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You can easily install a second alternator in a Promaster. It's done all the time. I have the Volta system in my van. Volta supplies everything: alternator, dc-dc charger, mppt charger, inverter charger, battery pack, harnesses and cables, etc. It's one big integrated 48V system. Of course there's also a converter to bring it down to 12V for all your appliances in the van. It's a one button system that provides no visibility into what's going on which I hate, but it's very reliable and very powerful which I like. I was told by a Volta engineer that the reason it doesn't start charging until the RPMs get above 1300 had something to do with vehicle emissions. It doesn't really matter though as there's a button to put the van in high idle if you want. The second alternator also charges the battery pack from zero to 13.5Kw in about 2 hours of driving. Volta seems to recommend using the Coleman Mach 48v AC unit with their system. It's kind of big and bulky on the roof. It's works, but it's not the quietest or most efficient thing out there. I can run it for at least 10 hours off the battery pack. In general I really like the Volta system, but I think you can build something comparable on your own for a lot less money. They have, however, done all the engineering for you.
 

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MMXVI - L2H2 in Indiana
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MMXVI - L2H2 in Indiana
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MMXVI - L2H2 in Indiana
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Thanks Phil.
The other three antennas must be HDTV, WiFi and cellular extender/booster.
If I understood the sales pitch, the van is pre-wired for various antennas, but they are dealer added options.
 

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You can easily install a second alternator in a Promaster. It's done all the time. I have the Volta system in my van.
Where does the second alternator get mounted?
thank you both for helping make my point. Which was…
The Promaster doesn’t have a second alternator option, and adding one isn’t viable IMO.
Which should have read “factory option”, although the context clues were there since I went on to reference the Sprinter and Transit factory options.
And, as I said “adding one isn’t “viable”. Meaning, “it’s mounted so low that people make aftermarket crash guards for it, which is a sign to me that it’s not a good location”. Particularly when one thing I don’t like about our Lexor is the low-hanging generator.

So the point here is, I don’t find the Promaster to be a good candidate for “all electric”. I would like to have enough to run the ac for short stints when firing up the generator isn’t ideal, but I wouldn’t want an all-electric Promaster due to the second alternator being an aftermarket-only possibility in a bad mounting spot.

back on topic, I still like the new Airstream, and might have chosen it over our Lexor had it been available at that time. .
 

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So the point here is, I don’t find the Promaster to be a good candidate for “all electric”. I would like to have enough to run the ac for short stints when firing up the generator isn’t ideal, but I wouldn’t want an all-electric Promaster due to the second alternator being an aftermarket-only possibility in a bad mounting spot.

I’m not sure what you mean by “all electric” since I consider both an Onan generator or second alternator part of electrical system. Having said that, the Airstream Rangeline relies on gasoline fuel for hot water and space heat, so not all electric anyway in my opinion. Some people refer to motorhomes without propane as “all electric”, even though they may use diesel for space and water heat; so it comes down to semantics or perhaps definition.

With a 2.8 kW Onan, I think all-electric is a good option for a well-insulated van, though it would require more battery capacity for air conditioning and heat if for more than +/- 2 hours. A single 270 Ah should last almost 2 hours in middle of day for A/C, and about the same for heat on cold day.

For overnight A/C, two more Battle Born 270 Ah for a total of 810 Ah should do. During day the Onan generator can power converter, which in case of Rangeline, is mentioned to be 100 Amps (guessing it’s an inverter/charger).
 

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And, as I said “adding one isn’t “viable”. Meaning, “it’s mounted so low that people make aftermarket crash guards for it, which is a sign to me that it’s not a good location”. Particularly when one thing I don’t like about our Lexor is the low-hanging generator.

So the point here is, I don’t find the Promaster to be a good candidate for “all electric”. I would like to have enough to run the ac for short stints when firing up the generator isn’t ideal, but I wouldn’t want an all-electric Promaster due to the second alternator being an aftermarket-only possibility in a bad mounting spot.
Two years and 40K miles later my second alternator with no crash guard is still there. Unless you do something incredibly stupid it'll be just fine. You're far more likely to hit the rear axle. If you're that worried about it, just spend a few hundred dollars and put in the 1.5" front lift kit. More clearance for the alternator and you get rid of a lot of the annoying downward slant of the Promaster. It sounds like you just don't want a Promaster.
 

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I’m not sure what you mean by “all electric” since I consider both an Onan generator or second alternator part of electrical system. Having said that, the Airstream Rangeline relies on gasoline fuel for hot water and space heat, so not all electric anyway in my opinion. Some people refer to motorhomes without propane as “all electric”, even though they may use diesel for space and water heat; so it comes down to semantics or perhaps definition.

With a 2.8 kW Onan, I think all-electric is a good option for a well-insulated van, though it would require more battery capacity for air conditioning and heat if for more than +/- 2 hours. A single 270 Ah should last almost 2 hours in middle of day for A/C, and about the same for heat on cold day.

For overnight A/C, two more Battle Born 270 Ah for a total of 810 Ah should do. During day the Onan generator can power converter, which in case of Rangeline, is mentioned to be 100 Amps (guessing it’s an inverter/charger).
Any of the van brands can be set up for running air conditioning off of the battery pack and charging it up from an auxiliary alternator.

There are 12 volt (and other DC voltage) air conditioners out there - and they work - but all motors benefit from having high magnetic fields and the easiest way to do that is with higher voltages. That is why my suggestion is to buy a high quality, 120 vac based air conditioner and run it off of the inverter. Something in the 13 - 15 KBTU size range.

The way that I do it is to use a 48 volt LiFe pack - usually battle borns and when possible - 2 packs in parallel. Very approximately that will give you ~ 1 hr of run time / 1 kW-hr of usable battery capacity so it isn't too difficult through the night. (since it is slightly cooler / no sun beating down)

You don't have to use 48 volts - 24 volts can work, but doing it with 12 volts is perhaps the most difficult to pull off just because it is difficult to move 4 - 6 kW from the aux alternator to the battery pack at such a low voltage.

A generator based approach will definitely be lower cost, but using the engine + aux alternator approach can be very convenient and the noise levels are pretty low.
 

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Extensive video review of Rangeline from Hershey Show. Segment starts at around 21:30.

A/C is Coleman 13,500 BTU/hr unit with factory-installed Soft-Start, so A/C should run on 2,000-Watt inverter for a short time (an hour or two unless extra battery capacity is added). I’m not sure if A/C is wired to inverter from Airstream. Since Rangeline has Onan generator, the air conditioner may not run off battery.


 
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