This unit is unusually large for a peltier based thermoelectric dehumidifier. But it's very typical of these units inside.

The mystery capacitor was just across the power rails. The pair of switches also had a small signal wire to light the "Tank full" LED.

The small dehumidifiers are only suited to very warm and humid environments. They require a significant temperature differential to extract moisture from the air. I ran this unit in my cold house for three hours and it formed frost on the condenser fins which only dripped off when the unit was turned off.

If you need a dehumidifier and have a warm house I recommend getting a traditional compressor type dehumidifier as they will pay their way quickly with very efficient and fast extraction of water from the air

If you need to use a dehumidifier in a cold location then the best type is a desiccant drum dehumidifier, which uses a rotating drum of desiccant material to absorb moisture and then extract it again with heat. They will pull out a lot of water in cold areas, and also put out a stream of dry warm air.

I use both types. Compressor in the summer and desiccant drum in the winter.

Another valid option for reducing humidity in cool areas is ventilation. Particularly if you use a humidity controlled fan. In remote locations you could use a filtered 12V equipment fan with small solar panel to draw air out and a plain filtered grill to allow fresh air to flow in.

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