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Discussion Starter · #1 ·
I've got a 2019 Touring with tow package and understand from other posts that this has a 190a alternator. I'm considering adding either a 40a or 20a DC to DC charger, either from Redarc, or Renogy to charge my RV Travel Trailer batteries while I'm towing. Could the vehicle support up to 40A load being sent to a trailer? Or, would it be best to stick with a 20A? Also, any suggestions on circuits to use, or if there is existing wiring that runs to the back I could tap into? I'd like to avoid running more wire if there is something I can leverage. Thanks for any tips.
 

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Unfortunately the 7 pin connector is almost useless if you need any kind of significant current draw. The wire is too thin of a gauge to support any kind of heavy current. My F450 has dual alternators that combined, put out near 400 amps. But almost none of that gets to my fifth wheel because the 7 pin connector is too limited.

The best way to do this is to indeed use a DC to DC charger like the Redarc. The OP will need to run a calculation to figure out what gauge of wire he's going to need to use based on distance and amperage. This is the setup folks with big rooftop solar panel arrays on fifth wheels use. However as to the specs of the Ascent's generator and how much stress it can take, I have no idea.

The round 7 pin tow lighting connector is supposed to have a hot charging wire in it

View attachment 6667
 

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Discussion Starter · #4 ·
Thanks all for the info. From what I’ve read, generally speaking, and from this guy’s blog who did to his truck what I’m thinking of doing to the ascent, 7pin puts out a max 2-4 amps. Agree on all points of needing to do the calculation run lengths and wire gauge.

Since the post I’ve done a bit more research using my ODBC scanner to see how ouch headroom I have in the alternator, it seems like a lot. 190a is actually pretty big and with the odbc with all brights in, seat warmers, radio, blowers, heat, phone charging it seems to max out at around 36% of capacity (190amps) if I’m reading this right, the absolute load value in the screenshot (tell me if I’m not). If so, thinking it could send back 40a -50 amps easily.
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Going with either hi-amp charger, will require running new + & - wires of sufficient gauge, to both the charger & the trailer. The existing wire is likely only going to handle about 10A at vehicle charging voltage, with no compensation for different battery types.
Look into Anderson Connectors for your cable disconnects at the hitch. for 40A, I'd recommend 8 or 6ga fine stranded wire
After reading about both chargers you mention, I'd skip the Renogy, from past poor reports from them. (I'm a moderator on a solar forum and live off grid)
Remember, to get 40A out of the charger, it will need at least 45A input to account for conversion losses
 
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Discussion Starter · #6 ·
After reading about both chargers you mention, I'd skip the Renogy, from past poor reports from them. (I'm a moderator on a solar forum and live off grid)
thanks for the tip. Perhaps a bit off topic but which forum is that you moderate? Also, I was thinking this unit from renogy as it has built in MPPT solar controller, something I wanted to upgrade to anyway and can read battery levels via Bluetooth. If you’re aware of any success/issues of this particularly, let me know. DCC30S 12V 30A Dual Input DC-DC On-Board Battery Charger with MPPT
 

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Renogy is the low end of gear, and just doesn't seem to hold up.
The charger should be mounted in the trailer near the batteries - to reduce errors from voltage loss in the cable to the battery being charged. The feedline to the charger will be about 40' of cable (20' for the -, 20' for the +) and the Redarc states plainly what input voltage it works with. That's important. A $10 meter will tell you battery voltage, and it's unlikely Bluetooth would work 20' from trailer to your cab.
Me: https://www.solarpaneltalk.com/member/1076-mike90250 ( The forum of fewer illusions (many solar forums are overly optimistic about solar & results))
and this post: Charge level and settings - Solar Panels - Solar Panels Forum about trailer power conservation
 

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I am currently working on a "Power box" - camping battery and decided to test my luck with AliExpress - buy device for battery charging "on-the-go". Will let you know (if it does not explode :) )
Mine is for 8A (will charge from cigarette socket) but they've got similar for higher currents ( 20A, 30A), which you'll have to connect with own wires directly.
 

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Discussion Starter · #9 ·
Thanks for the tip, let us know if your Ascent explodes! At this point, I'll be sticking with a vendor I can contact with support. My purchase horizon is a few months out as we're still waiting for our trailer to be delivered. I've been in touch with Redarc, and I've bought a Tow Pro Elite from them in the past and have been very happy with the device and support. I checked out the forums recommendations, and while Will at Mobile Solar Power: Made Easy! DIY Off-grid Solar Power! seems to like the Renogy, It'll max out at 25A to the trailer based on how it's designed. Think I'm leaning to the Redarc, but not in a rush. Will update here when I pull the trigger and my experience.
 
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