Conversión refrigerador 110/220 Vca a 12/24 Vcd para auto caravana o camper

Table of Contents 00:00 Introduction 00:31 What type of refrigeration is used to convert to 12/24 Vdc 01:29 Compressor sizing 01:57 In the physical replacement the terminals must match 02:25 Electrical installation of the compressor to 12/24 Vdc 03:54 Converting a thermostat terminal to two independent ones 05:56 Gas charging against current 07:01 Refrigerator operation test in 12/24 Vdc There are two details that make the automatic ones not suitable for use in a solar system, one of them is that they use an electronic card that works all the time, 24/7 and in these systems these energy vampires are undesirable. The second point is that they include resistance for defrosting and fans, which provide additional consumption and some are 110 or 220 V. You have to check the capacity of the refrigerator, it has 4.4 cubic feet, equivalent to 124 liters, checking the compressor specification tables, for that volume a minimum 1/10 HP compressor is required (In reality the one that comes from the factory is overrated, it is 1/5 HP) and the compressor they brought me is 1/8 HP, perfect for the project. To physically replace the compressor there is no complication, you just have to verify that the suction, discharge and service pipes are connected correctly as appropriate, in this case they match as is, if you do not have equipment, a refrigeration shop can do it for you. Just one observation, the compressor came without oil, you have to put it in, it has 6 ounces. Where there may be a trick is in the electrical part, but even so it is very simple. This compressor only requires power (positive and negative) for basic operation, whether it is 12 or 24 Vdc, it detects it automatically, and also the connection of the two independent cables of the thermostat, neither should go to negative or positive or to any other point. To use the wiring that this refrigerator already has, the first thing is to identify the cables, this white one that comes from the plug and that has a derivation for the compressor and for the internal light is the neutral in AC and will be our negative in DC. The other cable that comes from the plug, black in color, is the phase and will be our positive in DC, this same cable originally enters for the phase of the internal light and also in this model connects internally with a terminal of the thermostat. The blue cable is the only one left and is the output of the thermostat. Remember that I mentioned that the compressor uses two independent terminals, here I am going to place a car relay, which is easy to get, to this relay you have to connect a negative connection to the coil (terminals 85 and 86) and the blue cable that comes from the thermostat, which once converted will send 12 V when it closes and will make the relay close. In terminals 30 and 87 we will have the two independent terminals that replace the original thermostat, they close when the thermostat closes and open when it opens. If in your refrigerator not one, but two cables come out from the inside, they will surely be the two independent terminals of the thermostat and you can use them directly without a relay, you should only check with a multimeter or tester, that there is no connection with any other cable. We already had power in the compressor, we only need to connect the independent terminals of the thermostat to those marked C and T and the refrigerator will be working in its minimum configuration, which is actually convenient, it is the one that generates the least electrical consumption. With the entire system connected, you have to create a vacuum, in order to subsequently charge the refrigerant gas R134a in this case, but here is a very important detail. When I broke the vacuum I was distracted and did not close the valve when reaching 0 PSI, when I returned it was stable at 50 PSI, in another type of refrigerator nothing happens, because you have to keep putting gas with the compressor running, but not here, it takes up little space, it even gets stuck if you put it to work with that overload. With the compressor running you have to adjust the correct charge according to the current specified by the compressor manufacturer, in this case at 12 Vdc and 2000 RPM the objective is to leave it at 4.1 A (At 24 Vdc the current consumption is half). This refrigerator since its start, in one hour made its first stop, with a temperature of -9.8°C in the freezer and 12 °C in the cooler, the cooler will lower the temperature more with more cycles, this reached 5.6 C°. Now at full operation, without opening the door, at room temperature of 30°C, the compressor runs for 7 minutes with a 17-minute rest period, which is actually a very good time. And here is the 12V LED light that fits into the same E-12 socket. Ready, here is a sample of the ice cubes made and the temperature of a jug of water that I left for example, all that remains is for you to measure your Ah consumption to complete the wind or photovoltaic system.