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DC to DC Charger

boogielander

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Boogielander, thanks very much for the detail, and please do let me know which engine bay IGN fuse number you connected to and the description of this fuse from the owner's manual (just because our different model year trucks might have a slightly different fuse layout and fuse numbers).

I encountered the exact problem you did with insufficient voltage to charge my camper battery from the starting battery. I use portable solar panels so the Renogy DCDC with mppt allows me to both direct charge and solar charge via one device that has similar capabilities as your Victron.

And the only place I can find to mount this charger is in the very back of my camper, so I'm using 4 AWG wire, and other than this our setups are very similar.

I think that several readers of this forum would appreciate your detailed writeup and photos when you get to it.
oh yeah if I didn't have a Renogy solar controller then I'd be looking at options with MPPT.
Another method that my friend uses is way more capacity but also bank:
Same Victron setup, but instead of Ecoflow Delta 2 he uses Delta 2 Max with 2 Delta 2 Max Add-on Batteries giving him 6kw of power total. Delta 2 Max has dual input capacity, so he also has 2 Bouge RV 200w solar panels permanently mounted on the roof of his GFC. That pushes out around 600w on a sunny day while driving. No MPPT controller needed since Delta 2 Max has that built in.

But the downside is, that is a $5k setup excluding Victron lol BUT at the same time we were using air fryer to make breakfast and his +1 can use hairdryer. Oh, and we can run Starlink whole night too. In addition, he has fridge hardwired to his truck (with stock dual battery setup) from years ago, so he also has a noco charger that charges the two batteries while engine's not running.

For me i'm happy with 3kw of power because i'm not using air fryer and hair dryer when i do solo overland. I don't have an air fryer and being single with military style hair cut means no hair dryer needed. I can still run fridge and Starlink whole night on just a bit over 1kw/ night and charge it all back within a few hours of driving. All other smaller items that charge via USB can be plugged to the truck or EcoFlow if needed. For days that I establish basecamp I also have portable panels (2x160w Ecoflow portable). I also have one Renogy 170w flexible sitting at home to be installed back on (my old Renogy 100w flexible panel flew away... long story short it was attached to my soft shell wedge style RTT and it held on for half a year until I decided to do 90mph into headwind right around Memorial Day. I'm still trying to find a good solution to attach the new panel)
My setup is only $2496 before Victron.
 

boogielander

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Boogielander, thanks very much for the detail, and please do let me know which engine bay IGN fuse number you connected to and the description of this fuse from the owner's manual (just because our different model year trucks might have a slightly different fuse layout and fuse numbers).

I encountered the exact problem you did with insufficient voltage to charge my camper battery from the starting battery. I use portable solar panels so the Renogy DCDC with mppt allows me to both direct charge and solar charge via one device that has similar capabilities as your Victron.

And the only place I can find to mount this charger is in the very back of my camper, so I'm using 4 AWG wire, and other than this our setups are very similar.

I think that several readers of this forum would appreciate your detailed writeup and photos when you get to it.
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I used F54 PCM. Just note that you'll need to cut/ trim the fuse box side a bit to allow wire to come out. I'm not a fan of just forcing the lid on because it can damage the wire that you're running and potentially leave a bigger hole on top for water and other elements to get in.
I recommend using a small dremel bit to trim, but a sharp cutting tool does the job too. I was in a rush that day so I just use a small sharp pair of cutters that I use to trim zipties to make a V-shaped cut instead of breaking out the dremel and the stylus attachment.
 

PeterB

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Super, thanks much! And I was wondering about whether to drill a small hole in the fuse box cover or put a small notch where the cover joins the base, so thanks for your recommendation; just cutting a small notch will be easy.
 

boogielander

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Super, thanks much! And I was wondering about whether to drill a small hole in the fuse box cover or put a small notch where the cover joins the base, so thanks for your recommendation; just cutting a small notch will be easy.
yeap just cut a small notch will be fine. I believe I also trimmed inside of the cover as well to reduce the amount of notch i have to cut on the bottom side.
 

rdugedug1

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I read this once or twice but I don't believe anyone has used the 30 amp 7 pin that is built into the truck.

Food for thought, I will add a renogy 1212-20 to the truck side of the 7 pin with OEM wiring which is 10 gage. I suspect roughly 10-12 feet from fuse box to the 7 pin connector. Renogy installation chart shows this to be acceptable to supply this unit. From the 7 pin to the trailer is also 10 gage wire and in my case 10-12ft, this also is acceptable to Renogy. For testing I can use the half current option on the unit and test bumping it to the full 20amps. My concern is where to mount the Renogy? Under the bed would be nice but note a clean dry environment. In the bed would be ok except for running wires back and forth. I mostly have the bed covered anyway.

If there were any issues with this then they wouldn't have spec'd a 30 amp fuse for the line?

Any takers?

I have an etorque hemi also. 200W solar 100AH lifo for fridge and furnace but would like to boost the pack while driving. I also have 3 85 AH lead acid in bed of truck for invertor for coffee and hair dryer. They charge while I drive but draw down the lifo while driving. Testing at 10amps would be because the same 10 gage wire is already delivery 3-10 amps to the lead acid. I would have to choose carefully when I could switch to 20 amps if it was even necessary.
 

Ddubya

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Interesting discussion. I have a 2023 ETorque and have been thinking about how to charge the trailer Lithium batteries. My understanding of the Ram Etorque charging system is that the generator feeds the on board 48 volt battery and a dc to dc 12 volt charger for the 12 volt truck system.
Has anyone researched the possibilities of either a dc to dc converter fed by the 48 volt generator or a dc to dc converter fed by the 12v truck dc to dc converter. My thought is that the truck dc to dc converted will not have enough output to power another dc to dc converter to charge the trailer batteries.
 

Bt10

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Interesting discussion. I have a 2023 ETorque and have been thinking about how to charge the trailer Lithium batteries. My understanding of the Ram Etorque charging system is that the generator feeds the on board 48 volt battery and a dc to dc 12 volt charger for the 12 volt truck system.
Has anyone researched the possibilities of either a dc to dc converter fed by the 48 volt generator or a dc to dc converter fed by the 12v truck dc to dc converter. My thought is that the truck dc to dc converted will not have enough output to power another dc to dc converter to charge the trailer batteries.
Why would you have the truck dc-dc converter power another dc-dc converter? 12 & 12?
 

Ddubya

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To isolate the truck convertor or in case the truck convertor cannot supply enough current. Most importantly the truck convertor is set up to charge a wet cell battery and a lot of trailers are using lithium batteries. I would also like to know if a 48 volt to 12 volt convertor would work from the truck generator.
These are questions that should be answered before I would try it.
 

boogielander

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so e-torque is achieved with 48v generator that converts to 12v for starter battery.
Theoretically plugging in a dc-dc converter at the 48v part should work. (meaning, using the 48v battery to charge the aux battery via dc-dc converter) there are products that work with 48v and step it down to 12v while boosting wattage output.

HOWEVER, because of the complexity in design and cost to replace should something goes wrong, I much rather just grab power from the 12v side and step it up to boost wattage output than mess with the 48 system.

The simplest solution, without messing with the 48v portion, is to run power from the starting battery to a dc-dc charger to step the output up to charge the aux battery. You will need a strong dc-dc charger to step up enough wattage to charge the aux battery fast though. My way of doing it pushes out around 200watt/ hr of power to charge my EcoFlow, but replacing the current charger with a more expensive one I can probably push another 100W out.
 

hogger

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Not doing this with an e-torque, but I've set up a 200Ah LiFePO4 set of aux batteries to charge from a Victron 12-12V/30A DC-DC converter. So about 400 watts to the batteries. I'd recommend you watch your wire sizes, and maybe go for an actual charger instead of just a DC-DC converter. And at those currents, wire the GND back up to the front, as the rear GND point from my research is spec'ed for max 50A, which my set up can exceed under worst case conditions. I kinda wish I'd gone with a heaver gauge wire, and someday I may swap out, but it works well enough that it's not a top priority for me atm.
 

Ddubya

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Ok, it appears that the charge line on the 7 pin trailer connector is fused at 30 amps. With that in mind a DC to DC charger in the trailer should be all that is needed.
 

Rickyrocket

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Plenty of success with this project on YouTube,never heard anything about the ""battery pack" having problems.
 

Bruno Sailor

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I have a 2023 ram Etorque. I was going to do Dc to dc charging for my travel trailer but decided against it. I was advised by 3 independent sources not to do it. One was a Ram service manager at a local ram dealership stating that the level of complexity of the controls on the system will probably go into an error code and possibly worse. The second was from Explorist life an expert in converting rvs and vans to LiFePo4. The 3rd was also an expert in solar rv. That was enough for me to not risk causing massive damage to my new truck.
 

boogielander

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I have a 2023 ram Etorque. I was going to do Dc to dc charging for my travel trailer but decided against it. I was advised by 3 independent sources not to do it. One was a Ram service manager at a local ram dealership stating that the level of complexity of the controls on the system will probably go into an error code and possibly worse. The second was from Explorist life an expert in converting rvs and vans to LiFePo4. The 3rd was also an expert in solar rv. That was enough for me to not risk causing massive damage to my new truck.
ive been running not one but TWO DC-DC charger on my etorque. one is victron 12/24 that powers my ecoflows and another one is Renogy 50A DC-DC with MPPT. both are hooked to the starting battery with their own breaker and power line, and both are ign triggered.

as long as you're not running it to the 48v on the etorque you're fine. Also as long as you're using quality components (Renogy Victron etc with ign trigger) and use quality parts (Blue Sea breakers) you're going to be ok. Those smart chargers know when to kick in and when not to so they don't put too much stress on the e-torque system
 

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