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Old 09-22-2017, 01:56 PM   #31
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I've gone back and forth many times on the issue. We are getting the extra insulation, also ordered with our production order with MB. I'll also have insulated panels for the windows. We'll have one MAX fan/vent.

I've agonized about going with the standard SMB electrical with 2 4D AGM's, no rooftop a/c and a 2nd Max fan in lieu of the a/c. The basic guy in me wants that. Especially considering the use of the rooftop a/c and lithium set-up is probably under 5% of total use. At best.
You might want to order the MB feature that allows hooking up a rear Heater/AC. Then SMB can install an evaporator/heater core in the rear. It will do a lot better job in the back of the van.

I had SMB run the hot water pipes to the rear heater core under the floor down the center of the isle (on top of the extra floor insulation) so I have nice floor heat.
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Old 09-22-2017, 04:52 PM   #32
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Actually it's not. The insane part is doing it at 12 volts.

There are all kinds of high energy tasks being done these days but done at a much higher voltage of DC. Even something as mundane as the A/C in my Chevy Volt car uses 3k watts off the lithium pack on high, but at 300 volts. I'll go out on a limb here and say that as the large lithium packs find there way into more RV applications the systems and their equipment (A/C, refrigerators, inverters, 2nd alternators, generators, ect) will operate at much more efficient higher voltages. And be isolated from the vehicles. Or not, what about a hybrid propulsion system for boost going up hill and a re-gen system that harvests the power for house needs. I realize this doesn't help your current goals. I hope you keep on this pursuit this IS crazy and awesome.

-Eric
I agree, I believe Advanced-RV is now using a 48 volt system by Volta Power Systems

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Old 09-22-2017, 05:53 PM   #33
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[QUOTE=Scalf77;212600]I agree, I believe Advanced-RV is now using a 48 volt system by Volta Power Systems

Nothing but the best in ARV. Glad to see they are using the "Smart Plug" for their shore power plug.

I changed mine from the "Twist Lock" to the "Smart Plug" after I smoked the twist lock. Good idea to ask SMB to use the Smart Plug.
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Old 09-22-2017, 06:09 PM   #34
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Smart plug way to go. Just added that as an upgrade my last overhaul on my sailboat. Easier to connect and pretty much "sailor proof".

Didn't know that was an SMB option. Added to the list!
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Old 09-23-2017, 08:30 AM   #35
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Its important to remember that advanced has a goal of off-grid A/C. That’s a massive amount of power storage and generation. Even with that huge alternator, they still have a lot of solar panels AND auto gen start for the van. That’s the only way this works for them. Their buyers have a much different usage profile than most SMB-type owners.

With our new build, we’re investing a bit more in insulation and are likely going to skip roof A/C. It gets cold enough st night in the west that we really won’t need it at night. And with a platform bed on slides, we won’t have room for passengers (a main reason for A/C originally).
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Old 09-23-2017, 01:02 PM   #36
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Its important to remember that advanced has a goal of off-grid A/C. Thatís a massive amount of power storage and generation. Even with that huge alternator, they still have a lot of solar panels AND auto gen start for the van. Thatís the only way this works for them. Their buyers have a much different usage profile than most SMB-type owners.
ARV is not afraid of complex systems and state of the art devices. We watch them with interest.

I wonder if trying to do off-grid AC with electric doesn't result in running the van engine most of the time to keep up with the electrical requirements. They might be better off with a different approach like running the AC compressor directly off the engine and storing cold rather than electric. All this new stuff is fun to play with. I'm sure the solar panels don't make a dent in their requirements.
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Old 09-23-2017, 04:21 PM   #37
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They might be better off with a different approach like running the AC compressor directly off the engine and storing cold rather than electric.

Heat sinks require a large mass of something with a high molar enthalpy of freeze/thaw state change, as well as refrigeration apparatus capable of sub-freezing temperatures. Then there is the fact that it is difficult to insulate the frozen mass for an effectively long time unless the volume to surface area ratio is considerably large. All of this makes it extremely inefficient for something mobile and relatively small, like a Class B travel van.
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Old 09-23-2017, 04:47 PM   #38
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Heat sinks require a large mass of something with a high molar enthalpy of freeze/thaw state change, as well as refrigeration apparatus capable of sub-freezing temperatures. Then there is the fact that it is difficult to insulate the frozen mass for an effectively long time unless the volume to surface area ratio is considerably large. All of this makes it extremely inefficient for something mobile and relatively small, like a Class B travel van.
Well we already insulate the fresh water tank. Lets take it down to 35 degrees. Then there is a gray water tank. I haven't done the math but that would be enough mass so the engine would not have to run all the time..... If you want warmer cold water at the sink a mixing valve would fix that.

Just thinking outside the box...
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Old 09-23-2017, 05:22 PM   #39
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ARV is not afraid of complex systems and state of the art devices. We watch them with interest.

I wonder if trying to do off-grid AC with electric doesn't result in running the van engine most of the time to keep up with the electrical requirements. They might be better off with a different approach like running the AC compressor directly off the engine and storing cold rather than electric. All this new stuff is fun to play with. I'm sure the solar panels don't make a dent in their requirements.
There is nothing new about what they're doing. They just have to scale up with the battery capacity. All the other systems are the same as what's been used for years. 12v, 24v, 48v - nothing inherently complicated between one or the other.
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Old 09-23-2017, 05:31 PM   #40
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Well we already insulate the fresh water tank. Lets take it down to 35 degrees. Then there is a gray water tank. I haven't done the math but that would be enough mass so the engine would not have to run all the time..... If you want warmer cold water at the sink a mixing valve would fix that.

Just thinking outside the box...
I think what ARV is doing is thinking outside the box. 48V system with massive lithium batteries stored under the van in an insulated, armored box. You could get 2 days of comfortable temperatures if you use a thermostat for the A/C and have a big solar array. They can recharge those batteries from solar, shore power, or driving the van.

If you store cold, you have a finite amount of time to use that cold, and you can only regenerate it with the engine. That seems like a step backwards to me.
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