Adoption of Electric Vehicles (EV) is expected to reach a third of the global fleet, i.e. 159 million vehicles, by 2050. This means that millions of batteries will be soon made available in the market to support electric mobility. Knowing that these batteries will be considered exhausted for EV applications after only 20% of capacity decrease, one can expect serious environmental threats in the next decades coming for a sudden increase of half-drained batteries no longer useful for vehicles' industry. Finding alternatives to introduce a efficiency in the energy storage uses, by prolonging the lifetime of these batteries through a second life is an urgent condition to avoid an environmental catastrophe. A potential use for Second Life Battery (SLB) is the behind the meter space, providing benefits to prosumers and the grid. While the availability of SLB increases, the need of storage in the grid will increase, as policies are pushing towards a highly decarbonized grid. Nevertheless, the main barrier for the deployment of a SLB market oriented to distribution grid prosumers is the quantification of the economic value brought by the SLB and the effect of costumer type, operating conditions and tariff scenarios. This paper proposes a second-life valuation methodology to compare the value of SLB for different prosumers in California, under different conditions and tariffs.