7-way charge line compatible with DC-DC converter?

[chasc]

I’m not interested at this time in running a separate high gauge wire for charging and know this will limit max amperage. I was hoping to put a DC-DC charger in my trailer, inline with the charge wire from the 7-way plug, to boost the voltage for charging LiFePO4 batteries. I saw a couple posts on other Ford model forums that made me worry the circuitry in the Ranger tow controller may not enable charging unless it sees a trailer battery’s voltage first and thus may be incompatible with a DC-DC charger. Does anyone have experience in a ‘24 Ranger to know if this works?

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[stormrider151]

Based on the limited information. It would seem to achieve that an RV converter would be your best bet. Or maybe I'm completely off base. My SD charges my travel trailer through the house converter.

 

[chasc]

I do have a “converter” that charges the batteries when plugged into shore power. I’m interested getting some limited charging while driving and connected to the trailer plug. I’m hoping to understand what interlocks the truck has before it supplies power to the battery charge pin of the 7-way connector: Ignition on, door closed, voltage sensed, etc.

 

[stormrider151]

I'm not sure how it does it but when I'm plugged into the truck and driving the truck does charge the trailer battery. Some trucks are always hot at the pin and others are hot only when driving. The best way to know is test the pin when the truck is off and then on. I just use a test light on the pin but you can also use a multimeter. It is pin #4 on the truck side.

 

[Jason B]

I'm not sure how it does it but when I'm plugged into the truck and driving the truck does charge the trailer battery. Some trucks are always hot at the pin and others are hot only when driving. The best way to know is test the pin when the truck is off and then on. I just use a test light on the pin but you can also use a multimeter. It is pin #4 on the truck side.

That might work, but on some vehicles there is nothing at that connector UNTIL a trailer is hooked up.
I don't know if that's how it is on 6G, because in the excitement of buying a new truck, my greed resulted in getting one without the tow package.

 

[MedicineMan4040]

Looks like this thread was forgotten
Just got a Ranger XLT, soon to get a camper (Casita). The Casita in question has the new 12vdc only 4.3cf Everchill which is supposed to be super efficient, e.g. small amp draw (start up 8-9amps and then 0.8amps running). I'm hoping via the 7 pin charging line the Ranger can get enough amps to the Casita (and I know I'll have line loss back to the battery) to run the fridge while driving down the road and not slowly deplete the lithium battery. We'll charge up the Casita battery on shore power but when just getting from A to B the refrigerator/freezer and electric trailer brakes are the only need to haves that I can think of. Eventually we'll add DC-DC charging via an Orion XS but in the mean time.......

 

[chasc]

@MedicineMan4040 this was a good reminder to follow-up on my original question here: On our last trip I wired an Orion XS inline (in the trailer) between the charge wire from the 7-way plug and the batteries. Prior to adding the Orion XS DC-DC charger I saw only infrequent and inconsistent charging of the LiFePO4 trailer batteries from the Ranger. After wiring it in I see somewhere in the range of 8 Amps during bulk charging consistently.

Only the HTML version of the operator's manual specified a maximum number of Amps you can draw from the trailer charge wire, the PDF version had no numbers. Ford says not to exceed 15 amps. I set the amperage limit on the Orion XS to be below that just in case.

Note: Trailer power feed can provide a maximum output rate of 15 amps.
Note: Never place more demand than 15 amps of power on the trailer power feed, this may damage the trailer lighting.

So far I haven't messed with any of the engine-running detection features of the Orion XS. Since it never seems to draw more than 8 Amps and the truck already stops power to the 7-way plug when the ignition is off, it hasn't seemed to be a problem to let it attempt to charge whenever the truck supplies power.

It's not going to replace a generator for charging your batteries while at the camp ground at only 8 amps, but it's definitely better than nothing to be recharging slowly during long drives.

 

[MedicineMan4040]

Chasc thanks so much! Excellent info you've provided.
Also you said 'the truck already stops power to the 7-way plug when the ignition is off', that means the camper cant drain my Ranger starting battery. That's good.
So if/when I run 4 gauge (+fuse) from the Ranger's battery to the Orion XS, I would set the draw amps in the Orion app to 25 amps. That's below the 30amp max I read in other posts that I can pull from the Ranger alternator. Agree? The camper we're picking up comes with a 300ah Renogy lithium, more amps would be better, but like you said some is better than none. We've (wife and I) talked about adding a 2nd 300ah. That would give use real boondocking advantage and 4-5 days of autonomy from having to find any charging source. If we can pull off a 600ah lithium bank she could even run the air conditioner 2-3 hours a night for 3 nights. We've also talked about ditching the Coleman Mach 8 it comes with and trying one of the 12vdc compressor air conditions like the Outequipepro model and cutting out the loss of conversion from 12v to 110v; that might buy another night at 2-3 hours.

 

[chasc]

@MedicineMan4040 the note about it stopping charging when ignition is off is anecdotal, I didn't test it in a controlled way to say that's 100% true in all conditions. Just a heads-up in case anyone relies on that being the case.

My personal recommendation would vary a lot depending on what your goals and expectations are. Even with just the 300AH battery it would still take 6 hours to recharge the battery from 50%. I wouldn't personally consider idling my truck at a campground just to recharge because the engines aren't designed for that. Thus I wouldn't consider running the high-gauge charging line as an alternative to having a standalone Gas or Propane generator.

If you're just looking for something to maintain the fridge and boost your battery a bit while driving long hours to your destination, for me personally the 8 Amps from the 7-way is sufficient. It saves the need to modify the truck to run the 4-gauge, don't have an extra Anderson connector to worry about when hitching/unhitching, don't need to modify the trailer to run the 4-gauge in, don't have to worry about the Orion XS battery detection settings (because if you run directly to the battery you will rely on that to avoid draining the truck battery). That's a lot of extra work to get faster charging, but still not really fast enough to make a big dent in a 600AH battery bank.

 

[MedicineMan4040]

Can't argue with anything you said. Especially about NOT idling the Ranger. We do have a couple of generators, big and small, but I just told the wife over lunch that if she has 600ah charged on board when leaving the house she wouldn't have to do anything for days......unless she gets hell bent on running a rooftop air conditioner. Historically in a campervan we relied on 2 12vdc fans because the campervan's air conditioner was shore power dependent. These fans saved us many times boondocking in Florida and we'll use two of them in the trailer https://www.amazon.com/dp/B01LDY4TE4?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_15&th=1

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