Spend 400 bucks for dual alternators on new Ram build?

[new2this44]

Hello. I am building a Arctic Fox 990 and a Ram to pull it. Is it worth building my ram with dual alternators so as to more efficiently charge my camper while driving?? Or will such a set-up require all new wiring, etc. to actually help?

Thank you.

[Bedlam]

The way I have understood it is there is a primary and secondary and the secondary is only electrically engaged based on current draw rather than running all the time. I do not believe the secondary functions in a fail over mode. Typically they are identical, so you could physically swap them.

[zcookiemonstar]

If you get dual alternators and one of them goes bad does the other one still charge? The electrical systems on these newer vehicles is strange it would not surprise me if one alternator died the system would see a problem and shut down the whole charging system. Not saying this is a reason not to get them but if one still works if the other dies it would be nice.

[valhalla360]

travelnutz wrote:
The thread OP is from/living in the Midwest where solar is very iffy at best and there's trees everywhere too which virtually block out the sun's rays anyway. Note that the promotors of solar are from the desert/bleak/virtually treeless areas of North America. We know the difference as that's where we live in the Midwest also and very smartly opted for dual alternators on our ordered diesel truck and been so happy we did.

Remember that the alternator works equally fast in recharging in any area/location you might be in unlike with iffy solar. Alternators are not affected by cold, altitude, clouds or trees, rain or snow, and is very fast and dependable.

We had solar on our boat in Michigan and it put out fine. Yeah, if you are in dense woods it won't do much but more often than not in Michigan, we have a decent amount of sun.

The big advantage is if you aren't moving daily, you still get charging with no fuss.

[valhalla360]

Another issue...even if you spend a few hundred extra to install massive charging cables back to the camper...unless it's a massive battery bank, the batteries won't absorb 400amp.

The max charge rate is around 25% of the amp-hr rating, so to absorb 400 amps, you would need around 1600amp-hr of battery...and even then once you get up around 80-90%, they will absorb less.

[new2this44]

Good information in here. I appreciate it folks.

[Ron3rd]

camp-n-family wrote:
I went with the larger 220amp alternator option. It’s only a $50 upgrade from the factory and it’s more than sufficient to quickly charge both batteries.

X2. That's what I did

[theoldwizard1]

NRALIFR wrote:

GeoBoy wrote:
If you don’t have solar installed get it installed. Great way to keep the batteries charged while traveling.

Solar is good until the sun sets. You can also harvest more amp-hours from the truck than any solar install on a TC roof. One of the reasons I choose the Redarc DC-DC charger is because it has a built-in MPPT solar controller, and the unit will always take as much power from the Solar input as it can before supplementing that power, up to the maximum rated output, from Vehicle power input. Best of both worlds. :):)

Sounds like an EXCELLENT solution !

OP - stay with the largest SINGLE alternator you can get and put the money you saved into something like NRALIFR suggested.

[pianotuna]

Shocking from a solar advocate. Buy a Harbor freight 3500 watt inverter generator with electric start instead of playing with alternators.

Next choice would be dc to dc charging.

[KD4UPL]

On a brand new truck that's likely $50,000 plus what's another $400? I'd get the duals for sure.
Now, will it help charge your camper batteries? Not without significantly larger wire feeding them thru a separate Anderson style connector or one like used for tractor trailer lift gates. If you're going to be putting hundreds of AHs of battery in the camper/truck I would upgrade the wiring to match.
For my use I typically have stereo amplifiers, amateur radios, inverters, etc. along with the RV. I will absolutely be getting dual alternators on my next new truck.

[time2roll]

Cummins12V98 wrote:
I thought I wanted dual Alternators but the sales manager said it was more if I snow plowed.

Yes and more commonly needed on a chassis to build an ambulance or similar.

[Cummins12V98]

I thought I wanted dual Alternators but the sales manager said it was more if I snow plowed.

[Bedlam]

My last two trucks have been ordered with dual alternators (Ford and Ram). Unless you have dedicated wiring run to your camper, you will not see the benefit from buying two and I question whether you will even see a benefit from an upgraded single.

I have a constant duty solenoid triggered by an upfitter switch to heavy cabling running to the back of my current truck. My setup is little different with a flat bed and storage boxes than a pick up, but this might give you some ideas:

In my lower truck storage boxes I have two banks of batteries that are tied to the truck charging system, to the truck camper and to a third bank of batteries on my enclosed trailer. Interconnects for the camper and trailer are large diameter Anderson 2-pole plugs. All three banks of external batteries can power the camper and all four banks of batteries can be charged via truck, camper generator, camper solar or campground electric.

I used the connections to the heavy lines in the camper running to the generator starter motor as my tap to the external interconnect Anderson plug. All sources of power have a resettable circuit breaker if there is any short or overload condition.

[noteven]

I installed an isolator on the truck and ran size large battery cables to connect the deep cycle camper batteries with a rated quick plug. I disconnect the “12v +” little wire in the camper plug. Automotive alternators taper the charge as battery resistance increases as they charge. I would make sure to connect the converter charger to 110 ac once in a while so the batteries recurved a full charge.

I expect there are fancier isolator/chargers available nowadays that will alternator charge deep cycle batteries properly

[time2roll]

new2this44 wrote:
Or will such a set-up require all new wiring, etc. to actually help?

Thank you.

Yes I believe you would need to upgrade the wire to really make it effective to directly charge the TC battery. You could have 10 alternators but you can only get so many volts and amps through the #12 wire.