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Lots of companies sell vans with greater than 6KW of battery: Coachman, Winnie, Thor, and many others. I have 10KW in mine. Not sure why you think 6KW of battery is any more dangerous than 1KW.
 

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2021, Promaster 159 HR 2500, Silver
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Discussion Starter #22
Another route that no one seems to ponder is to use an auto-start system that monitors interior temperature. IMO it would be no different than using the ESS feature used in Jeep models that have the 3.6L.
That would be something to look into. I have law enforcement friends who have mentioned the hot dog system that k9 patrol cars utilize. Looks like I have more homework to do.
 

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Okay, ya'all have thought about this way more than I have. I trying to say that it could not be done safely, just that it takes a bit of design effort to do so. Is'nt a wire carrying 50+ amps more dangerous than wire carrying 10 amps?

10KWH Wow! I wonder if that is the biggest battery bank of anyone on this forum?
 

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MMXVI - L2H2 in IN
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2014 3500ext Gas - VA
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Boondogger... my personal experience supports previous posts in this thread... that installed power systems have a tough time cooling even a well-insulated van over any extended period of time. As a result, I’ve adapted my design to focus on ventilation when not connected to shore-tie/generator and the miracle of AC when shore-tie/generator is an option.

Once you solve the power problem, I invite you to learn from my experiences... I’ve gone from rooftop AC to interior portable dual hose AC vented thru the side to portable dual hose AC vented thru a window adapter... there are pros/cons to each... what is best for you will depend on your needs and wallet.

VanCave Website
 

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2021, Promaster 159 HR 2500, Silver
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Discussion Starter #26
Thanks Phranc. I have two opening windows on the side that I can run the dual ducts out. I think this might be where I start. If it is going to work and I want a more streamlined set up I could do some vents out the side and keep the windows covered.
 

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Are there really companies that will install a 6kwh or more battery system in a van? Would love to know how much that system costs installed. This seems like the realm of the DIYers with an engineering background. Not only is this incredibly complex and expensive, its also very dangerous! Id be suprised if a company would accept the liability but then again there are companies bolting bench seats to the sheet metal floor. If done correctly Id expect this battery system to cost a small fortune.
Yes - my small van electrical shop does this. Technically 4 and 8 kW-hr versions but yes and for this exact application.

My shop is in Livermore, CA, but you don't need to drive here. I ship the systems to customers as well.

And yes, my degree is in engineering.
 

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Another possible alternative for you is to buy a small trailer and use it for the generator and related fuel.
 

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2016 3500 ext-ht
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Another possible alternative for you is to buy a small trailer and use it for the generator and related fuel.
And, an additional landscape for much more solar than can fit on top of the van. Not practical if you don't want to haul the trailer everywhere but really practical if you boondock.
 

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2019 159 High Top - White, of course!
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Maybe a Tesla or Leaf battery (or 2) slung under the chassis? Just have to figure out a way to charge it. A second alternator (higher voltage) would probably be required, along with idling for hours....
 

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2021, Promaster 159 HR 2500, Silver
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Discussion Starter #32
No trailer for me. If I wanted to haul something I would have bought a pull behind camper which would have been much cheaper.

I will either modify my plans or keep adding batteries/power until I get it. :)
 

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No trailer for me. If I wanted to haul something I would have bought a pull behind camper which would have been much cheaper.

I will either modify my plans or keep adding batteries/power until I get it. :)
It is good to have clarity - makes decisions easier.

Somewhere around the 8 - 12 kW-hr capacity range, not a great deal more ends up helping in this application, but "rough budget numbers" air conditioning takes ~ 1 kW continuous average power to run.

There are some ways to charge a van house pack using EV charge stations in case that is sometimes useful.

Some van setups support auto starting the engine when the battery SOC reaches a "low" set point. It has been a while since I looked in detail at the promaster capability, but it might be an option that is built into the passenger side pillar connector area. The same method can be used to auto start a generator if it has electric start capability.

High idle and larger / more alternators can be used in some vehicles to increase output. Again - have not studied the ability to add additional alternators to the Promaster platform. There are some pretty impressive alternators on the market, mostly driven by car audio enthusiast.
 

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I had one of those portable AC units that I used while converting my van. It was so loud that it was impossible to sleep in the same area. So I gave it away.
A somewhat better solution would be something like this: Roof AC for RV
 

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It is good to have clarity - makes decisions easier.

Somewhere around the 8 - 12 kW-hr capacity range, not a great deal more ends up helping in this application, but "rough budget numbers" air conditioning takes ~ 1 kW continuous average power to run.

....cut....
For a small space like a van, the first priority should be to reduce cooling load to no more than 50% of that 1 kW.

My personal interest to cool with battery power is more at night, and that’s well below 500 Watts average already. During peak heat of day, a budget of 1 kW may be required for a rooftop A/C (like 11,000 BTU/hr Power Saver), but I’m pretty sure I can reduce that also.

Next time I’ll spend more on insulation, dual pane windows, and much higher efficiency A/C. Averaged over 24-hour day, I expect 500 Watts (12 kWh per day) should be possible. It should be cheaper overall than buying more batteries, and also greater charging rate to go with that greater capacity.

Obviously, all that could change if OEM offer it as part of vehicle from factory.
 

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2021 Promaster 136 HR (if I can actually buy one)
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The air conditioning unit that you linked to is a single-hose exhaust model. That means that it draws outside air into the van, cools down the air in the van, and then exhausts hot air out. Unfortunately, because it continually draws in hot air from outside, this technology has very low energy efficiency. Also,, it's rated at 7.6 BTU/watt, which is a very poor efficiency to start with. If you use a dual-hose model of a portable air conditioner you can get an efficiency of up to 12 BTU/watt, which is similar to what the best roof-top air conditioners offer. The best window air conditioner for efficiency is the Midea U, which is rated at 15 BTU/watt, just about double what the TOSOT is going to give you best case.

Insulation of your van needs to have a very good blended R-value for air conditioning on battery to be feasible. This is actually pretty hard to achieve unless you create a closed-off area in the van that is insulated from the front cabin area. So let's start by thinking of creating a box within the van and insulating it to R-9 or better. Then air condition and ventilate that space. Here's the math: a 6x6x10 foot box has 312 square feet of surface area. R-9 translates to a U-value of .1111. So BTU/hr per degree F will be 312 x .1111 or about 35 BTU/hr per degree of temperature difference between the inside and outside. If it's 100 outside and you want it 70 inside that is 30 degrees of difference, so 30 x 35 = 1,050 BTU/hr. And then if your air conditioner has an efficiency of 10, that would be 105 watts. So you can cool that space with nothing in it for 12 hours using 1,250 watt hours of electricity.

That is before you ventilate it, which could add as follows: 20 CFM x 1.08 x 30 degrees = 648 BTU/hr. Again, with an efficiency of 10 that is 64.8 watts, and then for 12 hours that is 778 watt hours.

Then if you have two people (or the equivalent) in that space, they will generate about another 682 BTU/hr of hear. At an air conditioner efficiency of 10 that is 68.2 watts, and over 12 hours that is 818 watt hours

So, total is 1,250 + 778 + 818 = 2,846 watt hours by the end of 12 hours. This is a bit of a back-of-an-envelope level as the temperature varies throughout the day, and we have not factored in humidity, but it's going to be in the right ballpark for your planning.

Most vans do not really create a controlled environment. You will have to be obsessive about this to use an AC on battery.

My quick thought on your build plan: Solar needs to be at least 660 watts for it to make much difference. Lithium batteries need to be at least 4,000 watt hours and topped up every night. Insulation should be at R-9 for a space of no more than 312 cubic feet. Air conditioner should have an efficiency of at least 10 BTU/watt.

A Honda 2200 generator at 1,800 watts should top up your batteries in 3 hours of run time on about one gallon of gas. This is assuming that you only air condition for 12 hours per day. Plan on maybe $100 per month to run the generator, but less if the weather isn't bad.

I've been working on the possibilities of running an air conditioner on batteries. It's fairly daunting but not impossible. Very, very few van builds include a truly controlled environment and consequently the effective R-Value will be closer to 4, and the square footage will be closer to 500. In that situation 500 square feet x .25 (U-value) gives a cooling load of 125 BTU/hr per degree of temperature, which is about 3,750 BTU/hr just to deal with the space cooling when it gets to be 100 out, so the totals almost double and then it starts to seem ridiculous.
 

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2016 136WB low roof diesel, converted to an RV by Sportsmobile, TX
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High idle and larger / more alternators can be used in some vehicles to increase output. Again - have not studied the ability to add additional alternators to the Promaster platform. There are some pretty impressive alternators on the market, mostly driven by car audio enthusiast.
You can add a second alternator to the gas engine, but it will be basically at the bottom of the engine. I have a friend with a gas Promaster with a second alternator, and he often gets worried about it when he is in a clearance needed situation.

For those of us with diesels, we are out of luck - there is no way to add a second alternator; you have to rely upon the 220A alternator on the diesel (plus, in my rig's case, a DC/DC converter to charge the 24V LiMnFePO4 house batteries).
 

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2018 3500 EXT Camper Conversion in CT (TX for now due to Covid)
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I've been working on the possibilities of running an air conditioner on batteries. It's fairly daunting but not impossible. Very, very few van builds include a truly controlled environment and consequently the effective R-Value will be closer to 4, and the square footage will be closer to 500. In that situation 500 square feet x .25 (U-value) gives a cooling load of 125 BTU/hr per degree of temperature, which is about 3,750 BTU/hr just to deal with the space cooling when it gets to be 100 out, so the totals almost double and then it starts to seem ridiculous.
I was thinking you were really about to be dissappointed until I got to the last part of your post. My experience with my well insulated van is that the 5000 BTU air conditioner can just barely handle it when the temperature is 100 degrees and 70-80% humidity when I am parked in partial sun.

The solar load is very important here. In theory you can insulate really well, but if you are parked in the sun that is a significant additional thermal load that has to be accounted for. White vans are better for this, but they all have metal heat conducting ribs. I have added some additional insulation in some critical areas since my last test, but the van will never be perfectly insulated. I have r10 in a lot of areas, but I still have the cab area with windows (which if not covered is basiacally a greenhouse capturing heat).
 

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2019, 159", High Roof, 2500
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IIRC Viper and Compustar offer temperature start features.
Still poking around, AceK9 Automatic Engine Start Software Option with Engine Stall Sensor
Great suggestion on the viper or compustar remote units. I’m eyeing both of their higher end (viper 5906 or Compustar ProT13) adding cellular lte so temp can also be checked via app on phone.

That AceK9 unit is slick.

Following this thread as the elements of being able to keep van cooler in summer while away for a few hours landed on my requirement list too, but nothing as long or as hot as BoonDogger here.
 
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