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DRTDEVL's avatar
DRTDEVL
Explorer
Apr 23, 2018

How to figure out what electrical components are present.

OK, I have almost finished prepping the RV I inherited from my grandparents for actual use, and plan to use it extensively this summer.

The specs:

1980 Winnebago Minnie Winnie 20RG
1979 Dodge CB300 Chassis with 10,400 GVWR heavy package.
5.9L 360 c.i., 727 Transmission
Generator Prep package (but no generator)

There is no power inverter, only a power converter and "charge sentry" system to keep the 12v up and running when plugged in. At least, I don't think there is an inverter, as I have never seen one nor any switch or remote panel that would turn on the 110v system when not hooked to shore power.

I plan on mounting a 3000w continuous (6000w peak) inverter with a remote panel in the generator bay, as there is already a large gauge positive battery cable running there as well as an electrical junction box to wire a generator to the 110 system. This seems to be the most logical choice for me... but I don't know if there is an automatic power transfer switch installed from the factory as a part of the generator prep package. Later today, I am going to remove the back seat and check to see what the back side of the converter/breaker/fuse panel looks like, but I am not sure if I would recognize an automatic transfer switch from 38 years ago. If not, I can always try to remember to turn off the inverter prior to plugging into shore power, but I would like to make it "dummy proof" in case someone else is hooking it up in the future.

Anyone know much about these old units?

23 Replies

  • Well Drt,

    You got a set of answers from one of the tribe that gives good juice answers. What he was too kind to say is,"ARE You out of your Mind?"

    A 3000VA inverter will require a forklift battery for support and real welding cable to attach it.....

    Also as Mex said, the existing converter is probably junk. If it is a big heavy box, it most certainly is. Replace it first. If you replace the house bank with a pair of 6v golf cart batteries in series (to make 12v) and figure out what generator you can shoe horn in there, you will be worlds ahead. You should be looking for a 40~60 amp three or four stage converter/charger.

    My coach is only 7 years older, and I can tell you about a lot of mistakes to not make. Idling the main engine to charge the house bank would be a good one to not make. First off, the alternator output isn't all that much, but then you also have to include the fact that nothing good happens when an engine is idling.

    Now, about older coaches. They can be reliable. The only reason mine is not on the road to day is that the engine was getting weak and burning oil at about 95K miles. The thing to thing about is that all the rubber stuff is dying of old age. Not just the tires. I hope someone told you that tires live to a maximum of about 8 years under the best of treatment and that is with no regard for miles. I have see tires with mold nubbies still attached blow up...

    All the belts and hoses should at least inspected and the cooling and brake systems both flushed and the fluids replaced. Also look at any rubber fuel line. Fuel lines have a double whammy. First is age that would be a gotcha in any case, but then the new "motorfuels" are real tough on old materials.

    Shop locally for a good used generator if you plan to do anything but FHU "camping". To run a single A/C, you need about a 4kW unit. Just make sure it runs and the carburetor is clean before you shoehorn it into the space. There are lots of used units around because so many people have not taken care of the roof leaks (that is a hint).

    If you have other questions or problems come on back here.

    Matt
  • This won't be used for serious boondocking, as we have a 7 month old son. We'll take it to White Sands as a shelter from the elements, and up into the mountains for 2-5 days at a time, sometimes in real campgrounds, sometimes dispersed camping in the woods. I have a generator for backup power if necessary, and am adding a second house battery to double the capacity. The alternator will do most of the "top-up" duties for the house batteries when driving from place to place, and I can always start up the engine and charge the house batteries if I need to.
  • Personally I know of no converter that was built in that era that isn't a profound "battery killer". Ferro-resonant out-of-control regulation of DC voltage that over time creeps up toward fifteen volts continuous.

    It gets worse. These caveman specials use a huge ceramic resistor to bleed a few amps of charging current.

    Select something that will charge a car battery size RV battery at 40 amps per battery if you do any serious boon docking that lasts more than a week at a time.

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