American Sand Association

I want to be able to charge the battery in my enclosed trailer with my M/H or pick up as I tow it down the highway. I use a seven prong plug right, that has two empty slots. Can someone line me up with the correct procedure for this. Do I need to install a "Trickle Charger" somehow? I would like to do this with 12V if I can. Thanks... Keith

Hummmm this is what you come up with at 1:30 am...
I have never tried this but it would work...

Put a 12 volt DC inverter at your battery,
(the inverter changes 12 vdc to 120 vac)
Put a switch so you can turn it off and on in your cab of truck or MH.
Hook line voltage to battery
Hook load voltage to small trickle charger
Run output of trickle charger to plug on your trailer; use at least #10 awg (voltage drop and all). If #10 doesnt fit into plug splice short piece of wire to plug.
In trailer run plug to battery run both + and - from charger all the way to back battery...
It should work, just fuse the output + of the charger as a precaution...
This system will work any time you turn switch on, but beware, if you leave switch on, your truck/MH battery will drain down completely! But I like it...

Good Luck,
Steve

OR, just run a FUSED 12v hot line to your plug and then another 12v hot line, FUSED, from the plug to your trailer batteries. (In newer tow vehicles, the trailer tow package should already includ a 12v hot wire. On the trailer side, the plug should already be wired to accept the 12v hot wire, if it was professionally manufactured.)

When driving, the tow vehicle's charging system will also charge the trailer batteries. When parked, the batteries will 'equalize', (both the trailer batteries and the tow vehicle batteries will trade their charge until both are equal, and then discharge at the same rate, but using both batteries like this effectively doubles you battery bank.) so be careful and disconnect your plug so the trailer doesn't drain your tow vehicle battery.

With this hook up, you can drive your tow vehicle around and return to camp, hook up your trailer plug to your tow vehicle and the batteries will 'equalize', which will bring up the trailer batteries charge. Just don't forget to unplug the trailer awhile later so you don't drain your engine start battery.

This is how most RV plugs are wired and works well. If you worry about draining your tow vehicle battery, you can always install an isolator or solenoid. If wired properly, this will allow the trailer batteries to only charge when the engine is running.

(The above statement is my own opinion and not that of the ASA's.)

Tim Wight
Mesa, AZ.

Ignorance and Apathy are just as dangerous as an environmentalist with a cause and a lawyer!

Edited by - azsandrider on 04/17/2002 11:11:51 PM

THANK YOU BOTH.... That is exactly what I wanted to know. My trailer is a brand new Carson Racer, with the seven way plug.The plug and wire is moulded together in one piece, but there is a junction box about 12" away.Carson did not send me a wiring diagram of the plug, I wonder if either of you could tell me which specific plug or color is normally assigned that charging wire?

Ya know graveyard shift is killin me.... but if I really put my mind to it, I bet I can come up with even better questions (lol)

Thanks again... Keith Hyde

Looking at your 7 point plug, the first prong on the right clockwise is your positive that will charge your trailers battery(s).

Check out your trailers electrical either by looking at the schematic, or simply follow the corresponding wire back to the battery.
If the wire is common with the trailer batteries + , then you're ok and the tow vehicle will do the work of charging your trailers battery, and your tow vehicles voltage reg will probably keep from over charging it too.

I'd bet a beer youre ok.

Make sure the first prong is energized or "hot".

Edited by - trailer park cassanova on 04/18/2002 5:49:06 PM

Believe me the dude that wired your MH probably didn't run a big enough wire for it to charge. A number 12awg will not do it. Basically Tim and TPS are totally correct, butthey will not charge when you are stopped, or maybe I just wanted to give you 'A Different' way of doing it. Plus you get a 110 outlet under your hood.

Hey it was 1:30 pm!





How come I feel like the big proud bull in the back of the pick-up truck, after loosing the finals of the state fair on the way to the slaughter house?
Right...........right
http://clubs.yahoo.com/clubs/glamisdunersforcleandunes

Steve is right, I re-wired my motorhome with 7 in 1 wire, using the 10 gauge wire as the 12v hot. I also suggest that you solder your conections and shrink wrap them. That way you will only have to do it once! (I hate crimp connectors as they will eventually fail or corrode)

DON'T FORGET THE FUSES!!!! Because, even if you do everything right, stuff happens!

(The above statement is my own opinion and not that of the ASA's.)

Tim Wight
Mesa, AZ.

Ignorance and Apathy are just as dangerous as an environmentalist with a cause and a lawyer!

Tim and Steve, On my pick up I have a 10ga wire in the center of the seven plug. It runs a Warn 2000 winch, that I have on my flat bed. The wire comes directly from the battery of my truck and goes through a 50amp fuse. If I use the center of the male plug on the trailer and run a 10ga wire to the battery, (FUSED of course), would that charge the trailer battery and would my truck alternator keep from overcharging the trailer battery? I could do the same on the Motor home, but it's 34ft or so, if the process I described above is correct, I could run 4 or 6ga wire from the M/H battery back to the plug?? OK, I guess that does it...
Waiting patiently for your replies......Keith

If possible, in order to prevent the trailer battery from overchargeing, you run a dome light (or equiv) continuously. The trick to deep cycle batteries is to charge them slowly and discharge them slowly.
Keeping a load on the battery while it's chargeing is the equiv of a slow charge.

If you can manage to not completely charge the battery thats a plus too. It leaves it room to operate and not cook.

If anyone still has the owners manual for your trailer, look at the battery maint instructions, and you'll see most the makers, Fleetwood, Skyline ect, recommend this for long battery life.