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Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Roger & Susan in Home2 on October 02, 2018, 07:44:04 pm

Title: JC-Refrigeration Conversion, Measured Power Consumption
Post by: Roger & Susan in Home2 on October 02, 2018, 07:44:04 pm
Quote from: Roger & Susan in Home2 –
Douglas (ScubaGuy) asked me to post this about their JC-Refrigeration Conversion.  This converted their LP refrigerator to a 120v compressor driven refrigerator in their 1997 40' U320.

They hooked up a Kill-a-Watt meter to monitor actual power consumption.  It has been in place for about 25 days. As of last night the second test has recorded 12.83 KWh used over the past 198 hours ( a little over 8 days). They are running the refrigerator at level 5 to achieve the measured interior refrigerator and freezer temperatures they want.

12.83 KWh for 198 hours is an average of 64.8 watts per hour.  1555 watts per day. For reference our 19 cu ft Samsung averages about 70 watts per hour.

What does that mean in AmpHrs?

If you have an older inverter that is about 88% efficient and your batteries are at 12.5 volts that is about 5.9 amps average draw on your batteries or 141 amp hrs per day.
Title: Re: JC-Refrigeration Conversion, Measured Power Consumption
Post by: Roger & Susan in Home2 on October 02, 2018, 07:55:22 pm
Here is an update from ScubaGuy.

Their 120v JC Refrigeration conversion has used 63.3 kWH in 986 hours.  Tht is an average of 64.2 watts per hour.  About the same as the earlier shorter test.
Title: Re: JC-Refrigeration Conversion, Measured Power Consumption
Post by: bbeane on October 02, 2018, 09:34:41 pm
So in the end about the same. No free lunch. We just had JC Refrigeration replace the cooling unit on our Dometic 1282 with gas unit. It's works great. He is working on a 12v unit that may be a game changer, no inverter needed.
Title: Re: JC-Refrigeration Conversion, Measured Power Consumption
Post by: Caflashbob on October 02, 2018, 10:02:20 pm
Straight 12volt may benefit from increased wire size versus 110 volt.  10% power loss to convert 12 to 110 by inverter.

How efficient would a 12v compressor be versus 110V
Title: Re: JC-Refrigeration Conversion, Measured Power Consumption
Post by: George and Steph on October 03, 2018, 01:18:47 pm
Not what I had hoped to see but a viable option.  We will stay with propane.  Going to add the fire protection systems on the inside.  BBoard, fire extinguisher and keep the ARP.  Extended boondocking is important to us.  Ours was new and still in plastic when we purchased 3 years ago.

I had noticed several times on our external monitoring the temperature increased and thought it might be an overheating system shutdown.  I decided to place one of the recording thermometers in the unit to see when the temperature variations occurred.  Defrosted and removed all items to the house fridge.  What I found was an increase in temp on a recurring basis as if on an extended schedule.  Based on a google search found that the control board is programmed to do this to keep the fins ice free. 

Somehow I missed that in my work up.  What appeared to me as a random malfunction was a designed increase.  Since it isn't broken, we will stay with its' boondocking capability's.
Title: Re: JC-Refrigeration Conversion, Measured Power Consumption
Post by: Caflashbob on October 03, 2018, 01:37:32 pm
Great info on the auto function.  I wonder if it's bypassable? 
Title: Re: JC-Refrigeration Conversion, Measured Power Consumption
Post by: George and Steph on October 03, 2018, 01:49:20 pm
Bob not sure on that but it appears those boards were added circa 2006 or so. 
Title: Re: JC-Refrigeration Conversion, Measured Power Consumption
Post by: Roger & Susan in Home2 on October 03, 2018, 04:59:43 pm
The power use numbers reported by Scuba Guy are measured at the refrigerator.

I don't think the motor in the 12 v option would use less power than the 120 v motor but there is 5 or 6 watts in the inversion process plus the power required just to have the inverter on.  If you are a mostly plugged in sort of user or have 600 or so spare watts of solar power it should be good.
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