400 dc-dc mods

AndreO · January 2022

Has anyone completed a dc-dc install for lithium on a 400? I have a 2018 standard 400.

It does not appear to use the frame as a DC ground.

Looking to put in a Redarc 50amp bc-dc. But it looks like a complete circuit would require 90 feet round trip of 4/0 cable to get from the front of my F150 to the back of my 400. Both very heavy and expensive. So I'm looking to use the frame as the dc ground as it will cut cable length to between 45 maybe 50 feet of 2/0 cable.

Anybody with any similar experience doing so?

Thx

Andre

Dutch061 · January 2022

Andre,

I used a Victron DC-to-DC Charge Controller but an 18 Amp. My 2021 F-250 has an isolation relay already, so it was simple to configure.

Installation was super simple; I have a couple of pictures below. In the first picture you can see the yellow on the end of the wire that I added after removing the factory installed charging wire.

I installed the Controller under the curb side dinette right behind the factory power distribution center.

Image: https://us.v-cdn.net/5021717/uploads/editor/ei/m12m2u5pti2c.jpg

I chose the Orion Smart Controller since it can easily be configured with the Victron App. I tied the 2 grounds together since they go to the same bus bar anyway. I ran the new wire from the power distribution center to the output and connected the factory charge wire to the input.

I chose the 18 Amp because my TV has a 10- or 12-gauge wire installed that is fused at 30 Amps. I didn't want to hassle with additional wiring on the TV etc.

This took me from 2 to 4 amps to 18 with the truck running. Additionally, the Victron ah intelligence built in to determine when the vehicle is running if you don't have a factory installed isolation relay.

I am using 400 Ah of BB with a PD9160ALV Converter within a foot of the battery junction block.

Brad

AndreO · January 2022

Hi @Dutch06,
Thx for the input.

Do you also have solar?
Do you know what the voltage is coming into the victron?
I calculate a 1.7volt (15%) drop on that 12 gauge from the truck but you say you are getting the full 18 amps at the Batt. That's really impressive performance by the victron.

They say the recommended voltage drop should be less than 3%. I wonder if I could cut down the cable size on my plans and still get decent performance.

However, by my estimates at the full 18 amps charge capabilities ( and assuming a 4.25 amp paracidic drain for fridge etc.) I estimate it would take 14.5 hrs drive time to recover 200ah on your lithium.
I'm aiming at 4.3 hrs via the 50 amp Redarc.

Do you have any stats on what your actual recovery rates are? All these estimates are theories, it would be nice to see how close they come to reality.
Andre

Dutch061 · January 2022

Andre,

Yes, I have the 192 Watts of Solar on our 2020. I just installed the Victron and have not travelled with it yet, but as you well know the DC-to-DC Controller not only limits the amperage (non-issue for most) but also boosts the output voltage to the level set. The low amperage on OEM is due to the higher voltage requirements of Lithium.

I did notice that I had an extreme voltage drop (I think it was around 10 volts under load while monitoring with the Victron App) caused by my 7-pin connector terminals. Even with this low voltage, the Victron was able to boost it to 14.6 volts and provide 18 Amps output as measured by my BMV-712. I could however feel the heat in the 7-pin due to the dirty terminals. Cleaning the 7-pin connector fixed that voltage drop and heating issues.

In addition, I have installed a PD9160ALV Converter as mentioned very close to the battery junction block. This resolves the charging issues inherent with ALL RV's caused by excessive resistance and/or distance between the converter and the battery bank. When I was using 200 Ah, I could fully charge in less than 3 hours, now it will take over 6 with the additional Ah. But I figure with minimal sunlight on the panels, I should be able to go 6 or 7 days easily. So, I can also use a generator for a couple of hours and add back capacity very quickly too if necessary.

As mentioned, I chose 18 Amp due to the truck having a 30 Amp fused charging circuit with an isolation relay. I wanted to stay under the maximum amperage to prevent any other issues and the hassle of running a separate wire and connector. Even if the NET is 14 Amps and I only drive 6 hours, I will still gain 84 Amps which is plenty for 2 days if you are conservative, which I am not.

I chose Victron due to the other 2 Victron devices and ease of set up. Currently, the Charge Controller is not able to operate on the Victron Network, but I suspect that it may be added in the future. There are some who have concerns about temperature, specifically low temperature and the inability to shut off the Charge Controller in extremely cold weather. If it was on the Victron Network, this information could be shared, since I have the temperature probe also. In my experience so far this winter in NC, the lowest I have seen the battery temperature is 37 degrees. I believe Battleborn has their low temperature charging shut-off set to 25 degrees. Again, another reason that I chose the higher priced quality products route.

Disclaimer: I am not compensated in any way by Battleborn or Victron. I chose their stuff because it is robust, highly tested, and nearly bullet-proof. Life is too short to be hassled by selecting things that I have to do the R & D on.

Brad

RFraer · January 2022

I install the Victron 30 amp dc-dc charger. Amperage was to high for the 7-pin so I use a Anderson connector with 6awg wire. 6awg is the largest wire the charger terminal would accept. Not sure why you are using 90ft, that most be the +&- side combined. I used the + wire length from the alternator to the charger, (25 ft) to select gauge, that was my largest run between the fuse and load. My 2020 400 does have a cassis gnd.

AndreO · January 2022

@RFraer,
Thx for your input.
RedArc suggested I use round trip for voltage drop calculations hence the 90'. Granted it's a guesstimate. They recommended location for the bc-dc is within 3 feet of the Batts and being 50 amp to mount it to the frame to use as a heat sink. My Batts are literally as far back on the trailer as you can get. That's because the 2018s are tongue heavy. So I'm trying to load balance the much lighter lithiums.

The RedArc 1250D will be mounted under the trailer to the frame just behind the back wheel, just about where the red and blue water pipes turn under the kitchen cabinet. (It is 100% weatherproof) It can also prioritize solar at the same time but Nucamp no longer installs solar aftermarket. No big deal, I figure should I decide at some later date, the BC-DC is in a great location for a standalone panel. My control Center is off to the right under the closet. I know they moved it but not sure where for which year.

The 2018s, as far as I have been able to tell so far, only has the AC side of the Power Center grounded to the frame. I think they changed that 2019 or 20.

Not that it matters because I do plan on using the frame for DC ground cutting the length of cable by almost half hence reducing cable size. Exactly how to do that with out creating any issues is what I'm still trying to figure out.

It doesn't help I drive a truck. Guessing the routing through the truck back to the Andersen is going to be 25'. Add 18' back to the BC-DC on the 400. Also taking into account it the actual length of the cable and not distance between starter and BC-DC.

It looks like @Dutch061 wired his victron DC-DC through his Control Center. Did you? I was planning to wire mine directly to the Batts to cut down on cable. I figure the feed from the Batts back to the Control Center should handle fridge etc on the move.

Andre

Denny16 · January 2022

Sounds like a plan Andre, whilst you have the rear storage area floor up, you might consider adding some additional supports under the top floor plywood panel, to allow better use of the storage area for heavy items, like canned goods or additional batteries…

I plan on adding some additional support under this area in our 2018 TaB400.
Your lithium upgrade install came out very lovely.
cheers

Dutch061 · January 2022

Andre,

I removed the charge wire coming from the 7-pin connector inside on the power distribution panel. I installed the Charge Controller in between. Yes, having it closer to the batteries would have been best but I figured the 8 gauge that is factory installed should handle the 18 Amps without an issue.

At least in testing in my driveway, that seems to be my observation that getting 18 Amps through the BMV-712 which is right next to the battery junction block is possible. If I had used a 30 Amp or larger, I would have definitely had to use additional wiring etc. and running any wires inside is a major task.

Brad

RFraer · January 2022

It looks like @Dutch061 wired his victron DC-DC through his Control Center. Did you?

No, i ran 15' of 6awg +&- back to my trucks bumper and into an 50 amp Anderson connector. I put a 60 amp breaker near the vehicle battery.
On the camper side I followed 7-pin cable to the frame. Drilled two 1/2" holes in the frame, put in rubber grommits and passed the wires under the floor. I came through the floor near the air conditioner, ran the wires under the bath then into the 30amp charger input. On the output i ran 3' of wire to the lithium batteries with as second 60 amp breaker on the + wire.

DenisP · January 2022

I installed the 30A Victron D/DC charger on my 2018 400 which has 200 watts of rooftop solar with a Victron solar controller and a Victron BMV 712. I connected the DC/DC charger with 6 g wire from my Tundra’s battery to an Anderson connector at the rear bumper and then to the rear of the tab. I the two 6g wires through an existing access for the ground wire in the compartment under the closet and finished up in the Alde compartment next to the solar controller. I secured the wired to the frame and enclosed under the coloplast covering under the camper. I purchased the 6g wire from Amazon as TEMCo WC0204-150' (75' Blk, 75' Red) 6 Gauge AWG Welding Lead & Car Battery Cable Copper Wire BLACK + RED | MADE IN USA which was easy to work with and well insulated. The installation is similar to @RFraer description.

I do not have lithium batteries yet as the original AGMs are still functioning well. Covid has severely limited my camping since the Dc charger install but I have travelled round trip to Sugarcreek (1300 miles) twice and made a few 100 mile camping trips and have been pleased with fully charged batteries. I have a long trip upcoming in March (10,000+ miles) to visit the remaining 12 states of the lower 48 that we haven’t yet camped which should be a great test for my current setup with only half of the campsites with shore power.

AndreO · January 2022

Thx for the input @DenisP,
Looks like at least so far everyone has solar and used 6 Guage both directions to a Victron.

I double checked the numbers and see that at running at 30 amps, 75 feet of #6 awg (86F) and assuming you have 20 min run, you would have a 9.51% or 1.14 volt drop.
Suggested cable size for a max 3% drop would be a #1awg cable.

Obviously it works for you guys! So I think I'll contact RedArc to see if they suggest something higher than a 3% drop is axceptable for their product.

I know that both products will prioritize solar. (Which I don't have) so maybe the added solar reduces the draw from the Dc-dc making the #6 awg enough?

How much of the 75' of cable did you end up using?

Andre

DenisP · January 2022

@AndreO I roughly have 30 feet remaining of the 6 g.

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