HOW TO: Redarc DC to DC 11 Amp Output Trailer Charger Installation

[John E Davies]

FYI, related thread and discussion: https://olivertraveltrailers.com/forums/topic/4759-redarc-trailer-charger-mounted-inside-the-ollie-for-100-lithium-charge/?tab=comments#comment-49376

https://www.etrailer.com/Battery-Charger/Redarc/RED96FR.html

I won't add much commentary, it is pretty self explanatory. The instructions allow you to mount in any position, I chose horizontally with 1" cooling holes and a 1/2" gap between its housing and the mounting plate for cross flow of air. Note that there is a ton of extra space, I plan to add a small Victron MPPT Solar charge controller for my portable panel, it will go just to the rear of the Redarc, and there is room for another circuit breaker too.

 

More....

John Davies

Spokane WA

 

Edited March 12, 2021 by John E Davies

[John E Davies]

My Land Cruiser 200 charging voltage is 13.6 volts with the trailer hooked up (using a digital OBD2 Scan Gauge).It never gets above 14 volts, regardless.

Here is the history using my VictronConnect app, showing the initial parasitic load (propane detector and stereo mostly) of about minus 0.3 amps, then the engine starts and the trailer battery voltage and current shoot up nicely, to just under 11 amps. It maintains that charge rate right up until the batteries are close to full.

, 

The only fly in the ointment is that the wiring needs to be 12AWG or larger, all the way from tongue to charger. My Hull # 218 had a splice from 12 AWG down to 14 AWG, so I had to rewire the entire 7 wire harness, essentially. That is another thread. ... https://olivertraveltrailers.com/forums/topic/5271-how-to-junction-box-for-the-7-wire-trailer-harness-under-the-front-dinette-seat/?tab=comments#comment-54709

I went on a 90 minute, 40 mile test drive yesterday, it worked flawlessly, I can monitor the Victron app inside the truck, the sky was hazy high clouds, not ideal solar conditions, but the total charge current kept around 16 amps, going up to 22 when the sun broke through a little. 

Total cost was about $312, not including all my labor! Questions are welcome.

John Davies

Spokane WA

Edited March 12, 2021 by John E Davies

[BackofBeyond]

Thanks JD, eager to hear the long term evaluation.

RB

[Geronimo John]

Owners; 

NOTE 15 OCT 202 updates are in BOLD.  GJ

Note that JD's 12-12 charger has an output of 11 amps. 

Those going to Lithium may want significantly more power.  It appears that many of our owners are using or are looking at the Victron Orion 12-12 30 amp charger.  Depending on your vehicle and Oliver cable run length and wire size.  For my F-150 Crew Cab the length of wire needed for the upgrade was 108 feet actual (I had purchased 110) 4 AWG as suggested by BatteryCablesUSA.  

For the 4 AWG, you would need the Anderson 120 amp or 175 amp connector to handle the diameter of the cables.  For running the two 4 AWG cables from the battery back to the firewall, across the firewall (To avoid both the Cat and the right side turbo), zigzagging back under the cab between the frame and body, and back to the hitch is an easy, but long run.  Note:  I chose to run two cables (Pos and Neg) and not rely on the vehicle chasis for grounding.      

I found Mike at BatteriesUSA to be exceptionally helpful.  If you think you know your cable line measurement,  I highly recommend you add another ten feet!  Mike can give you the voltage drop for the various types of copper stranded cable.  Specifically you can buy 4 awg welding cables or 4 awg power cables.  Both are the same AWG.  BUT they are not the same strand count.  This can certainly impact which lugs you buy for the same 4 awg size.  I chose stranded copper cable, not welding.  

Finally, for DC circuits you can go well above the normal 3% voltage loss.  So if you are new to large DC cabling, measure twice, add an additional ten feet, and consider giving him a call at BatteriesUSA.  

[John E Davies]

GJ, great comments The beauty of the Redarc is that it doesn’t require disturbing the wiring in the TV. An exception is if you have a “smart” alternator, then you have to run a small voltage sense wire up to the TV battery positive, and also one inside the Ollie.

I once wired a TV and a Nash travel trailer as you describe, I used OO welding cable. This was about 1988, there was no such thing as lithium batteries. It worked quite well, but it is NOT a mod to be taken lightly with today’s sophisticated computer controlled electrical systems.

CAN Controller Area Network

John Davies

Spokane WA

 

 

[Geronimo John]

 

John: Very correct. 

The intent in my post above was directed only towards charging wire size between TV and Oliver.  You bring up other equally important concepts that those wanting to use a newer TV's with smart Alternator to charge up their trailer batteries.  

Direct connecting TV to Trailer where you have L.A. to L.A. or AGM to AGM can be done as Raspy posted a couple of years ago (Battery to circuit breaker to Anderson Connection to Trailer batteries).  The reason is that the two systems operate at the same voltage and have the same charge profiles.  The voltage drop (I.E. a measure of cable resistance over its length) from the front battery to the back batteries will to some degree self limit the amount of power that could flow.  This in turn provides a good measure of protection to the TV electrical systems.

However mix a L.A./AGM TV to a Lithium Trailer batteries using direct connecting will really cause grief for several reasons:

• The internal resistance of the Lithium's is insignificant to that of the AGM or L.A. batteries.  This would allow HUGH currents to flow from the TV to Ollie.  If properly fused at both the TV battery terminals you would just be inconvenienced a lot.  However, you are still at risk of damaging the TV charging/battery.
• Lithium batteries generally require a three program charge process that a direct connect does not provide.  
• A smart TV alternator varies the output voltage to match the need.  As a result, it will tend not to provide high enough voltage much of the time that the Lithium's need to get charged up.  

So to use your TV smart alternator to charge your lithium's, you need a current limiting device, that also acts as a "Buck Boost" transformer, and provides the computer smarts to provide the lithium's their three phase charge program.  The unit you suggest appears to do all these tasks at 11 amps.  A larger unit is the Victron Orion 12 -12  30.  The "12 - 12  30" translates as:  A 12+/- volt input providing a 12 to 14+ volt charge voltage to the lithiums, with up to 30 amps continuous (if needed), with current limiting and smart charging profiles.

If you have a smaller battery bank, and drive many hours a day, a 11 amp charge system would work great and save you $$$.  But we are now seeing Lithium battery banks commonly in the 200 to 300 Ah range.  And some up to 630 Ah (such as Galway Gal's and the Oliver OEM Pro set up).  For those, you likely would want the larger Victron Orion 12 - 12 30 charging system.  

Just a reminder these auto smart transformers are not 100% efficient.  In the case of the Orion, it can continuously produce 30 amps at the correct voltages as needed, and is listed at 87% efficient.  So that would mean your TV alternator/batteries could see up to a continuous 34.5 amp current draw.  This means that there will be about 57 watts of power lost to the heat sink.  So be careful where you locate this unit, and provide cooling holes/vertical space for the heat to dissipate (See JD's Posting On This Topic). 

 

Edited October 5, 2021 by Geronimo John
relooked with fresh eyes and made it an easier read. No significant changes.

[Jps190]

Hey guys, I am considering doing a DC to DC charger and was wondering if you could evaluate my thoughts.  I have a 2021 GMC 2500 duramax.  The charge wire on the trucks 7 pin is fused at 30 amps so I am assuming it is a 10AWG wire ( will verify this).  At idle with no load I am showing 14.7 volts at the 7 pin connector on the bumper.  My Oliver has a 10AWG ground and charge wire (black and white) running all the way back through the trailer.  I am considering the Victron Orion 12/12-18 DC to DC charger.  If I mount the charger under the front dinette seat I could minimize the run of 10AWG wire to between 30-35 feet which would have a voltage drop to about 12% to 12.9 volts assuming a load of 20.5 amps due to the 87% efficiency of the charger.  This is within the input range for this charger.  I could then run larger 6 AWG from the charger to the batteries to avoid any more losses.  I have the 3 lithionics batteries in my trailer.  

 

Thanks for your thoughts,

John

[John E Davies]

On 1/13/2022 at 2:45 PM, Jps190 said:

Hey guys, I am considering doing a DC to DC charger and was wondering if you could evaluate my thoughts.  I have a 2021 GMC 2500 duramax.  The charge wire on the trucks 7 pin is fused at 30 amps so I am assuming it is a 10AWG wire ( will verify this).  At idle with no load I am showing 14.7 volts at the 7 pin connector on the bumper.  My Oliver has a 10AWG ground and charge wire (black and white) running all the way back through the trailer.  I am considering the Victron Orion 12/12-18 DC to DC charger.  If I mount the charger under the front dinette seat I could minimize the run of 10AWG wire to between 30-35 feet which would have a voltage drop to about 12% to 12.9 volts assuming a load of 20.5 amps due to the 87% efficiency of the charger.  This is within the input range for this charger.  I could then run larger 6 AWG from the charger to the batteries to avoid any more losses.  I have the 3 lithionics batteries in my trailer. 

I think this would be OK, but verify the wire sizes visually! As I mentioned in another thread, I found an undersized wire inside the hull. If I had not discovered and fixed that, there could have been an electrical melt down. Mine definitely were not 10 AWG! 

https://olivertraveltrailers.com/forums/topic/5271-how-to-junction-box-for-the-7-wire-trailer-harness-under-the-front-dinette-seat/

I am a little concerned about the Victron environmental specs, specifically the “Humidity - Max 95% Non-condensing”. Depending on your location, that may be exceeded often. If you are in the arid West, it wouldn’t be a big deal. I have seen these chargers installed in high end expedition campers, so it may not matter. One thing I like about the Redarc one is that it is fully waterproof, you could even hang it below the hull.

Maybe an email to Victron USA about the humidity limit might be advisable. You also need to consider waste heat management, can you find a spot where there will be adequate airflow? As delivered, all the Ollie electronics bays are very poorly vented. You should plan on adding vent holes. Take a look here:

https://olivertraveltrailers.com/forums/topic/5301-how-to-lithium-battery-powered-vent-system/

If you proceed with this project, please start a new thread with pictures. We all love pics.

John Davies

Spokane WA

[Geronimo John]

On 1/13/2022 at 12:45 PM, Jps190 said:

Hey guys, I am considering doing a DC to DC charger and was wondering if you could evaluate my thoughts.

October 2022 Post Project Edits in BOLD.

 

A  With three lithiums, I am assuming you have at least 300 AH  capacity.  With that in mind I was wondering why you have chosen the 18 amp Victron?  The incremental cost to their 30 amp one may something to consider.  

B.  Your cable length of 30 to 35 feet warrants a re-look.  For my "Little" F-150 Super Crew to OE2 will require cables ( plus and minus) ffrom battery to battery of right at 110 feet of #4 AWG.  This is due to needing to run both cables from TV battery to Oliver LiFePo4 battery box.  

C.  The voltage loss is calculated for both the out and back length.  It likely will be in the 100+ foot range for your big rig.  At that length I would have concern with just using #10 AWG for 18 amps as well as the voltage loss at that distance and cable size.  May want to re-look at that.  In my case I went with the Orion 12/12 - 30amp and with a 54' run both ways (108' Total Cable Length Used) the 4AWG was strongly suggested by BatteryCablesUSA.

Should my above thoughts actually apply to your project, the logical conclusion is that you'll be running new cable front to back.  Should that be the case, with your three lithiums, I would go with the larger charger and power it up with twin AWG #4 stranded copper cables.

Concerning mounting the Victron in the front dinette under seat cabinet,  that is where I have posted and where I plan on mounting my 30 Amp Orion 12/12-30.  My thoughts are that since the only time that the charger will be generating heat is when I am on the move.  I will be removing the cushion and under- seat storage cover to allow the heat to escape to the trailer cabin.  This solution does not add to the under bed heat build-up issue mentioned above.

Good luck.  

[Jps190]

Thanks for your thoughts guys. I have been mulling this over for the past few days and have come to the conclusion that I am just going to run some large cables and go all in.  I also have a dual zone fridge/freezer that I want to be self sufficient in the truck bed so there might be a second DC to DC charger installed there. I have a 400 watt AC plug in the truck bed so this is still up in the air.  I am thinking of something similar to what Galway Girl did on his rig.  Geronimo John, Did you ever get answers to the questions you posted on Galway Girls thread?  I would be interested in the answers.  As far as wire size you are planning on running 2 AWG?  Are you going to use welding cable or a marine grade cable with tinned copper?  Is there an advantage to running a return all the way back to the battery as opposed to using the frame?  As far as the trailer wiring have you determined where you are going to enter the trailer.  I would like to go through the front of the hull down behind the propane tanks but I have't checked for what access is available.  Is there access under the vanity to that area?  Have you sourced all your parts yet?  I would be interested in what you have and where you got it.  Are you going to clean up and move your battery box wiring?  I am planning on moving all wires into the hull through some busbars/lynx distributer.  Probably going to swap out the charge controller as well.  John Davies, have you decided if you are going to switch over to series wiring for your panels?  My list of things to do keeps getting bigger so I guess I need to just start with the truck wiring!!! ;-)))))

 

Thanks,

John

[Geronimo John]

On 1/18/2022 at 3:34 PM, Jps190 said:

As far as wire size you are planning on running 2 AWG?  Are you going to use welding cable or a marine grade cable with tinned copper?  Is there an advantage to running a return all the way back to the battery as opposed to using the frame?  As far as the trailer wiring have you determined where you are going to enter the trailer.  I would like to go through the front of the hull down behind the propane tanks but I have't checked for what access is available.  Is there access under the vanity to that area?  Have you sourced all your parts yet?  I would be interested in what you have and where you got it.  Are you going to clean up and move your battery box wiring?  I am planning on moving all wires into the hull through some busbars/lynx distributer.

John:

First, welcome to the Oliver Family!

I need to clean up my documents, but they are 95% done.  PM me with your E-mail address and I'll send you a materials list showing sourcing and costs for my entire Lithium project, as well as my edited version of pirated copies of other members many suggestions.  (Galway Girl, Minnesota Ali, John Davies, Overland, etc.)  

I am using 4 AWG stranded premium copper cable from BatteryCablesUSA.  Found them to be the best price.  Also they are VERY helpful in calculation the actual voltage drop.  that size cable is also what the voltage drop will be. 

As far as return back yes on the run both out and back.  Also use high temp wire loom as likely it will be passing by your turbo's and/or exhaust at some point.  For my 3.5 EB turbo area, I will also be wrapping the loom with heat shield.  You want to minimize connections and also the higher resistivity of the frame.

Yes, for the hull penetration, use the same method that Galway Girl documented in her report.  It runs below the bathroom floor.  You can see the path from under the front dinette seat.

Yes on the clean up and removing all not required cabling from the battery box.  

GJ

[GarryandKristi]

On 1/13/2022 at 5:45 PM, Jps190 said:

Hey guys, I am considering doing a DC to DC charger and was wondering if you could evaluate my thoughts.  I have a 2021 GMC 2500 duramax.  The charge wire on the trucks 7 pin is fused at 30 amps so I am assuming it is a 10AWG wire ( will verify this).  At idle with no load I am showing 14.7 volts at the 7 pin connector on the bumper.  My Oliver has a 10AWG ground and charge wire (black and white) running all the way back through the trailer.  I am considering the Victron Orion 12/12-18 DC to DC charger.  If I mount the charger under the front dinette seat I could minimize the run of 10AWG wire to between 30-35 feet which would have a voltage drop to about 12% to 12.9 volts assuming a load of 20.5 amps due to the 87% efficiency of the charger.  This is within the input range for this charger.  I could then run larger 6 AWG from the charger to the batteries to avoid any more losses.  I have the 3 lithionics batteries in my trailer.  

 

Thanks for your thoughts,

John

I’d be very surprised if your Oliver has 10 awg wire for both charge and ground wire. Ours (2018 elite 2) has 12 awg charge and 14 awg ground.  However as @John E Davies mentioned (I think in another post) he noticed a splice inside the trailer in which the wire gage was reduced.  I need to check this myself in hopes of getting a tad more amperage.  You may have already completed your charge modifications, but I can vouch that with the existing 7 pin and wiring, and especially with Lithium hose batteries you’ll be lucky to get any charging. I only get 2 or 3 amps. I like John’s idea of not having to mess with TV and TT wiring and just being satisfied with somewhere in the range of 11 to 18 amps. In our case that would at least offset the adsorption fridge draw of about 15 amps. I added a relay in our oliver that is triggered by the taillight (green) 7 pin wire so at least I could isolate the batteries and only attempt to charge (turn lights on) when the conditions are good. With the newer “smart” alternators sufficient voltage to charge with the existing 7 pin setup is dubious. There is no way that a 7-pin system can cause overcharging and  too much lithium house battery draw as the voltage potential difference is just not there and much amp draw would increase the voltage drop and lessen the voltage potential difference.  I am considering unplugging the wire from the shunt on the negative post of our truck battery to get a constant higher voltage from the alternator - at least for a test.  If it seems ok I would only disconnect for times were were both traveling quite a distance and then dry camping. I am just not sure of what other electrical systems might do with the smart alternator feedback interrupted.