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AnEv942's avatar
AnEv942
Nomad
Oct 08, 2019

Truck inverter to power camper fridge

Running fridge on AC from trucks inverter...
Not a how-to, certainly not a recommendation- cut every corner I could with a ton of round to-its.
Just what I concluded and installed...may or may not help anyone but another thread caused me to realize
I could run fridge on higher wattage AC if I added inverter, existing wiring would work and control fridge.

Problems- If inverter AC (or other source) not available fridge goes to 'check'. (which requires, on mine, resetting
fridge even if power restored)

As fridge board 'remembers' and will reconnect to last selected source, simply turning off fridge or 12v power to
board and reconnecting when source power to be available will keep fridge from going to 'check'.

Easiest method, when shutting down truck is to run inside camper and shut off fridge. Turn back on when source
power to be restored. Or adding a toggle somewhere outside that is more accessible to turn fridge on/off.
3rd, use relay on fridge main 12v supply, trigger/controlled by truck ignition or manual switch.

As I already have ignition controlled relay set up 10 years ago (been using DC for 20 years) if I added an AC
source I'd have option to run AC or DC, good to go. My ignition trigger goes thru dash switch to enable or disable.
(Note: If using relay, a bypass switch will need to be used when camped or as I did, a selector switch that
determines source of relay trigger wire)
___________________________________________________________

All that out of the way, installing the inverter.
Least expensive I could find-1000 watt modified sine. Expected use ~350 watts. Test with 600 watt heat gun.
    Hurdles:
  • Location of inverter,
  • Routing inverter AC out to camper
  • Routing battery cables inside truck to inverter from engine bay
  • Hardwire camper/Fridge selection of AC source
Location:

My only option was behind drivers seat on rear wall. Required making brackets to hang inverter.

Under window is formed sheet metal box. Only place to attach. Brackets hold inverter out an inch from back wall, with 1/2" gap at top 1/4"
above bottom formed carpet bumpout that brackets set against.


Inverter mounted. Already decided I'm mounting a bed receptacle, camper will plug into it. Though temporarily used an extension cord to
plug in fridge. A 14ga cord out from inverter, cut off female end and routed thru existing rubber plug at truck back wall. Cord goes out
under and up between bed walls to make connection at bed receptacle.

Routing inverter AC:

Bed receptacle was a puzzle as most RV AC pre-made stuff is going in wrong direction, truck is hot side. Need Fixed live female on truck,
umbilical the male (can never be made hot). Standard wet location box with an in use cover just too big.

Going thru parts found this in use wet location box. Intended for a pole light -perfect just had to trim curved back.
Shallow- weather proof in-use.

I looked all over and could not find another to purchase but for bed mounting ideal. Shear luck.


UPDATE 06/2020- stumbled across source- Solus SCO-930BK 120V Grounded Convenience Electrical Outlet w/Rain Shield for
Outdoor Lamp Post and Poles, Energy Saving and Weather Resistant
Amazon link as long as it lasts https://www.amazon.com/dp/B07XTNRM5H


Routing 4ga battery cables:


This hole in floor covered by rubber boot leads to area that's inside double wall floor, boxed. About 6" to left on other side of box is an
identical hole. It allows cable to enter from engine bay, make a relaxed S turn that lets cable lay flat once it enters cab. Located between
clutch and brake and not anywhere near boot movement.
Route around seat and up rear wall to inverter,

Once routed pulled excess into engine bay.

Once I had cables into cab cut and added inline fuse holders to fix lengths. Plan is to get some loom material, fully cover cables and a
dozen or 2 zip ties. However holding off until I decide how to add lugs to cables and replace fuse holders. These work well, easy to use on
cut cable,no lugs required- but I just don't trust them. Not wanting to pull cables so may pick up crimper. roundtoit.

Inverter mounted, battery cables run, inverter cable run, bed receptacle mounted. Last is to hard wire camper but waited until we returned
from week out to ensure this works before spending energy to wire camper.

Used an extension cord plugged into bed receptacle, draped across front of camper and thru fridge cover.

And it worked!. Surprisingly well, way better than hoped for. We had the fridge remote thermometer inside truck to watch temps...


Hardwire camper/add split receptacle at fridge


Again, cut off female end of 14ga cord. Drilled hole, installed plastic grommet and pushed cable into camper leaving about 30" outside.
Routed inside across water tank.

Under floor of slide to existing cable hole of slide that enter seat box. This leads into outside cabinet that is beside refrigerator


Poked thru to fridge. Removed boxless receptacle, install new box.


Wired new receptacle as split, 1 source camper the other truck.
Switching AC source will be a matter of plugging into desired source. Our normal would be truck.
Swapped the fridges right angle pigtail for shorter straight plug. Labeled- done.

Well, convert the fridge cover to hinged for easier access...
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/29974858.cfm



Added power strip for ease of access and other stuff that might be used.


Had to replace compressor switch in dash. Used drill and heat gun on the wiring. Nice. Also tied the dash inverter remote switch thru
ignition triggered relay to turn off inverter if I forget. Though inverter can be used without engine on by using its case mounted switch
could quickly lead to dead batteries. The fridge is ignition triggered and goes off with ignition so no real load but just extra measure...

19 Replies

  • AnEv942 wrote:
    .. But again I question using factory inverter, everything Ive read shows 300 watts max while driving. Even IF 400 watts available, at 325 watts of fridge AC heater+, inverter would be running near full load?


    What's wrong with running factory inverter at full load?
    So far I tested the inverter with 2.5A air compressor and it starts under the load just fine.
    I am also thinking about making idiot-proof cord that would unplug itself in case I forget.
    Getting older sucks and better be prepared ...
  • Work2much: Ya that was kind of my conclusion as far as cabling, plus previous mods led me to this route. If starting from scratch might have done differently. Inverter power to camper is solely dedicated to running fridge. The other factor and real motivation, was simply wanted an inverter in truck.

    Kayteg1, there are several options as far as auto switching and was really on the want list. I may revisit, be nice upgrade project if this gets old but probably not. We move plugs inside camper from shore to inverter use, not a real inconvenience. Still would be nice.
    Must be someplace between inverter and dash you could tap, add another receptacle, short cord to bed. But again I question using factory inverter, everything Ive read shows 300 watts max while driving. Even IF 400 watts available, at 325 watts of fridge AC heater+, inverter would be running near full load?
  • I'm doing something similar, but a different approach. I have a Magnum Technologies 3kw Inverter/Charger permanently hardwired into the TC. It has a built in transfer switch and is intended to cut the shore power cord and run the whole TC when activated.

    I turn on the inverter, fridge kicks over to 110v.

    I then ran a set 4ga cables from the truck batts to the camper batts, through 100amp breakers at each end.

    When I get where I'm going to park, I trip one of the breakers to disconnect the truck batts from the TC.

    I also have 800watts of solar on the roof, so on a sunny day, I run the fridge off electric also. On a sunny day, I can peak-out my solar controller at 60 amps charge. Fridge heater is a 400watt element, that comes on and off on a as-needed duty-cycle so keeping up on solar is no problem.

  • Nice report. I have been kicking around the idea of installing an inverter in the truck that could be used to power the camper, charge the battery etc while driving. It seems like a good alternative to running large dc cables for battery to battery charging.
  • That's what I have been considering since I have factory inverter in my Ford.
    Just not enough motivation to go with it and I don't like the light duty 120V extension cords run across truck cabin.
    Trying to figure out how to make HD cord to the 120V plug I have on dashboard.
    (Ford installed 400W inverter behind rear seat, but the harness is very hard to tap into).
    I would also think about automatic 120V transfer switch, who defaults
    to camper power and switches when you activate truck inverter.
    That will eliminate the need for manual cord switching.
  • I run a 3000 watt AIMS Power Inverter placed as close to my batteries as possoble which is out of sight under the bed step. Mine has it's own fans and my FW tank is under the step as well so there is plenty bulk (cold FW tank ro absorb the heat produced by the Inverter. I 'borrowed' a couple already installed shore power outlets for the Inverter and labelled them as such.
  • I did the same thing on another RV I owned long ago but I put the inverter near the battery of the trailer. It drew about 30A through the trucks charge pin but worked fine.
  • “Easiest method, when shutting down truck is to run inside camper and shut off fridge.“

    lol. Doesn’t sound like tooooo much fun to me. Why not install an adequate solar system including batteries? Do it right, do it once. Then no running is required.