Tested my setup
as described here.
Ambient temps inside home 20°C (68°F)
Fridge placed in the most shaded corner of the house
Peltier fed 12 volts / 3 amps from a laptop charger (placed away from the fridge) continuously
Load: ~4.5 liters (4.8 US quarts) of beer and juices
Various container types (2 x 0.5 liter plastic bottles, 1 x 0.5 liter aluminum can, 2 x 0.355 liter aluminum cans, 1 x 0.25 liter aluminum can, 1 x 1 liter aluminum can, 2 x 0.55 liter glass bottles)
Results:- Cools the load (overnight) to the temperature of a glass front commercial fridge. (Which is slightly warmer than a classic home fridge, 7°C or warmer. Look at the bottom display next time you buy beer from the store.)
- Aluminum cans are coolest, glass bottles don't cool themselves as well, plastic bottles are worst.
- It doesn't matter if containers were already cooled when bought or just room temperature. Overnight they cool just as well, only the container material makes the difference. Insulative containers like plastic bottles did not allow enough cooling to happen, even overnight.
- The actual size of the load makes little difference either, it cools in a similar way with 2 bottles or 9 containers.
- Charger (power brick) temps were in the <40°C range, usually 36-38°C.
This makes it very suited to beer, juices or wine, but a rather poor storage method for food.