Time is the coin of your life. It is the only coin you have, and only you can determine how it will be spent. Be careful lest you let other people spend it for you. -- Carl Sandburg
There's only one rule that I know of, babies -- goddammit, you've got to be kind. -- Kurt Vonnegut

June 8, 2011

New Converter

I completed the WFCO Ultra III WF-9855 converter kit installation last weekend.  It was a fairly involved procedure so I am late in documenting it.  This replacement started when I blew fuses and discovered the source was 3 melted wires to the NEG post on the DC fuse board.  That was a simple enough fix (wrap the melted insulation with electrical tape) but that left the question of why was the post so hot that it melted the insulation?  Anything getting that hot is not a good sign and could well be an electrical fire hazard.  Rather than just patch it up and forget it, I looked into correcting the why and making it work properly in the future.

It appeared that the wire sizes were too small for the loads.  They had used 8 AWG wires to get the battery power to the fuse board.  It was especially bad when I ran the water pump and the POS post got very hot.  From my research on the web, this seems to be a fairly common problem and other people had serious charing in places near the converter.  I also wanted to have a good 3 stage battery charger to take better care of my batteries.  This led me to replace my Parallax 7355 converter/charger with the Ultra III 9800 series kit that included a new and better fuse board.

The converter had 6 AWG aluminum wires from the DC side for the fuse board.  I really don't like aluminum wiring.  It has much less conductivity than copper.  That means more resistance which means heating.  Since heat was the problem to begin with, I decided to replace those wires with copper.  I wanted to use 4 AWG wires (largest size the lugs can use) but they are too fat to get thru the access holes so I got 6 AWG copper wires to replace the aluminum.

The fuse board can accommodate 4 AWG wires so I got that size to replace the battery POS and NEG wires along with connectors for the other end.  I figured if I am going to fix this, I may as well get the fattest wire I can to reduce the resistance.

After the installation, I tested the board and even with the water pump running for quite awhile, there was no detectable heating of the lugs.  So it appears that undersized wires were the root cause of my problems.

What I would do differently:  waited to get the high strand count, flexible welding wires for everything.  Anything else is too stiff and made handling the wiring much more difficult than it needed to be.   The wires I used work fine, and everything is now staying cool.
Here's the procedure I used to rewire and install my new Ultra III Converter and fuse board.  See here for what I bought.  This applies specifically to my LTV Free Spirit 210B van and replacing the wires with double the size.

Replace Parallax 7355 Converter and Fuse Panel with Ultra III WF9855
in 2005 LTV Free Spirit 210B Van
  Replace red and white wires on new converter with 6 AWG copper wires
     comes with 6AWG aluminum – replace with copper
     Need 5/32” long hex driver Access holes are not big enuf for 4 AWG wire
  Measure battery pos wire
  Measure battery neg wire
     Cut 4 AWG wire to fit
     Fit lug on far end
     treat both wires with dielectric grease
  Wrap pos wire in red tape
  Label both ends of each wire
       Converter Battery NEG to Ground screw
       Converter Battery POS to Battery Switch
Switch 12V off on main panel
Switch all AC breakers OFF
Unplug shore power
Disconnect NEG terminals on DS battery
Disconnect POS cables on DS battery
Original AC Breaker Box
  Remove old converter
    Remove converter unit cover
    Remove screws holding housing unit and slide the housing out of the hole
    Remove AC cover
    Remove the Fuse board
        Remove the fuses from the board including the 2 30 amp fuses
        Unscrew fuse board & pull out 2 screws above the fuses
        Remove the fuse wires
                Make labels for each fuse wire
Fuse board removed, fuse wires labeled

AC Converter is pigtailed to outlet circuit
                Remove F1 wire and put wire label on it
                Repeat for all 9 fuse wires
        Remove the Batt POS cable -    red
        Remove the Batt NEG cable -    black
        Remove the Conv POS cable -   blue
        Remove the Conv NEG cable on back of board - white
        Discard the fuse board
      Remove AC Converter wires
            Trace the Converter wire to breaker #3 right
Converter black and white (neutral)
 wires removed
                Remove the converter black wire from the breaker
            Trace the Converter wire to neutral bar
                Remove the converter white wire from the neutral bar
                Pigtailed to outlet circuit, remove
Old Converter removed
            Apply labels to the black wires to the other circuits
    Remove old converter from the base
            Unscrew the 4 nuts from the side flanges
            Slide the converter out from the housing
       Discard old converter
   Drill new access hole into fuse box for bigger wire
        Screw in hole grommet to protect the wire
New access hole in DC side
Install new Ultra III converter Model WF-9855
        Place the new Ultra III unit in front of housing
            Pull 3 AC wires (white, black, green) thru the top left hole
            Snip wire tie to the converter housing & wrap metal edge with tape
            Wire tie the 3 AC wires near the plug to keep them tidy
        Slide the converter into the housing
            Feed the AC wires thru the left side housing holes
New converter AC wires fed thru hole
DC wires left out
            Ensure the hole guards are seated firmly
        Screw the 4 nut screws into the holes on the side of the new converter to attach it to the housing     
        Pull the 6AWG red and white DC wires thru the right side hole into the fuse area
        Wire the AC side
            Make wire labels for the 3 AC wires & place labels on each wire
                #3Converter Hot Black wire
                Converter Neutral White Wire
                Converter Ground Green wire
New converter inserted
            Wire nut the black outlet wire, converter wire & pigtail together
            Route black pigtail wire to Converter breaker & screw it into the terminal firmly
            Route white wire to Neutral bar and screw it firmly
            Route Green wire to Ground bar and screw it firmly
            Dress the wires so they are neatly in the box

        Wire the DC Side
                Note all the connections are on the face of the new fuse board
Pigtail black wires, green to ground bar,
white to neutral
                Apply dielectric grease to each connection
            Route the RED Conv POS wire behind the card and over the top to the Conv POS lug
            Conv POS is on the top middle of the fuse card
                Screw down firmly
            Route the WHITE Converter NEG wire to the leftmost Batt NEG lug
            Batt NEG are on the 2 lower right hand side of the card
                Screw down firmly
DC Converter wires pulled thru
Access holes lined up perfectly
            Route the new Black Battery NEG (ground) wire thru the access hole in the rear of the housing
                Remove the old wire
                Insert into the right side of the Batt NEG lug on the bottom of the fuse board
                Screw down firmly
                Connect the other end to the Van body ground screw
                Ensure the wire has a label
Fuse board wired: Batt POS & NEG,
Conv POS & NEG
            Route the new RED Battery POS wire thru the access hole in the rear of the housing
                Remove & Discard the old wire
                Route the wire behind and over the top of the fuse block
                Insert into the right side of the Batt POS lug on the upper right of the fuse board
                Screw down firmly
                Connect the other end to the Battery switch on the LOAD side
                Ensure the wire has a label
Rear of power housing with wires
            Wire each fuse wire to its appropriate fuse lug and screw down firmly
            Ground the chassis
                Use the old black battery NEG wire (8AWG)
                Label the wire Converter Chassis Ground
                Insert bare wire ends into the right side of the ground lug located at the right bottom of the unit
                Screw down firmly
                Route the other end through the open cavity on the right side
Fuse wires attached
                Connect the other end to the Van body ground screw
    Finish the installation
        Insert the appropriate fuse into each fuse holder on the fuse board
        Reattach the AC face panel
        Switch all AC breakers ON
        Dress the cables in the back of the unit to ensure they are out of the way and not pinched
        Slide the converter/power housing unit into its place
        Screw the housing unit to its supports
Fuse board screwed to housing
        Screw the hinged vented access plate into the housing face
        Close the upper lid and latch
    Connect the battery
        Reattach POS cables on DS battery
        Reattach NEG terminals on DS battery
        Check for voltage
        Reset the 50 amp breaker located below the fuse panel if necessary
        Switch 12V on on main panel (above side door)
Installation finished
    Test unit operation  


  1. Hi! I just got caught up on your blog. It's interesting that you built up your back bed, as I had a similar idea, and for the same reasons.

    Your blog is full of neat mods, and I've thoroughly enjoyed reading it. Keep up the posts.

    And thank you for your well-wishes!

  2. I'm totally in awe of your ability tocomprehend this stuff!

    For some reason,your blog doesn't show up on my reading list :( I remember to check in, fairly frequently for updates, until I miss a couple days and then I forget :(

    I have the same problem with a few blogs. I don't know if it's blogger, or me.
    Cyndi & Stumpy @ RVly Ever After

  3. I made a blog for my dog to see how the updating is. This blog updates properly on it so I don't know why it doesn't on other blogs. I tried doing all the things mentioned in the help files but it doesn't seem to make any difference. Wonder if you deleted it off your list, saved it, then added it again if it would work properly?

    As for comprehending it, I spend quite a bit of time studying internet writeups and recommendations before I jump. I look & trace what I have. I also ask questions about the things that I don't understand. You have to be careful about that because there is just as much good info out there as bad.

    For these things that are complicated, I write all the steps as they apply to my exact thing so I don't get lost in the "make a decision and here's how" instructions given in the item's installation instructions. This also makes me go thru each step in my mind and I have to do a dry run before the install. So by the time I actually do the install, I know exactly what I am going to do and why.

    And I got to this point because a pro shop just did a minimal patch to fix the problems which promptly broke again a few months later. I want to fix it once and for all and I don't want to pay someone to do a simple patch that won't fix the root cause.

    It helps that I spent several years at my former job testing, then writing installation instructions for a complicated computer system. Got pretty good at figuring out how to write clear instructions and learned a lot along the way.

    But then, I've spent a lot of time on these mods.


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