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