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Discussion Starter #1
We are trying to get a 12volt refer unit for the City.
It requires a 130 amp alternator and the data for the City says it is
a 160 amp unit. However Thermo King is saying it is not large enough.
How do I find out the model and data for the stock alternator in the City?
Not on the parts lists yet.
I cannot see the name plate in the engine compartment.

prohbob
 

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We are trying to get a 12volt refer unit for the City.
It requires a 130 amp alternator and the data for the City says it is
a 160 amp unit. However Thermo King is saying it is not large enough.
How do I find out the model and data for the stock alternator in the City?
Not on the parts lists yet.
I cannot see the name plate in the engine compartment.

prohbob
He is probably right. Don't forget the total load you need to operate the van without any add ons like the lights, AC, engine fan, blower, stereo, etc. If the TK eats up 80% (160a less 130a) you are left with squat to operate the rest of the van.
 

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2014 Ram Promaster 2500 159" diesel
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We are trying to get a 12volt refer unit for the City.
It requires a 130 amp alternator and the data for the City says it is
a 160 amp unit. However Thermo King is saying it is not large enough.
How do I find out the model and data for the stock alternator in the City?
Not on the parts lists yet.
I cannot see the name plate in the engine compartment.

prohbob
If the unit to be installed is the B-100
Specifications are
Vehicle alternator rating: 125 A
Vehicle battery minimum rating: 90 Ah
http://www.thermoking.com/products/product/b100.asp?mn=b100&pg=specs&mainURL=&cat=9
 

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Discussion Starter #4

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Those specs say that "on the road" electric motors use:

12Vdc - 63 A


I'd call and confirm, but expect a 160 Amp alternator will keep up as long as engine is kept running. It may require some type of idle speed control if left idling for long periods.
 

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I'm curious: if you are willing to run the engine, why not just use the pmc a/c? Or are you hauling produce or something.

I was thinking if i wanted to do hvac on the cheap, i'd go battery, inverter, and one of those $250 rolling room a/c units with a dryer vent out of an ajar window. Cheap, effective, non-parmanent.
 

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Discussion Starter #7
Insulating

I am looking at insulating and hauling produce.
Need to keep under 40 degrees.
prohbob
 

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2014 Ram Promaster 2500 159" diesel
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That is why I am wondering unless the rating is for a second alternator dedicated exclusively for the refer unit. That is what the rating may indicate
The City has a 160 amp alternator and a 90 plus AH battery.
Not all vehicles come standard with such a high output alternator the chevy express is only 105amp as standard . The Promaster City is new and it may not be in their books yet and they haven't a clue. The questions to ask TK is what size alternator do I need on my van, if different than the spec sheet why. As for idle on the City it may have auto idle up ask your Ram City dealer. Must new vehicles do, this is so they can put a smaller battery in and not carry the dead weight when not needed.
 

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I am looking at insulating and hauling produce.
Need to keep under 40 degrees.
prohbob
Hi,
I think a lot depends on how you well you insulate.

If you built an insulated box in the back for the produce that was made from 6 inch thick polyiso (R6 per inch) that was 9 ft long, 6 ft high, and 6 ft wide, thats 288 sq ft of heat loss area. If its 40F inside the box and 90F outside, then the heat loss is (90F - 40F)(288 sf)/R36 = 400 BTU/hr.
This assumes you build it carefully with a door that seals and is also well insulated. It also assumes that the produce goes in already cooled so you don't have to cool its mass down to your target temp.

If you convert this 400 BTU/hr directly to electricity, its 400/3412 = 0.117kw, or 117 watts. At 12 volts that's only 10 amps.
That's at 100% efficiency, but most refrigeration equipment operates as a heat pump and effectively does better than 100% because they transfer some of the heat in the box to the outside.

Just as a sanity check, take a look at good refrigerators -- many of them (even large ones) these days operate on less than 2 KWH per day -- thats an average wattage of 2000 WH/24 hrs = 83 watts, and they are not really all that well insulated.

Maybe something like a well insulated box coupled with a refrigerator kit -- something like this: http://www.novakool.com/products/conversion_units.htm this one is too small, but there are probably larger ones out there -- or salvage the guts out of large freezer?

If you did this sort of efficient insulated box and kept the average amperage down to 10 amps, a couple of golf cart batteries (220 amp-hr) would keep you going for about 12 hrs if you limited discharge to 50%, or 18 hrs if you took them down to 20%. (with no other loads).

Gary
 
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