Parts
Sonoff DC uController
Temperature Probe
Small Pure Sine Inverter (300w - size depends on fridge)
Diagram
Wiring using Sonoff SV
The trace is 2 mm wide. By assuming the PCB trace thickness is 1 oz/ft^2 you can calculate the current: 2A
If you are using more than 2A be sure to put more solder on the solder traces.
Wiring using Shelly 1 Plus
The Shelly 1 Plus with the Shelly Plus Addon should be able to handle the power requirements.
See Shelly 1 Plus
To be continued....
Fridge Specifications
| Running Power | 70 w |
|---|---|
| Amperage @120V | 0.6 A |
| Amperage @12V | 6 *1.2 = 7.2A |
| Power Using Inverter | 50*1.2 = 60w 70*1.2 = 84w 60-85w |
| Idle Power | 40 w |
| Amperage @120V | 0.6A |
| Lowest Temp | 3.9 C |
Batteries
| Battery | Ah | Watts |
|---|---|---|
| Battery 1 | 110Ah | 1.3 kw |
| Battery 2 | 110Ah | 1.3 kw |
| TOTAL | 220Ah | 2.6 kw |
Runtime Calculation
| Battery Power | 2600 w |
|---|---|
Daily Power Consumption (70w*24) | 1600 w |
| < 2 days |
In reality, it should only run 8 hours out of the day which should reduce the daily power consumption to about 500w or 42 Ah.
This would give me a run time of roughly 5 days with no other loads on the system.
Measurements
There is something wrong with this fridge.... Not sure if this is a result of limited ventilation or not...
References
| Reference | URL |
|---|---|
| Tasmota Sonoff SV Details | https://tasmota.github.io/docs/devices/Sonoff-SV/ |