Lithium Upgrade with (630AH) Lithionics Batteries


This last summer we camped, off-grid, in our early 2015 Unity MB for 6 weeks. We already had 500W of solar but still needed extra battery capacity for the cloudy days. Now that the weather is cooler here in Arizona, it’s a great time to upgrade to lithium. It started with a PM question to SSTraveler which led to a constant correspondence of excellent guidance, and many, many, great suggestions. So this is definitely a joint effort. We are all so fortunate to have Sandy as an anchor to this forum. Her knowledge base and willingness to help others is extraordinary!

I want to document this in detail to help cut the learning curve for others that may wish to take on this project themselves. I'm not a professional electrician. If you do this yourself, I would suggest you do your own research and have your work reviewed by a professional.

I started with a wiring diagram for my road map and updated it as I made changes. The first thing I did was remove all chassis power. I started by disconnecting the solar array. You can cover the panels, or trip the breaker to the solar charger but use a tester to confirm power is not getting to the batteries from your solar panels. Disconnect shore power, flip the generator breaker off, disable generator auto-start if installed, remove the batteries, and also disconnect the lead from the isolation solenoid under the passenger seat to the original battery compartment. It's not really that difficult to remove the seat. There are 4, 11mm bolts that attach the seat. The trick is to swivel the seat to gain better access. It will be easier to remove the isolator relay and connect the cable from the starter battery to the cable going to the DC-DC charger/MPPT discussed later.

I decided to use 2 Lithionics Lithium, 315A batteries for a total of 630AH. They only weigh 68lbs each, are 20.3”L x 6.4”W x 10.0”H, and have an internal Battery Management System plus a heater kit. They are hand-built and tested in Florida and are of great quality. The space below the wardrobe closet seemed like the best place to locate the batteries and most of the wiring. The Victron Multiplus 3000/12, and the Victron SmartSolar 100/50 would be installed in the tall vertical outside rear storage compartment (opposite side of the wardrobe wall).

I removed the two drawers below the closet and the wood divider between the draws for better access. To take the wood divider off, remove the 4 screws on the backside of the divider. Next, remove the 2 right-side metal drawer guides plus the 2 lower wood panels below the drawers. This area is a little cramped and you will need all the space you can get. Next, remove the inverter and the mounting bench. Disconnect the inverter wires. One of the white, 14/2 wires originate from the 15A, entertainment breaker on the WFCO8955 power distribution box by the TV. The other white, 14/2 wire goes to the inverted receptacles. You will eventually need to install a junction box to combine the two wires together. Once the wires are combined, the same 15A breaker will now be the AC source to the previously inverted receptacles. There are 2, 4AWG wires that need to be disconnected from the old inverter. The red one originated from the switched side of the BlueSea Switch (Battery Disconnect) located on the side of the TV cabinet next to the step entry. It originally supplied 12vDC from the house batteries to the inverter. I didn't use it in this upgrade so disconnected it from the switch, then bundle tie the other end with the other wires in the front part of the new battery area. The black 4AWG cable was the inverter ground and originated from the ground lug in the step compartment. I repurposed it to run from the positive busbar in the new battery area to the "OUT" lug on the new Renogy 50A DC-DC charger/MPPT that I located in the old battery step compartment with an 80A ANL inline fuse. I also didn't use the white, thick ground wire that was attached to the old inverter case. When that is done, you still have to rearrange the other wires and remove the flexible heater duct to make room for the new batteries. This is what it looks like when first opened up:
PIC 1,2
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The objective is to relocate the wires and heater duct to open up space for the two batteries. This space is only 23" deep. The batteries are 20.3" in length so everything must fit in the front 3" to make space for the new batteries. I removed the heater duct, capped off the exit hole on the heater, and made a new vent through the front cover of the heater which I will cover later in the blog.
PIC 3,4
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Bend the propane tubing (see pics above) as close to the heater as possible without actually touching the case. Bend it slowly and carefully so you don't crimp it or cause it to crack. Drill a couple of ½” holes in a low profile junction box and install it on the upright divider between the two bottom panels. Cut off the excess wire from the two 14/2 white covered wire pairs from the old inverter and combine them in the j-box. The wires from the heater will need to be lengthened to move them forward and out of the way too.


PIC 5,6
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The wire access hole between the new battery area and the large outside storage compartment on the other side of the wall needs to be enlarged to move the wire bundle forward and out of the way of the batteries. To gain access, pry off the carpeted plywood wire/vent enclosure on the floor in the back of the storage compartment. It has a few staples and is screwed down. It came up ok without noticeable damage. You might be able to access the screws thru the vent holes if you have smaller hands. Enlarge the hole and move the wires forward.
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This is a good time to drill three holes in the floor for four wires. The larger, most rearward hole is for the 4/0 (not 4AWG) cable that will run from the 500A, negative busbar thru the floor to a new chassis ground. Pre-drill with a long small diameter bit to make sure you hit the right space which is limited beneath the floor. It’s an excellent place because it’s next to the frame and there is already a bolt thru the frame to make a new chassis ground. It’s best to take a disc sander and sand off the area to bare metal before securing the new cable to the frame. The hole location is in the front, right corner of the new space. The next two holes are slightly forward but very close together. The middle one is for the 2/0 red cable (not 2AWG) that goes from the positive busbar in the new battery area to the old step compartment positive busbar. The old busbar was mounted on the front wall of the step compartment with a 200A fuse. It will need to be relocated to the lower, left back wall of the step compartment. The forward hole is for two strands of 10/2 (w/Grnd) Romex wires. One goes from the Transfer Box attached to the WFCO panel to a new J-Box mounted on the sidewall of the new battery area so it can be combined with a piece of 10/2 stranded wire to connect to the new 30a BlueSea main breaker mounted next to the Multiplus. From there, another 10/2 stranded wire will go to the AC IN on the Multiplus. The other one goes from the AC OUT of the Multiplus to the 30A main breaker on the WFCO panel (wiring discussed later). Now the entire coach can be supplied with inverted power from the Multiplus/Lithionics batteries or the shore/generator power will pass-through the Multiplus to supply the coach's main power distribution panel.
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There wasn’t room to reroute the heating duct around the new batteries. The new battery area has plenty of ventilation and the furnace doesn't run continually when the cabin is up to temperature. It cycles occasionally, only putting out heat for a few minutes each time. So it has no impact on the batteries. We have only used the furnace a handful of times, but I want it available if we ever need it. So It would be fairly simple to create a new direct duct to the hallway. I ordered a new vent that was similar to the original hallway vent. I removed a matching vent from the storage compartment and installed the new one in its’ place so both vents in the hallway matched. I drilled a 4” hole in the panel that is mounted directly in front of the heater, then inserted the vent in the hole to trace a circle on the faceplate of the heater. I removed the faceplate and cut the circle out then mounted the vent in the panel board and reinstalled the panel with the new vent. The vent penetrated about a ½” into the heater, not far enough to touch the furnace chamber. It was a good, solid fit. While I still had the area open, I turned on the furnace for about 15 minutes. I set the temperature to 90 degrees (80 degrees in the coach). I measured the temp inside the vent at 220 degrees. The outside lip of the vent, in the hottest place, measured 165 degrees. The metal casing on top of the furnace got as high as 127 degrees. The cap where I capped off the previous heat duct got as high as 125 degrees. On a hot AZ summer day, the interior alone can get over 130 degrees. I was very pleased with the test results.
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Before we discuss wiring in detail, I would like to cover the mounting of the Victron Multiplus, SmartSolar MPPT 100/50, Cerbo GX, Touch 50 Display, the 2 BlueSea disconnect switches, and the Renogy 50A DC-DC charger/MPPT.

The rear tall vertical storage area is perfect for the Multiplus (M/P). It’s directly on the other side of the wall from the batteries, it’s well ventilated and has easy access. I lined the install area for the M/P with 3, 12”x18” light gauge, plated steel sheets I purchased at Lowes for about $6/ea. The ones on the ceiling and back wall are uncut. The top of the sidewall (toward the batteries) has a 1.5”x.075” lip I covered with part of the 3rd sheet. The corners of the lip were edged with ¾” aluminum angle. The remainder of the sheet was used for the sidewall. All metal was mounted with short metal screws. This not only provided the area with some fire protection but helped with the heat dissipation too. The center of the bracket for the M/P was positioned 5” from the back wall and the top of the bracket, 3” for the bottom of the upper lip. This gave about a 1/4” space from the back wall for extra ventilation. You might even want to space it slightly further away.
PICS 17,18
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The SmartSolar is mounted 2.25” from the edge of the M/P to the edge of the black mounting plate of the SmartSolar and 3” from the top of the black mounting plate to the bottom of the lip above the SmartSolar. The BlueSea Battery Disconnect switch is centered between the M/P and the 30A Main Breaker. Other measurements are depicted on the pic below.
PIC 19

The mounting wall is a double panel, 1” thick with a ¾” space. If you want to surface mount the 2 BlueSea Switches and the 30a Main breaker, you will need to cut out a section of the back panel in the new battery area. I removed it with a Dremel tool.
PIC 20
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The Victron Cerbo GX (GX) is the communication center for the Victron products. It gathers information directly, via a RJ45 UPT cable from the Multiplus, and Victron V.E Direct cables from both the SmartSolar Charger and the SmartShunt. The Touch 50 color screen connects directly to the GX with a built-in HDMI cable with its own, short, USB cable to receive power directly from the GX via the nearest USB port to the HDMI connection. The GX, MPPT SmartSolar charger, and the SmartShunt all have built-in Bluetooth capabilities. Regardless, all information from all the Victron products are collected and analyzed by the GX, and is available thru the GX Bluetooth connection. Since the Touch 50 HDMI cable is only 10’ long, it must be mounted fairly close to the GX. I chose to mount both the GX and the screen in the faceplate of the little nook to the right of the microwave. The area directly behind the boarded nook is currently used by LTV to provide a place for their pre-wire satellite cables. I gained access to this space by taking a small piece of 2x4 and knocking the faceplate rearward with a hammer. It is stapled in and will be damaged but is replaced with a 1/8” thick fiberboard from Lowes. I cut another 5”x6” hole for access to the same area in the upper front of the wardrobe cabinet and made a cover for it from the same fiberboard. The GX is not made to be face mounted but rather stuck in a cabinet somewhere within 10’ of the Touch 50. There was a discussion on another forum stating the Bluetooth range from the GX is limited so wanted it to be as accessible and as close as possible to the seating area. By-the-way, you don’t have to purchase the Touch 50. Any screen with an HDMI cable will work or the information is available by Bluetooth without the screen. I like it because it is a touch screen and can program a few of the items on the MP directly (change "input current limit" for example) plus it looks pretty sharp. I face mounted the GX by tracing around the unit on the new faceplate and carefully cutting out the hole with a flexible Dremel. It is mounted mostly by pressure fit and then secured with a bead of silicone on the backside to keep it in place. Because the USB ports are on the top of the unit and close to the front of the unit, the face can only protrude a short distance. I painted the faceplate gloss black to match the microwave. The Touch 50 is made to face mount. I evenly spaced it below the GX. You will have 4 cables attached to the GX; Touch 50 w/USB, 2 V.E. direct cables, and the power cable w/fuse for the GX. Start from their sources and make a wire tie bundle about every 8” from there to the nook cabinet. I attached the new faceplate with 3 screws from the back.
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The Renogy 50A, DC-DC charger with a built-in MPPT solar charge controller is the perfect charger for this electrical upgrade. Although Mercedes specifies keeping alternator charging of an auxiliary battery to a maximum of 40 amps, I prefer to have at least 50 amps because of the large lithium bank. The charger is also compatible with mixed chemistry batteries which work with my AGM starter battery and lithium house batteries. It prioritized charging to the house battery and then at a set voltage point, starts charging the starter battery. The nearly empty step compartment is the perfect mounting place as it’s between both batteries and is well ventilated. I already removed the two 6 volt batteries earlier and moved the location of the 200 amp fused busbar from the front of the compartment to the left rear wall near the bottom. There were 3 cables connected to the busbar; a 1/0 cable going to the generator for generator starting, a 4awg cable routed to the BlueSea Switch (Original Battery Disconnect near step), and a 4awg cable routed to the isolation solenoid under the passenger seat. I disconnected the latter to connect it to the “IN” bolt of the DC-DC charger when mounted and left the others connected to the 200 amp fused busbar. I drilled 4, 1” vent holes on the right side wall near the back for additional ventilation. I drilled an additional hole for 2, 8awg solar cables from the single 50w monocrystalline solar panel I just installed for this Renogy, 50A DC-DC/MPPT, charger. (I also added another 100w panel to my existing 500w for a total of 650w on the roof). The charger is very simple to install. Unlike the smaller Renogy 40A charger, the 50A charger doesn’t require an ignition wire to signal the charger to turn on unless you have a newer “smart” alternator as is the case with 2019 and newer vehicles. There are only 4 input bolts; ALT, OUT, PV+(solar), and NEG. Connect the cable disconnected from the positive busbar, that originally went to the isolation solenoid, thru an 80 amp breaker mounted by the charger to the “ALT” bolt. Use a continuity tester to determine which 4awg ground cable was originally wired from the old inverter to the ground post in the step compartment. That cable has been repurposed as the positive cable from the positive busbar in the new battery area to be connected to the “OUT” bolt on the DC-DC charger. It requires a 65 amp fuse or breaker on that line. I wired it thru an 80 amp ANL fuse mounted close to the positive busbar in the new battery area. The 50w Renogy solar panel was mounted on the roof by the step ladder. It was mounted using the optional Renogy "Z" brackets. After cleaning the bottom of the brackets and the roof attachment points with acetone, I glued the panel to the roof with an ample amount of Dicor sealant. (This is the same method I used 2 years ago when I installed my original solar array. I didn't drill any additional holes in the roof and the panels are extremely secure.) I ran a positive and negative 8awg cable from the panel, thru the roof, into the narrow, tall coat closet by the entry step then down thru the floor and into the step compartment. The negative cable was wired to the negative ground bolt in the compartment and the positive was wired thru a 30 amp breaker switch mounted in the step compartment to the “PV+” bolt on the charger. I ran a 4awg cable from the grounding bolt in the compartment to the “NEG” bolt on the DC-DC charger. There is a small button close to the “ALT” bolt that can be repeatedly pressed until it changes to the correct color of your house battery type. In my case, I toggled until the light on the case changed to the color blue to select the lithium charging profile. I also connected an 18awg wire to the “ALT” post and ran that back to the new battery area to connect to the SmartShunt for starter battery monitoring. Disconnect the isolation solenoid under the passenger seat and connect the two 4awg cables together. That’s it.
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PIC 29
Battery Compartment Sidewall Electrical Overview
The placement of the batteries determined the location for the M/P and the SmartSolar controller. Both items needed to be close to the batteries. Once they were mounted in their perfect spots, it was easier to decide where to mount more of the upgrade items. With all the major items mounted, it was more logical how to connect the dots with the wiring. I started with drilling the holes thru the wall in the storage compartment thru to the battery compartment for wire and cable access to the M/P and the SmartSolar charger. Once these holes were drilled, it was more obvious where to place the busbars, fuses, and other items. This is an overview of the battery compartment sidewall. Additional pics will show more detail with the Legends below.

1. Backside of the BlueSea Solar Disconnect Switch
2. Backside of the BlueSea 30A Main Breaker
3. 60A ANL fuse between the SmartSolar Charger and the 500A Positive Busbar
4. 10/2 stranded wire from the grey junction box to the 30A Main Breaker (#2). This wire carries shore/generator, 120VAC from the Automatic Transfer Switch thru the 30A Breaker (#2) to the AC IN on the M/P. The 10/2 wire, #13, is wired from the Automatic Transfer Switch to the grey junction box (#7) to be connected to wire #4 for a more flexible connection to the breaker. More detail on how and where that wire was routed, will come later.
5. Backside of the Battery Disconnect Switch
6. 500A Positive Busbar
7. Grey junction box to combine the #13, Romex 10/2 wire, with a flexible 10/2 wire, #4
8. 200A ANL fuse passes 12VDC from the Positive BusBar (#6) thru the 2/0 cable (#11) to the Positive Busbar in the Step Compartment. How it is routed and wired will be covered later
9. This Romex, 10/2 wire starts at the AC OUT port of the M/P and goes to the 30A Main Breaker on the WFCO 8955 Distribution Panel to supply AC to the AC breakers. This 120VAC power is either “passed thru” if shore or acceptable generator power is connected. If not connected, the 120VAC power will be inverted from the battery bank instead. All AC breakers on the WFCO Distribution Panel can be supplied by the batteries thru the inverter. The wiring route will be discussed later.
10. 500A Negative Busbar
11. 2/0 cable carries 12VDC from the 500A Positive Busbar to the Positive Busbar in the Step Compartment. The Positive Busbar in the Step Compartment supplies 12VDC to WCFO Distribution Panel via the original Battery Disconnect Switch (also step operation and stabilizer jack reset on the unswitched side side of the switch). Provide 12VDC to the generator for generator starting.
12. 80A ANL Fuse on the cable that provides 12VDC from the Renogy DC-DC charger “OUT” bolt to the 500A Positive Busbar in the new battery area. This cable was originally used for the old MM612 converter ground wire connected to the grounding bolt in the step compartment. It was repurposed as a supply line from the DC-DC charger to the Lithionics batteries via the Positive Busbar in the new battery area.
13. This Romex 10/2 wire supplies shore/generator, 120VAC from the Automatic Transfer Switch thru the 30A Breaker (#2) to the AC IN on the M/P. Routing will be addressed later.
14. This is the Victron 550A/50mV, SmartShunt. It is installed upside-down to better align with the battery cables. The negative cable of the battery bank must connect to the “Battery Minus” bolt. Nothing else may be connected there. The 4/0, new chassis ground cable (#15) and the 4/0 cable to the Negative Busbar (#10) connect to the “Load” bolt. The smaller, black, Victron Direct V.E cable runs from the shunt to the Cerbo GX. The 18awg green wire go to the ALT bolt on the Renogy DC-DC charger in the Step Compartment for starter battery monitoring. The small gauge fused, red wire, runs to the Positive Busbar (#6) to supply power for the shunt.
15. This 4/0 cable runs from the shunt, thru the floor, and is connected to the new chassis ground bolt on the frame directly below the shunt.
16. This junction box was already mounted on the wall by LTV. It combines wires from the generator with a 10/2 wire to the Automatic Transfer Switch. I moved it lower on the wall to provide more room for me to do my new wiring. Leave the wires connected. Just unscrew the wall screws and move it to a lower position.
17. This is a wire bundle that goes to the Cerbo GX. It contains the V.E Direct cable from the shunt, the blue RJ45 UPT cable from the M/P, and the fused power cable for the Cerbo GX. As it gets close to the SmartSolar Charger, this bundle picks up its V.E. Direct cable.
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PIC 30
. Victron V.E. Direct cable coming from the SmartSolar Charger and bundled with the other
cables/wires going to the Cerbo GX. The bundle includes three other cables/wires; the blue, Victron
RJ45 UPT cable from the M/P, the black, V.E. Direct cable from the SmartShunt, and the red, fused
power cable from the Positive Busbar. The red power cable had to be lengthened to 12’ with some spare
small gauge wire I had on hand. It was only about 5’ in length. This bundle continued across the top,
back of the new battery area, then up thru a hole in back left of the wardrobe closet to enter the Cerbo
GX mounting nook via a hole in the access door to the satellite pre-wire cables. Refer back to picture 24.
19. The blue, RJ45 UPT cable from the Victron bundled with wires to the Cerbo GX
20. 6awg negative solar cable (from 600W array) to SmartSolar Charger Negative PV screw
21. 6awg positive solar cable (from 600w array) to the Solar Disconnect Switch (#1)
22. 4awg cable from the Battery Positive screw on the SmartSolar Charger to connect to ANL
fuse (#3), then direct to 500a Positive Busbar (#6)
23. 4awg cable from the Solar Disconnect Switch to the Positive PV screw on the SmartSolar Charger
24. 4awg cable from the Battery Negative screw on the SmartSolar Charger to the 500A Negative Busbar (#10)
25. 4/0 cable from the 400A T-Fuse just off the positive terminal of the Lithionics battery pack
connecting to the Battery Disconnect Switch (#5).
26. 10/2, 120VAC, stranded wire from the BlueSea 30A Main Breaker (#2) to the AC IN on the
M/P. Note this breaker is a double-pole breaker that breaks the white neutral and the black
power leads. The incoming leads (#4) are connected to screws on the top and the outgoing leads
26) connect to the screws on the bottom. The negative green wires are combined with a crimp or
wire nut. Standard practice is to also wrap a wire nut with electrical tape on mobile installations
to prevent vibration from shaking it loose
27. 4/0 cable from the Battery Disconnect Switch (#5) to the 500A Positive Busbar (6)
PIC 31
28. 4awg cable from the 60A solar ANL fuse to the 500A Positive Busbar
29. 2/0 cable from the 500A Positive Busbar to the 200A ANL fuse (#8). 12VDC continues via a 2/0 cable underneath the rig to the 200A Positive Busbar in the Step Compartment
30. Red, small gauge, fused, power lead wire runs from the 500A Positive Busbar (6) in a wire bundle (17) to power the Cerbo GX. The black ground wire with the power lead connects to the 500A Negative Busbar
31. Red, small gauge, fused, power lead wire runs from the 500A Positive Busbar (6) to power the SmartShunt (#14)
32. 4awg cable from the 500A Positive Busbar (6) to an 80A ANL fuse (12). Ultimately wired to the Step Compartment (repurposed old 4awg inverter wire) to the “OUT” bolt the DC-DC charger.
33. 4/0 12VDC cable from the Battery Disconnect Switch (#5) to the 500A Positive Busbar (6)
34. 4/0 12VDC cable from the M/P battery BAT+ bolt to the 500A Positive Busbar (6)
35. 4/0 12VDC cable from the M/P battery BAT- bolt to the 500A Negative Busbar (10)
36. Victron V.E. Direct cable from the SmartShunt to bundle (17) to go to the Cerbo GX
37. 4/0 cable from the 500A Negative Busbar to the Load Minus bolt on the SmartShunt
38. 18awg green wire runs down thru the floor and routed to the “ALT” bolt on the DC-DC charger for starter battery monitoring
39. 4awg cable that originally ran from the old MM612 inverter to the Step Compartment but now repurposed to run from the 500A Positive Busbar (6) via an ANL 80A fuse (12) to the “OUT” bolt on the DC-DC charger for alternator charging of the Lithionics Battery Bank
40. 4awg cable from the case ground of the M/P to the 500A Negative Busbar (10)
41. 4awg cable (existing wiring by LTV, previously used to ground the old MM612 inverter to the chassis ground bolt in the Step Compartment. It’s now been repurposed to be the cable from the DC-DC charger to the new battery bank for alternator charging. It is connected to the “OUT” bolt on the DC-DC charger
PIC 32
We covered drilling 3 holes in the front right corner of the new battery area to run 4 cables/wire. You might want to review pics 9, 10, & 11. This is what it looks like when pulled thru the floor.
PIC 33
The 4/0 black cable (15) goes straight down to the new chassis bolt. The red 2/0 cable (11) is in its’ own wire loom as well as the 2, 10/2, Romex wires, and the green 18awg wire are in another wire loom. Normally you do not want to run DC & AC wires together (cross at 90 degrees) but it was short-run and provides better protection. The destination for the red, #11 cable is the 200A Positive Busbar in the Step Compartment. The 2, orange, Romex wires (9,13) will be routed up thru a hole in the floor just behind the WFCO 8955 Distribution panel. The green 18awg wire (38) will enter the far side of the Step Compartment to connect to the “ALT” port of the DC-DC charger for starter battery monitoring. I removed the green wire (38) from the wire loom to route it on to the Step Compartment when the Romex wire loom entered the area behind the WFCO Distribution Panel area. The routing of both looms was fairly intuitive. I just followed LTV’s looms and used bundle ties to attach to them together. The 2/0 red cable (11) enters the Step Compartment on the back, lower-left corner thru a hole I drilled earlier. It attaches to the 200A Positive Busbar in the Step Compartment.
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PIC 34,35
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The Romex loom (wires 9/13) entered the area between the back of the WFCO Distribution Panel and the outside wall. Take a longer small drill bit and drill a hole from the inside thru the floor to locate the entry point then drill a larger hole for the wires with the loom.
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Remove the parameter screws around the WFCO Distribution Panel and slide it as far forward as possible. Remove the Converter (charger unit) located in the lower section. It is wired to breaker #2 labeled “Converter”.


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Remove the orange, Romex, 10/2 wire that exits the Automatic Transfer Switch and connects to the 30A Main Breaker in the WFCO Distribution Panel. The old system sent the Shore or Generator power from the Automatic Transfer Switch directly to the WFCO Distribution Panel. This electrical upgrade directs the Shore or Generator power directly to the AC IN on the M/P via a junction box (17) and a Blue Sea Double Pole 30A Main Breaker (2) in the new battery area. Connect the M/P “AC IN” wire (13) to the same wires where you removed the old Romex from the Automatic Transfer Switch, which were originally connected to the 30A WFCO Distribution Main Breaker. Now the Shore/Generator power will be directed to the M/P instead of the WFCO main breaker. Connect the “AC OUT” wire (9) to the WFCO Distribution Panel 30A Breaker. (Note; this is not one of the newer split-buss power distribution panels (WFCO8930/50) like Leisure now uses on the newer models. There is no neutral bar to split with one source.) With this setup, all breakers are inverted if an outside AC source is not present. (Another note; the 14/2 Romex (12/2 on some coaches) wired to the #4 “Entertainment Breaker” on the WFCO Distribution panel was connected to the old MM612 inverter in the new battery area. The other 14/2 Romex wire on the inverter went to the inverted receptacles. By wiring them together in the j-box on the vertical divider between the drawers in the new battery area, the Entertainment Breaker now supplies either direct or inverted 120VAC directly to the preciously inverted receptacles.
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PIC 42
I already installed 500w of solar several years ago but as a part of this upgrade, I wanted to add as much as possible to compliment the new 630AH Lithionics Lithium battery bank. I was able to relocate my antenna and add another 100w Renogy Monocrystalline panel to my existing array. By adding a Renogy 50A DC-DC charger with a built-in MPPT solar charger controller, I was able to add an additional 50w panel to be wired to the Renogy DC-DC Charger/MPPT as a second array for a total of 650w. This 50w panel charges the house batteries first and then at a set voltage, charges the starter battery. That’s a plus when our coach is in outside storage. The original array was wired in parallel thru a combiner box. The two 6awg solar wires then passed thru a 2-wire gland into the tall closet by the entry and down thru the floor into the Step Compartment where I had 2, 6V Interstate batteries. Now that my batteries are in the rear of the coach, and I now have a SmartSolar 100/50 MPPT, I wanted to mount this new solar charger close to the batteries. I decided to add another 2-wire gland and rewire my 6, 100w panels in series/parallel to take advantage of upping the voltage and reducing the amps to use smaller wire and increase the solar capture time. I ran 6awg solar wires thru the roof close to the ladder into the top of the bathroom closet and over the wardrobe closet to the SmartSolar.
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I changed to 4awg wire at the Solar Disconnect Switch and from the MPPT controller to the 500A Positive (6) and Negative (10) busbars. The solar charger wiring was shown on the earlier overview diagram. Since I needed to run the new 50w panel solar wire into the Step Compartment, I used the old 2-wire gland entry and ran the 8awg wires thru the roof, down the back of the tall closet, and into the Step Compartment. The positive 8awg solar wire was wired to a 30 breaker in the Step Compartment and then to the PV bolt on the DC-DC charger. The negative 8awg solar wire was wired directly to the negative chassis ground bolt in the same compartment. The green (38) wire enters the front side (toward the engine) of the Step Compartment thru the same hole as the two 8awg solar enter to be connected to the Renogy 50a DC-DC/MPPT charger. The green (38) wire is connected to the “ALT” screw on the charger.


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Lastly, I added the batteries, which fit nicely into their new space. I strapped them down with 4 Footman’s Loop tie-downs and straps.

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One thing I did include in the electrical upgrade was a Micro-Air Easy Start for my air conditioner. It was very straight forward to install. It took me about an hour to complete. I didn’t take pics but there are several posts with references on the installation including this one by SSTraveler (Easy-Start),

Well, the day came to turn the switch on. I was a little anxious and very nervous. I was hoping it wouldn’t go up in smoke. I flipped the switch on and heard this terrible, loud grinding noise! I quickly flipped the switch back off. My heart was pounding as I frantically looked around and smelled for smoke and then I saw it! Since my electric step was retracted, I had placed a heavy wooden box in front of the door for a step. When I flipped the switch on with the door open, the step extended scooting this heavy box across the cement. I was shaking for 10 minutes. Other than that, it was perfect!

Our motorhome, “Gracie”, was really pretty nifty before this upgrade. We had 500w of solar and more importantly, we had a 25-gallon auxiliary water tank for a total water capacity of 50 gallons. It’s our most beneficial and favorite upgrade. If it was sunny most of the time, we could Boondock for 5-6 days without having to empty our tanks and refill the water. We like going to Pacific Grove, CA to escape the summer heat but the coast can be cloudy and misty for days on end. We stay in a place where operating the generator is not an option and it was a nuisance to have to drive to a less populated area to run the generator without disturbing the neighbors. Additionally, I thought it would be nice to heat snacks up in the microwave occasionally, and also, it would be great to run the air conditioner for 20 or 30 minutes on a hot night before we went to bed or to keep our two pups cool while we are shopping without having to run the generator. Well, this upgrade solved all of those issues in a big, big way. We now have a fantastic, Boondocking machine!

I can’t believe how quiet the AC is when the compressor first starts up. We only hear the sound of the fan. You almost have to be watching the Touch 50 screen to notice when the compressor engages. I’m still new to programming the M/P. I purchased the M/P, Cerbo GX, Touch 50, and the SmartShunt from AM Solar (highly recommend). They programmed the M/P for me, without charge, and have been great. Their prices match Amazon for the most part and only charge $12 shipping for the full order. That’s less expensive than Amazon plus their tax.

I know some of you will be curious about the empty weight. Me too. I took everything out except for the shore power cord, septic hoses, etc. then filled it with fuel, window washer fluid, DEF, and diesel. Our coach still has everything on it including, a Diesel generator, 25-gallon auxiliary water tank, 650w solar on the roof, and stabilizer jacks. The septic, grey, and water tanks were empty. The empty weight is 9980lbs. Yes!
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I want to thank Sandy (SSTraveler) again for the great collaboration on this upgrade. I don’t know who did the most work. She’s relentless! If you decide to tackle this upgrade and run into a problem, please PM me, or if you wish to have the original pictures on this post, that’s ok too, let me know.
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2020 Unity MB
Great descriptions and documentation. I thought it was very clever moving the furnace duct to free up space for the batteries. I am in the middle of installing almost identical components so your post is excellent timing for me.


2020 LTV Unity MB
This write is timely and awesome. Thank you so much for taking the time to write and include the pictures with notes.

I'm curious where your aux water tank is?


2014 LTV Unity Murphy Bed
I think you could have squeezed one more 50w panel on that roof, LOL! 😆
I'm glad you really don't use that furnace, so in the future you can easily remove it to add yet another 315ah battery and one up your Fantastic Boondocking Machine! JUST SAYING! 🥰

What a fun project, boy did I learn a lot! Thanks James for including me in your awesome upgrade! What's/When's the next project? :unsure:

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