Wiring - Charging

[IamJEEP]

I researched a bit online and according to a couple of RV forums, 12g wire at 10amps of charge is all you need for a trailer battery. So I would say you can use the trailer 7 wire to charge you trailer battery with no issues.

Sal, I agree that a deep cycle would be the ideal battery here. Trickle charge is the way to go, but I think you would need a battery monitor to stop charging when full.

[Sal-XK]

I always go back and read this when I talk about this kind of stuff or I'm planning any work with electricity. It always jars the cobwebs loose.
Ohm's Law Defined

Ohm's Law defines the relationships between (P) power, (E) voltage, (I) current, and (R) resistance. One ohm is the resistance value through which one volt will maintain a current of one ampere.
( I ) Current is what flows on a wire or conductor. Current is measured in (A) amperes or amps.

( E ) Voltage is the difference in electrical potential between two points in a circuit. It's the push or pressure behind current flow through a circuit, and is measured in (V) volts.

( R ) Resistance determines how much current will flow through a component. Resistors are used to control voltage and current levels. The higher the resistance, the smaller the amount of current is allowed to flow. Resistance is measured in ohms.

( P ) Power is the amount of current times the voltage level at a given point measured in wattage or watts.

V = I x R
I = V / R
R = V / I

[cico7]

What i ended up doing is getting a heavy plug with lighter type attachmentl. Ran 10ga wire
to the front, followed the existing wiring harness. I add this plug. This is a low draw system,
not starting or trying to fast charge the battery.

Right now, this is my wifes old battery. I will replace with 2 storage type batteries.

[Sal-XK]

I researched a bit online and according to a couple of RV forums, 12g wire at 10amps of charge is all you need for a trailer battery. So I would say you can use the trailer 7 wire to charge you trailer battery with no issues.

Sal, I agree that a deep cycle would be the ideal battery here. Trickle charge is the way to go, but I think you would need a battery monitor to stop charging when full.

I think a proper battery charger would be the way to go to protect the trailer battery. That should work both ways protecting the starting battery as well and you can skip the isolator then as well.

[cico7]

I think a proper battery charger would be the way to go to protect the trailer battery. That should work both ways protecting the starting battery as well and you can skip the isolator then as well.

The regulator will keep it from over charging and I can disconnect the charging wire if I
think it will be an extended time period. But it would put out a higher rate of charge.
The charger idea is good, but can you find a battery charger that runs off a battery?

I am enjoying this discussion and everyone's input on this.
Beauty rest is in great need. Great Great need at this point.
So I must retire for the evening.

Hoaxci5, IamJeep, Sal, thank you very much. I will continue tomorrow.

[IamJEEP]

WAKE UP!!!!!!!!!!!!!

Morning all, I could'nt stay up any longer so I crashed for the night.

I read somewhere (too many sites to remember) there is a battery tender that runs off of the vehicle battery and switches off with the ignition. So, it only charges when the vehicle is turned on (or keyed on). I think it was like $110 or so and had all the fetures you would need. I'll look for it today during lunch.

[IamJEEP]

Question:

Hi, Have converted from 4 pin to 7 and everything is working fine. Question is, is all I need is #10 wire and inline circuit breaker? Do I have to do anything at the fuse block on the Fj? and Will the in-line circuit breaker prevent my truck battery from being run down? or do I need something to prevent drainage?

asked by: dana



Expert Reply:

You have it figured out. You will need an appropriate length of 10 Gauge Wire, item # 10-1-1, and a 40 amp circuit breaker, item # PK54540, to provide 12 volt power to the trailer connector at the rear of your FJ. This will provide a maintenance charge to the trailer battery while towing the trailer. You will not need to make any changes at the fuse block on your vehicle. The 12 Volt power wire connects to the number 4 position inside your 7-way connector, see the photo in the trailer wiring diagrams FAQ linked here.

The power wire is connected from the trailer connector to the Auxilliary side of the circuit breaker and from the Battery side of the circuit breaker to the positive terminal of the vehicle battery. You should remove the ground cable from the vehicle battery before connecting the power wire from the circuit breaker.

The inline circuit breaker will protect the vehicle and trailer from any type of short circuit or power surge that may occur, but will not isolate the battery from the trailer connection when the the trailer is connected to the vehicle. Most people simply unplug the trailer from the back of the vehicle when they get to their camping destination, to keep the vehicle battery from being discharged.

We do offer the Tow Ready Battery Isolation Solenoid, item # TR118665, which will shut down the connection from the vehicle battery to the trailer connector when the vehicle ignition is off. It would be a good idea to install the battery isolator if you plan to leave the trailer connected to the vehicle for extended periods, when the vehicle is not running. The isolator also installs inline with the power wire to the trailer connector. You will need a switched ignition source to attach to the 12 volt source on the isolator and the isolator needs to be mounted to the vehicle chassis for a ground connection.

expert reply by: Bob G

I quoted eTrailer.com here 'cause I thought this would help. Just ignore the fact that they are talking about an FJ, LOL...

PS: If I've violated any rules by doing this, please advise and I'll delete.