The amount of energy from a 1 tonne mass dropping 1 meter is about 10,000J (https://www.wolframalpha.com/input?i=%281+tonne+*+9.82m%2Fs%...)

The amount of energy stored in a Tesla is about 100kWh or about 3.6e8J.

You would need 36,660 tonnes suspended by a meter to store an equivalent amount of energy (or 1 tonne suspended 36.7km). https://www.wolframalpha.com/input?i=100kWh+%2F+%281+tonne+*...