i've done some searching but i'm still unsure.
i just recently bought a new power tongue jack for my 7x14 enclosed tool trailer because the old hand crank one is getting pretty tough to turn. or "i'm just getting lazy"
anyway, i have an extra 7 pin trailer plug end. so can i wire that up from the power jack to get my power from the truck plug end?
i'm guessing use the #4 pin if so, is that correct?

or, will i need to run a wire back from the battery with a connector of some sort? thanks for any input in advance..

 

How much power does that jack pull?

 

IF your truck has the power wire in the plug for use to charge an RV battery lets say, hen there is an adaptor made that you plug into THAT connector on the truck and it provides 12volts and ground right there, and is plenty to run that electric jack.

 

You need to find this out.. Becarefull. There is a fuse to protect that + wire in the 7 connector but that is for charging batteries, Not for running 30 amp jack.. I think the + wire is 16 gauge.

 

thanks guys for the help, i looked in the paper that came with it but that's only mounting instructions. it also has an inline fuse that can be added in with it, that's 30a 250v . i think it says 4mm on thr fuse wire.
i also looked at the #'s on the wire from the motor and it has a # of "bvr ho74-r 450/750v "

i don't no if that helps any or not. i'll try to look back on the site i bought it from.
thanks again.

 

What jack do you have?

Steve

 

this one.

http://www.ebay.com/itm/3500-lbs-Electric-Power-Tongue-Jack-RV-Boat-Jet-Ski-A-Frame-Trailer-Camper-12V/310745583609?_trksid=p2045573.m2042&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D27%26meid%3D1943034169488108349%26pid%3D100033%26prg%3D1011%26rk%3D1%26rkt%3D4%26sd%3D310745583609%26

 

My thought, if you are actually worried about amp draw is to fuse it with a smaller fuse and see if blows. I have had several of that model in the past and I never ran an amp draw on it, but I would be surprised if it draws more than about 15 amps once it starts. Most of the RV motors take a momentary leap and then drop back like any electric motor. In the end, the worse thing that will happen is a blown fuse.

Another options, provided you have a jump box is to run the jack off that. Just ground to the trailer frame and hot to the motor lead.

I agree with you regarding using a power jack. That is the first thing I add to any of our trailers.

Steve

 

Look and see if you have an "AWG" number such as 14 AWG or 14 SAE, etc on the wire...

There has to be a wattage or amperage listed in the specs that came with that jack.

 

ya, i think i'm going to just give it a try, good ideal on the lower amp fuse . i'll do that.

notta thing on either, checked and double checked.

 

RV's use the Battery from the coach to run the jacks.. They have a larger wire to support, 10/12gauge instead of a 20 foot 14/16 gauge wire running to the truck battery

Dad had a 7 pin fire in the garage, luckily he went into the garage for something and noticed the smoke.. The 7 way had a + chaffed wire touching the ground. It was also fused, That didn't matter. The fire happened and i had to replace all the wires in the back of the truck. That is why i said. "becareful" Giving electrical advice can be scary.. Advise can be miss understood , Houses/Garages/vehicles can be expensive

 

Good advice! Know what you are doing. Don't work "over your head" and understand what you are doing or research it before doing it.

The thing about batteries, wire sizing, and all that stuff is the amp draw is empirical. I always want to know what it is. Some of the motors draw 2 or more times their running amps on start up, but if you do not have your meter set on "hold" it happens so fast you will never know it. I think the most important issue in deciding which path to take is what the jack motor actually draws.

Whenever I am working with an unknown draw, I use my jump box and I always use a fuse in the line no matter how familiar I am with the system. In this particular case, it seems to me the simplest course would be to use a jump box and that takes care of all the other issues.

And perhaps sounding like a broken record I say this so often on FTE, amp draw, not voltage is the crucial number in most situations concerning anything towable. If you do not have a meter and know how to read amp draw, leave it alone!!

Steve

 

thanks everyone, i'm going to send an email to the company and see if i can get some more info. i was hoping for the ease of ,plug in power...raise or lower jack... unplug... plug in lights.... roll on.

 

I think what you have is an Ultra Fab, although not the current model. I used to see them around a good bit, but almost never now. Isn't it fused at 25 amp with 10 ga. wire? If I was working where a unit had one, I would run it up and take am amp draw, but none in sight at present.

Here is your question as answered on the etrailer's website. Different jack, but same issue and approximate amp draw.

"Power Source For Electric Trailer Jack

Question:
How is the Jacks power. provided? Can it be powered through the power plug on the tow vehicle? If not is sufficient cabling provided for inside 12 V battery?
asked by: Willard R

<input name="question" id="question" type="hidden" value="How is the Jacks power. provided? Can it be powered through the power plug on the tow vehicle? If not is sufficient cabling provided for inside 12 V battery? ">
Expert Reply:
The Husky Brute Electric Trailer Jack, part # HT87247 uses a 12 volt system. The jack will perform better by drawing power from a nearby source rather than through the 7-way wiring harness.

I would recommend you use a trailer mounted battery if possible.This jack has a 4500 lb weight capacity and has a 25 amp draw on a normal rated load.

If you prefer to use your vehicle power, this can be done by splicing into the trailer harness wiring. I have attached a photo that shows the position of the 12 volt power pin on the 7-way connector. Make sure you connect the black wire from the jack to the wire coming from the 12 volt power wire pin on the connector. I have linked you to an installation video that shows wiring to the trailer harness that plugs into the vehicle."


Steve

 

thanks steve, i sent an email out earlier to them, i'll post there answer when i get it.
i should probably rethink this one. the 7 pin plug wasn't desinged for this.
i just didn't want to have to carry a jump pack or mount another battery.

also, it came with a 30 amp in line to wire in with installation.