Tesla pours cold water on the practice of cooling Supercharger connectors to increase charging rate

Ever since a popular automotive reviewer tested the claim that cooling a Supercharger connector with a wet cloth speeds up the charging process, the practice has become somewhat viral.

"Another extreme wet rag Supercharger test," read the Out of Spec post at the time. "Slapped that room temperature soaking wet rag, and it climbed back to 119kW where it hit the internal charge profile limit."

People have been cooling charging connectors with methods ranging from a damp towel and frozen peas bag to directly pouring water over them for a good while now, so Tesla's charging team had to intervene with a cautionary message.

"Placing a wet cloth on Supercharger cable handles does not increase charging rates and interferes with temperature monitors, creating risk of overheating or damage," advises Tesla. "Please refrain from doing this, so our systems can run correctly, and true charging issues can be detected by our systems," it warns.

As usual, those who swear by this method beg to differ, pointing out that the wet rag really cools the charging handle itself and doesn't just trick the sensor to make it increase the charging rate. The handle is the hottest part of the assembly, and the task of the thermal sensor there is to lower the rate before it gets uncomfortable to hold.

Wrapping a wet towel around it aids in heat dissipation, so the sensor conveys to the charging circuit what it reads so that it maintains higher rates for longer. The electric current flows all along the charging cable, though, so anything wonky has a higher chance to affect the safety of the whole process.

Still, even Rivian owners are now getting in on the trend to make the free Supercharger adapters that Rivian sent them charge faster. "I highly recommend using the wet towel over the charger/adapter method to keep the charge from de-rating," says one. "I saw charge speed increase by 40 kWh just by pouring some cold water on the handle," indicating that this method can save them about 5 minutes on the charger.

Needless to say, Tesla is having none of it, and doesn't want anybody tinkering with the safeguard thresholds built into the Supercharger system for rather dubious charging speed advantages.

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