Slow 3500 lb Electric Tongue Jack Wiring and Fuse Questions

[Crik Walker]

Hi folks, I just installed an electric tongue jack (used) and, yup, it's slower than molasses. This seems to be the chief complaint with these things.
I pigtailed it into the emergency brake away wiring as it's right there but now I'm thinking it should be connected to the house batteries instead? It draws 9 Amps so maybe it'll will have more "jam" w heavier guage wire/direct to the LiFePO4 batteries connection.
I see some come factory wired with a 7 pin male plug-in, the engine's alternator would be the best source by far but for leveling purposes I'd prefer the jack be independent from my truck.
Or....could you use both? I don't know much about electricity so I'm just throwing this out there. Both are 12V sources and I only need 9A DC but the jack seems to "fade" quickly, it's not uncommon for it to stop completely, I wait a bit and continue on. I've got 200Ahs and they are seldom below 80% SOC so I can't see my trailer source being an issue. My tongue weight is ~400 lbs.
It is a 2nd hand unit, so maybe it's best days are behind it, I dunno.
Baring the top end (*re expensive) units out there I'm hoping these entry level Jack's can perform adequately, as an example I've read excellent reviews on the Vevor brand units. Chinese cheap right there but will they last is the question. Thoughts?
Enjoy the day everyone.

 

[Kirk]

I pigtailed it into the emergency brake away wiring as it's right there but now I'm thinking it should be connected to the house batteries instead?

While the break-away wiring is powered by the RV battery, that is not the proper way to connect the jack. The break-away should come from the RV battery to the normally open break-away switch, then to the trailer brakes. The tongue jack should be wired directly to the RV battery. The towing umbilical cord also charges the RV battery, so when the jack is connected to the battery it can also be supported from the tow vehicle alternator.

I don't know much about electricity so I'm just throwing this out there.

I suggest that you get help from someone who does understand the RV electrical systems,

 

[Crik Walker]

Hey thanks Kirk, just because it's convenient doesn't make it right, right? These answers are greatly appreciated, I'll be running proper guage wiring to direct to the recently installed battery distribution blocks. The jack has an internal circuit breaker but I'll install an in-line 15A fuse for safe measure.
As for help? That's what these forums is for my friend, "Teach a man to fish" so to speak...I've learned lots by asking the question over the years, I'm grateful for all replies. That and I learned a long time ago that anything RV sales, service and most assuredly dealerships are a waste of trust, time and money.

 

[Chef Duane]

I put on one of these so no tapping into the trailer electricals. I carry sockets that fit it, the stabilizer jacks, and lug nuts. And Ryobi One+ 18v driver, 2 x 6v batteries and a charger.

 

[Crik Walker]

I wasn’t aware this style jack was compatible with the 3 bolt pattern typically found on travel trailers. I do know my Ryobi cordless 18V Impact gun has more than enough torque to crank most anything over. I’m a welder and I do like to play, it wouldn’t be too difficult to cut the crank handle back and center a nut into place, being careful it turns fairly true before you weld it. You could even cut threads into the top of the ACME screw, thread a nut on too flush then use a Center punch to damage the “just showing” threads. Welding is ALWAYS better but I might be a little bias here, lol.
My preferred choice is the electric jack tho, just easier all around.

 

[richclover]

I wasn’t aware this style jack was compatible with the 3 bolt pattern typically found on travel trailers. I do know my Ryobi cordless 18V Impact gun has more than enough torque to crank most anything over. I’m a welder and I do like to play, it wouldn’t be too difficult to cut the crank handle back and center a nut into place, being careful it turns fairly true before you weld it. You could even cut threads into the top of the ACME screw, thread a nut on too flush then use a Center punch to damage the “just showing” threads. Welding is ALWAYS better but I might be a little bias here, lol.
My preferred choice is the electric jack tho, just easier all around.

While you’re at it best lube that second hand jack. Is there a rubber cap on top covering the emergency manual crank? Start there.

 

[Crik Walker]

Yes, it has a pretty good quality rubber plug sealing the emergency crank spindle underneath. Unfortunately the hand crank was MIA when I bought the jack, buddy had no idea where it was.
This “driveshaft” stem looks to be ~ 1/2” square, it shanks thru a sealed plate, I can’t see the gear assembly and as such doesn’t appear to need lubricant at 1st glance.
But opportunity knocks here Rich, I can use an extension/socket combo w my cordless 1/2” impact to see just how “fast” this jack can operate. I will be extra cautious as I suspect everything’s plastic down there. I’ll follow up here next trip to the trailer, it’s ~3 hrs away in storage unfortunately….or fortunately according to the DW, she says I’d be putzing around all day, every day, she's probably right.

 

[Chef Duane]

I wasn’t aware this style jack was compatible with the 3 bolt pattern typically found on travel trailers. I do know my Ryobi cordless 18V Impact gun has more than enough torque to crank most anything over. I’m a welder and I do like to play, it wouldn’t be too difficult to cut the crank handle back and center a nut into place, being careful it turns fairly true before you weld it. You could even cut threads into the top of the ACME screw, thread a nut on too flush then use a Center punch to damage the “just showing” threads. Welding is ALWAYS better but I might be a little bias here, lol.
My preferred choice is the electric jack tho, just easier all around.

The one shown in my pic (Trailer Valet) is not the actual one I used. The one I installed does have the same 3 bolt pattern as my tongue. There various ones available on Amazon. All I had to do was use my floor jack to raise the tongue up and install the new one. I just like the convenience of having one tool (Ryobi) for use on the jack, stabilizers, and lug nuts.
Here's a better example:

Amazon.com

 

[Crik Walker]

Gezus that thing looks bullet proof, you've tweeked my interest here. There might be a gently used electric trailer jack for sale in Northern Alberta soon, lol.
I see two available on Amazon.ca: $130 & $150, and curiously they are 5000 lb, no 3500 lb options available.
I've got two manual Jack's welded onto the corners of my rear bumper, that rotate/lock 90° for traveling. I've often thought how easy it would be to remove their handles & weld a nut onto that driveshaft.
Well, I think I'll use the impact on the electric jack and if it proves satisfactory I'll definitely modify those corner Jack's to operate the same way.
Sure do appreciate your follow-up Chef Duane, this forum remains the domain of dandy ideas.
Stay well eh.

 

[Kirk]

The jack has an internal circuit breaker but I'll install an in-line 15A fuse for safe measure.

As a retired electromechanical tec. I would agree with that choice. I'd put the fuse very near to the supply end of the wire to prevent any issue such as abrasions of the wire itself. I would use 14AGW wire. It should be pretty simple to run as your jack uses a chassis ground for the return, via it's mounting bolts. I would use some star washers on the three bolts just to insure a good electrical connection.

 

[Crik Walker]

Good afternoon Kirk, yer input brings this greenhorn peace of mind, thx for this. I'm realizing just now how, what's the word, crappy, some of my electrical upgrades/installs have been/still are these past 4 years.
Fuses - I have conveniently ignored 'em till now, sorry to say.
Proper sized fuses are now in my 200W solar set-up. I'll be bolting 150A fuses to the + posts on both LiFePO4 batteries next trip out. My 2000W Inverter now has a 150A circuit breaker ~2' in-line on the + lead wired to the Auto Transfer switch.
I do have questions here, I just added a 2nd LiFePO4 100Ah battery (#2) in parallel. To connect both to the solar controller "YouTube" shows I connect the + lead from solar controller to battery #1+, & its -- lead to #2 battery --.
If correct, can I leave solar charging in place while on "shore power"? My generator powers the PD- 9345: so 45A.

 

[Kirk]

My 2000W Inverter now has a 150A circuit breaker

The current from the 12V side is 2000W divided by 12V = 166.66A.
The current out on the 120V side is 2000W divided by 120V = 16.66A.
When you fuse a power supply you should choose a fuse that is about 125% of expected current flow or 200A for the DC side and 20A for the 120V side.

 

[Crik Walker]

I think I understand how you determine the proper size fuse now, thx. I'm under by quite a bit on the DC side and, whoops, there's no fuse on the 120V out. I've just plugged a heavy guage extension cord into the Inverter and hard wired it into the "shore power" side of the transfer switch. I don't think there is an option to hardwire an "out" on this unit but I'll take a look.

 

[CharlesinGA]

I looked up a whole bunch of installation instructions for different electric tongue jacks. They are sorely lacking in reference to fuse size or wire size. I believe this is because on a new one they provide a long enough wire and inline fuse holder and fuse so they expect you to use what they supply.

I did find one that calls out a 30 amp slow blow fuse, another one called out 12 gauge wire, another one called out a 20 amp fuse, thats from five or six different sets of instructions for Lippert, Buyers brand, Stromberg Carlson, Barker and a couple of others.

I would suggest at least 12 gauge, and better yet, 10 gauge wire from the battery with an inline fuse close to the battery. 20 amp and if it blows, a 30 and see how that works.

These jacks work rather hard. In many cases they are being used to lift not only the trailer tongue, but the rear end of the tow vehicle when they are hitched together, to enable fitting the weight distribution bars of a weight distribution hitch. This is a common procedure included in most WDH instructions.

 

[Crik Walker]

This - bought used - jack is a 3500 lb Motomaster: model # 040-9619-0. No mention of Amps draw in the specs but it does have this, “Under heavy use the Internal Circuit Breaker may open, causing the motor to stop. Wait 15 seconds for the breaker to reset”.
I’ve yet to see this, it just slows to a stop - I’ve never run it to that point…no point & something might break.
When I rewire the jack next week CORRECTLY (thx RV Forum, you know who you are) I’ll use the clamp meter to see what she draws and post the results. Not considering a fuse at this time.
If it remains slow tho I’m gonna use the Impact gun to explore its “safe” operating speed & go from there.

 

[CharlesinGA]

User manual for the Motomaster tongue jack.

I would use a inline fuse holder, If the wire rubs thru on the frame or other similar short, you want a fuse to blow, rather than sparks and fire.

 

[Crik Walker]

Ubet, better to be safe than sorry. I'm going to wrap the wires & such a wire loom to protect against that, the weather etc. Good point.

 

[gwinger]

Yes, it has a pretty good quality rubber plug sealing the emergency crank spindle underneath. Unfortunately the hand crank was MIA when I bought the jack, buddy had no idea where it was.
This “driveshaft” stem looks to be ~ 1/2” square, it shanks thru a sealed plate, I can’t see the gear assembly and as such doesn’t appear to need lubricant at 1st glance.
But opportunity knocks here Rich, I can use an extension/socket combo w my cordless 1/2” impact to see just how “fast” this jack can operate. I will be extra cautious as I suspect everything’s plastic down there. I’ll follow up here next trip to the trailer, it’s ~3 hrs away in storage unfortunately….or fortunately according to the DW, she says I’d be putzing around all day, every day, she's probably right.

DO NOT use an impact. The hammering action will destroy the gears.
Same with the stabilizers if you have manual ones.

 

[Crik Walker]

K, good catch there as this makes sense, it's an entry level jack after all. I'll use a Milwaukee 3/8" cordless drill instead, see how it goes.

 

[gwinger]

K, good catch there as this makes sense, it's an entry level jack after all. I'll use a Milwaukee 3/8" cordless drill instead, see how it goes.

If your drill has high and low speeds, use the low speed. Less RPM, higher torque.