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Old 02-10-2019, 08:47 PM   #11
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I still don't understand. How are amps used determined by ambient temperature. Is it based on assumptions about compressor use over time, compressor on and off.

Bud
Outside Temperature
The amount of heat and the rate at which it transfers depends upon the temperature difference between the outside air and the refrigerant. The lower the temperature of the outside air, the more cooling is done by the heat exchanger, instead of the compressor. When the outside air temperature increases, the air-conditioner works harder to cool the home because the compressor works more.

https://sciencing.com/can-outside-te...-ac-23326.html
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Old 02-10-2019, 09:05 PM   #12
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Mike, need it dumbed down.

"the air-conditioner works harder to cool the home because the compressor works more."

Your link said "works harder ", does that mean turns on more, runs more?
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Old 02-11-2019, 04:39 AM   #13
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I still don't understand. How are amps used determined by ambient temperature. Is it based on assumptions about compressor use over time, compressor on and off.

Bud
The difference is not from the duty cycle (on and off). It is because the compressor needs more power to change the state of the refrigerant when the ambient temperature is higher.

The electric power input to an air-conditioner compressor increases with increasing outdoor air temperature due to the increasing discharge pressure caused by the decreasing heat transfer capacity of the condenser in the air-conditioner.

- - Mike
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Old 02-11-2019, 12:30 PM   #14
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The difference is not from the duty cycle (on and off). It is because the compressor needs more power to change the state of the refrigerant when the ambient temperature is higher.

The electric power input to an air-conditioner compressor increases with increasing outdoor air temperature due to the increasing discharge pressure caused by the decreasing heat transfer capacity of the condenser in the air-conditioner.

- - Mike
Thanks, feeling foolish as I should have picked that up somewhere in the last upteen years. I'll start reading as opposed to more questions.
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Old 02-11-2019, 10:39 PM   #15
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Iím no expert on ProAir but know that when a compressor runs off DC it can vary current draw through variable compressor RPMís depending on the cooling requirements ie outside ambient temperature and humidity.
I have mini split heat pumps in my house that work by inverter technology. They change AC to DC and the compressor runs at many different speeds based on demand.
Iím thinking this technology is creeping into our RVís.
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Old 02-12-2019, 02:06 AM   #16
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Iím no expert on ProAir but know that when a compressor runs off DC it can vary current draw through variable compressor RPMís depending on the cooling requirements ie outside ambient temperature and humidity.
I have mini split heat pumps in my house that work by inverter technology. They change AC to DC and the compressor runs at many different speeds based on demand.
Iím thinking this technology is creeping into our RVís.
Yes - that is the technology - I sure hope it is widely adapted by the RV industry. Inverters and variable speed compressors are making the newest heat-pump systems very appealing.
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Old 02-12-2019, 02:18 AM   #17
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The mini splits in my house are amazingly efficient. They heat and cool great and cost very little to operate.
The RV industry definitely needs to embrace this technology.
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Old 02-12-2019, 02:05 PM   #18
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I have a heat pump in my B but have never used it. If I have shore power, why wear out the thing? When I can use an inexpensive electric heater down on the floor where the heat should .........

I must be missing something.

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Old 02-12-2019, 02:18 PM   #19
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There wouldn’t be much advantage to using a heating option on a split AC in an RV since you always have a higher output heater available. I suppose when the temp is mild and you have shore power it might make some sense.
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Old 02-12-2019, 02:30 PM   #20
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The current trend in class B RVís is no propane and no generator. The are putting Lithium Battery packs in them to drive a 12 volt AC unit. The DC motor driving the compressor lends itself to increased efficiency to make that possible. The fact that the heating side is possible is just a plus.
That is the context of my reply to this thread.
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