Hey everyone! I'm gearing up for a two-week field sampling trip for my thesis and need to keep my samples frozen to ensure they stay viable. I'm setting up a solar-powered system for this. I've got a 400 watt solar panel and a 2000 watt power bank equipped with a built-in MPPT controller. The freezer I'm using is 52 liters and rated at 80 watts. I know that the power rating isn't the full story on its consumption, so I'm planning to test it out once everything arrives. I'm also considering adding a 100 watt panel and potentially a secondary 500 watt power bank as a backup in case my primary bank doesn't hold up through the night. I'll have the setup in my car with the solar panel mounted facing south at 180 degrees and I'm using reflective bubble wrap to insulate the windows and block out sunlight. Do you think this will work? Should I go ahead and order that extra power bank?
2 Answers
Generally speaking, a home chest freezer averages around 50W but that’s in a controlled climate. In your setup inside a car, it could heat up quite a bit, probably reaching around 100°F, which will affect power consumption. It's crucial to find out how many Watt-hours your freezer will actually use in those conditions. If you can, get a KillAWatt meter to measure its usage over a day. Your 2000W power bank should be sufficient to start and run the freezer, but just make sure it has enough Watt-hours to keep it going when the solar isn’t producing. With your 400W panel, expect around 1600Wh daily—which should be enough, assuming you don’t get too many cloudy days.
I’m hoping that the smaller size of the freezer will help with its power needs. I plan to test the setup for a few days to monitor the performance. If the cloudy weather is occasional, will that impact the system? I’m really considering that backup 500 watt power bank now, especially since it can run the freezer for two full days on a charge. I’ll definitely grab a KillAWatt meter, too—it’s a smart investment!
Just keep in mind that even with insulation, the car is likely to heat up more than the outside air temperature, and the freezer will also generate some heat while running. It could get pretty toasty inside that vehicle.
What alternatives do you suggest for keeping it cool?
You really might need that backup if you get a stretch of cloudy days. It’s always better to have a safety net, especially during critical field work.