More DC to DC charger installation tidbits

[Teaney Hull 292]

On 5/14/2025 at 12:49 PM, Carl Hansen said:

I have consider DC2DC charging for the last 4 years.  I wanted to consider how we use the trailer before installing the DC2DC charging.  We do longer trips and often stay at Harvest Host along the way.  It's nice to pull into a dry camping spot with a full charge on the batteries.  The solar does a pretty good job but not during the night and decreases effectiveness in bad weather.  

The following reasons made me decide to pursue DC2DC charging:

1. You got a guaranteed output of up to 700 watts, rain, night, it doesn't matter

2. Additional panels on the Elite 1 is not an option.  DC to DC is like adding additional solar panels to the rig.

3. How about portable panels? Portable panels are heavy and do not store well.

4. Portable panels only work during the daytime.  We are on the road most days.

5. Portable panels won't run the air conditioner. I do carry a portable generator with us which can run the air conditioner if necessary.

6. DC2DC is guaranteed output.  It is going to work all the time. (Maybe a duplicate of #1 but I think it is worth mentioning again.)

I think it depends on how you use your rig.  If you always stay at places with shore power, maybe the DC2DC charging doesn't make sense.  I believe the decision to install DC charging depends on your use model.  It may not make sense for everyone.

Carl

Well said. I totally agree. 

[Teaney Hull 292]

On 5/16/2025 at 5:51 PM, Carl Hansen said:

Well, I pulled the trigger today and ordered all my DC charging parts.  They will be coming in over the next week or so.  I would like to extend a big thanks to all the members of this forum, who over the years, have helped me with many questions and concerns  I would like to give a special thanks to Coddiwomple (David) who graciously invited me over to his shop to show me how he installed his DC charging in his LE1.  It was extremely helpful to see first hand.  He went beyond the mark by opening up his TV and trailer (including every access panel) and allowed me to photograph and video his trailer. He even went so far to give me copies of all his documentation and notes.  It's people like David and many others that make this community such a great place to communicate and share.

Thanks to everyone!

Carl

BTW... I just got notified by Highway Trailers in Salem that Oliver is sending them the Truma water heater parts replacement for the recall.  There is hope!

Carl, I feel the same way. What a GREAT Community of support. 

[Ronbrink]

3 minutes ago, Teaney Hull 292 said:

I do not have Solar on the roof

Exact same reason why the DC/DC was a great alternative to help keep my Oliver's battery bank charged. 

[Carl Hansen]

Well, it's finished! The installation of the DC to DC charging system in now complete and operational.  I first started the installation in the Oliver Elite I trailer (#924) and finished the installation with the Jeep.  I'm generally a DYI guy, but this was a bit of a stretch for me.  It's not that it was difficult, I stressed on doing something to the Oliver that would ruin it, especially penetrating the hull for the charging cables.  That was a big concern.  But with careful planning and a ton of help from this community, I was able to get this done.  Special thanks to Coddiwomple (David) for his help, patience, and guidance.  I first went out to his place to view his installation in his Elite I.  It's amazing how different his wiring was in just two model years.  Mine is a 2021, and David's is a 2023.  It was a bit confusing for me at first so a second visit was called for.  In the second visit, I pulled my trailer to his place and asked more questions and advice.  That second visit really helped!  Thanks again David!

Here is a few pictures I took during the process:

I followed David's idea of mounting the components on a board that I later installed in front of the street side wheel well.  I used the buss bars to step down in size from 2AWG to 4AWG which was necessary to connect to the Orion XS.

I think pulling the 2AWG wire was the toughest part of the installation.  A shout out to my son-in-law who was there helping that day.  Couldn't have done it without him!

Upon examination of the hull, I realized that under the sink (above picture) the hull is only a single layer thick, not a double hull there.  That made things a bit easier.  There was little existinting space to run additional cables through the hull, so I modified the housing for the propane tanks just a bit.

With the propane tanks and tray removed, it was easy access to the trailer font.  With my oscillating saw, I cut out an addition piece of the propane housing to the left of the three existing cables.  That gave me plenty of room to install two additional cable glands for the DC charging cables.  The way the propane tank housing is constructed and attached to the hull, the small piece I removed does not compromise the integrity of the housing.  The following pictures show the final hull penetration.

 

With the cables pulled, I was able to finish connecting everything to the DC charger.  I finished the umbilical cord that connects to the back of the Jeep.

 

I used the Trailer Vision enclosure to protect the Anderson SB120 plugs.

Onto wiring the Jeep.  (Much easier)

At the battery box, I used a KASS terminal extender to accommodate the fuse and the other cables.

I ran the cable along the chassis and installed the Anderson connector in a Trailer Vision enclosure which allowed me to mount it directly to the rear bumper of the Jeep.  

With everything installed and attached the batteries at both ends (Jeep and Oliver), I plugged it in and tested the amperage.  I was getting between 49 and 50 amps at idle.

Now the next step is to road test this on a long trip.  Can't wait.  Very excited to always have full batteries after a long day driving.

Thanks again to everyone who had a part in making this a success!

 

Carl

[Teaney Hull 292]

On 6/30/2025 at 11:34 AM, Carl Hansen said:

Well, it's finished! The installation of the DC to DC charging system in now complete and operational.  I first started the installation in the Oliver Elite I trailer (#924) and finished the installation with the Jeep.  I'm generally a DYI guy, but this was a bit of a stretch for me.  It's not that it was difficult, I stressed on doing something to the Oliver that would ruin it, especially penetrating the hull for the charging cables.  That was a big concern.  But with careful planning and a ton of help from this community, I was able to get this done.  Special thanks to Coddiwomple (David) for his help, patience, and guidance.  I first went out to his place to view his installation in his Elite I.  It's amazing how different his wiring was in just two model years.  Mine is a 2021, and David's is a 2023.  It was a bit confusing for me at first so a second visit was called for.  In the second visit, I pulled my trailer to his place and asked more questions and advice.  That second visit really helped!  Thanks again David!

Here is a few pictures I took during the process:

I followed David's idea of mounting the components on a board that I later installed in front of the street side wheel well.  I used the buss bars to step down in size from 2AWG to 4AWG which was necessary to connect to the Orion XS.

I think pulling the 2AWG wire was the toughest part of the installation.  A shout out to my son-in-law who was there helping that day.  Couldn't have done it without him!

Upon examination of the hull, I realized that under the sink (above picture) the hull is only a single layer thick, not a double hull there.  That made things a bit easier.  There was little existinting space to run additional cables through the hull, so I modified the housing for the propane tanks just a bit.

With the propane tanks and tray removed, it was easy access to the trailer font.  With my oscillating saw, I cut out an addition piece of the propane housing to the left of the three existing cables.  That gave me plenty of room to install two additional cable glands for the DC charging cables.  The way the propane tank housing is constructed and attached to the hull, the small piece I removed does not compromise the integrity of the housing.  The following pictures show the final hull penetration.

 

With the cables pulled, I was able to finish connecting everything to the DC charger.  I finished the umbilical cord that connects to the back of the Jeep.

 

I used the Trailer Vision enclosure to protect the Anderson SB120 plugs.

Onto wiring the Jeep.  (Much easier)

At the battery box, I used a KASS terminal extender to accommodate the fuse and the other cables.

I ran the cable along the chassis and installed the Anderson connector in a Trailer Vision enclosure which allowed me to mount it directly to the rear bumper of the Jeep.  

With everything installed and attached the batteries at both ends (Jeep and Oliver), I plugged it in and tested the amperage.  I was getting between 49 and 50 amps at idle.

Now the next step is to road test this on a long trip.  Can't wait.  Very excited to always have full batteries after a long day driving.

Thanks again to everyone who had a part in making this a success!

 

Carl

Carl, this Rocks. thanks for posting. I just ran my 2/0 cable like you did, and my helper/wife was on a conference call all morning long. Took me 2 1/2 hours by myself just to run the cable, 6 inches at a time, out the door to push 6 inch’s, back in the bath/front dinette/back dinette to pull 6 inches. So glad I saw someone post use soapy water and rag to make it easier to push the cable. Made a BIG difference. Not to get the Orian 50 amp wired/mounted/tested. 

[Carl Hansen]

I hadn't heard of or thought of soap water.  That's a great suggestion.  I will remember that for future use.

[Teaney Hull 292]

On 2/20/2024 at 2:55 AM, Snackchaser said:

I just completed installation of a Victron Smart Orion 30 amp isolated DC to DC charger after reading all the great information provided in this forum by MAX Burner, and others.  I really appreciated all their groundwork and details, so I wanted to share some of my experiences in the hope that others will find it useful.

I used #4 AWG wire for ease of installation and for better termination options.  BatteryCablesUSA recommended their “Jumper Cable” wire and it was the best deal I found at $197 for 55’ x 2.  It consists of a black and red cable joined together like zip cord, and it’s flexible enough to lay flat under it’s own weight.  Their lugs and heat shrink were also reasonably priced.  I sheathed the full length of the cable with 3/4” braided cable sheath for extra protection and good looks (Amazon Keko 100’ roll for $21.)  I seized the ends with Amazon XFasten fabric Wire Harness Tape (5 rolls for $14.)

BatteryCablesUSA also recommended Anderson SB50 connectors, instead of the larger #4 AWG rated SB120 connectors that I originally planned.  They said that #4 AWG wire would fit in the SB50 #6 AWG contact pins, which it did.

I used Trailer Vision covers for the Anderson SB50 connectors.  A TV-201426-50 surface mount receptacle with hinged cover plate was installed under the truck bumper.  It has a red LED power indicator that I discourage from connecting because it’s on all the time and annoyingly bright.   They also offer a flush panel style mounting.

The sheathed cord on the trailer side got the Trailer Vision TV-328993-50 plug cover.  It has a protrusion that catches on the mating receptacle’s hinged cover to stop it from pulling out.  It’s similar to how the 7-pin connector ports hold the plug in.  It also has a LED power indicator that’s more useful because it’s only on when connected.  It uses a compression gland for the cable that I filled with black RTV.

Powerwerx company sells Trailer Vision parts, Anderson connectors, and other accessories for reasonable prices.  Get at least 4 extra #6 Anderson pins for connecting to the Victron compression terminals as explained later.  Powerwerx also sells the “PanelpodSB,” which is a surface panel mount Anderson SB50 housing for $11.99.  I mounted one on the Oliver’s cargo box for “parking” the Anderson connector when it’s not plugged into the truck.  It keeps with my existing theme of parking places for the 7-pin cable and RAM rear view camera cable.  They also sell a tethered cap to keep it clean when traveling.

The engine compartment wiring was straight forward.  I connected the cable’s red wire to a 60 amp terminal post fuse on the battery positive.  The black wire terminated to the battery negative.

The trailer half of the sheathed cable went through a penetration behind the LP tanks.  A hole was drilled through the trailer wall next to the existing penetrations with a 1-1/8” step bit.  The sheathed cable passed though an Amazon PA66 1” nylon cable gland ($7.99 for two.)   I used a short piece of heat shrink over the sheathing where it passed through the gland and filled the gaps with black RTV.  The shelf under the bathroom sink has to be removed for access to the inside cable penetrations.  From there the cable can be simply pushed under the floor to the rear dinette seat where the Victron was mounted.

The Victron has some great safety features that will automatically reduce, or shutdown, the output if it gets too hot or the input voltage drops too low.  It’s important to take this into consideration because it would likely happen while driving, and you wouldn’t know it without constant monitoring.

Voltage drop especially comes into play with the new smart alternators that lower voltage output to save energy.  The Victron’s default voltage settings account for this.  However, due to the longer run of cable needed with travel trailer installations, the cable resistance can cause enough voltage drop where it can go below the default settings and cause the Victron to derate it’s output.

I calculated the voltage drop for different wire gauges at 35 amps (nominal input current) and a cable distance of 53’ x 2.  The results don’t include the connector and termination losses:

1.46 volt drop for #6 AWG

0.92 volt drop for #4 AWG

0.58 volt drop for #2 AWG

Per Victron’s instructions, a 0.6 voltage drop can cause a “Voltage Lockout” with the default settings.  There are many factors that can affect this, and fortunately the Victron defaults can be adjusted.  To account for my voltage drop, I decreased the “Start Voltage” from 14 to 13 volts, and the “Shutdown Voltage” from 13.1 to 12.8 volts. These setting were recommended by “Offgrid Power Solutions,” on a You Tube video called “Victron Orion-Tr Smart DC-DC Charger settings.”

Cooling is also an important consideration for the Victron because they create a lot of heat, and they derate charging current 3% for every degree above 104⁰ F.  That’s almost 50% performance loss at only 120⁰.  Maximum operating temperature is 131⁰, where I believe it shuts down completely.   This is why I installed cooling fans (but also for the fun of it.)

Amazon’s ”Sound Original” low profile blower fans (two for $9.99) were the right size, they had bearings, brushless motors, and a good mounting configuration for this application.  The Victron was mounted on 1/4” standoffs to keep its cooling fins off the mounting surface, and it also helps the fans to distribute air more evenly.  I used a Normally Open, 104⁰, 5 amp, thermostat switch to control the fans (Amazon Uxcell KSD9700 (2 for $5.49).  The fans get power from the input terminals on the Victron so they can only come on if the truck is connected, and the temperature is over 104⁰.  The thermostat switch resets at 86⁰.

The Victron was mounted on a painted plywood board that was attached to the forward battery compartment wall.  It’s an easy to reach, out of the way location.  I used 4 rubber well nuts that stay in place by themselves, but regular nuts and bolts could be used.

The sheathed #4 cable was terminated to the Victron’s input compression terminals, with the fans power leads.  I struggled at first with the Victron’s compression terminations, the wire wouldn’t fit, and I couldn’t find #4 square ferrels.  So I was pretty pleased to discover that Anderson pins can be filed down to fit perfectly.  Just be sure to cover the exposed barrels with heat shrink.

The negative output of the Victron went to the main chassis ground post under the rear dinette seat where there is a 2/0 cable going directly to the battery negative.   The positive output was connected to the line side of a Blue Seas 60 amp fuse block, from there it went to the line side of the existing inverter’s DC circuit breaker, which is jumpered to the battery positive with a 2/0 cable.

With the TV at idle and the lithium batteries around 60%, the Victron output was 35.8 amps as measured by a clamp-on amp meter.  The TV input was 42.5 amps.  This calculated to 84% efficiency, which is close to Victron’s 87% claim, which I assume is under perfect conditions.

I really liked the looks of the sheathed cable and Trailer Vision plug and receptacle,.  The hinged receptacle cover will keep the dirt out when not towing.  The plug and receptacle are locked together more securely with the Trailer Vision covers, otherwise the Anderson connectors can be fairly easily pulled apart and they might not stay together on a bumpy road.

Cheers, Geoff

Geoff, I need a little more help with your great detail. I ordered the 2 fans and Thermo switch. How are they wired together, and where does the + & - wire from the fans run to? Where is the fuse wired into the fans? One fuse for both? What size fuse? 

If I understand your drawing, the Neg from the TV goes to the Orian - in or to the Frame bolt? If the TV - goes to the Frame bolt, does  and another neg wire goes to Orian Neg in??? Your pic, looks like a wire with a red strip goes into Neg in. I don’t see the POS wire going into the Orian. What am I missing?  

Does another Neg wire coming out of the Orian go back to the Neg frame bolt? 

Does the POS out of Orian, after the 60 amp fuse then go the the bus bar, to the left top of the back dinette that is on the battery box? 

Sorry for all the questions, but I want to get this right. 

My head is spinning from what the almost 100 feet of copper and the copper lugs cost. Right at $7 a foot for 2/0 AWG and $5.98 for 2/0 copper lugs. OUCH?

Thanks in advance for the help.  Gary Hull 292

[Snackchaser]

2 hours ago, Teaney Hull 292 said:

Geoff, I need a little more help with your great detail.

Gary,

I think I understand where your difficulty is coming from.  My instructions are for the Orion 30 amp charger, which pre-dated the newly designed Orion 50 amp charger that’s different in several ways.  I believe you are installing the newer 50 amp Orion.

The first major difference is that the 50 amp charger is non-isolated, which means that the negative input and output use a common terminal.  The 30 amp isolated Orion has separate terminals for the neg input & outputs.

For the 30 amp, both the pos & neg wires from the TV go to the Orion’s respective pos & neg Inputs.  The Orion’s neg output goes to the Oliver’s ground bus, and the pos output goes to the battery circuit main breaker via the new 60 amp fuse.  With the 50 amp charger, you can run the TV neg to the ground bus, and a jumper from the ground bus to the Orion common neg.  The pos connection is the same as the 30 amp.

The second big difference is that the improved 50 amp charger is more efficient and it doesn’t have the significant overheating problems like the 30 amp Orion does.  The 50 amp doesn’t need cooling fans, although they still have some benefit.

If you choose to have fans, they are simply wired to the Orion’s pos & neg output so that their only energized when the Orion is charging.  The thermo switch and 2 amp fuse are wired “in-line” with the fans pos wire.  Let me know if a wiring sketch will be helpful.

Hope that answers all your questions.  Cheers!  Geoff

[Teaney Hull 292]

17 minutes ago, Snackchaser said:

Gary,

I think I understand where your difficulty is coming from.  My instructions are for the Orion 30 amp charger, which pre-dated the newly designed Orion 50 amp charger that’s different in several ways.  I believe you are installing the newer 50 amp Orion.

The first major difference is that the 50 amp charger is non-isolated, which means that the negative input and output use a common terminal.  The 30 amp isolated Orion has separate terminals for the neg input & outputs.

For the 30 amp, both the pos & neg wires from the TV go to the Orion’s respective pos & neg Inputs.  The Orion’s neg output goes to the Oliver’s ground bus, and the pos output goes to the battery circuit main breaker via the new 60 amp fuse.  With the 50 amp charger, you can run the TV neg to the ground bus, and a jumper from the ground bus to the Orion common neg.  The pos connection is the same as the 30 amp.

The second big difference is that the improved 50 amp charger is more efficient and it doesn’t have the significant overheating problems like the 30 amp Orion does.  The 50 amp doesn’t need cooling fans, although they still have some benefit.

If you choose to have fans, they are simply wired to the Orion’s pos & neg output so that their only energized when the Orion is charging.  The thermo switch and 2 amp fuse are wired “in-line” with the fans pos wire.  Let me know if a wiring sketch will be helpful.

Hope that answers all your questions.  Cheers!  Geoff

Great info and now I understand. Thanks. Hope to see you going down the road and return the favor. 

Gary