Bigger or Second Alternator?

mrfoamy

Mrfoamy
I cannot find this discussed anywhere. While there is extensive discussion of solar panels, batteries and generators, how useful is a bigger or second alternator? Would that be useful to charge house batteries faster? Or only to reduce load while running A/C or other appliances? I seldom use a winch, but designing A/C into my next truck camper is tempting. I prefer not to have a massive battery bank.

For a new F-350 there are a few options when ordering a truck:

Alternator – 157-amp heavy-duty (gas engine) Standard

Alternator – 175-amp heavy-duty (diesel engine) Standard

Alternator – 240-amp-extra-heavy-duty(gas engine) Option

Alternator – 332-amp extra-heavy-duty (diesel engine) Option

Would any of these alternator choices be very helpful in offsetting current draw? My preference is probably the gas engine with the 240-amp option. Opinions?
 

DiploStrat

Expedition Leader
Can be a complex issue. For an overland vehicle, I would always go with the biggest, baddest alternator I could get. That could be one big alternator or several smaller ones.

The real question, to which Verkstad alluded, above, is whether there is an advantage to a separate alternator/regulator/battery chain. The answer is often,"yes."

A lot of the toys we play with, intelligent relays, battery to battery chargers (B2B) and the rest are merely ways of dealing with the fact that the types of battery that are required for a starter and a camper/house are different. Whether the difference is subtle - starter vs. deep cycle, or huge, lead-acid vs. lithium. In the latter case, for example, a separate, dedicated alternator/regulator would be ideal as all of the settings could be different. You can achieve the same effect with the tools mentioned, but a totally separate system would be the ideal, especially as this could give you additional control over the specs of the alternator itself - derating it a bit, but getting a unit with a 100% duty cycle.

A lot depends on how hard it is to mount a separate alternator on your truck. The head banging car stereo freaques have helped as a lot of them add alternators and this has caused a proliferation of off the shelf brackets for different vehicles. Otherwise you may be in the fabrication business.

Which might be enough to send you back to a relay or B2B.

So, without looking at your needs, in detail, there is no way anyone can give you very meaningful advice.
 

Buliwyf

Viking with a Hammer
I went with the single gas alt. Whatever the extra HD plow kit alt is.

All the civvy diesels, I saw, had dual. I didn't get under the hood of the work trucks.

Just spec the truck out with the single regular alt. I'll bet you'll select an option somewhere, that'll select the proper alt for you. Plow kit bumps up the alt. Ice cold battery, tons of lights, electric pump, electric spreader. The camper kit might as well. I don't recall ever working an alt over too hard camping.
 
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rayra

Expedition Leader
Dual standard alternators would be a useful thing for redundancy and ease and affordability of replacement when far from home. Lots of solutions in the RV, Emergency vehicle and high performance car stereo markets.

OP should look in the 12v subforum, there's some discussions there and lots of other methods to either isolate or combine various power setups.
 

Umbrarian

Observer
1 is none and 2 is one.

Avoid Single Points of Failure.

Get the dual alternator. Factory wiring of dual alternators alone worth it right there over aftermarket.
 

mrfoamy

Mrfoamy
Ice cold battery, tons of lights, electric pump, electric spreader. The camper kit might as well.

Buliwyf, specifying the “Snow Plow/Camper Package” bumps the alternator up two levels from 157 amp standard to 240 amps, it appears. Ford does not mention anything about a “Ice cold battery, tons of lights, electric pump, electric spreader”…What is the pump for? What is an electric spreader? The price of the Snow Plow/Camper Package is about the same as specifying the Camper pkg and Alternator Upgrade separately. Are you sure that other stuff is included? Seems like Ford would sell that in the brochure. My concern is that heavier springs in the front may degrade ride quality, but it is not clear that springs actually will be heavier in my spec.
 

mrfoamy

Mrfoamy
Can be a complex issue. For an overland vehicle, I would always go with the biggest, baddest alternator I could get. That could be one big alternator or several smaller ones.

The real question, to which Verkstad alluded, above, is whether there is an advantage to a separate alternator/regulator/battery chain. The answer is often,"yes."

A lot of the toys we play with, intelligent relays, battery to battery chargers (B2B) and the rest are merely ways of dealing with the fact that the types of battery that are required for a starter and a camper/house are different. Whether the difference is subtle - starter vs. deep cycle, or huge, lead-acid vs. lithium. In the latter case, for example, a separate, dedicated alternator/regulator would be ideal as all of the settings could be different. You can achieve the same effect with the tools mentioned, but a totally separate system would be the ideal, especially as this could give you additional control over the specs of the alternator itself - derating it a bit, but getting a unit with a 100% duty cycle.

A lot depends on how hard it is to mount a separate alternator on your truck. The head banging car stereo freaques have helped as a lot of them add alternators and this has caused a proliferation of off the shelf brackets for different vehicles. Otherwise you may be in the fabrication business.

Which might be enough to send you back to a relay or B2B.

So, without looking at your needs, in detail, there is no way anyone can give you very meaningful advice.
DiploStrat, I like the “biggest, baddest alternator” suggestion as it is an inexpensive option that offers potential. I did wonder about replacing a single factory alternator with a bigger aftermarket unit. As for “without looking at your needs, in detail, there is no way anyone can give you very meaningful advice.” Well, my needs are endless if the opportunity exists to connect A/C, induction stovetop, etc, etc., so I my thinking is how much juice the truck’s engine can supply before adding more batteries and solar. And I can design around whatever battery accepts a charge the fastest/best to accommodate that big, bad alternator. Then I will know how realistic "MY NEEDS" are. Does that not sound like a step in the right direction when ordering a new truck?
 
I'd rather have a high output factory alt than a add on afternarket. Factory mounts are actually engineered for a real life cycle.
 

Buliwyf

Viking with a Hammer
Sorry, the pump, lights, etc, was just an example of the electric loads on a plow truck, that requires a big alt. And cold weather wrecks battery performance. I'm fairly sure that salt spreaders are electric.

Being that I'm going to be stuck working on my own ride, the 2nd alt is just another part in the way. Then again, if I had duals, I wouldn't need the spare under the back seat.

The front springs can be swapped in an hour. Easiest springs to swap on this whole forum. Except for a TJ, those fall off all the time. LoL.
 
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plainjaneFJC

Goofball
I have dual alternators on my 2017 diesel. I have not modded my truck in a way that I need them but it was a cheap option so I checked the box. I know some guys on ford-trucks.com that have them and complain about how it works. Evidently they will not charge or resupply something faster that a single alternator, they will just carry a bigger load at once if that make sense in non electric layman terms.
 

Buliwyf

Viking with a Hammer
And power at idle ain't much. Trailer batteries charge faster while you're on the highway.

Yet another reason plows needs alts. Mostly idle time and city.
 

mrfoamy

Mrfoamy
Let me expand my original question "Would that be useful to charge house batteries faster?" At high idle, or on the highway, does a larger alternator charge most house batteries faster or are the batteries generally the limiting factor, or some other device between the alt and the batts. I'm pretty new to electrical design.
 

Darwin

Explorer
You still have to get from the vehicles 12 volt system to 120 volts for A/C (air conditioner?) typical RV rooftop air conditioners use about 120 amps at 12 volts DC. You would either need a fairly large battery bank going from the truck to the bank, or a dual inverters one from the truck alternator feeding into another in the camper to supply "shore" power directly. IF you go from the truck to the battery bank consider that pulling 120 amps is a lot, creates a lot of heat, and requires large cables
 

rayra

Expedition Leader
alts with a higher amp rating will deliver those amps at higher RPMs. At or near idle, you get nowhere near as much. Depends on your wiring setup and how you choose to combine or separate the outputs of the two alternators, akin to how you arrange two batteries.
There are several very large topics in the 12v subforum, you really should go read / study them, instead of sitting here cheeping in your nest.
Your intended uses and power requirements make a difference in your system architecture choices. You don't just throw MOAR POWER at it.
 
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