Forum Discussion

mt-ed's avatar
mt-ed
Explorer
May 27, 2021

Happijac question....

Greeting all,

I attempted to offload my camper for the first time yesterday.
I experienced something that concerned me.

While lowering all 4 jacks towards the ground, they stopped
before reaching the ground. I understand that this is normal
as a safety measure.

The peculiar event occurred once the jack feet made contact with
the ground. Not long after the 4 jacks were lifting the camper,
their rpm's slowed rapidly, to the point I thought they were'
going to stop! I had barely lifted the camper an inch or two!

I checked my batteries, and it indicated 12.8V. They had been on shore power (charging) for more than 48 hours, without any drain.
I suspect that the jacks run exclusively on RV house batteries,
based on the robust receiver and all of those fuses! None the less,
I also hooked my camper up to shore power, but can't say I noticed any
significant improvement in performance by doing so.

I ended up raising the camper one leg at a time, and even this
did not result in any significantly improved performance.

So, my question is, is this the same performance that other Happijac users have experienced? Has anyone found any methods to overcome
the experience that the jacks are going to die when a load is
applied to them? Is it not advised, although there is the option,
to raise the camper using all 4 jacks at once, but instead, activate them,one at a time?

Thanks in advance for any insights!!
Truck Campers
  • jimh406's avatar
    jimh406
    Explorer III
    May 27, 2021
    Yes, they run on house batteries. Did you loosen the tie downs? Otherwise, you were trying to lift the truck. I assume you disconnected the tie downs.

    One other thought, you could be near the maximum length of the jack. In that case, you might need to adjust the jack bracket or use a block to allow them to raise higher. I believe you said you had a flatbed, so you could be higher than a normal bed.
  • Johnny_G1's avatar
    Johnny_G1
    Explorer
    May 27, 2021
    From owning HappyJac's I found that they were the biggest piece of Junk on the market and the tubes do bend with very little force and being electric was even worst, back to hydraulic jacks was the best answer but more work, was sure happy when it was sold. No more truck camper's for me and I should say Momma??
  • mt-ed's avatar
    mt-ed
    Explorer
    May 27, 2021
    jimh425 wrote:
    Yes, they run on house batteries. Did you loosen the tie downs? Otherwise, you were trying to lift the truck. I assume you disconnected the tie downs.

    One other thought, you could be near the maximum length of the jack. In that case, you might need to adjust the jack bracket or use a block to allow them to raise higher. I believe you said you had a flatbed, so you could be higher than a normal bed.


    Yep, I did remember to disconnect all attachments to the truck, so I know that wasn't a contributing factor.

    Yes, it did seem the legs were quite extended because in addition to it being a flatbed, it is also 4X4 so it's really up there. I seem to recall the bed, unloaded, was about 40-41" high!

    It will be very interesting when I raise the camper to reload it! I'm curious to see if it will start off like a jackrabbit, and then slow to a tortoise pace as the legs become "over" extended? Thanks much!
  • Homeless_by_Cho's avatar
    Homeless_by_Cho
    Explorer
    May 27, 2021
    Happijac sells leg extenders that would solved the problem of being "over extended". They are 6" tall, bolt directly to the bottom of the existing jacks, and pricey but well made. You could easily make your own to whatever height would be appropriate for your application.

    Happijac leg extenders

    LeRoy
  • Avid_Fox's avatar
    Avid_Fox
    Explorer
    May 27, 2021
    You said unloaded "for the first time". We must assume they would stop at full extension, rather than slow down. I'm going to suggest some maintenance disassembly and grease on the internal screws might help. Maybe it's just pushing too much resistance in an area of the screws that didn't see much use prior to your tall truck.

    I've had HJs on my AF1150 for 6 years, and never had an issue if the batteries are charged.
  • HMS_Beagle's avatar
    HMS_Beagle
    Explorer
    May 27, 2021
    How heavy is the camper? How heavy is the wiring feeding the control board, and from there to the motors?

    My Happijacks slow down some when loaded, and I don't run all of them at once - too big a draw. One end up a few inches and then the other. It is lifting a 3500 lb camper in my case. They should do better with the higher voltage from shore power, that is why I ask about the wiring servicing them. First step in debugging that is to measure the voltage delivered at the jack.

    Happijacks come in two versions, an Acme screw and a ball screw. The ball screws turn easier but are much more susceptible to getting dirty or rusty. It looks like on their heaviest duty jacks they've gone back to an Acme screw.

    Mine, and the ones on the camper before this, had an overload clutch that makes a nasty ratcheting sound if overloaded, or if run into the end stop. You didn't hear that?
  • mt-ed's avatar
    mt-ed
    Explorer
    May 27, 2021
    Well, I'm a bit ashamed to have to admit this, but I assumed that with a new camper, the batteries would be fully charged. Not only were they not charged (6.3v) but I found out that the batteries were severely lacking battery fluid! One took 16oz. of distilled water, and the other took 20oz! I called my local battery supplier (ironically one that sells this same brand of batteries), and they told me the only way batteries could be this low in fluid is if they were overcharged and boiled dry, or they were very old. They then advised me how to find out when they were made. Their mfgr. date was Feb. 2016!

    No wonder the poor things couldn't raise the camper!!!!!

    Boy, I'm learning SO much having this new camper!!!!
  • TxGearhead's avatar
    TxGearhead
    Explorer II
    May 30, 2021
    You say it's a new camper. New to you, as in in previously owned, or brand new off the assembly line? If it is brand new I would get the dealer to replace those 2016 batteries.
    The Happi Jacs should have a section of red paint on the black section of the inner jack to warn you that it's near the end of the travel.

About Travel Trailer Group

44,029 PostsLatest Activity: Jan 20, 2025