click when you turn the ignition key and your battery is dead.

Bruce

[48Rob]

Bruce,

I have a separate battery on my truck that runs a 2000 watt inverter.
I have a dual battery isolator/separarator (?) that allows the alternator to charge the secondary battery when the starting battery is full.
One of the cool features is a bypass switch that allows the secondary battery to start the truck when the starting battery dies.
On my Chevy...that is several times a year, whenever I let it sit for 3 days or more.
Second truck I've had that does that...
Anyway, when I hear that "dead battery" click, I just flip the switch and start it up.
Much better than battery cables!

Rob

[MtnDon]

The type that use a relay like this...

... are what we'll call a separator. Guaranteed to work with no charging loss as long as wire gauge is up to snuff. Simple to do an emergency start switch with. The isolators with a box that has cooling fins are the voltage lossy ones.

http://smile.amazon.com/gp/product/B002 ... UTF8&psc=1

[bdosborn]

Bruce,
I have a dual battery isolator/separarator (?) that allows the alternator to charge the secondary battery when the starting battery is full.

I can do a manual combine with my separator but I can only charge the battery, not start it. The wires to the truck battery are too small for starting current. But, I can start the generator and use the PD battery charger to pump around 30 amps back to the truck batteries. Or just use the solar panels if I'm not in a hurry.

I've had great luck with a Yandina separator. Super easy to install and it has Off/Auto/Combine mode.

http://yandina.com/c100InfoR3.htm

Going on 3 years and it's still works.

Bruce