In addition to the exemptions granted under the provisions of section 144.030, there is hereby specifically exempted from the provisions of sections 144.010 to 144.525 and sections 144.600 to 144.748 and from the computation of the tax levied, assessed or payable under sections 144.010 to 144.525 and sections 144.600 to 144.748, the sale at retail of separately measured electrical current to manufacturers of batteries in this state for conversion to stored chemical energy in new lead-acid storage batteries solely for the purpose of providing an initial charge in such batteries during the manufacturing process but not for the purpose of recharging any previously manufactured batteries. The sale at retail of such separately measured electrical current described in this section shall not be exempted from any local sales tax imposed under a local sales tax law, as defined in section 32.085.