Looking for LOWEST BTU Roof A/C Available

[bobinyelm]

I want a roof A/C that will happily work w/ my Honda 2000i generator, and the PO of my truck camper sized UP to 13,500 BTU (from the factory 7700BTU unit that appears discontinued) so the camper would cool instantly at commercial campgrounds, where power was virtually unlimited.

Even 7700 BTU is more than I need for my well-insulated Big Foot, but it would be OK for my Honda if they are available.

I've been unable to find less than 9200 BTU Coleman units online.

Anyone know of smaller ones available these days?

Thanks-
Bob

[TQ60]

Stay with a large unit as a large unit can set on low but a small unit is just that.

If you generator is too small then larger generator...

If you do change then look for something your generator can support.

Contact the manufactures of the ac and ask them.

[autofish]

Bob; The BTU rating is not the limiting factor look at the start up amp for the a/c as this is what limits gen usage. Not all gens can provide the start surge needed to get the compressor going even with a much lower run amp. Putting a hard start kit in the a/c can help some so look for an a/c with the lowest start up amps.

[bobinyelm]

Originally Posted by TQ60

Stay with a large unit as a large unit can set on low but a small unit is just that.

If you generator is too small then larger generator...

If you do change then look for something your generator can support.

Contact the manufactures of the ac and ask them.

Sure, I can get an industrial genset and tow it behind me, since there's no room in the truck for such a generator.

Seriously, I asked a specific question for a reason, and that was because the Honda fits in the rear footwell of my truck, and despite 4 back surgeries, I can lift it myself, since I camp alone most of the time. Since the A/C is a roof top unit on my 9.5ft Big Foot truck camper, there's no place for one in the camper (even the Honda).

The fact is I already have a Champion 3100 inverter generator I use with my 5th wheel w/ a 13,500 A/C, but that sits in the P/U bed and doesn't need to be lifted or moved. It weighs 85 pounds, and is too large to fit in the truck's footwell, even if I could safely lift it alone.

I have done enough research to know that a small A/C is PLENTY for the interior cubes of a small truck camper. Less noise, less gasoline, less weight (both the A/C and the genset) I previously had a Lance 11'6" truck camper with a 13,500 BTU A/C and a built-in 3500 watt genset, and even at 120 degrees, the 13,500 was way overkill, and the Lance was not a 4-Season, well insulated unit like the Big Foot, plus it was 50% bigger (cubic feet).

[bobinyelm]

Originally Posted by autofish

Bob; The BTU rating is not the limiting factor look at the start up amp for the a/c as this is what limits gen usage. Not all gens can provide the start surge needed to get the compressor going even with a much lower run amp. Putting a hard start kit in the a/c can help some so look for an a/c with the lowest start up amps.

Yes, you are correct, but the smaller units (7100 BTU DuoTherm (discontinued), Polar Cub 8300 BTU (discontinued), and the Mini-Mach 7700 BTU (discontinued) all were easily run by the Honda 2000i.

I have to admit that the newer "Power Saver" design A/Cs like the Coleman Mac 1 PS at 11,000 BTU use the SAME watts as many of the smaller units (Polar Cub 9201, 9200 BTU), and have even a lower LRA than the smaller A/C units (under 42amps LRA).

I could "downgrade" to the 11,000 BTU unit, though with more BTU and a blower that moves TWICE the cu ft of air, it will likely cycle a lot (since a couple of minutes running each time will cool the coach to the set point). On/Off/On/Off can be annoying, plus the louder, higher volume blower can be a bit much in the tiny truck camper. It might be possible to hide a small "AC speed control" unit in the box to slow the blower motor down, however, which would also reduce the amperage draw even more. PWM Speed Control

Those are my reasons, anyway, and I may have to settle for 11,000 BTU since none of the older R-22 A/Cs are made (unless I can find an "old-stock" NIB one discounted, or a good, used one cheap.

DuoTherm Dometic MAKES low BTU efficient A/C units, but you have to import them from Europe (they sell them only there), and the one I'd want would cost $2400 in USD, which is absolutely insane vs. $600 complete for the Coleman Mach 1 PS.

Given that my 13,500 unit is old (16 years), even though it has very little run-time (about 10hrs according to the PO, who only used the camper as a comfort-stop and bedroom while traveling to visit relatives), it is not a "power saver"

It's a DuoTherm Penguin 13,500 BTU with a Compressor rating of 12.4a + 3.1a blower, and says it needs a minimum 20a circuit breaker, or 3500 watt generator minimum. The LRA of the Compressor is 60 + Blower 8.8, for a Total LRA of 68.8 amps. No "soft-start" kit will likely tame that beast for my Honda (or even my Champion 3100i I suspect).

I posted my question on a couple of RV sites at the same time, and the info I posted above was a synthesis of what I learned from a lot of helpful folks.

Bob

[mhudson]

I just purchased the 11,000 BTU Airxcel for one of my work vans.
It is a model 48207c966
The full load amp draw is 9.5 amps (1025 W).
I run it off a Honda 2200w inverter genset with no problems at all.
The van is not insulated and it doesn't cycle.


http://www.rvcomfort.com/rvp/pdf_doc...data_sheet.pdf

[bobinyelm]

Originally Posted by mhudson

I just purchased the 11,000 BTU Airxcel for one of my work vans.
It is a model 48207c966
The full load amp draw is 9.5 amps (1025 W).
I run it off a Honda 2200w inverter genset with no problems at all.
The van is not insulated and it doesn't cycle.


http://www.rvcomfort.com/rvp/pdf_doc...data_sheet.pdf

Yes, that's the one.

One reason it may not cycle much in your van is that being not insulated, it takes a good bit of the capacity of the unit to cool the interior down.

My Canadian-made BigFoot is so well insulated, I suspect it won't run long each cycle to get the temp down to the thermostat set-point, which is why a lesser unit (7000 BTU) would be better suited, but given the low lower draw of this Mach 1 unit, and the fact no one makes low BTU units this side of the pond these days, it's the BEST solution for me as well.

Is it reasonably quiet, BTW? I was thinking of using a pulse width modulator in the fan circuit to reduce the fan speed (and cooling output a bit) below "Lo Cool" to cut down on airflow, and maybe noise.

Bob