Recording Ammeter

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Old 03-26-16, 07:35 PM
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Recording Ammeter

I have a Compressor fridge in my RV. I want to see how long it stays on during the day. It is 12 volt but I can plug the RV into 120 volts. What type of instrument would I use to record the amps that are used? I could then interpolate that information to see how long it runs.
 
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Old 03-26-16, 07:45 PM
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Old 03-27-16, 12:45 AM
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The Kill a Watt meter is a 120vac monitor. Since the fridge is 12vdc.... that monitor would actually be reading the DC converter current which is supplying power to the compressor and any thing else that is running on 12v.

A DC amp monitor is required here. I don't really know of one. You could use a DC ammeter to measure the running current of the compressor and then use a 12v hour running meter to see how many hours it ran. Then multiply the hours times the current.

12v compressor fridges are not very efficient and use a lot of power. I can't remember the last time I worked on one. What brand is it ?
 
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Old 03-27-16, 12:02 PM
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PJ max: I think the Kill-A-Watt Electricity Monitor is perfect for what I want to do. I would plug the camper into the unit and only have the frig on and would know exactly how many watts were used over a period of time then divide by the amount of watts the unit uses when it's running and the result would be the time the frig ran. Am I thinking correctly?
 
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Old 03-27-16, 01:28 PM
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You would register the draw from the fridge and from the convertor.
Any batteries connected to the convertor ?

If you're only concerned with the running time... get an hour meter.

This is only one..... there are dozens available.... Honeywell-Hobbs-Meter-Quartz-automotive
 
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Old 03-27-16, 08:02 PM
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PJmax: Yes there are batteries connected but I would hae them fully charged so they wouldn't be pulling any amp9erage. An hour meter looks good but don't know how I would hook it up to the frig
 
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Old 03-28-16, 01:17 AM
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If the fridge runs on 12vdc...... 12v will be sent to the compressor and should be easy to find.
If you decide to go this route.... leave me info on the fridge.
 
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Old 03-28-16, 12:12 PM
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PJmax: The problem is going to be, I only have access to above the top of the Frig and the bottom 1/4 of the frig due to the way it is installed. (there is nothing electical on the bottom) I can't get to any of the wires, the compressor or the fan from the top. I can pull the frig out but that is a big hassle. Would it be possible to attach the "Hour Meter" to the 12 volt input wire that operates the frig? Seems like the only time there would be amperage (to operate the frig and the hour meter) would be when the frig is on, so when the frig is off there would be no amperage?
Following is info on the Frig:
http://www.dometic.com/QBankFiles3/E...anual_5525.pdf
 
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Old 03-28-16, 01:01 PM
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Is there a vent grill on the outside of the trailer?
 
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