Choosing a DC-DC Charger

[jd1923]

When I get around to adding this mod, I want to do it right and I understand @MAX Burner and @rideadeuce and others here have gone down this path.

I want to add DC-DC capability but not overload the TV alternator. I also want to understand cable gauge minimum requirements, wanting required AWG without paying extra for overkill. Obviously a 30A charger requires less ampacity in cabling than a 50A model.

I'm thinking that 30A is enough at 60% the cost of the new Victron 50A model. What would you do? Victron doesn't even list this model on their website anymore. Amazon.com: Victron Energy Orion-Tr Smart 12/12-Volt 30 amp 360-Watt DC-DC Charger Non-Isolated (Bluetooth) : Automotive

They do show their new 50A model: Orion XS - Victron Energy

[rideadeuce]

No question in my mind… except the non-isolated vs isolated aspect. I still have not had the time to replace my alternator to a high output because I am not getting near the capacity with current setup. I used 4 awg wire from TV battery to Orion XS via Anderson connectors. 

 

Edited August 24, 2024 by rideadeuce

[Steph and Dud B]

I find this helpful when selecting wire: https://mgispeedware.com/wire-size-chart/

I also prefer using marine grade wire.

[jd1923]

Wow, I got all my answers in just 2 hours! 😂

Thank you @rideadeuce that video sold me in the first minute. I had no idea of the size difference, let alone efficiency and less heat produced.

Thanks @Steph and Dud B too, the table shows 4 AWG and the Orion XS 50 takes up to 4 AWG.

Guess when I work this, I'll have to bite the bullet for the $400 Orion XS and likely another $200 for cables and connectors.

[mossemi]

@jd1923  said, Guess when I work this, I'll have to bite the bullet for the $400 Orion XS and likely another $200 for cables and connectors.

I placed a bid of $280 for a Orion XS couple of days ago that was listed on eBay @$328.10.  At $280 it was still over $300 to my house.  I received a counter offer of $308.10 which I declined because I'm really not ready for that job, a refrigerator repair/replacement has top priority.   
Mossey

 

Edited September 2, 2024 by mossemi
Typo

[jd1923]

35 minutes ago, mossemi said:

I received a counter offer of...

I understand, timing is key. After posts today I looked up TEMCo 4 AWG on Amazon and they had a sale, so I purchased 50 of each red/black 4 AWG at a very good price. I can afford this now.

The $400 charger will have to be for Christmas or soon after...

[rideadeuce]

7 hours ago, jd1923 said:

 

Duplicate

Edited August 25, 2024 by rideadeuce

[rideadeuce]

15 hours ago, jd1923 said:

purchased 50 of each red/black 4 AWG

Just FYI, my Tundra install with placing the Orion in rear bay took around 60 ft of 4 awg red/black. Had some left over but I bought 50ft foot originally and had to wait on finishing the install to place a separate order. WIndynation.com also has good wire kits priced well that come with your choice of lugs and quality heat shrink tubing. 

https://www.windynation.com/products/4-gauge-welding-battery-cable-kit-includes-5-pieces-of-3-8-5-pieces-of-5-16-tinned-copper-cable-lugs-and-3-feet-black-heat-shrink-tubing?variant=43802376143070

 

Cheers,

Mike

Edited August 25, 2024 by rideadeuce

[Ronbrink]

17 hours ago, jd1923 said:

What would you do?

I can only state ‘what I did’! Started off with a Renogy 20A DC-DC charger and the 50’ WndyNation 4 AWG wire set @rideadeuce mentions. The larger than necessary gauge wire was installed to accommodate any future upgrade in charger size, which eventually came into play. The charger was installed in the rear dinette seat hatch, mounted vertically on the interior wall, in like manner as the Xantrex, but on the opposite side just forward of the above battery box/pantry. This position allowed for the shortest cable run to the battery bank, being four 6V Trojan T-105s at the time, and this charger was the alternative of choice since my OTT did not have solar. However in short order, I ungraded to LFPs to be able to run the a/c via the inverter, and subsequently upgraded to a Renogy 40A DC-DC to further offset draw on the battery bank when running the a/c while underway or during brief stops with the TV at idle. This practice proved to be too stressful on the aging stock alternator and thus a high output alternator was installed. I convey all of this knowing that you are fully aware, but there may be some that read this and find it helpful information. I simply choose Renogy as a cost saving measure, half that of a Victron, and have been very pleased. A Victron SmartShunt was also installed at time of the lithium upgrade and the Renogy’s output can be monitored via the VictronConnect app. 

[Coddiwomple]

Just finished install of Victron Orion XS 12-12 50A charger in my Elite 1. Special thanks to Geronimo John for helping me with my project. His expertise was invaluable. And highly recommend Artek Energy in Milwaukie, Oregon where I purchased most of the components, parts, and materials. They went above and beyond with advice and even helped with the settings on my existing Victron MPPT Solar Controller and SmartBMV712. 
Everything is now working together smoothly and efficiently.

At 80% SOC on the Lithium Batteries, the charger is pushing out 48.8 amps bulk charging at idle. Nice!

Replaced OEM 100amp alternator with Mechman 240amp alternator. 1/0 marine grade tinned cable from alternator to battery and then back to Anderson SB175 connector. Then 1/0 to busbars in trailer and reduce to 6 gauge for short runs to/from components and batteries.  

[Geronimo John]

On 8/24/2024 at 12:13 PM, jd1923 said:

Thank you @rideadeuce that video sold me in the first minute.

Yep me too JD!  Sadly last year I pulled the trigger on the Orion 12/12-30.  DRATS.

Anybody want to buy a 12/12-30?    😞

Seriously, good move on your part.... again.

GJ

[MAX Burner]

On 1/5/2025 at 9:01 PM, Geronimo John said:

Anybody want to buy a 12/12-30?    😞

No need to feel so sad, John!  

Our 30A Victrons do the job, IMO, for their intended use.  On our typical move between locations we target 4 to 5hrs (MAX) road time -- leaving in the mid-morning with, say, a 70% SOC, by the time we're stopped for the day, we're right at 100% in our 300A-Hr Battleborns.  The 4/0 cables you and I used for our applications handle the current perfectly.  

Still thinking we've both got the right 12/12 charger solution for our style of RV'ing (but, there is a bit of "Amp - envy" going on over here!).  Now, that said, if our rigs had the larger lithium AHr storage like @jd1923 JD has, the 50A charger would be warranted, concur?

[johnwen]

Just wondering... I have the 30a Victron as well, along with my Zamp solar controller, a Victron solar controller and the Xantrex 2000w inverter/converter. I reset all of them to accept the new 300ah x 2 Epochs using their generic lifepo4 settings.  They all seem to have slightly different charging parameters.  Should I just accept all as is or try  a different user  defined setting?  The Xantrex has Absorption value of 14.6v and Float value of 13.6v.  Seems high but don't know.  All seems to be working exceptionally well but don't want to exceed any voltage limitations for the Epochs.  Any suggestions/references I should follow concerning the percent usage before  charging i.e. let deplete to ? % once in a while instead of keeping topped off?  I rarely seem to go below 82% and the rooftop panels spend no time in boosting back to 100%.  One note to mention...when I set the Xantrex up for lithiums I was at Quartzsite and no shore power so I cranked up the inverter, changed the settings using the FXC control app and later noticed the batteries did not recover to previous levels after the first time we were on shore power.  Sure enough the battery setting on the Xantrex reverted to AGM.  I reset while on shore power and all seems to now be operating as expected.

John

Edited February 16 by johnwen

[jd1923]

46 minutes ago, johnwen said:

The Xantrex has Absorption value of 14.6v and Float value of 13.6v.

You need to reconfigure your Xantrex, both solar chargers, and your new Orion to the same Epoch suggested charge rates. These specs are from the Epoch Essential 300AH battery manual. Bring Bulk and Absorption charge rates down to 14.2V. It will not matter that you ran higher for a couple weeks, but lower charge voltage over time will extend battery life.

There is also no prescribed charge process like having to bring the batteries down to XX% SOC. Though if your only getting down to a min of 82% just use more 12VDC and 120AC power! Don't worry about leaving lights on (old camping habits), the TV or radio, use your microwave or oven, boil water in an electric kettle, or run your fridge on DC or AC, it doesn't matter. During our last trip to Q, the first morning we ran the HWH on inverted 120VAC and our 600AH dropped about 6%. But don't forget, leaving a high amperage appliance on. I'm sure you're checking the Victron Connect app often

We stay at campgrounds with hookups and most of the time I do not bother hooking up. Like you mentioned, it is good every so often knowing you're up to the full 100%. I hooked up when we got home after a week to bring them up to 100%. The next morning I put the cord away and this week while working in it, running lights, radio and furnace, our 600AH has always been over 90%.

And now you have DC-DC charging. Your system is in a great shape! 😂

[johnwen]

Thanks JD...just what I need :)

[Geronimo John]

On 2/16/2025 at 7:08 AM, jd1923 said:

You need to reconfigure your Xantrex, both solar chargers, and your new Orion to the same Epoch suggested charge rates.

JD:  Thanks for the comments. 

Both Art and I (And a bunch of others who went lithium earlier) have 3 ea 100 AH Battleborns,  Orion 12/12-30 truck chargers, and various solar panels. Would your approach apply as well?

GJ

[jd1923]

1 hour ago, Geronimo John said:

JD:  Thanks for the comments. 

Both Art and I (And a bunch of others who went lithium earlier) have 3 ea 100 AH Battleborns,  Orion 12/12-30 truck chargers, and various solar panels. Would your approach apply as well?

GJ

GJ, yes certainly.
The relevant charging specs are the battery manufacturer's specifications. Most chargers are configurable. I spent time programming our NEW Victron MP2 and our OEM installed Blue Sky solar charger to configure per Epoch LiFePO4 parameters, voltage settings for bulk, float, etc. This is a must, however...

For secondary chargers like the DC-DC charger, or for example a 30A MPPT solar charger, connected occasionally to a suitcase, it is so much less important! These chargers are temporary, so does it matter if the charge rate is somewhat off the specs? NOT. Your not using these secondary chargers to bring the batteries up to 100% SOC periodically. We use these secondary chargers when SOC is low enough to care and take the time to connect.

Use your LI batteries to their potential. It's crazy that one 300AH Epoch at $900 today would replace the 3x Battleborn batteries. But as long as yours are working and satisfying your needs, @MAX Burner has talked to this, just keep them charged! 

Another consideration is the charge rate (Amps). our Victron MP2 can charge up to a 120A rate. The Epoch batteries can handle up to 200A, but they suggest 50A as a conservative charge, so I set my MAX charge rate to 50A. When you park at a campground and connect after a few days disconnected, a 50A charge rate will always get you back to 100% SOC by the time you leave the next morning. 😂

[johnwen]

1 hour ago, jd1923 said:

so I set my MAX charge rate to 50A. When you park at a campground and connect after a few days disconnected, a 50A charge rate will always get you back to 100% SOC by the time you leave the next morning.

JD

I'm finding this to be be true for us...