AC Fridge overconsumption.

RitSim · Aug 8, 2023

Not questioning your numbers but at 12 volts that would be 166 amps using a 2/0 cable. You should be blowing fuses left and right. My compressor is wired to a 10 amp breaker using #12 wire.

jviss · Aug 8, 2023

RitSim said:
Not questioning your numbers but at 12 volts that would be 166 amps using a 2/0 cable. You should be blowing fuses left and right. My compressor is wired to a 10 amp breaker using #12 wire.

I think there may be a language issue here. He says "fridge in AC with water cooling," but I can't tell if it's a 120V or 220V AC fridge, or maybe an air conditioner. He must be plugged in, or have a generator.

Don S/V ILLusion · Aug 8, 2023

henri said:
Hello,

On my hunter I have a fridge in AC with water cooling. This type of compressors usually takes usually a 100W. In my boat it takes close to 2000W (yes two thousand. What could be the reasons of such an overconsumption ?

That is normal.
my understanding is that you refer to the air conditioner here. If I am correct, it’s not possible for that to require only 100W.
a typical 16,000 BTU air conditioner requires up to 10 amps at 230v Or 2300 watts. Or at 12v, it is equivalent to over 200 amps. Again, over 2300 watts.

JamesG161 · Aug 8, 2023

You should clean out your AC water discharge line.

I sometimes use Crushed, Spa Chorine tabs in the inlet stainer to keep my lines clean.

Also your cooling water temperatures have effects too.

Jim...

Terry Cox · Aug 8, 2023

Our boat has two 120VAC reverse cycle heat pumps; 16K BTU main cabin, 9K BTU aft cabin. Combined, they consume 12 AMPs of power, which includes the Little Giant sea water pump. That equates to 1,440 watts. Check for a good water flow out the through hull. Could be the compressor reaching end of life. Unclear whether it is the heat pump (air conditioner) or refrigerator.

MikeHoncho · Aug 8, 2023

AC = air conditioner or AC = alternating current?

Ralph Johnstone · Aug 8, 2023

henri said:
I had the same compressor on my other Hunter and consumption was one hundred watt not one thousand. What can it be wrong with my system, that would increase the consumption in such a way ?

What gauge or meter are you looking at to see the present 1,000 watt loading on the compressor. Are you reading the same output gauge or meter when you saw the 100 watt load ?

I can't see 100 watts running a compressor but 1000 watts does seem a little high.

I just stuck my nose inside our refrigerator and this is what I see for its draw :

115 volts X 3.5 amps = 403 watts for a 22 cubic foot freezer/refrigerator without a cooling water pump. Is there any way of checking the amperage draw on your cooling water pump alone ?

MikeHoncho · Aug 8, 2023

Ralph Johnstone said:
What gauge or meter are you looking at to see the present 1,000 watt loading on the compressor. Are you reading the same output gauge or meter when you saw the 100 watt load ?

I can't see 100 watts running a compressor but 1000 watts does seem a little high.

I just stuck my nose inside our refrigerator and this is what I see for its draw :

View attachment 218606

115 volts X 3.5 amps = 403 watts for a 22 cubic foot freezer/refrigerator without a cooling water pump. Is there any way of checking the amperage draw on your cooling water pump alone ?

His is 220 volt so it would be 200 watts

Ralph Johnstone · Aug 8, 2023

MikeHoncho said:
His is 220 volt so it would be 200 watts

Can't follow the math on that calculation.

My point in getting the amperage readings is : are these readings from a fixed panel mounted amp gauge or from a hand held ammeter ? Maybe one or the other has developed a problem with readout.

MikeHoncho · Aug 8, 2023

If the same unit was 220 volts, the amp rating would be 1/2 of what is on your label.

Ralph Johnstone · Aug 8, 2023

MikeHoncho said:
If the same unit was 220 volts, the amp rating would be 1/2 of what is on your label.

Yes the amperage would be half for his 220 V supply but the wattage would always be the same regardless of the supply voltage. Of course we can't put just any voltage into the same compressor but you get the idea. The work input to the compressor (measured in watts) will always be the same, regardless of the supplied voltage.

And that information along with $2.50 will get you a cup of coffee in most restaurants.

Project_Mayhem · Aug 8, 2023

A partially clogged refrigerant line could cause the compressor to work harder. I've also seen compressor motors draw more current than usual when their at the end of their life. Shorted windings perhaps?

Some compressors also have an extra winding just for starting

MikeHoncho · Aug 8, 2023

Ralph Johnstone said:
Yes the amperage would be half for his 220 V supply but the wattage would always be the same regardless of the supply voltage. Of course we can't put just any voltage into the same compressor but you get the idea. The work input to the compressor (measured in watts) will always be the same, regardless of the supplied voltage.

And that information along with $2.50 will get you a cup of coffee in most restaurants.

Sorry, meant to say amps not watts in my previous.

AC Fridge overconsumption.

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SBO Weather and Forecasting Forum Jim & John

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