Forum Discussion

Heavy_Metal_Doc's avatar
Heavy_Metal_Doc
Explorer
Aug 26, 2020

Tech info / advice on 5th wheel generator install

I attempted to search this topic every way I could think of and could not find any exact answers.....this might be a bit long and technical....here goes....

I have a new Jayco 5th wheel unit with a residential fridge which runs off of an inverter. As I understand it, it is essentially one 110V circuit which is wired separately from the rest of the unit and powered by the inverter so that the fridge stays powered off of the batteries at all times, regardless of outside power. The RV power panel keep the batteries topped off as long as there is shore power.

I am about to install a Cummins / Onan QG 5500 LP generator. I'm wondering if there are any changes for the inverter that should be considered (or just a good idea / improvement) while messing around with all the wiring. Or, simply "tee" in the generator between the shore power and the existing RV power panel and let the rest stay as it is?

I have seen Progressive Dynamics mentioned often as good power products for RV's (tell me if that's true or false), so I have found one of their transfer switches with built in surge protector I'm thinking of ordering for this setup.

I'm also a bit confused on the generator mounting. I know the older units in a 5th wheel front compartment required a heat-shield box to be built to surround the generator, seal to the compartment door, and only allow air to circulate in that space and out the open bottom. But then I see the info on this new generator says that it's fully enclosed and doesn't require extra shielding. I've seen pictures of new units with / without the heat shield. I a have also heard / read that the batteries need to be separated from the generator, which mine are in their own steel box vented out the bottom of that compartment. This also leads to another minor issue -- my unit has an auto-leveling system which the MFR has chosen to mount the "brain" of the system dead center in the top of the compartment where the generator will be mounted. I have measured things out and would JUST BARELY be able to reach past the generator to get to fuses / wiring on the that module in the even of a failure. (I'm a technical service guy, so I plan to work on things and try to make service / repair easier on myself). IF I have to fabricate a heat shield box around the genny, there's no way I'd reach around it to that module in an emergency breakdown situation. In this case, I'll move the module somewhere else - possibly move to one end of the compartment or else move it to the other side of the wall into the "basement" and build a protective cage over it so it doesn't get beat up by gear stored in there.
  • MrWizard's avatar
    MrWizard
    Moderator
    Aug 26, 2020
    You need to find out what is in the BRAIN
    If the leveling sensors are in there, then it needs to stay centered for best operation
  • time2roll's avatar
    time2roll
    Nomad
    Aug 26, 2020
    I thought most of these inverter/fridge installs had a transfer switch to power the fridge direct when 120vac is available. Post the inverter model number so we know.

    If the setup has just 2 batteries and you plan to do a lot of off-grid camping you may find 4 batteries it a bit easier to maintain charge.

    As for actual battery charging it would be best to post the converter or charging system model number to give realistic charging expectations. Of course if you are running the A/C from the generator 12+ hours a day the converter may not matter much.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Aug 26, 2020
    Progressive Dynamics makes excellent products. BUT for Surge Protection I recommend Progressive Industries HW-30/50C (30 for 30 amp rigs 50 for 50)

    If you have a good INVERTER generator you do not need surge guard on the generator side of life.. but you should have it when you are on shore power.

    There are two kinds of "Surge protection"
    The ATS with built in surge guard, at least evey one I've looked at offer only the first type ... Spike supression is what I call it. They clip high voltage "Spikes"

    The HW-50/30c do that as well but they do more
    1: When power is applied they hold off for a couple minutes (time optional on the PI-HW's or at least it was last I checked but set to LONG delay please) This means if power BLINKS (goes off and back on) air conditioners have time to bleed down so they restart normally not with a full head of pressure (Very hard on the compressor)

    They also monitor for low voltage (also hard on compressors) and over voltage.

    We often read of the poor sod who pluged into a 30 amp 240 volt outlet here in the forums.. if he'd had an HW-30 (or 50 with dogbone adapter) he'd not be so poor as the display would say "240 volts do not bypass".
  • JoeH's avatar
    JoeH
    Explorer III
    Aug 26, 2020
    I suggest you install heat shield/sound dampener material regardless if it is "needed". If boondocking, you'll appreciate the reduction in heat/noise while running the genset. Dynamat is one supplier of material and/or you can look at marine quality engine room insulation materials.
  • theoldwizard1's avatar
    theoldwizard1
    Explorer II
    Aug 26, 2020
    Heavy Metal Doctor wrote:
    I have a new Jayco 5th wheel unit with a residential fridge which runs off of an inverter. As I understand it, it is essentially one 110V circuit which is wired separately from the rest of the unit and powered by the inverter so that the fridge stays powered off of the batteries at all times, regardless of outside power.

    While possible, this seems very unlikely. You need to confirm this !


    Heavy Metal Doctor wrote:
    The RV power panel keep the batteries topped off as long as there is shore power.

    The DC power distribution panel is usually separate from "converter" (converters AC to DC to charge/maintain the batteries)

    Heavy Metal Doctor wrote:
    I am about to install a Cummins / Onan QG 5500 LP generator. I'm wondering if there are any changes for the inverter that should be considered (or just a good idea / improvement) while messing around with all the wiring. Or, simply "tee" in the generator between the shore power and the existing RV power panel and let the rest stay as it is?

    DO NOT JUST "TEE" IN ! This will put 120VAC on the power inlet plug on the side of the trailer !

    Heavy Metal Doctor wrote:
    I have seen Progressive Dynamics mentioned often as good power products for RV's (tell me if that's true or false), so I have found one of their transfer switches with built in surge protector I'm thinking of ordering for this setup.

    Their reputation is accurate !

    A more expensive, but much more convenient solution is to replace both your current converter and inverter with a combination inverter/charger/automatic transfer switch. Easy installation and even easier to use (everything is automatic, including optional generator start).
  • dougrainer's avatar
    dougrainer
    Nomad
    Aug 26, 2020
    Jayco just installs an INVERTER ONLY for the Residential refer installs. That Inverter has PASS THRU power. That means when you are connected to Shore or gen Power, the 120 volts goes thru the Inverter and the Inverter if ON, goes to stand by. When the 120 input is disconnected the Inverter then starts Inverting 120 power to the refer. There is nothing you have to do other than install the Genset and connect the wiring to the Genset. IF the Jayco is prewired for a Genset, the 120 wiring and the Transfer box should already be installed. I have NEVER seen the Leveling system control box on a Jayco installed in the Genset compartment. This must be something new Jayco is doing. They usually install the Control module in the first Storage compartment ceiling in the middle between the sides of the RV. I know people complained of that because when they needed to access the fuses and such, they had to remove all their storage items they stored in that large compartment. Doug
  • Heavy_Metal_Doc's avatar
    Heavy_Metal_Doc
    Explorer
    Aug 27, 2020
    Lots of good responses / things to consider!



    dougrainer wrote:
    Jayco just installs an INVERTER ONLY for the Residential refer installs. That Inverter has PASS THRU power. That means when you are connected to Shore or gen Power, the 120 volts goes thru the Inverter and the Inverter if ON, goes to stand by. When the 120 input is disconnected the Inverter then starts Inverting 120 power to the refer. There is nothing you have to do other than install the Genset and connect the wiring to the Genset. IF the Jayco is prewired for a Genset, the 120 wiring and the Transfer box should already be installed. I have NEVER seen the Leveling system control box on a Jayco installed in the Genset compartment. This must be something new Jayco is doing. They usually install the Control module in the first Storage compartment ceiling in the middle between the sides of the RV. I know people complained of that because when they needed to access the fuses and such, they had to remove all their storage items they stored in that large compartment. Doug


    Thanks for that info.
    I wasn't sure about the inverter having a/c power to pass through. It sounds like I'll just leave that alone.

    I do not think my unit is prepped for a generator, but I'm hoping to open up some access points and check out the wiring / components this weekend.

    The issue on the leveling unit position is actually something I read about when looking up info before ordering any parts / generator. A commenter in a similar discussion said he was stranded when an auto leveling malfunction occurred and acessing that unit was blocked by the generator. Im hoping to preempt that situation. I understand the unit must be level with the unit, but I doubt it matters where it gets mounted. If its ok to be at the very front end of the RV, then I doubt I would care if its moved to right or left end of that compartment. I was also thinking of of just fabricating the heat shield box so its easy to remove the top to reach past / above that area.
  • dougrainer's avatar
    dougrainer
    Nomad
    Aug 27, 2020
    If Jayco prepped, you will see a 4 by 4 metal electrical box in that Gen compartment that houses the 120 wires going to the Transfer box IF there is a Transfer box. If no electrical box, it is not prepped. What Year/Model are do you have? Doug
  • Heavy_Metal_Doc's avatar
    Heavy_Metal_Doc
    Explorer
    Aug 27, 2020
    dougrainer wrote:
    If Jayco prepped, you will see a 4 by 4 metal electrical box in that Gen compartment that houses the 120 wires going to the Transfer box IF there is a Transfer box. If no electrical box, it is not prepped. What Year/Model are do you have? Doug


    No metal junction box in the front compartment. 2019 Eagle 355MBQS.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,187 PostsLatest Activity: Jan 14, 2025