So I'm planning on a F350 6.7 4x4 CCSB SWR. Then a 30+ft travel trailer, and at some point will full time in a 5th wheel. Do I really need dual alternators/batteries for the future??? Why??
This forum rocks!!! Thanks y'all!!!

 

I have the same truck you want in a 2017. I also tow a 32foot 5th wheel. The truck comes with 2 batteries but I did not op for the duel alternators. I have never had an issue recharging my 2 6 volt batteries while towing

Tony P

 

Need, probably not but depends on other options you may want like quick heat. May be other options.

 

Better to have it and not need it than need it and not have it.

I've used the power inverter in my F-350 to run shop lights to illuminate my trailer when I had to work on it at night at the storage lot. Being able to recharge a couple of laptops while on the road comes in handy. The non-dual alternator setup could probably provide enough power, but I'm not real sure about that.

The rapid supplemental heater is nice, as mentioned above.

Keeping the (dual 6v) RV batteries topped off while running the fridge and furnace is always a good thing.

 

Ya not going with the supplemental heat. But might have a small in-cab fridge out of my Kenworth. Had one of those drain a F-150 battery overnight once. I'll stay tuned! Thanx!

 

There are several features and packages that "require" dual alternators on the 2017+ Super Duty. Many trucks have them for that reason. With the previous generation of diesel Super Duty (2011-2016), dual alternators were relatively rare.

If you order the snow plow package, upfitter switches, and the 110v outlet...you get dual alternators included for free. If you order supplemental heat, you get the higher output dual alternators.

Otherwise, it looks like you'll get a single 220A alternator.

As for plugging in a fridge, be advised neither the 12V or 110V outlets work when the truck isn't running. You also only have 400W to work with from the 110V outlet.

Dual batteries are standard on any diesel.

As far as towing a 5th wheel, the factory trailer plug can only supply 30A of power for charging and powering your trailer. Clearly that doesn't require dual alternators.

The supplemental heat draws 150A when it is running. That's a lot of power, more than half the standard alternator and 40% of the entire output of the heavy duty dual alternators.

No consider the six upfitter switches: 4 of them can supply 25A and the other two can supply 40A. That's another 180A that theoretically could be running simultaneously. So if supplemental heat and all upfitters were running at max draw at the same time, that would only leave 47A to run the entire rest of the truck, which also has heavy draw items like a rear window defroster, HVAC blower, mirror heaters, seat heaters, etc. It would certainly be possible to overwhelm the capabilities of the alternators. Not to mention, the alternators don't produce peak output at idle.

But most of the time, a single 220A alternator would be totally fine. Many people towed very nice 5th wheels for years with single alternators with earlier trucks.

 

I'm gonna have to scrutinize the Ultimate Lariat Package and Ultimate Towing Pakage. The dual alternators might come in one of these. Thank you for the detailed response! It helped ALOT 👍👍

 

dual alternators were rare which meant different size belt and rare alternator(s). if you plan on keeping for long time when belt or alternator failure might be a factor then consider parts stores wont carry one or both alternators and belt(s)

i think you can order just a single upgraded alternator that would be better. they might be more popular on 17+ but not sure.

not to mention shoehorning another altermator in there. still single belt?

 

which trim?

limited includes min 332 amp dual standard, then depending on options up to 377amps!!!

any trim with rapid heat is 377 dual amp

 

Yes, it is still a single belt for the dual alternator setup. Regular maintenance schedule calls for the belt to be replaced at 150,000 miles. A quick check of RockAuto.com shows belts for dual and single, with both in stock.

 

There is nothing rare about these dual alternators. Most rigs with duals are going to get the 377A setup. That means you are getting one 220A alternator and one "standard" 157A alternator which was used as the base alternator on Super Dutys for years.

RAM offers duals on the Cummins rated at 440A!

 

i should have said prolly more popular on 11+ (6.7L)

it seems like the more popular setup is the 67A 332A dual alts

 

Another consideration for dual alternators from my standpoint is having an operable alternator remaining should one of them fail.

Likely a rare occurrence for sure but for those that travel to very remote locations as we do it can be a real event saver.

The bummer? As far as I can tell there is no way to know if one of them has stopped working.

 

That's a good point. An aftermarket gauge (standalone gauge or something like ForScan lite) can report volts but that could be misleading. I think you would need to see amps.

 

it could also fail in a bad way that leaves you straded

ie seizes