Tesla has announced that the first two installations of its new Solar Roof power system are up and running, using its roof-tile sized solar panels to charge one of its Powerwall home batteries. However, the two homes have paid quite a lot for the privilege of the near-unspottable solar system – between $50k and $100k. It’s still early days for the technology, which should come down in price as production scales. The first home to launch had spent ‘mid $50,000’ on the complete system, after discounts from the federal solar tax incentives, but only had one Powerwall battery. The other home, owned by Tri Huynh, has three of the batteries, and cost around $100,000, before government incentives were applied –…